Fungicide Products

Insecticide Products

Restricted Use Compounds

Restricted Use Compounds require a PRIVATE APPLICATOR CERTIFICATION to buy, handle, and apply. This certification is available through the Massachusetts Department of Agricultural Resources (MDAR): www.mass.gov/pesticide-examination-and-licensing.

Restricted Use Compounds

State restricted because of groundwater concerns (and all products with same active ingredients)

• ACTARA (thiamethoxam)
• BRAVO, ECHO and others (chlorothalonil)
• INTREPID, INVERTID and others (methoxyfenozide)
• SCORPION, VENOM (dinotefuran)
• SIMAZINE (simazine)
• ZEUS, SPARTAN (sulfentrazone)

State restricted because of health concerns

• Weedar 64 (and all other products containing 2,4-D ≥ 20%)

Federally restricted because of avian and aquatic toxicity concerns

• DANITOL (fenpropathrin)
• DIAZINON (diazinon)
• FANFARE (bifenthrin)

Compounds Requiring a Respirator

specific to formulations and labels, not active ingredient. It will be specifically listed on a pesticide product label under personal protective equipment. Note that there are no “engineering controls” in cranberry applications and you must wear the personal protective equipment listed for mixer and loaders.

Compounds that require a dust/mist filtering respirator - dusts, powders, mists, and sprays

Use a NIOSH-approved dust/mist filtering respirator: 
(NIOSH/MSHA approval number prefix TC-21C or any N, R, P or HE filter)

• Bravo Ultrex, Echo 720, Echo 90DF
• Ferbam
• Nexter
• Sevin XLR Plus, Carbaryl 4L

Compounds that require a respirator with an organic-vapor removing cartridge - gases and vapors

Use a respirator with an organic-vapor removing cartridge with a prefilter approved for pesticides:

• (MSHA/NIOSH approval number prefix TC-23C) or a canister approved for pesticides
• (MSHA/NIOSH approval number prefix TC-14G) or a NIOSH-approved respirator with an organic vapor (OV) cartridge or canister with any R, P or HE prefilter
  • Diazinon 50W, Diazinon AG500
  • Echo 720, Echo Zn, Echo 90DF
  • Imidan 70-W

Compounds requiring a powered air purifying canister-type respirator (gas mask)

Equipped with organic vapor canister and incorporated HE filters (MSHA/NIOSH approval number prefix TC-14G):

• Diazinon AG 600 WBC

Compounds Requiring Mandatory Posting

Mandatory posting of no-entry signs is required for the most hazardous pesticides. The signs prohibit entry into pesticide-treated fields until residues decline to a safe level. 
If REI is 48 hours or greater, sign posting is required.

If REI is 48 hours or greater, sign posting is required.

• Badge, Champ, Cuprofix, Kocide, Mastercop, Nu-Cop (coppers)
• Diazinon 50 W, Diazinon AG500, Diazinon AG 600 WBC (diazinon)
• Imidan 70-W (phosmet)
• Metastar 2E, Ridomil, Ultra Flourish, Xyler (mefenoxams)
• Weedar 64 (2, 4-D compounds)

"Danger" compounds that also require posting:

• Bravo Ultrex
• Echo 90 DF

Compounds Requiring Protective Eyewear for Application and Additional Decontamination Water for Handlers due to Eye Toxicity

• Chlorothalonils
  • Bravo Ultrex
  • Chlorothalonil Zn
  • Echo 720, Echo 90 DF
  • Equus DF
• Coppers
  • Badge, Champ, Cuprofix
  • Kocide, Mastercop, Nu-Cop
• Diazinon AG500, Diaz AG600 WBC
• Fanfare
• Intensity, Intensity One, Select Max – clethodim
• Metastar 2E – mefenoxams
• Penncozeb 75DF
• Phostrol, Rampart – phostrols
• Pyramite/Nexter – pyridaben
• Rimon – novaluron
• Weedar 64

Fumigants

Basamid (dazomet) and Vapam (metam-sodium) are soil fumigants that can be used on cranberry beds.  They can only be used if fruit will not be harvested and delivered for 12 months post-application. DO NOT USE FUMIGANTS AS A SPOT-TREATMENT IF ANY VINES WITHIN A DIKED SECTION WILL BE HARVESTED.  If it is used on part of a section, no fruit can be harvested or delivered from the entire (contiguous) section. If you are renovating an entire section, a portion of that section can be spot-treated with a fumigant.  More information on the use of fumigants may be found in the “Planting New Cranberry Beds” Fact Sheet. Contact the Weed Specialist if you have any questions about using these chemicals. 

You must complete EPA fumigant training before applying any fumigant. You must get certified/pass the module on EPA's web site.  As required by updated soil fumigant product labels, certified applicators must successfully complete an EPA-approved training program covering the new soil fumigant provisions. Basamid is listed under the name “dazomet” on the EPA web site. Please go to the EPA’s web site for more information: https://www.epa.gov/soil-fumigants/soil-fumigant-training-certified-applicators 

You must take Modules 1-4 plus the module specific to your use; Basamid (dazomet) is discussed in Module 7.  Vapam is metam sodium (Module 8).  The certification process is NOT regulated by MDAR; it is totally a federal EPA requirement.  This is a NEW regulation.  

Note: There is a provision that if you are already certified in a soil fumigation (sub)category and your state is listed with additional training option and requirements, you can bypass the training.  Massachusetts is NOT one of these states! So you must take and pass the modules.   

Cautions

1. Pesticide-treated bogs may need to be posted. Check labels. Workers and scouts should be notified prior to treatments and informed about re-entry times. See the CCCGA website for more current info on sign posting: www.cranberries.org/growers/advisories.html
2. READ AND FOLLOW LABEL INSTRUCTIONS. The label is the law! Current labels and MSDS can be found on the CDMS website: www.cdms.net/Label-Database. Do not use a pesticide for control of a pest not on the label unless a specific recommendation is made by a person authorized to do so.
3. Make all pesticide applications in a manner to prevent contamination of streams, ponds, and public ways, and impound water as long as possible after applying.
4. Be aware of and adhere to guidelines regarding distances from site of chemical application to protected areas. Consider addition of drift retardants.
5. Many insecticides are highly toxic to bees. Check label and choose options that are least toxic.
6. Stored pesticides may deteriorate. Avoid freezing of liquid formulations. It is usually not advisable to use heldover materials in opened containers. Follow regulations of the MDAR Pesticide Program when disposing of pesticides and their containers.
7. CONCENTRATE SPRAYS may injure new growth, bloom, and small berries, particularly in hot, humid weather or if the emulsifiable concentrate (EC) content nears 50% of mixture.

Prepared by Martha M. Sylvia and Katherine M. Ghantous

Pesticide resistance is an inheritable (genetic) characteristic of a pest that makes it less sensitive to a pesticide and can occur in all types of pests (weeds, insects, fungi, etc.).  Repeated use of the same pesticide (or pesticides with the same mode of action) over time kills pests that are susceptible to the pesticide and leaves behind individuals that are less sensitive.  These then reproduce and pass on the genes that let them survive pesticide exposure to their offspring. The goal in resistance management is to not repeatedly use compounds that fall within the same group.  Resistance management may include alternating products with different modes of action or limiting the total number of applications per season.

International groups have been founded to foster a cooperative approach to resistance management.  They have assigned group numbers to pesticides to help growers make decisions on how to rotate pesticides. They are based on mode of action – how and where the chemicals in the pesticide work on the target.  

In an effort to manage resistance with our pesticides, most labels now come with a “group” number assigned to them.  The group number is specific for each type of pesticide (e.g., Group 1 insecticides have no relation to Group 1 herbicides).  The following 3 pages show the groupings for our cranberry pesticides.  Some active ingredients are available under several different product names, and different active ingredients have the same mode of action. When rotating pesticides for resistance management, use the group number as your guide and NOT the product name or active ingredient.  

The group number is located on the first page of the label, and is usually displayed similarly to this example:

Insecticide Resistance Action Committee (IRAC) 
The Insecticide Resistance Action Committee (IRAC) has been formed to assemble the information for insecticides.  For cranberry, organophosphates and neonicotinoids have the most compounds within their group. We are reliant on several compounds in these groupings.  As long as growers remember to alternate between groupings and not repeat same mode-of-action compounds over and over, we should be able to keep newer compounds viable for decades.  See Cranberry Insecticides by grouping on the next page.  

Fungicide Resistance Action Committee (FRAC)
The group that advises for fungicide resistance is the Fungicide Resistance Action Committee (FRAC).  Their goal is to prolong the effectiveness of fungicides that are likely to encounter resistance problems. For cranberry, Ridomil and Abound are fungicides that are at high risk for resistance development, while Indar and Proline are at medium risk.  They should not be used repeatedly and should be carefully alternated with other fungicides from other groupings.  See Cranberry Fungicides by grouping on following pages.  

Herbicide Resistance Action Committee (HRAC)
The Herbicide Resistance Action Committee and The Weed Science Society of America (WSSA) have developed a classification systems of herbicides.  Previously the WSSA used numbers while HRAC used letters to designate the categories.  As of March 2020, these two systems have been integrated and use numbers to represent groups by mode of action.  One of the purposes of these classification systems is to make it easier for farmers and farm advisors to understand which herbicides share the same mode of action without having to actually know the biochemical basis.  

A key step in resistance management is to minimize the continuous use of herbicides with the same mode of action through rotations and combinations of products. In cranberry, our biggest concern for developing resistance is our reliance on Callisto.  Clethodim and other grass herbicides are also at risk.  Be sure to rotate other compounds into your herbicide schedule.  Do not treat the same bog with Callisto and/or clethodim year after year.    See Cranberry Herbicides by grouping below.

Prepared by Leela S. Uppala and Martha M. Sylvia

UPRIGHT DIEBACK

Causal Agent/Pathogen

Three different fungi have been associated with this disease:

1. Phomopsis vaccinii (primary)
2. Fusicoccum putrefaciens (often)
3. Synchronoblastia crypta (rarely)

Factors aggravating disease incidence and severity

• Growing seasons with prolonged periods of drought or heat stress.
• Stress weakens the vines and makes them more susceptible to infection by fungal pathogens.

Critical Phases of Infection

• Spores of the pathogen would be produced from overwintering cranberry tissue in April and May and the emerging buds are particularly susceptible to infection.
• Infection most probably occurs during or shortly after bud break when tissues are susceptible.
• Infection may also occur during the entire growing season.

Typical time to monitor for symptoms

Once infected, plants show symptoms (dead uprights and leaf drop) when weather-related stresses weaken the plants. There are three phases when symptoms likely appear:

1. Shortly after the winter flood has been withdrawn.
2. June and early July.
3. Late August and September.

Symptoms

• Individual uprights that die back from the growing point toward the runner.
• Every upright may be infected on some runners, while other runners may only have one or a few infected uprights. In severe cases, the entire runner will be stressed or dying.
• Scattered uprights may be infected or whole patches of dieback may show up, particularly in newer beds.

Suspect upright dieback? Please get samples diagnosed by a plant pathology lab before applying fungicides.

Management

• Avoid stress (by properly timing irrigation) on the plants especially through the hottest (and potentially the driest) portion of the growing season.
• Early season fungicide applications at bud break and/or early bud expansion (approximately around April 25 through May 15) are proven to given excellent control of the disease.
• Fungicides targeted for fruit rot control also provide a degree of protection against this disease during early and mid-season infection periods.

UPRIGHT DIEBACK FUNGICIDE RECOMMENDATIONS

For all above chlorothalonil formulations: Hold water for 3 days after application. In beds subject to Zone II regulations, growers must follow the required process (See Zone II section) to determine if these products may be used. As per the label, the maximum allowable number of chlorothalonil applications in a growing season is 3. If one chlorothalonil application is used for upright dieback, only 2 applications are allowed for fruit rot.

PHYTOPHTHORA ROOT ROT

Causal agent: Phytophthora spp.

Factors aggravating disease incidence and sevrity

• It just takes a few infected roots (and runners) to initiate and spread the disease to a new location. However, symptoms of infection develop in only a small percentage of the exposed acreage, due to the excellent drainage and low pH values (3.0–4.5) of cranberry soils in most beds.
• Poor drainage or water-logged areas are the first places Phytophthora infections occur.
• High temperatures (>50 ºF) facilitate the reproduction and spread of the pathogen.

Symptoms

• Infected root systems are poorly developed, have few feeder roots, are reduced in mass and show necrosis.
• Infected roots cannot uptake water and nutrients, resulting in stunting, dieback of plants and reduced drought tolerance. Other symptoms include runners rot, fewer (mostly off color) leaves per plant which may turn red prematurely in the late summer, or may be delayed in turning green in the spring. If the outer layer of the underground runner is scraped off, the internal tissue will be discolored olive green to dark brown.

Suspect Phytophthora?

• Symptoms of Phytophthora are similar to those of related root disorders such as damage by root-feeding insects and nematodes, other fungal diseases such as fairy ring, or simply “wet feet.”
• Because management of each of these problems differs, it is extremely important to get an accurate diagnosis before undertaking any control measures.
• If you suspect Phytophthora infection, please get samples diagnosed by a plant pathology lab before applying fungicides.

Management

Adequate control can be achieved only through several integrated strategies.

• Drainage: Improve drainage (through tiles, stones, underdrains or new ditches) in low areas of the bed. Existing ditches should be maintained to the proper depth. Following rain, irrigation, or frost protection event, examine the soil surface for standing water. Problems arise where soil drainage is highly variable, and it is not possible to irrigate sufficiently in well-drained areas without over-irrigating poorly drained areas.
• Irrigation Uniformity: Examine the distribution of sprinkler heads and the total capacity of irrigation system to make sure they are irrigating the bog uniformly. For irregular beds, sprinkler heads placed closer than specified in the design should be outfitted with reduced-volume nozzles. Repeated cycles of wetting and drying, especially extreme cycles, are conducive to root rot. Schedule irrigation timing to consistently maintain soil moisture near the optimum level, rather than leaving long intervals between irrigation events.
• Sanding: Apply a uniform layer of sand to the areas of dieback to get those areas up to grade with the remainder of the bed.
• Fungicides: After the drainage is improved, the ideal time to apply fungicides (foliar application of phosphonates or soil application of phenylamides) is when soil temperatures are conducive for root development and pathogen multiplication (May, June, July and August).
  • Spring applications (if a diagnosis is confirmed and drainage is improved) could slow down the infection.
  • If summer application cannot be done, a fall application can be considered before winter hardiness. However, fall application is only effective in early harvested beds or if there is a warm, extended fall season.
  • Multiple applications per season may be needed until vine recovery is visible. These applications can revitalize the canopy by encouraging root growth and help the plant uptake water and nutrients.

Additional notes for new beds

• Creating uniform drainage should be a high priority on new beds. Before planting, examine the bed for low points or poorly drained areas that may be vulnerable to Phytophthora development. Implementing a drainage plan during new bed construction may avoid problems down the road.
• Irrigation systems should be carefully laid out so that sprinkler heads are placed according to design specifications.
• Basamid fumigation prior to planting has been recommended for renovations that had a history of Phytophthora infestation in the soil. EPA regulations require EPA fumigant training to use this chemical. See “Fumigants” on page 7.
• Newly planted vines may not be able to absorb the phosphonate fungicides until sufficient shoot growth has occurred, whereas Phenylamide fungicides with a.i. mefanoxam (Ridomil Gold SL, Ultra Flourish) applied through chemigation could offer excellent root uptake.

Precautions to prevent the spread of the pathogen

• Machinery, equipment, footwear, etc., should be sterilized using steam, bleach (freshly prepared 10% bleach solution), or 70% alcohol. If possible, the sequence of flooding the beds during water harvest should be adjusted to flood heavily infected beds last.
• Exercise caution when purchasing/moving plant material or soil from other bogs. Be certain that materials are not coming from infected beds.

PHYTOPHTHORA ROOT ROT FUNGICIDE RECOMMENDATIONS

*Soil applications must be watered in after application. Run the sprinklers for 3 hours after application to water the fungicide into the root zone. Too much water, however, may push the chemical past the root zone. Therefore, do not apply if more than 0.5 inches of rainfall is forecasted or if sprinklers will run for more than 5 hours during the first few days after the application.

FRUIT ROT

This is the most prevalent disease problem that cranberry growers face from season to season. The disease is generally divided into two distinct categories: field rot and storage rot. The field rot phase is expressed pre-harvest and constitutes a major component of direct crop loss. Storage rots cause a reduction in the quality and shelf life of fresh, refrigerated fruit.

Causal agent

• Fruit rot is a disease complex associated with more than 12 fungal pathogens. The most common isolated in MA are Allantophomopsis lycopodina, A. cystisporea, Botryosphaeria vaccinii, Coleophoma empetri, Colletotrichum gloeosporioides, C. acutatum, Fusicoccum putrefaciens, Phomopsis vaccinii, Phyllosticta vaccinii and Physalospora vaccinii.

Factors aggravating disease incidence and severity

• The degree of fruit rot in different beds in a given season is dependent on many factors (e.g., weather, cultural practices, fruit rot fungal inoculum). Not all factors are completely understood.
• Bog microclimatic factors: Factors that leave the cranberry vine wet for long periods of time (e.g., rain, fog, dew or irrigation) provide optimal conditions for fungal growth and increases the risk of fruit rot incidence and severity. Other factors include dense vine growth, poor air circulation, high humidity, slow drying-out of dew, and poor drainage.
• Cultural Practices: Any practice that promotes excessive vine growth such as excessive N fertilizer, frequent late water, holding water high in ditches, too frequent irrigation, and not cleaning the bog of berries/detached plant tissues (they could serve as sources of overwintering inoculum) from the previous cropping season could favor fruit rot development.
• Bogs planted with susceptible cultivars and with high fruit rot levels in the previous season.
• Rot develops rapidly only after the berries are detached and floating on the flood surface. Thus, the time the berries are left in the harvest floods is an important factor too.
• Not following bog sanitation: Cranberry leaves, stems, and fruit left behind after harvest (trash) are colonized by several fungi that cause field and storage rot.
• Improper timing and frequency of fungicide applications: The fungicides should target the most susceptible stages of infection (bloom and early fruit set). Applying fungicides after this period will not be of use. The frequency of fungicides should be decided based on the history of fruit rot infection in the previous growing season.

Critical phases of infection

Flowering and fruit development are the susceptible phases of infection. Spores of the fruit rot fungi germinate from overwintering sources of inoculum and spread by wind or wind-driven rain to bloom or developing fruit. If there is a suitable layer of moisture present for 6 to 8 hours and the cultivar is susceptible, the fungi will infect these tissues.

Symptoms

In general, after the infection, although the fungal pathogens are multiplying with developing fruit, the fruit rot symptoms (break down of berry tissue and rot) are not apparent (latent infection) until later in the growing season or until the berries have been harvested and held in storage.

Management

Adequate control can be achieved only through several integrated strategies.

• Canopy Management: Practices that increase air circulation such as pruning will reduce disease pressure. Sanding can also reduce disease pressure by burying excess runners and improving airflow, as well as burying sources of disease inoculum.
• Late Water: Holding late water (flooding from mid-April to mid-May) once in three years will improve berry quality by disrupting the life cycles of fruit rot fungi and increase fungicide application efficacy by synchronizing bloom. In the year late water is used and in the following year, the number of fungicide applications can be reduced in beds with a history of low fruit rot pressure. The fungicides should not be eliminated completely, or vine diseases may be a problem the following growing season. Fungicide regimes should be brought back to normal in the second year after late water.
• Trash Removal: Remove trash from water-harvested beds during harvest, or as soon after as possible. If the bed was dry-harvested, trash should be removed from the bed with a postharvest flood in the fall or from the winter flood before it is withdrawn. Trash piles should not be left next to the bed and should be deposited at least a quarter mile from the bed if possible. Self-pollinated seeds in berries left behind on the bog may germinate in the soil and possibly produce plants that are the typical "mongrels". These genotypes may produce much vegetation but few berries, and in worst-case scenarios, may take over the productive vines in the bed.
• Irrigation: When irrigation is necessary, sprinkler systems should be run in the early morning, and not in the early evening. Morning watering allows vines to be watered with minimal evaporation, and the surface of the vines can then dry out in the sun’s heat. When watering is done in the early evening, the vines are kept wet for an extended period, thus creating favorable conditions for infection by the fruit rot fungi. On days with excessive temperatures (>100°F on the bed), particularly in newly planted or recently sanded beds, sprinklers should be run in the late morning or early afternoon to cool the vines and berries and may prevent injury. Sprinklers should be run to prevent scalding of the fruit when all of the following conditions persist: (1) dewpoints of 55°F or less during midday and afternoon hours, (2) high temperatures of 80°F or more, (3) clear or scattered sky conditions during the day, (4) bed soil moisture is low, (5) wind speeds average greater than 11 mph, and (6) no rainfall has occurred during the last 48 hours (2 days). This "forecast" is based on research performed in New Jersey. Scalded berries are typically browned on one side, with a clear demarcation between the brown area and the green (usually) area of the fruit. The rotted area in a berry affected with fruit rot typically has an area of anthocyanin production (reddish border) adjacent to the affected area. After 7 days, a scalded berry will be hard to discern from a rotted berry, particularly since fungi will colonize the stressed scalded berry.

• Resistant Varieties: When replanting bogs or planting new bogs, varying levels of disease resistance against fruit rot among varieties should be considered.

  Relative Field Rot Resistance by Cultivar

  Highest field rot resistance	Moderate field rot resistance	Lowest field rot resistance
  Mullica Queen, Howes, Black Veil	Stevens, Crimson Queen, Early Black, Scarlet Knight, Haines	Ben Lear, Demoranville

• Fungicides: For adequate control, fungicide applications should have good coverage and take place before fungi infect plant tissues. Most fruit rot infections occur during the bloom period and early fruit set before berries start to size up. Applications typically should begin during early bloom (mid-June, before 50% of flowers have opened). Once the fruit has set and begun to increase in size (mid-late July), fungicides are no longer necessary or effective. Fungicide decisions such as the choice, frequency and interval between fungicide applications are dependent on the individual bed, its history of fruit rot severity, products allowed by respective fruit handlers and Keeping Quality Forecast (KQF) found on the Cranberry Station’s website. If the KQF forecast is good to excellent, consider fewer applications and/or longer application intervals. Cranberry beds prone to fruit rot may need up to 4 fungicide applications. One or two fungicide applications may be adequate for a bed with very little fruit rot in previous growing seasons. Storage rot is usually not a concern for berries that are water harvested, as these berries will immediately be frozen in most cases. If in doubt, call the Extension Plant Pathologist.
• Note for newly planted beds: One or two fungicide applications during the first two years after planting will help reduce fungal inoculum and may reduce fruit rot in subsequent years.

FUNGICIDE RESISTANCE MANAGEMENT FOR FRUIT ROT

Fungicide resistance, defined as reduced fungicide sensitivity in fungal populations, is a real and serious threat to the cranberry industry. It could severely impact the efficacy of fungicides used against fruit rot pathogens. The Fungicide Resistance Action Committee (FRAC) developed a code of numbers and letters that can be used to distinguish the different fungicide groups based on their mode of action. Repeated and ineffective use of fungicides from the same FRAC group can accelerate the development of resistant pathogen populations and once this occurs, fungicide applications will provide very little or no disease control.

Two key groups of fungicides employed in fruit rot management (Mancozebs/EDBCs used since 1960; Chlorothalonils used since 1985) have no Maximum Residue Limits (MRLs) in key international export markets such as the European Union. Many handlers restrict the use of these fungicides for export markets, and growers are increasingly relying on the newer, single-site mode of action fungicides from FRAC Group 3 and 11. These newer fungicides (eg., Abound, Indar, Proline and Quadris Top) can be equally effective in controlling fruit rot fungi and are perceived to be less harmful to human and environmental health when compared to the older, multi-site mode of action chemicals (chlorothalonil and EBDCs/Mancozebs). However, newer fungicides are at higher risk of selecting for fungicide-resistant pathogens than older fungicides. To preserve the effectiveness and durability of the few effective registered fungicides we have available, it is CRITICAL to incorporate the fungicide resistance management strategies listed below:

• Follow ALL label instructions, including application interval and recommended rate. Never use less than the lowest recommended rate on the label.
• Alternate or mix fungicides with different modes of action.
  • Use FRAC codes on labels to determine the mode of action. The same FRAC codes indicate that fungicides have the same mode of action. For example, Indar and Proline have different trade names and active ingredients, but they have the SAME mode of action and FRAC code (3).
• For best control and fungicide resistance management, mix Abound with Indar or Proline, or use Quadris Top.

FRUIT ROT FUNGICIDE RECOMMENDATIONS

FRUIT ROT FUNGICIDE ADDITIONAL NOTES

FAIRY RING

This disease is sporadic in occurrence and the severity of symptoms varies from year to year.

Causal Agent/Pathogen

• Some fungi such as Psilocybe agrariella var. vaccinii, Helicobasidium sp. (anamorph Thanatophytum sp.), Rhizoctonia-like fungi, Pezicula, Dermea, Crytosporiopsis and Neofabrea have been associated with this disease. However, the role of these fungi in fairy ring disease is not completely characterized.

Factors aggravating disease incidence and severity

• Damage caused by this disease is usually worse during growing seasons with limited rainfall (drought) and hotter than normal temperatures. Excessively dry soils could promote this disease.
• Stevens, Ben Lear and Howes are highly susceptible, while Early Black is less susceptible but not resistant.

Symptoms

• Initially, a small area of weak or dead vines occurs, usually in higher spots in the bog or near the ditches.
• When environmental conditions are favorable for disease spread, the area of dead vines expands outward in all directions and opens the canopy for weed invasion.
• The outside edge of the necrotic zone is sometimes bordered by a ring of cranberry vine overgrowth which are unproductive. In heavily infested beds, numerous rings will be present and they may overlap or combine, resulting in whole sections that are devastated by the disease.
• Reduces yield 50-60%. Increases fruit rot incidence.
• Increases the need for replanting.

Precautions to prevent the spread of fairy ring from infested areas/beds to healthy areas/beds

• The mechanism of dissemination of this disease is unknown. It is possible that movement of vines, during harvest or any other means, could spread the disease from infested areas to healthy areas of bog or even among various bogs.

Management

• Control strategies for this disease have still not been worked out thoroughly.
• During those summers with low rainfall, plants should be properly irrigated.
• Sprinklers should be run for several hours in the early morning hours, when there is little evaporation, to ensure that the root systems are properly watered.
• Raising the water level in the ditches can help in this regard. This can be a problem, however, if there are low areas in the same bed where Phytophthora root rot may also be present. Beds should be properly graded.

* Indar and Abound soil drench.  Using a drench method, one can treat up to a tenth of each acre while remaining within the label restrictions (one-tenth of an acre is approximately 4,300 ft2). 

A. Estimate the area to be treated:

1. Measure across the center of the fairy ring (this gives you the diameter).
2. Divide by 2 to get the radius.
3. Add 10 ft to the radius to include a buffer around the fairy ring.
4. Use the formula: 
   Area = r² x π (r is radius, π is ~ 3.14)

B. Calculate the rates of Indar and Abound for your fungicide mix.

• The rate for Indar will be equal to the fairy ring area (ft²) multiplied by 0.0028 fl oz.
• The rate for Abound is equal to the fairy ring area (ft²) multiplied by 0.004 fl oz.

For every ft² to be treated, use 0.1 to 0.2 gallons of water. Apply the tank mix evenly over the affected area (entire ring area plus the 10 ft outer margin). If you need assistance in managing the fairy ring or calculating fungicide rates or if the area is larger than one-tenth of each acre, please contact the Extension Plant Pathologist at the Cranberry Station.

DISEASE MANAGEMENT NOTES

1. Read and follow label instructions. Always check the label for variations in restricted entry intervals and worker protection standards.
2. Ensure that all pesticide applications are made in a manner that prevents contamination of streams, ponds, and public areas. Impound water (as per label) for as long as possible after applying.
3. THREAT FOR DEVELOPMENT OF RESISTANCE: The risk for resistance to Abound, Indar, Proline, and Quadris Top by fruit rot fungi is very real and serious.
   • Applications should be made pre-infection rather than post-infection to minimize resistance development.
   • These products are most effective when applied during early to mid-bloom (20-50%).
   • It is highly recommended not to use Group 11 products (e.g., Abound, Satori) as standalone products; instead, mix them with Group 3 products (e.g., Indar or Proline).
   • The number of fungicide applications should be based on the label instructions and the Keeping Quality Forecast.
4. When applying half-rates, the maximum number of applications (not total material applied) must not be exceeded. It is not recommended to use a rate below the lowest recommended rate on the label.
5. Use Abound very carefully and avoid drift if the bed is next to a McIntosh apple orchard, as the fungicide is highly phytotoxic to this cultivar.
6. PRE-MIX fungicides with a small amount of water until a smooth suspension is obtained before final dilution. Use immediately.
   • Blossom injury may occur with concentrate sprays, especially when applied by air when the temperature on the bog is above 85 °F.
   • Do not combine any copper fungicide with an insecticide.
   • Do not tank mix copper compounds with Aliette or any of the phosphites for Phytophthora unless appropriate precautions have been taken to buffer the spray solution; otherwise, severe phytotoxicity will result.
7. Consider delaying harvest to obtain acceptable color in thick vines or when mancozeb is used.
8. SANDING and FERTILIZING: Regular and uniform sanding most likely helps to reduce inoculum of the fungi that cause fruit rot. Sanding and late water flooding should not be done during the same year.
9. SPREADER STICKERS are contained in most fungicides.

Prepared by Anne L. Averill and Martha M. Sylvia

Essential Points!

• Start scouting bogs early May.  Black-headed fireworm, green spanworm and winter moth larvae may be active early but larvae are difficult to see until mid-May.  Always gauge levels of pest caterpillars in their early stages!  As the caterpillars of many species grow larger, they cling more tightly to the vine or hide in daytime and are harder to pick up in daytime sweep netting.
• Immature cranberry black bug and blunt nosed leafhopper appear as tiny green/yellow nymphs in mid May.  These must be discerned from harmless springtails (Collembola).  Be aware that most pests can be very patchy or in coves or edges, particularly scale, black bug, cranberry weevil, spongy (gypsy) moth, black-headed fireworm, and brown spanworm. Thorough assessment of total acreage is essential.  
• Vaccinium scale can be detected in spring by walking the bog and looking for off color or weak areas. Carefully look for live scales on the oldest parts of the uprights.
• Keep an eye on Cranberry Fruitworm.  Management with Altacor has reduced populations, but there may be pressure.   Cultivars with the earliest fruit sizing up may be hard hit with egglaying. Be aware that there may be two peaks of fruitworm egglaying: a large one in late June, early July with a second smaller peak towards the end of July.  
• Be careful with advanced growth.  Be aware that the new growth and early flower buds on newer cultivars, sanded areas, and renovations may be magnets for pest insects.  Cranberry weevil, in particular, can move to beds with advanced vine development.  Feeding on new growth and egg-laying is of concern. All insect activity could be moved 2 weeks forward.
• Sweep netting.  Using a 12” net and 180° sweeps into the vine, sweep netting should be conducted at least once a week.  A sweep set consists of 25 sweeps across the bog.  The insects in the net should be properly identified, counted, and recorded.  Conduct 1 set of 25 sweeps for each acre.  For larger pieces (more than 20 acres), at least 1 sweep set/2 acres is advisable.  In multiple-acre pieces, calculate the average number of each insect in all of your sweep sets.  Treat only after the average numbers of each insect in your series of sweep sets exceeds these values, and after other external concerns have been considered including cost of application, expected returns, weather, etc. 
   
   

In sweep net sampling, the average numbers of a pest that we use to trigger a management measure is only a guide.  It serves as an indication that an insect pest is being sampled at numbers that we consider high and worthy of attention.  Significant pressure by cranberry weevil and particularly by black-headed fireworm and Sparganothis fruitworm should be attended to in the spring; infestations are harder to manage in the summer.  

Reducing inputs to cut production costs. Key insect management practices should be the last ones eliminated to save money. It is seldom advisable to skip the first cranberry fruitworm spray (initial spray in IPM-based programs when most pinheads have set and berries have begun to size up) unless late water has been held. This first spray targets the largest portion of the population.  Sweep netting in early to mid-May is important to detect spongy (gypsy) moth and black-headed fireworm.  Finally, walk the bog both early and late in the season to inspect for injury from scale and fireworms to detect pests that have long term impacts.

Pheromone traps. Traps can be used for timing management of black-headed fireworm and Sparganothis fruitworm and should be up by June 1.  Use 1 trap/10 acres.  Place on upwind side of bog.  Check and clean traps weekly, recording number of moths captured.  Change bait every 3 weeks. 

Based on pheromone trap catches… 

• For black-headed fireworm: treat summer generation with Altacor or Intrepid and apply 2 weeks after onset of moth flight (~6/20), and again 10 days later. For Sparganothis fruitworm: if treating with Altacor or Intrepid, apply 3 weeks after the moth flight begins (~late June), and again 10-14 days later. If using Delegate, apply 10-14 days after peak moth captures, (~mid-to-late July); vines wet with Delegate spray pose high risk to bees, time the spray to allow drying by morning. Dried residues are considered safe.
• For Sparganothis fruitworm: if treating with Altacor or Intrepid, apply 3 weeks after the moth flight begins (~late June), and again 10-14 days later. If using Delegate, apply 10-14 days after peak moth captures, (~mid-to-late July). Vines wet with Delegate pose a risk to honey bees. Dry residues are considered safe. Time spray to allow for drying by morning.

BEES!!!  Most insecticides are toxic to bees, especially direct applications.  Do not apply or allow to drift to cranberries in bloom or nearby blooming plants/weeds if bees are foraging.  Bumble bees may be equally vulnerable to sprays applied at bloom; populations will dwindle over time if they are not protected. 

Bee protection is complicated

If possible:

• Leaving some beds of untreated flowers allows dilution of pesticide concentration experienced by bees. Even for pesticides considered bee-safe (fungicides, Altacor, Intrepid), unbroken areas of treated mass bloom may result in risk for colonies.
• Expanding the number of days pre-bloom that many insecticides are applied may reduce residues in pollen. Bee-toxic Sevin, Diazinon, and Actara are absorbed by the plant and move systemically into developing flowers and contaminate the pollen.
• Research in other crops has shown that the combined effect of some insecticides/fungicides (tank mixes of Altacor/Indar, Altacor/Proline, and Altacor/QuadrisTop) impact honey bee colony health.

Cranberry Insect Pests Commonly Encountered in Massachusetts

Previously Common Insects but Seldom Seen Now

Chemistry Families of Cranberry Insecticides

• Diamide-based compounds. Altacor, Exirel and Verdepryn are newer chemistry insecticides registered in the diamide class of chemistry and provide a new mode of action compared to all other classes. They cause paralysis of the insect by sustained contraction of the muscles. It has excellent activity against our key lepidopteran pest (cranberry fruitworm). Altacor also has long residual activity and is safe to key natural enemies. Exirel and Verdepryn in comparison have high bee toxicity and cannot be used during bloom. For all these compounds, a good chemigation system, under 6 minutes, is likely necessary to get good efficacy. Target eggs and tiny larvae, these compounds will not manage larger caterpillars effectively.
• Bacillus thuringiensis (B.t.) based products. Examples labeled in cranberry are Dipel, Xentari, Crymax and Biobit. These compounds are most effective when applied multiple times and in low gallonage against small caterpillars feeding on foliage. Thorough coverage is essential. Well-timed chemigation systems are critical for good efficacy (6 minutes or less rinse time). Early attention to infestation is critical. Caterpillars stop feeding after eating compounds but may take several (3-10) days to die. Use aerial application or low-volume ground applications when possible to improve performance.
• Insect growth regulator products. (Intrepid (methoxyfenozide), Confirm (tebufenozide) and Rimon (novaluron)). Growth regulators are caterpillar-specific, need to be eaten to work, and conserve natural enemies and pollinators. These compounds are most effective when applied multiple times and in low gallonage against small caterpillars feeding on foliage. Intrepid is restricted use and is Zone II restricted. Coverage and well-timed chemigation systems are critical for good efficacy (6 minutes or less rinse time); excessive chemigation washout will remove active material. A spray adjuvant should be used. 6 hours drying time following application is required. New vine growth is not protected. Larval death may not be observed until a week or more has passed. Pollinator safe!
• Spinosyn-based products. These include Delegate and Entrust (an organic formulation). Delegate is more active and provides longer residual control than Entrust; Delegate is the compound of choice. Spinosad-based products are fast-acting nerve poisons but are still reduced-risk compounds. Allow 7 days between applications. These compounds are the better choice (compared to Intrepid) once the caterpillars have reached a larger size. For Delegate, only use lower rates if rinse time is 4 minutes or less. Keep in mind that spinosyn products can be toxic to natural enemies and are highly toxic to bees. Sprays made when bees are actively foraging must be avoided (this includes Entrust, even though it is an organic formulation!). Wet residues are toxic, dry ones are considered safe. If treating during bloom, be sure that overnight conditions are such that evening chemigation applications will dry by morning.
• Neonicotinoid products. Neonicotinoids affect the nervous system of insects but have low human toxicity. They are the most toxic insecticides to bees. Do not apply during bloom. There are a number of neonicotinoid compounds registered in cranberry including Actara (thiamethoxam), Assail (acetamiprid), Scorpion/Venom (dinotefuran) and Admire (imidacloprid). While these compounds could help manage our insect complex, you should be informed before you use them.
• Organophosphate and carbamate products. Organophosphate and carbamate products are in an older class of chemicals and are nerve agents acting on the enzyme acetylcholinesterase. These compounds are generally acutely toxic to bees, wildlife and humans. Do not apply during bloom. Diazinon, Imidan, Orthene and Sevin remain in use although much reduced. Sparganothis fruitworm, cranberry weevil, tipworm and leafminers are resistant to this chemistry.
• Pyrethroids. (Fanfare, Danitol, Pyganic) Pyrethroid insecticides are an older class of chemicals and disrupt nerve signals by disrupting the sodium channel (sodium channel modulators). These compounds are acutely toxic to aquatics. They have low human contact toxicity but high oral toxicity. Do not apply during bloom.

NOTE:  Restricted Use Insecticides (Actara, Diazinon, Fanfare, Intrepid, and Scorpion/Venom)  
A private applicator certification is required to purchase, handle and apply these compounds to your bog.

Reflooding Options

1. Late Water Flood – Starting April 10-20, hold water for 30 days to manage cranberry fruitworm, southern red mite, gypsy moth, and cutworms. See Late Water section.
2. Spring Flood – mid-late May, 24-hour reflow manages false armyworm and blossomworm, 48 hours necessary to impact black-headed fireworm and yellow-headed fireworm. Care must be observed as these floods must be completed before roughneck stage or likely to increase fruit rot and seriously reduce the crop.
3. Summer Flood – Mid-May to mid-July kills all insects, especially cranberry root grub and white grub, but with the loss of crop and impact on following years as well.
4. Fall Flood – Sept. 20-30. Flooding within this time for 1 week every third year discourages girdler and blossomworm. A 3- or 4-week flood at this point will manage cranberry fruitworm. These floods are best done when fruits have been removed. Research shows that this flood timing may negatively impact vine health.

Organic Options for Insect Management

Organic production may not be a profitable unless there is low to moderate insect pressure and a good water supply. Cranberry fruitworm, black-headed fireworm and cranberry weevil pose the greatest threats to viability.   Certifiers work under standardized USDA rules. Growers who wish to be certified organic need to go through Bay State Organic Certifiers (www.baystateorganic.org). All inputs must be listed with OMRI (Organic Materials Review Institute; www.omri.org).  Some products are listed as A (allowed) others as R (restricted).  The restricted products have certain conditions attached to them that have to do with the generic materials in the product (amounts or frequency of application, etc.).  OMRI also has a Generic Materials List.  Three years of no synthetic chemical applications (transition period) are necessary before a crop can be certified organic.

Cultural Practices

Use of cultural practices (sanding and water floods) is the most effective strategy in organic management.

• Late Water - Holding late water is an excellent choice to reduce cranberry fruitworm pressure; however, moths may move into late water-treated beds from other areas of infestation.  False armyworm, blossomworm, gypsy moth, and southern red mite may be managed with late water. See Late Water Section.
• Fall Flood - May be used to reduce cranberry girdler populations.  Flood for 10-14 days as soon as possible after harvest.  May also impact vines to some degree.  Warmer water temperatures enhance effectiveness.
• Sanding - If you can sand, populations of most insects should be less abundant.
• Winter Flood - If you can maintain a good winter flood, populations of most insects should be less abundant.

Options cleared for organic management on cranberry, but efficacy has not been quantitatively assessed

Prepared by Hilary A. Sandler and Katherine M. Ghantous

New Herbicides and Updates 

Check our web site (ag.umass.edu/cranberry) and upcoming newsletters for further information about any new uses or products. UPI has discontinued the production of Devrinol 10G and 50DF formulation. It is still legal to use remaining stock. Follow the label of the product you are using!

Cranberries have been removed from the Princep label. Other products with the same active ingredient (simazine), such as Simazine 4L, are labeled for cranberry and registered in Massachusetts. We are unaware of product availability or efficacy. 

Special Labels available for herbicides (see Cranberry Station website under “Services” for labels):

• Callisto: Special Local Need (24c) label for concentrated spot-treatment, and adjusted adjuvant rate for chemigation.
• Cutrine-Plus: 24c for management of algae in late water flood. See Late Water section.
• Devrinol 2-XT: 24c for the use of 1) multiple applications on new plantings and 2) multiple applications before bloom or after harvest on established beds.
• Intensity One: 24c allows for application by chemigation, and application between hook and fruitset. NOTE: The 24c for Intensity has been rescinded, and ONLY Intensity One can be chemigated.
• QuinStar: 2ee to permit shorter injection times.
• Spartan 4F/Zeus XC: 24c to allow use for control of moss and other susceptible weeds. NOTE: The 24c for Spartan was added in 2023, and will be the only sulfentrazone available when Zeus expires December 31, 2024.

Weed Life Cycles 

Annual plants complete their life cycle in one year and reproduce by seed (e.g., dodder). They germinate from seeds, grow to maturity, flower, and make seeds all within a single growing season. Biennial plants take two years to complete their life cycle. They typically germinate from seeds and grow vegetatively in the first year, then enter a period of dormancy over the winter. They flower and make seeds the following growing season. Perennial plants can live for many years and may reproduce by seed, runners, rhizomes, etc.  Most of the weeds in cranberry production are perennials. With the exception of dodder, annual weeds are much less common and easier to control than perennials. However, infestations of annual weeds should not be taken lightly, especially on new plantings. Annual plants are designated with an (A). Unless otherwise noted, all other weeds are perennials.

Weed Priority Ratings (Very High, High, Medium, and Low)

The Priority Rating of each weed is determined by considering the following: 1) impact of a given weed on cranberry, 2) the biological form or type of weed, 3) its invasive and/or reproductive capacity, and 4) its adaptation to the cranberry habitat. Each criterion has 4 possible values (1, 2, 4, or 8). The values of the 4 criteria are added together to determine the rating. Totals of 24 to 32 points = Very High Priority, 16 to 23 = High, 8 to 15 = Medium, and 1 to 7 = Low. Please see the ID Guide for Weeds in Cranberries (available for purchase at the Cranberry Station) for the specific ranking criteria of each weed (pp. 261-272) for more details. Page numbers in the ID Guide are provided in this section as appropriate. Some weeds are in the Chart Book but were not included in the ID Guide and have been given a Priority Rating by the Extension Weed Specialist.

Weed Mapping

Weed maps can help you organize the management of your weed problems, especially with perennial weeds. Weed maps should be done every few years, depending on weed pressure and management objectives. Several steps are involved: 1) Correctly identify the weeds, 2) Document the location of the weeds (by drawings, GPS, or photographs), and 3) Designate a priority rating to the weed. Growers may change and adapt weeds into priority ratings to best fit their own management program.

Weeds

Herbicides

OFF-BOG AQUATIC WEED CONTROL

OFF-BOG USE: WEED MANAGEMENT OUTSIDE OF PRODUCTION AREAS 

• AQUATIC WEEDS. Reports of grower problems with aquatic weeds have been increasing. Aquatic weeds can be submersed, floating plants, floating leaf plants or emergent plants. Common aquatic species for our area may include fanwort, variable watermilfoil, bladderwort, hydrilla, duckweed, and water lilies. Be sure to get a correct identification of the weed problem before treating. Treatment of some water areas may require a permit. Non-chemical methods (e.g., harvesting, suction, hand pulling, dredging) are available but are very expensive. The use of grass carp for aquatic weed control is NOT permitted per MA Fish and Wildlife. Call 508-389-6300 for more information.
• DIQUAT. This herbicide should only be used on water weeds growing in areas outside of the bog. Do not use in any ditch associated with the production area. Diquat will control water weeds such as bladderwort, coontail, elodea, and pondweeds. A non-ionic surfactant (e.g., Induce, Activator 90) may improve performance. Check the label for rate information, and directions on spot treating surface weeds.
• RODEO. This glyphosate product can only be used to control weeds that occur outside of the production area. Application is spray to wet leaf surfaces, not to runoff. Extremely cool or cloudy weather following application may slow the activity of this herbicide. Best control is obtained when plants are at late growth stages approaching maturity. Weeds under stress will not be controlled as well as healthy plants. Rainfall within 6 hours of application may reduce effectiveness, and heavy rainfall within 2 hours of application may necessitate reapplication. Do not add ammonium sulfate to Rodeo mixtures.
• ALGAEICIDES 
  Algaecides for control of algae (green scum) are usually prescribed on an acre-foot basis. An acre-foot is the amount of water needed to cover one acre of bog with one foot of water (~300,000 gallons of water). These include products like Cutrine Plus (can be used both off- and on-bog, see Late Water section), which are labeled for use in ponds, ditches, and canals.  Read all product labels carefully before using.
• NAUTIQUE (by SePro) is a copper carbonate (double-chelated copper formulation) product that is labeled to control floating, emerged, and submerged vegetation in still or flowing aquatic sites such as reservoirs, ponds, slow-flowing water bodies, crop and non-crop irrigation systems.  Use lower rates if carbonate hardness of the water is less than 50 ppm (this is generally the case in MA); as water hardness increases (>50 ppm), efficacy may be decreased and non-target toxicity may be increased. If applying to public waters, check with the local authorities for permit process. Nautique can be mixed with other aquatic herbicides; check the label. When applying to irrigation ponds, hold water for a minimum of 3 hours before irrigating plants. It is highly corrosive and carries a DANGER label. It may be fatal if absorbed through the skin. Be very careful with this product!! Wear all recommended protective equipment. Application rate varies by vegetation density and depth of treated area. Please read the label. If you have any questions, please consult with a Weed or Aquatic Weed Extension specialist prior to treating.
• NOTE ON IRRIGATION SOURCES TREATED WITH AQUATIC HERBICIDES: In some instances, municipalities or homeowner associations (or similar) may opt to apply aquatic herbicides to water bodies that cranberry growers use for irrigation or flooding. Some products may or may not have a tolerance, some have ‘incidental tolerances’ and some are tolerance-exempt. Depending on the product and timing of application, the impact to your farm operation could be small or great. Please reach out to the Station and your handler if you anticipate that a situation might occur.

OFF-BOG WOODY AND BROADLEAF PERENNIALS CONTROL 

(not in ditches or canal banks)

Hand pulling is most beneficial in Spring and early Summer when the soil is moist and the plants are fairly small. 

CROSSBOW, WEEDONE (2,4-D). Crossbow and Weedone are labeled for non-bog use only and are State Restricted Use pesticides. Be cautious! Crossbow contains triclopyr for which there is no food tolerance. Do not use Crossbow or Weedone on dikes or canal banks. Use it only on weeds located far away from the bog.  These products have considerable potential to evaporate and cause crop injury. They have the potential to drift far from the site of application, and can injure nearby plants such as apple trees, grapes, etc. Avoid applying 2,4-D on hot, sunny, and humid days when there is little air movement. 2,4-D products can be highly effective at controlling some weeds.

• Weedone 650 (WSSA/HRAC Group: 4)    
  Follow spot treatment instructions    
  Spray to wet. Avoid drift onto bog. Controls woody plants on roadsides and non-crop areas.
• Crossbow (WSSA/HRAC Group: 4)    
  1-1.5% solution, see spot treatment instructions    
  Drift to desirable plants may cause injury (esp. grapes and tomatoes). Do not apply to water. Read the label! See Notes on 2,4-D.

RENOVATION AND NON-PRODUCING BOGS

• FUMIGANTS. Basamid (dazomet) and Vapam (metam-sodium) are soil fumigants that can be used on cranberry beds. They can only be used if fruit will not be harvested and delivered for 12 months post-application. DO NOT USE FUMIGANTS AS A SPOT-TREATMENT IF ANY VINES WITHIN A DIKED SECTION WILL BE HARVESTED. If it is used on part of section, no fruit can be harvested or delivered from the entire (contiguous) section. If you are renovating an entire section, a portion of that section can be spot-treated with a fumigant. More information on the use of fumigants may be found in the Planting New Cranberry Beds Fact Sheet (http://ag.umass.edu/cranberry/fact-sheets). Contact the Weed Specialist if you have any questions about using these chemicals.
• You must complete EPA fumigant training before applying any fumigant. You must get certified/pass the module on EPA's web site. As required by updated soil fumigant product labels, certified applicators must successfully complete an EPA-approved training program covering the new soil fumigant provisions. Please go to the EPA’s web site for more information:
  https://www.epa.gov/soil-fumigants/soil-fumigant-training-certified-app…
• Note: There is a provision that if you are already certified in a soil fumigation (sub)category and your state is listed with additional training option and requirements, you can bypass the training. Massachusetts is NOT one of these states! So you must take and pass the modules.  
• REGLONE, and others (Diquat dibromide). Non-selective herbicide. Reglone and other diquat products registered for use on non-producing beds should only be used on bogs that will be renovated or will not be harvested for 1 year. The intended use is as a site-preparation product, not for use for spot weed control on an active farm. This product works as a plant desiccant and should be used as a directed spray. Reglone cannot be applied by chemigation. Use 1.5-2 pt/A in a minimum of 15 gallons water by ground. May need repeat applications. Add NIS. WSSA/HRAC Group: 22.
• FUSILADE (Fluazifop). This selective grass herbicide can only be used on non-producing bogs. It is used postemergence for control of true grasses. Sprayed grass will turn yellow and die back over a 1-4 week period depending on climatic conditions. It is rainfast after 1 hour. Add a COC at 0.5-1% v:v or 0.25-0.5% v:v if using a NIS. Use 0.75 fl oz herbicide per gallon water. REI is 12 hr. WSSA/HRAC Group: 1.

DITCH MANAGEMENT

• WOODY AND BROADLEAF PERENNIALS ON DIKES (BOG-SIDE)
  Cultural controls include mowing the ditch and dike areas during the summer months. Some areas may need to be done more than once. Hand pulling is most beneficial in the spring and early summer when the soil is moist and the plants are fairly small. Controlling weeds on the dikes may be useful in reducing spread of these weeds onto bogs.
• DITCH WEEDS (e.g., Arrowhead, Pickerelweed, Pond lilies, Bur-reed, Duckweed) 
  Clean ditches by hand or mechanically preferably twice a year. Draining ditches can sometimes be helpful in killing some aquatic weeds (e.g., duckweed). Preemergence herbicides registered for use on the bog may NOT be used in the ditches for weed control. Roundup use is permitted in dry ditches as a wipe or a spray. See notes on Roundup. Flame cultivation may be an effective nonchemical tool for ditch weed management. 

CAUTIONS AND OTHER NOTES

1. Chemicals not registered for use on cranberries must not be used.
2. Herbicide use may weaken vines and crops may be reduced.
3. To be most effective, rain should follow the application of any dry herbicide formulation within 4 days or the bog should be irrigated.
4. Wash equipment with soap (or detergent) and water immediately after using. Rinse with ammonia after using hormone-type herbicides (such as 2,4-D).
5. Hand wiping with glyphosate products is often practical with some weeds if roots are weakened. This is particularly useful for dewberries after late water or a summer flood.
6. Mowing of tall weeds helps to prevent shading and reduces seed formation.
7. Late water causes general reduction of annual grasses and may reduce dewberry populations and re-growth.
8. Agricultural burning of brush or grass is allowed under regulations from the Director of Air Pollution Control, Southeastern Office of the Dept. of Environmental Protection and under permit from the local fire chief.
9. Review the Weed Management BMP in the UMass Best Management Practices Guide: 
   ag.umass.edu/cranberry/publications-resources/best-management-practices

Prepared by Carolyn J. DeMoranville, K.M. Ghantous, and P. Jeranyama

The Commonwealth of Massachusetts 330 CMR 31.00 Plant Nutrient Application Requirements for Agricultural Land and Land Not Used for Agricultural Purposes took effect in 2018.  The regulation requires that nutrient management plans for agricultural lands, including cranberry, will be based on plant needs (as determined by testing and research) and UMass Extension recommendations. This section of the Chart Book encompasses UMass Extension recommendations for cranberry nutrient management. Use of these recommendations constitutes a Nutrient Management Plan as required in the regulations. Having a copy of the Chart Book and the required records of your applications satisfies the final version of the regulatory requirements – you are not required to have a separate written plan.

Tools for Nutrient Management

The Cranberry Station website provides information regarding nutrient management planning and record keeping based on Chart Book recommendations. To view these resources, follow the 'Nutrient Management for Cranberries' Quick Link on our home page (http://ag.umass.edu/cranberry). Resources include a plan template and Excel files with sample record keeping formats and nutrient calculators (determine fertilizer rates based on how much nutrient you want to apply). Growers may also choose to use the BOGS system, available from the Cape Cod Cranberry Growers Association. It is an online tool designed to plan and keep records that meet regulatory requirements for pesticide and nutrient applications.

Plants are primarily made up of carbon compounds (the products of photosynthesis) and water.  Mineral elements, the materials provided in fertilizer and the soil, are present in much smaller quantity, making up only about 10% of the plants' dry mass.  The essential mineral elements required for the plant to grow, develop, and produce fruit need to be provided in the right amounts, in the right form and at the right time.  Management must be flexible, adjusted for changing weather and observations of the plants.  It should also be implemented in an environmentally sound way.

Cranberry is a perennial plant.  As such, many of the mineral elements and carbon compounds are stored over the winter in stems and roots, then remobilized to support new growth in the spring.  In addition, decaying plant material in the soil can provide minerals, especially Nitrogen (N) and Phosphorus (P), back to the growing plants.  In a mature cranberry bed, these processes account for about half of the plant's need for mineral nutrition.  The rest is supplied in fertilizers.  The plants in new sand-based cranberry plantings depend primarily on fertilizers for their nutrients.

Nutrient requirements must be met to assure optimum growth and to achieve the yield potential possible for each cultivar.  The plant must be healthy, with an adequate root system in order for it to take up the nutrients it needs.  Overly saturated or dry soil or soil outside the pH range optimal for cranberries (4.0 to 5.5) can limit yield.  Uniform irrigation is essential to maintain moist, but not saturated soil.  Pest pressure, frost, or shading are other potential limiting factors.  Additional fertilizer applications will not compensate for any of these problems.

The recommendations in the Chart Book are developed based on knowledge of mineral content in a healthy productive plant.  The recommendations focus largely on Nitrogen (N), Potassium (K), and Phosphorus (P).  Added nutrients are required to replace minerals removed in the harvested crop and associated leaf trash. 

• N is found in the highest concentration of all of the nutrient elements in plant tissue, and is removed in the greatest quantity in fruit and harvest detrashing.  
• K is found in the highest concentration in cranberry fruit and as a result, K removal in crop harvest is similar to that of N.  
• P removal in crop harvest is much less than that of N and K, but research trials support the need for a modest annual addition of P to producing cranberry beds.
• The remaining mineral elements are seldom deficient in plant tissue tests and/or are found in substantial quantity in the bog soil.  Their application is primarily recommended when a deficiency exists and not on a routine basis.

NITROGEN (N)

The N fertilizer is not primarily used to produce fruit in the current year, rather it supports the building of the new growth that is the photosynthesis factory to support future production.  In our research, current season N applications correlated to current season yield only 10-15% of the time, while in almost all cases applied N correlated significantly with production in the following two years.

Recommended N fertilizer rates are based on the amount of N removed during harvest (in fruit and in trash).  To replace the removed N, we need to apply fertilizer.  Plants are not able to take up all the fertilizer applied.  The amount of N removed is then multiplied by a correction factor of 1.4 to account for the less than 100% efficiency of fertilizer uptake.  The base rates can then adjusted based on seasonal conditions, observed plant growth, previous summer tissue tests, and historic bog responses. The base rate recommendations for N vary by cultivar group.  The N concentration in fruit and new growth is similar among the cultivars.  The N amount in biomass (fruit and plant material) produced and then lost in harvest operations differs among the groups.  

N Lost in Fruit:

• Each 100 bbl of fruit contains 5.1 lb of N.
• As crop size increases, scale up from the 5.1 lb/100 bbl base based on the total bbl/A produced or expected.

N Lost in Detrashing During Harvest:

• Each acre of Early Black loses 13.4 lb N in plant biomass (in addition to what is removed in the fruit). That amount is likely similar in Howes.
• Larger fruited cultivars are larger plants with bigger leaves, and lose more biomass per acre.
• Ben Lear and first generation hybrids such as Stevens and Grygleski, lose 20.1 lb N per acre.
  • 1.5 x Early Black rate to compensate for larger plant size.
• Newer Rutgers and University of Wisconsin hybrids lose 26.8 lb N per acre.
  • 2 x Early Black rate to compensate for larger plant size.

The base range reflects varying crop loads: up to 600 bbl/A for the newest hybrids and up to 300 bbl/A for the others.  This does not mean that higher yields necessarily would require more N.  In fact, for all but the newest cultivars, adding more N than required can result in yield decline.

The aim is to provide enough N to produce a stand of uprights with optimal density and length that will support an optimal crop of good quality fruit.  When the upright stand is too dense or too long, shading occurs, pollinators may be impeded, and conditions are perfect for fungal rot infections.  A thin, stunted stand will not support a large crop since there will not be adequate leaf area, leading to a deficit in photosynthesis and a shortage of carbohydrates for making fruit.  

Within the recommended rate ranges, previous observed outcomes, tissue test results (see page 85), and observations of the plants color and growth should be used to adjust your rate.  Some potential yearly adjustments to the recommendation based on growth and tissue test N:

• If vines are stunted or yellowed and tissue N is low - use more
• If vines are stunted or yellowed and tissue N is high - look for other limiting factors
• If vine growth is adequate and tissue test is in the normal range - continue with the chosen rate
• If vines are rank or leggy and tissue N is low - use less or change timing; vegetative growth is being favored over production
• If vines are rank or leggy and tissue N is high or adequate - use less
• If yield potential is limited by pest damage or frost - use less

Length and density of uprights.

The table below shows adequate stand density and upright length for four common cultivars assessed at hook stage (mid-June).  Uprights generally should not be longer than 4 inches.  An even and adequate stand of both flowering and vegetative uprights is important, as about 80% of this year’s vegetative uprights will flower next year. 200 flowering uprights/sq. ft., each producing an average of 1 berry, will give a crop of 200-300 bbl/A. To sample upright density: count all uprights in a circle 4 inches in diameter. Total upright density (approximate) for 'Early Black' should be 50/sample; density for 'Howes', 'Ben Lear', or 'Stevens' should be 35/sample.  Multiply the amount in the 4-inch diameter cicle by 12 to approximate the number per squre foot.  

• Density of total uprights per sq ft, >40% should be flowering
• Upright length above the fruit on a flowering upright should be 1.5 to 2 in.

Leaf greenness

Leaf greenness is related to the pigment chlorophyll that is involved in carbohydrate production through photosynthesis. Along with adequate growth (length) of the uprights, chlorophyll content is an important determinant of yield. Overall intensity and shade of leaf greenness (chlorophyll) is related to adequate N nutrition. With experience, growers can assess intensity of greenness by visual observation. 
A bog with thin vine cover, pale leaves, or stunted vines may not be getting enough nitrogen. Vines that are too long and too dense have nutritional assets diverted to vegetation and not to fruit (small berries, poor fruit color, increased fruit rot, and inability of bees to reach pollination sites).

Nitrogen timing.

Plan nitrogen fertilizer applications based on soil type and soil temperature. 

• On sandy soils (<1% organic matter), nitrogen fertilizer may be applied throughout the season.
• On more organic cranberry soils and older beds, applications should be based on soil temperatures.
  • For typical cranberry bogs (1-4% organic matter), applications of N should not be necessary early in the spring. From flood removal until soil temperatures exceed 55°F, adequate N should be available through biological processes (mineralization; the process by which microbes convert N to plant-available forms).
  • Nitrogen is slowly released from the soil early in the spring when the cranberry plants are dormant. This leads to a 'flush' of ammonium availability when the plants are breaking dormancy.
  • As soil temperatures increase from 55°F to 70°F, release of N through mineralization is only moderate. Fertilizer applications should be beneficial. This corresponds to the period from roughneck stage through bloom.

During spells of hot weather, when soil temperatures exceed 70°F and air temperatures exceed 85°F, soil N release increases and crop development slows, so planned fertilizer N applications should be reduced, delayed, or eliminated especially on beds with high organic matter in the soil.

It is best to time N applications by the growth stage of the plants.  Cranberries primarily use N during three stages: early season leaf production, fruit set, and bud set.  When N is applied pre-bloom, it is rapidly taken into the plant and moved to the new leafy growth.  While such applications can assure adequate upright length, adding too much N at this stage can lead to excessive growth.  Fruit production is a very high demand period that extends from earliest set to about 3 weeks after the final fruit are set.  Bud set is occurring during fruit set, so set applications also support this function.

Since the fruit set window is such a high N demand period, it is not unusual to see some loss of green color in the leaves above the fruit as the fruit are drawing N from both those leaves and the soil.  Minor yellowing is normal, severe overall yellowing can indicate inadequate N fertilization.  This should not be confused with Yellow Vine (see page 83), a patterned yellowing related to root stress and not improved by the addition of N.

Nitrogen sources

Most cranberry growers in MA apply N in NPK fertilizer (aka 'complete fertilizers') primarily to reduce application costs when N, P, and K are all needed.  In such fertilizers, the first number on the bag or jug is the percent N in the material.  Since P requirements are substantially less than those for N and K, materials with high middle numbers (phosphate) should be avoided. Note that when using liquid fertilizers, the percent on the jug is based on weight, so to calculate pounds per acre applied, one must correct for the liquid density (weight per gallon x gallons per acre x percent).

The best available evidence indicates that cranberries respond poorly to nitrate N especially in the absence of ammonium N; the AMMONIUM FORM is recommended. Monoammonium phosphate is an excellent source but can provide excess P (see the Phosphorus section below). Ammonium sulfate is also an excellent source. Light rates of urea, a material that breaks down to ammonium, are suitable to correct N deficiencies quickly (when the urea is dissolved and used as a foliar feed). Use blended fertilizers with ammonium N and excellent uniformity of particle size or ammoniated materials. Non-uniform blends may sort during application, giving poor results. Liquid formulations designed to be applied to the soil and taken up through the roots can be substituted for granular materials.

FISH HYDROLYSATE FERTILIZER is available commercially, is useful for organic production, and has been shown to be a suitable substitute for granular, inorganic NPK. It may provide benefits in soil conditioning and reducing movement of nutrients out of the root zone. Fish fertilizer is a good choice where the bog holds water poorly and/or has a history of needing larger than normal fertilizer rates. The nitrogen in fish fertilizer is tied up in organic compounds. As these degrade in the soil, nitrogen is slowly released for use by the cranberry plants. Leaching losses of nitrogen are reduced. Therefore, 20% lower nitrogen rates provided as fish fertilizer should give the same result as a higher nitrogen rate provided in granular, inorganic fertilizer. This has been demonstrated on commercial bogs.  Fish is especially useful in the spring and can be incorporated into a program that includes other inorganic fertilizers if organic production methods are not required.

PHOSPHORUS (P)

PHOSPHORUS (P) RATES OF 10 LB/A (20 LB/A P2O5) OR LESS ARE STRONGLY RECOMMENDED ON NATIVE OR FIRST-GENERATION HYBRID VARIETIES UNLESS A DEFICIENCY IS DOCUMENTED.  

Phosphorus is important for plant metabolism; it plays a key role in energy transfers, in transporting the sugars produced in photosynthesis, and is part of the DNA molecule.  If P is deficient, growth and yield can be impacted.  However, P does build up in the upper soil layers and some of that is available to the plants.  This stratification often confounds P soil test results, making them difficult to interpret.  Therefore, application recommendations are based on crop use and tissue testing.  Of the three main nutrients, P is required in the smallest amount (compared to N and K). P removed during harvest accounts for only about 5 lb/A (250 bbl/A contains approximately 2.5 lb P and normal harvest and subsequent detrashing removes another 2.5 lb).  Pruning operations can also remove P; 500 lb of vine prunings contain about 1/2 lb P.

P is often added with N in NPK fertilizers and is the second number on the bag.  Fertilizer convention is such that the second number is actually percent phosphate (P2O5), so to calculate the actual P, that number is multiplied by 0.44.  

Important considerations regarding P use and use reduction:

Very little P is removed from the bog in the harvested crop! Cranberries require additions of phosphorus fertilizer for sustained productivity, but there is no evidence that more than 20 lb/A actual P is required for productive cranberries (for native cultivars and first generation hybrids). 

Research studies on P have shown:

• On high P sand soils, there was no response to P fertilizer on beds with adequate tissue P.
• On native cultivars, the greatest yields were on plots receiving 10-15 lb/A P, with no improvement at higher rates.
• If tissue P was in the sufficient range, rates well below 10 lb/A gave the best yields.
• If tissue P was in the deficient range, 20 lb/A gave the best yield.
• At several commercial sites, growers applying an average of 10 or less lb/A/yr P over a period of years have seen either no change or an improvement in their crops.

Based on these data and observations, the P rate recommendations in this Chart Book were developed.  The only exception to these recommendations for native varieties and first-generation hybrids are for new beds with fresh sand planting medium. The recommendation for those is to use up to 20 lb/A at planting and no more than a total of 30 lb/A on new or renovated beds until the canopy is established.

Second generation hybrids produce much higher yields than native varieties and first generation hybrids, and tend to be larger and more robust plants. These varieties are reported to have moderately higher P demands than older varieties. On-going research is being conducted to quantify the increased nutrient demands.

P can be an environmental pollutant. Adverse environmental impacts are reduced by using moderate P rates (no more than 20 lb/A per season on native varieties) and by careful attention to harvest flood management. When bogs are flooded, especially when soil and water are warm, P from the soil can move into the flood water. When the flood is released, the dissolved P then leaves the bog system.

To minimize P release in harvest floods:

1. Hold harvest floods for 2-4 days to allow settling of P-containing particles.
2. Release gradually (to avoid flushing particles) so that discharge is completed within 10 days. Research has shown that holding floods beyond 10-12 days in the fall can result in oxygen depletion and release of P from iron in the soil.
3. Use no more than 20 lb/A P in fertilizer -- laboratory research showed that with higher P use, P movement into the flood begins immediately upon flooding and then accelerates as oxygen depletes. With low to moderate P use, P release into water is minimized.

Research on Stevens, Ben Lear or native cultivars showed 10-15 lb/A P is sufficient to maintain productivity if tissue test P is in the sufficient range (0.1-0.2%). In plots and demonstration sites, production and fruit quality were maintained with an average of 10 lb/A; no significant relationship between P rate and yield was observed.  As P fertilizer use was reduced, P output from the bog (in flood water) also decreased. Based on these studies, growers have reduced P applications well below the previously recommended maximum of 20 lb/A (5-year rolling average of ~10 lb/A) with no reduction in crop. When implementing a reduced P rate, it is important to collect August tissue tests and follow these recommendations: If P is <0.10% - increase the P rate and retest next season; if P is 0.10-0.11% - maintain the P rate and retest next season; if P is 0.12-0.15% - maintain the reduced P rate and retest in 2-3 years; if P is 0.16% or more - further P reduction should be considered.

These numbers above are based on Stevens, Ben Lear or native cultivars. Recently MA cranberry growers have adopted high-yielding second-generation hybrids. There is evidence that more P is being removed through harvest as yields of over 400 barrels per acre have been reported. To replenish P available for plant uptake slightly higher lb P/A may be required with the second-generation hybrids. It is suggested that up to 30 lb P/acre could be adequate. Ongoing research continues to quantify nutrient demands for these varieties.

Phosphorus timing and sources.

Phosphorus ties up in the soil quickly, binding to iron and aluminum.  Therefore, P should only be applied when the plants are actively growing.  Phosphorus is generally added with nitrogen and potassium (NPK) or as super phosphate (0-25-0) or triple super phosphate (0-45-0).  Research indicates that foliar P or soil-applied liquid fertilizer that contains P, bone meal, or rock phosphate can supply the P needs of cranberry bogs as well.  The second number on the bag of NPK fertilizer is phosphate - P₂O₅.

* To determine pounds of P in 100 pounds of fertilizer, multiply 0.44 by the second number on the fertilizer label. 

When choosing fertilizers, remember that research indicates there is no horticultural benefit to high P rates (in excess of 20 lb/A actual P per season) and that high P applications can be associated with degradation in water quality. If tissue P is in the sufficient range, we do not recommend fertilizers with high P (middle bag number). In fact, excellent results have been seen in recent years with 1:1 or near 2:1 N:P ratios (for example, 18-8-18). It is highly recommended that growers use reduced P ratio fertilizer on their bogs, especially if high N applications are planned.  

Use no more than 20 lb/A actual P (~45 lb/A P2O5) per season except on new beds or second-generation hybrids. See calculations on the last page of the Nutrition section.

POTASSIUM (K)

The amount of K in cranberry leaves is second only to nitrogen among the mineral nutrients and K is the element in the greatest abundance in the fruit.  Potassium is important in the movement of sugars in the plant, in maintaining plant hydration, and in many enzyme reactions in the plant.  Cranberry sand soils are naturally low in K, leading to an annual requirement for K additions.

Potassium rates.

K is often added with N in NPK fertilizers and is the third number on the bag.  Fertilizer convention is such that the third number is actually percent potassium oxide (K2O), so to calculate the actual K, that number is multiplied by 0.83.  When tissue and soil tests are in the sufficient range, the K requirement is roughly similar to that for N, so choosing an NPK with similar first and third numbers works well.

Potassium timing and sources.

Supplemental K may be applied as soon as the soil warms in the spring, generally in early May.  Otherwise, K is generally added with nitrogen and phosphorus (NPK).

Supplemental K is often added with magnesium (SulPoMag or similar product), but may be applied as a foliar spray (of little value in research trials) or as potassium sulfate (0-0-50). Muriate of potash (KCl, potassium chloride, 0-0-60) may be less desirable due to the adverse effects of chloride on cranberry vines when used at high rates over years.  However, modest rates appear to have no adverse impact. While foliar applied K seems to have little utility in cranberry production, soil-applied liquid products containing K have been used with good results.

OTHER ELEMENTS

Calcium and Magnesium.

The other major elements, Calcium (Ca) and Magnesium (Mg) are seldom lacking in cranberries.  However, Mg is often added with K in SulPoMag or KMag.  On bogs with Yellow Vine (see below), magnesium sulfate (Epsom salts) may alleviate symptoms.   Diagnosed deficiencies (using tissue tests) of Mg or Ca may be treated with 30 lb/A of the deficient element in granular form applied in the spring or with liquid supplements pre-bloom.

Soil balance of K, Mg, and Ca is important. Excessive use of any one can induce deficiency of the others. This is especially a risk with large soil applications of Ca. Lime can have adverse effects by changing soil pH and is not recommended for use in cranberry production.  Products that supply Ca may improve fruit quality or firmness.  Examples of Ca supplements suitable for cranberry include those that are gypsum based (gypsum and some formulations of Solu-Cal) and liquid supplements such as Full Measure CAL 30TM (this material increased Ca concentration in cranberry fruit in research trials).

Yellow vine (YV) manifests as an apparent nutrient deficiency. Beginning with older leaves, yellowing presents along leaf margins and between the veins on the leaf, leaving green only along the veins. Tissue tests of such leaves often show higher than standard potassium and low-normal magnesium. However, extensive investigation has shown that the nutrient imbalance is secondary to the primary problem – root insufficiency due to too much or too little moisture. Cranberry bogs with patches of YV were found to have soil water content (in the YV areas) that was either much higher or much lower than that in the surrounding green areas. Additionally, in greenhouse experiments, plants subjected to very shallow or very deep water table conditions developed YV. The consistent finding in the field has been that the rooting depth in YV areas is shallower than that in unaffected areas. In most cases, YV appears in areas that were too wet early in the season leading to poor rooting depth. Rooting depth can be improved by keeping the bed well drained early in the season. When the water table is closer than about 6 inches below the surface, root development and root function is impaired. Examine your drainage and irrigation practices if you see YV on your bog. Another symptom of poor drainage is high manganese (Mn) in the tissue test. YV usually appears as temperature and water stress increase during mid-summer and may be more severe if Casoron has been used since it can affect rooting and root function.  

Minor elements.

• Minor element deficiencies are rare in cranberries due to low requirements and high availability in acid soils. Deficiencies may be brought on by mineral imbalances or stress conditions (drought, waterlogging).
• If deficiencies are suspected (visual symptoms), confirm with tissue testing.  If confirmed, deficiencies are best corrected with foliar sprays. Such sprays are applied between bud break and hook stage.
• CALCIUM-BORON (5% Ca, 0.5% B, no other minor elements) sprays were the only minor element supplements to give increased crops in our research on non-deficient bogs. Response was greatest on bogs yielding at or below 150 bbl/A. We found that 2 applications of 2 qt/A improved fruit set.

TIMING:     10% bloom, mid-bloom. The second application seems most effective. Application by sprayer is more effective than sprinkler application. This is a foliar feed - apply accordingly; do not wash off the leaves.

CAUTIONS:  1. Manganese-containing fertilizers or fungicides (Mancozeb group) may cancel any beneficial effect of CaB if applied with or around the same time as CaB.
2. DO NOT use when leaf analysis is above 75 ppm B.
3. If B levels are elevated, but below 75 ppm, eliminate the FIRST application.

APPLYING FERTILIZER TO CRANBERRY BOGS

• SPRINKLER SYSTEMS may be used to apply liquids, flowables, and foliar feeds. Make sure not to mix incompatible materials (jar test first). When using sprinkler systems to apply fertilizer - make sure that coverage is ADEQUATE AND UNIFORM. EVERY EFFORT SHOULD BE MADE TO PRESERVE WATER QUALITY - avoid application of fertilizer to water in ditches and canals.
• Foliar feeds should not be washed off the leaves. Liquid fertilizers should be washed onto the soil. Be sure that you know which you are applying. Liquid products that have recently been integrated into cranberry management in Massachusetts are primarily designed to be soil-applied and watered in.
• FISH FERTILIZER is a liquid fertilizer. It should be washed in.
• Make sure ground application equipment is properly calibrated.

SOIL pH

The optimal pH for cranberry soil is between 4.0 and 5.5.  Use of sulfate containing fertilizers (SulPoMag, ammonium sulfate) does not affect soil pH. However, acid is released into the soil as the plants take up ammonium N. Otherwise, to substantially lower soil pH, elemental sulfur (S) application is used. Soil pH may influence the types of weeds that invade a bog. See the Weed Management section for information on the use of sulfur for weed suppression. Prior to making S applications, seek advice from Extension specialists or consultants. Apply no more than 500 lb/A/season in one or two applications. Apply elemental S only to well drained soils and test soil pH prior to application.

Use this table (courtesy of the Wisconsin Cranberry Crop Management Newsletter) to calculate the amount of S needed to lower soil pH based on desired amount of change and soil organic matter content from the soil test. This is a SLOW process depending on bacterial activity in the soil - pH change will occur over a period of months. Change will be fastest when soil is warm.
 

SOIL AND TISSUE TESTS

Soil and tissue tests are tools that a cranberry grower can use to help diagnose deficiencies of mineral elements, monitoring soil pH, and aiding in the decision making process for choosing fertilizer (tissue tests). These tests are also required for Nutrient Management record keeping.

However, there are no 'cookbook' type formulas for fertilizing a cranberry bog based on the test results. 

1. standard soil tests poorly predict availability of nutrients and poorly correlate with yield in cranberry;
2. as a perennial plant, cranberries store nutrients from the previous season(s) making it impossible to base fertilizer choices only on soil content and yield potential;
3. there is virtually no variability in soil test N values from bog to bog;
4. tissue test N concentration may vary depending on length of upright (N concentration in the tissue does not always correlate well with added N);
5. nutrient availability changes with soil pH and soil pH is not uniform from bog to bog; and
6. common soil test methods for P do not give results that correlate well with cranberry yields due to very acid soils in cranberry production – standard P tests are of no predictive value if soil iron is above 200 ppm.

With these warnings in mind, tissue and soil analyses can be beneficial as a long-term record of changes in your bog. Soil and tissue tests are particularly useful when compared to one another - a soil test alone is virtually useless in determining a fertilizer recommendation for cranberry. Use periodic soil testing to monitor any change in soil pH; we recommend testing soil every 3-5 years for this purpose.  

Tissue tests are more useful for setting target fertilizer ranges. Regular tissue testing meets the mandate for testing in the Massachusetts Nutrient Management Regulations since this is the UMass recommended testing for cranberry. We recommend tissue sampling every 2-4 years (but see also P use and P reduction section above for protocols when adjusting P rates). Keep the results and use them in conjunction with your records of your bog management and performance (growth and cropping) to aid in making fertilizer decisions. For further information regarding tissue testing, refer to “Cranberry tissue testing for producing beds in North America” fact sheet (available at http://scholarworks.umass.edu/cranberry_factsheets/6/).

When and how to test

The results you receive from a soil or a tissue test are only as good as the sample you supply to the analytical lab. Follow the instructions for sample collection provided by the lab you are using. Collect one composite sample for each management unit as instructed below. A management unit may vary in size but will generally be a single variety that is treated uniformly, often under one sprinkler system.

Tissue samples: Samples for cranberry tissue analysis should NEVER contain roots, soil, runners, fruit, or trailing woody stems. In general all of these contaminants contain less nutrients than the upright tips. Including them will give a falsely low analysis. Tissue samples are best collected from mid-August to mid-September. Samples collected at that time should include upright tips only (do not strip off the leaves). Collect no more than the top 2 inches of new growth (mix flowering and vegetative uprights). As you walk a transect across the bog, collect enough material to make about 1 cup (at least 50 upright tips). You may collect directly into marked bags as samples should not be washed. Collect samples when the plants are not wet. Do not mail samples in plastic bags. Moldy samples give poor results. Always request nitrogen determination. This increases the test cost, but nitrogen levels in the tissue test are an important indicator of plant status and the success of fertilizer programs.  

Sampling other than in August-September: Tissue samples may be collected at other times of the year if absolutely necessary. However, nutrient levels change more rapidly outside of the recommended time and make interpretation of the results more difficult. If sampling in the spring, samples should be collected in June and consist of new upright tissue only. Do not include last season's leaves - they will lead to a falsely low result. In June samples, nitrogen should be 1.2-1.5%, phosphorus 0.15-0.19%, and potassium 0.7-0.9%. Interpretations for other elements are challenging in June samples.

Tissue samples should also be collected when deficiency is suspected or diagnosis of a specific problem is needed.  For problem diagnosis, collect 2 separate samples - one from the problem area, and one from nearby 'normal' vines.

Samples collected after mid-September give lower analysis values than those collected earlier. This is especially true for nitrogen (it is transported out of upright tips and stored in older tissue as dormancy approaches). Also, late in the season the uprights become more woody so that more of a tip sample is stem tissue. Stems have less nutrient content than do leaves so the overall result is a lower analytical value.

TISSUE STANDARDS (August 10 to September 15 collection)

Standards developed in conjunction with researchers throughout the cranberry growing areas of the USA

Soil samples: Samples for analysis of soil nutrients should NOT contain stems, leaves, or the surface duff layer (trash). These are all organic contaminants and will bias the organic matter (OM) determination for the sample. The inclusion of some roots is generally unavoidable. Use a soil probe with a 1-2 inch diameter to collect cores of 4-6 inch depth. Minimum requirements: 4 cores for up to 1 acre; and 1 core for each additional 2 acres up to a total of 10 cores/management unit. After the trash layer on the surface of each is discarded, these cores are combined to make a sample. Collect enough soil to fill a 1 qt plastic bag about ¾ full. At home, open the bags and dry the soil at room temperature for a day or two. Clearly mark each sample bag. Orangic matter determination (usually an additional charge) is often useful.

Methods of analysis vary by lab - pick a lab and stick with it. The UMass Soils Lab uses the Morgan test. However, the Bray test for soil P is the most commonly used in other labs for samples from the eastern United States. The Bray test, like all common P soil tests, is of limited value in cranberry soils. Standard P ranges for both methods are provided on the next page. The best time to sample cranberry bogs is when the soil is not waterlogged. Wet soils give falsely high P values. Soil samples may be collected with tissue samples in the late summer if no sanding is planned. Otherwise, sample soil in the spring.

UMass provides soil analysis services at the Amherst lab for a fee. Submission forms for this lab are available at https://ag.umass.edu/services/soil-plant-nutrient-testing-laboratory/or… .

Base saturation: Ca should roughly equal the sum of K and Mg. Base saturation is the proportion of the various positive cations in the soil. In acid soils, 45-70% should consist of hydrogen ions (these replace much of the Ca that would be found in higher pH soils).

Cation Exchange Capacity (CEC): Measures ability of soil to hold positive ions (cations or bases). If CEC is low (<10), base saturation proportions are important. If CEC is high and all cations are in the normal range, the proportions in the base saturation are less critical. 

If soil iron is above 200 ppm, soil P tests will not accurately reflect P availability.

IMPORTANT CONSIDERATIONS FOR CRANBERRY NUTRITION

• REVIEW the Nutrient Management BMP in the Best Management Practices Guide for Massachusetts Cranberry Production on our website (http://ag.umass.edu/cranberry/publications-resources/best-management-pr…). Excellent information and decision trees for planning N and P management are available as well (http://ag.umass.edu/cranberry/publications-resources/books-pamphlets). Select Nitrogen or Phosphorus for Bearing Cranberries articles.
• The Cranberry Station website has an entire page devoted to Nutrient Management and planning (http://ag.umass.edu/cranberry/publications-resources/nutrient-managemen…). There are templates for record keeping and nutrient calculator tools that can be downloaded from that page.
• GOOD DRAINAGE AND ADEQUATE IRRIGATION are essential for best response to fertilizer. Monitor and maintain adequate soil moisture. Small, frequent irrigations may not be adequate to provide moisture to the root zone. For further information, refer to the Irrigation section (pg 93) and BMP https://ag.umass.edu/cranberry/publications-resources/best-management-p… .
• KEEP GOOD RECORDS. Comparison of rate/material and crop response over time will help to refine fertilizer practices tailored to YOUR bog. OBSERVE YOUR BOGS OFTEN -- fertilizer timing depends on growth stage/plant development. Rate can be refined as plants respond during the growing season. For growers managing 10 acres or more, records of nutrient applications are required under Massachusetts regulations.
• Cranberry bog soil has little capacity to HOLD cations (e.g., K, Mg, Ca). Much of the holding capacity is taken up by hydrogen ions. It is important to maintain a BALANCE among cations. Overuse of one can induce deficiency of the others. When you test bog soil for pH, check this balance as well.
• WHEN SYMPTOMS OCCUR - rule out water management issues, disease, and pest problems first. Then look at nutrition. Collect tissue for testing if necessary.

CAUTIONS:

• PRESERVE SURFACE WATER QUALITY - avoid applying fertilizer to water in ditches and canals. As possible, lower water levels in ditches prior to fertilizer application and impound water during and after fertilizer applications.
• AVOID HIGH RATES APPLIED AT ONE TIME, particularly on bogs constructed on mineral soils or very sandy bogs. Such applications may lead to lateral movement of fertilizer into water.
• EXCESSIVE NITROGEN FERTILIZATION leads to over vegetative plants. This may increase susceptibility to disease, spring frost or insect feeding. High nitrogen rates are associated with poor fruit quality and may delay color development in the fruit. High nitrogen rates can have adverse carry-over effects in following years -- excess applied nitrogen leads to high nitrogen concentrations in plant tissues such as stems and roots that can be remobilized in the plant and lead to excess vegetation, particularly when more nitrogen is added to the soil.
• FALL FERTILIZER (after harvest application) is not recommended, particularly if crop was small and no deficiencies have been noted. Late-season applications may not be properly taken up by the plants depending on soil temperature and state of dormancy. Generally, if uptake does not occur in the fall, the nutrients are no longer available the following spring. Organic types of fertilizers may be the exception. If you choose to use fall fertilizer, use low N and low or no P formulations.

EFFECTS OF WEATHER:

• WINTER INJURY. If leaf drop occurs after withdrawal of winter flood, early spring fertilizer applications will aid in recovery by encouraging rapid, early production of new leaves. Do not skip spring fertilizer. SulPoMag (or similar material) at 100-200 lb/A may also aid recovery.
• COLD SOIL/AIR TEMPERATURES, particularly in the spring, will lessen or eliminate response of cranberry plants to fertilizer applications. If plants are already under stress, they may respond even less. If this occurs, care should be taken not to reapply before you are sure that the plants are not going to respond to the initial application. Soil temperatures should rise to 55°F before application of fertilizer to ensure response. If long-lasting, slow-release, controlled release, or organic forms were used, reapplication may not be necessary -- response may only be delayed.
• IF FLOWER BUDS ARE DAMAGED BY SPRING FROST, high N rates can lead to overgrowth. Use lower rates.

EFFECTS OF PESTS AND CULTURAL PRACTICES:

• BOGS CONSTRUCTED ON MINERAL SOILS without a permeability restricting or confining layer have little ability to hold nutrients in the root zone. Use organic or slow-release N and avoid large rates applied all at once.
• DECREASE fertilizer rate if the bog has been SANDED. Sanding promotes production of new vegetative uprights from the runners. Sanding combined with high fertilizer rates can lead to overgrowth.
• DECREASE fertilizer rate if late water has been held. Spring fertilizer rate may be eliminated on late water bogs. Overall fertilizer rate may be decreased 30% or more. However, do not decrease fertilizer N by more than 40% at the risk of adverse impact on the following season crop.
• ELIMINATE fertilizer applications for the entire season if the bog has been subjected to a long SUMMER FLOOD (May-July, see Insect section) for grub control.
• If eliminating crop using a FLASH FLOOD, reduce fertilizer rate. Two low-rate applications, in the spring and mid-season, should suffice to support the plants.
• PRUNING stimulates growth - reduce spring fertilizer on heavily pruned bogs. However, if the bog has been mowed, fertilizer applications are required to encourage the production of new uprights.

Calculating Fertilizer N and P Rates -- important for planning

Fertilizer labels have three numbers that are N-P-K. These numbers are percent by weight, and also the amount per 100 lbs of fertilizer. 

Nutrient Planning Example

Since we fertilize based on nitrogen -- decide how much N you need.  Then choose a fertilizer and calculate how much N, P, and K you will apply.

My bog requires 35 lb N/A; I want to use 12-24-12. 
To get 35 lb N -- how much 12-24-12 do I need per acre?

1. Divide rate of N needed by percent N (first number on bag)
2. Then multiply by 100 to convert the percent into lbs

If you are going to use this fertilizer, you should then calculate how much P you will also be adding.  

1. Multiply pounds of fertilizer by middle on the bag number (24 in this case)
2. Then by 0.44 (to convert to actual P)
3. Then divide by 100

If you are going to use this fertilizer, you should then calculate how much K you will also be adding.

1. Multiply pounds of fertilizer by last number on bag (12 in this case)
2. Then by 0.83 (to convert to actual K)
3. Then divide by 100

That's more P than I expected! What if I switch to 18-8-18?

Prepared by Giverson Mupambi

Fruit quality is becoming very important in cranberry production. The major driver towards adopting fruit quality standards in cranberry production has been the introduction of new hybrid varieties. The new hybrid varieties are high yielding leading to an overabundance of fruit available on the market. Consequently, handlers are becoming stricter about the quality of fruit they are willing to accept. Currently, the fruit quality parameters being evaluated by handlers include fruit color, firmness, and size. Fruit quality standards are dependent on handlers and are not standardized throughout the industry. Also, depending on the handler, growers sometimes get paid an incentive for specific fruit quality parameters such as color and firmness. Growers can be assessed for fruit not meeting size requirements. Growers are advised to check with their handler every year to see which quality incentives are available. Currently, the options available for fruit quality management are very limited. As more research is conducted, more fruit quality management options will become available to growers.

Fruit color

Fruit color is an important quality parameter in cranberry production. The timing of cranberry fruit harvest is often based on red color development. The majority of fruit produced is processed for cranberry sauce, fruit juice, and sweetened dried cranberries. Uniform fruit color is very important for processed fruit. Currently, growers can use canopy manipulation and weed management to improve fruit color. Another option for growers is to plant varieties that develop color easily.

Canopy management

Pruning and sanding are cultural practices that improve fruit color in cranberry with minimal yield reduction. Pruning and sanding increase light penetration into the canopy. Light is essential for the formation of anthocyanins, which give cranberry their deep red color. Another option for improving fruit color in cranberry bogs that are overgrown is mowing. Mowing is a last resort as it will result in yield loss during the year in which it is done.

Weed management

Certain weed species such as dewberry, sawbrier, poison ivy, or dodder can sprawl across the cranberry canopy, thereby reducing light penetration that is essential for the anthocyanin formation. Weed management is also very crucial when pruning. Weeds such as moss can grow into the open space created by pruning, or weed seeds on the soil surface can germinate and establish thereby negating the benefits of pruning.

Choice of variety

When renovating, growers should plant varieties that develop color easily, keeping in consideration other parameters such as fruit size, firmness, rot, and yield potential. Varieties such as Demoranville, Crimson Queen, Scarlet Knight, HyRed and Ben Lear have been shown to color up easily under Massachusetts growing conditions.

Fruit firmness

Fruit firmness is another important quality parameter in cranberry production. Firmer fruit are easier to slice during the process of making sweetened dried cranberries (SDCs). Depending on handlers, cranberry growers are paid an incentive for fruit with high firmness, thereby increasing their returns. Factors that influence fruit firmness in cranberry can be divided into pre and postharvest factors.

Preharvest factors

Excessive nitrogen fertilizer can result in reduced fruit firmness.

Postharvest factors

Several postharvest factors can result in lower fruit firmness. Leaving fruit to float for extended periods after harvest results in a loss of fruit firmness. Slower reeling has shown a negative impact on fruit firmness compared to faster. When pumping the fruit off the bog, higher pump speeds have been shown to be associated with a loss in fruit firmness. When cleaning fruit with higher pressure nozzles, overripe fruit could show significant loss of firmness at higher pressures. The height of the truck used to deliver the fruit to the receiving station also affects fruit firmness, fruit at the bottom of a higher truck will be under increased pressure due to the sum of total weight from the berries above them.

Fruit size

Currently, there are no options for increasing fruit size in cranberry except renovating. If renovating, growers should plant new hybrid varieties that have been shown to have larger fruit size compared to the native varieties. 

Prepared by Peter Jeranyama

Water management is a key component of sustainable intensification of cranberry production in Massachusetts. Previous research has shown that water management directly affects (a) crop yield (Caron et al. 2016), (b) environmental impacts (Kennedy et al. 2016), (c) production costs (Olszewski et al. 2017), and (d) regulatory scrutiny (Mattson et al. 2015). One challenge facing Massachusetts growers is that soil moisture conditions are generally too wet to achieve optimal crop production (Lampinen, 2003). Water management is arguably one of the most critical issues affecting the cranberry industry for four major reasons: (a) crop production, (b) environmental concerns, (c) costs and (d) regulatory scrutiny.  This section's objective is to introduce the concept of crop water stress index (CWSI) and discuss soil moisture monitoring devices such as tensiometers, moisture sensors and water level floats.

An evaporative demand study conducted in Massachusetts showed that for many weeks during the growing season, most cranberry beds were too wet (Lampinen, 2003).  Wet conditions, which often derive from inadequate drainage, may enhance root rot (mostly Phytophthora cinnamomi) and fruit rot (many different fungal pathogens) diseases, restrict nutrient uptake, inhibit root development, and reduce fruit retention and productivity.   Fruit rot in cranberry is an infection by many different fungal pathogens, among them Allantophomopsis lycopodina and A. cystisporea that causes black rot.  These organisms are more prevalent under wet conditions, and a wet canopy may create a microenvironment for fruit rot pathogens to thrive.

Traditionally, cranberry beds received one inch of water per week from either rain, capillary action from the groundwater, irrigation or some combination of these.  But conditions can vary from bog to bog so the one inch (1”) rule does not always result in ideal soil moisture conditions.  

Plants maintain hydration and internal temperature through a process called transpiration in which water is moved from the soil, through the roots to shoots, and out through pores (stomata) in the leaves. As this process occurs, moisture is depleted from the soil.  The plant can control the rate of transpiration by controlling the opening of the leaf stomata to let the water out.  In other crops, crop water stress index (CWSI) is used to measure plant transpiration from canopy temperature and air dryness.  However, there is evidence that cranberry has poor control over its stomata and therefore, its transpiration process. Since cranberry has poor control over its transpiration process, leaf measurements alone may not sufficiently define CWSI for cranberry and we have no such index specific to cranberry yet.  

Ideally, irrigation scheduling should consider plant phenology in conjunction with the soil water matrix's status to quantify water stress with different soil conditions.  Summer irrigation also coincides with the application of nitrogen fertilizers, which are highly susceptible to runoff during irrigation events.  Surface runoff of nitrogen reduces soil nitrogen available to the cranberry plant.

Measurement of soil water status is based on two technologies: (i) measuring the amount of water in the soil (e.g., 'feel test', water float, or volumetric water sensor) and (ii) measuring the energy status (water potential) of the water (e.g., tensiometer).  In general, the following bog conditions exist in MA: (i) new renovations and constructions (0-10 years old) with a constructed subgrade, (ii) renovated beds that have a peat/hardpan natural underlayment, and (iii) older beds that have developed layered soil in the root zone (alternating sand and organic layers with root mass).  The layering structure of these older bogs will present challenges to getting uniform contact with monitoring devices.

Soil probing can be used as a check on other monitoring methods and is especially useful in monitoring the depth of penetration of irrigation applications and rainfalls.  Sometimes other problems, like compacted soil layers, can be detected from probing.

Appearance and Feel Method

Although measuring soil water by appearance and feel is not precise, with experience and judgment, farmers have been able to estimate soil moisture level with a reasonable degree of accuracy.  However, this can be very challenging in sandy soils and is not a recommended method for cranberries.

Note: A general problem with estimation of soil moisture arises because of the heterogeneity within soils, with single point measurements rarely being representative.  Ideally, several devices should be distributed across the management area covered by an irrigation system.    

Water Level Floats

In cranberry, water level floats have been used to determine when to irrigate. Note that this technology depends on the presence of a water table in the bed.   Water level floats have the advantage that you can see the level of the water table without walking onto the bog.  They measure the level of the water table and do not include any plant processes or plant evaporative demand. See Instructions for constructing a water level float.

Water demand by vines can be assessed by comparing the water level in the center of the bed to the water level in ditches to see if water is moving fast enough across the bed.  By observing the water level float through several irrigation cycles, you can determine the number of hours required for an adequate irrigation.  

Tensiometers

A tensiometer is a sealed, water-filled tube with a vacuum gauge on the upper end and a porous ceramic tip on the lower end.  A tensiometer measures the soil water potential.  As the soil around the tensiometer dries out, water is drawn from the tube through the ceramic tip.  This creates a vacuum in the tube that can be read on the vacuum gauge.  When the soil water is increased, through rainfall or irrigation, water enters the tube through the porous tip, lowering the gauge reading.

Tensiometers provide a valuable measure of the energy status of water in the soil, thus providing a rigorous indication of the water availability to plants, with values that allow comparisons between a set of growing conditions.

A tensiometer reading in the 2 to 5 cbar range should be expected as long as the water table is between 8 and 18 inches.  This range is adequate for cranberries (see Table 1).

NOTE: Tension readings are technically negative, but for simplicity of concept, we have chosen to report them in this book as positive numbers.

Volumetric Water Content

Volumetric water content measurements are simple, reliable and inexpensive and indicate how much water is present in the soil.  They can be used to estimate the amount of stored water in a profile or how much irrigation is required to reach a desired amount of water.  Installing these sensors into the soil allows you to collect long-term measurements.

The spaces between soil particles are referred to as pores.  Based on our current research, cranberry bed soil appears to be saturated (all soil pores are filled with water), when volumetric water content is 30 to 40%. This volumetric water content corresponds to a tension reading of 1 and 2 cbar (or kPa) on a tensiometer. Irrigation should be stopped before saturation to promote water and solute uptake by the plant.  

Field capacity is reached when the soil has drained all its free water and at this stage the soil is ready for irrigation. In our research, field capacity was reached between 5% and 15%, which corresponds to a tension reading of 4.5 and 6.5 cbar (or kPa) on a tensiometer (Jeranyama et al. 2017).

Using a tensiometer, irrigation should be initiated when a tension of 4.5 kPa (field capacity) has been reached and stopped when a tension of 2 kPa (before saturation) has been achieved. Using a volumetric water sensor, irrigation should be started when a water content of 10% is recorded and stopped before 30% moisture content.

Irrigation in response to the drying of the soil should be initiated at 4.5 kPa where the graph flattens. Further increases in tension are associated with little changes in water content in the soil as the remaining water is being tightly held by soil particles and is not readily available for plant uptake.

Figure 2 shows that Section 4 is drier than Section 3 as indicated by the higher tension readings at any given time. Precipitation of 0.1 inches dramatically dropped tension readings by <-1.5 cbars on both fields. Section 3’s tension was dropped to water saturation levels on Julian day 244 (September 1, 2014), but tension readings rose again as the field gradually dried up. Worth noting is that a slight precipitation caused the tension readings to remain less than -4.5 cbars (trigger point to set irrigation) and even three days after the precipitation, the tension did not rise to previous levels (especially in section 3). This provides solid evidence that irrigating every other day in summer may be too high a frequency, as the field will remain considerably too wet, providing a good environment for disease development.

Soil tension readings in July (flowering period) and August (fruit formation) affects cranberry yield as shown in Figure 3. As the cranberry bed is kept relatively dry in these critical months, the yield is greater than in wetter areas. Soil tension reading accounted for >80% yield variability in Early Black and almost 70% in Stevens. The maximum yields were obtained at a tension greater than -6 cbars. The trend for Howes was less clear and more work is needed to validate this data. Our data corroborates findings of researchers in Quebec that optimum yield is obtained if cranberry beds are kept at about -6 cbars, with the optimal soil tension range for cranberry soils being between -3.5 and -8.0 cbars (Bonin, 2009), limited at the upper matric potential level by, presumably, aeration constraints and at the lower by low unsaturated hydraulic conductivity (Bonin, 2009). A decrease in yield in the low soil tension areas is likely due to a decrease in photosynthesis and production of buds (Caron et al., 2016), as well as the reduced oxygen reaching the root zone due to saturated soils (Bland et al., 1996).  

References

Bland, W.L., J.T. Loew, and J.M. Norman.1996. Evaporation from cranberry. Agric. For. Meteorol.81(1-2):1-12.

Bonin, S. (2009). Régie agroenvironnementale de l'irrigation en production de canneberges (Vaccinium macrocarpon Ait.). Québec, Québec, Canada: M.Sc. Thesis. Département des sols et de génie agroalimentaire, Université Laval.

Caron, J., S. Bonin, S. Pepin, L. Kummer, C. Vanderleest, and W.L. Bland. 2016. Determination of irrigation set points for cranberries from soil-and plant-based measurements. C. An. J. Soil Sci. 96(1):37-50.

Jeranyama, P., C. DeMoranville and C. Kennedy. 2017. Evaluating tensiometers and moisture sensors for cranberry irrigation. Acta Horticultarae. 1180:369-372.

Kennedy, C.D., P. Jeranyama and N. Alverson. 2016. Agricultural water requirements for commercial production of cranberries. Canadian Journal of Soil Science, 97(1):38-45

Olszewski F., P. Jeranyama, C. Kennedy and C. DeMoranville. 2017. Automated cycled sprinkler irrigation for spring frost protection of cranberries. Agricultural Water Management 189:19-26.

Prepared by Leela S. Uppala, H.A. Sandler, and A.L. Averill

Late Water (LW) is a one-month spring flooding practice (applied from mid-April to mid-May) before the plants have lost dormancy/before bud break, typically recommended once in 3 years. Several benefits of LW are documented, such as protection of plants from spring frost damage, reduction of fruit rot, some insects (cranberry fruitworm and scale), weeds (dewberries also known as brambles), enhancement of fruit quality and improvement of the keeping quality. LW also synchronizes bloom, producing fewer flowers per upright with a larger percentage setting fruit than their unflooded counterparts. Through bloom synchronization, LW helps to improve the efficacy of fruit rot control measures. Newly set berries grow to a more uniform size than fruit on unflooded controls. Due to these factors, LW beds can yield as well as beds not receiving LW. LW also reduces the pesticide and nitrogen requirement significantly for the year of LW.

FLOOD MANAGEMENT

When to use LW

It has been our long-time recommendation that LW should be used no more than one year in three. However, many organic growers and others trying to reduce costs have, in recent years, been using LW in successive years, the impact of which on the crop is not well documented. The most important factors in deciding to use LW in any given year are a thorough evaluation of the vine appearance and a review of factors that can lead to negative LW outcomes. If the vines are healthy and if the previous summer was very sunny and none of the adverse weather conditions listed below are present, the use of LW should be considered for its benefits in insect, mite, disease, and weed control (see below). Growers could also consider the preliminary KQ forecast issued by the Cranberry Station in early April to aid in decision making regarding the use of LW.

When not to use LW

To minimize crop reduction, LW should not be used when the vines appear stressed after the winter flood is removed. Bogs with poor quality water supplies may not be good candidates for LW. Beds that are severely out of grade may be poor candidates for LW. Any condition that leads to a reduction in the plant's carbohydrate reserves can lead to a poor LW outcome. Such conditions include a heavy crop, abnormally warm late fall, low previous year sunshine, oxygen deficiency, and winter temperature extremes. Do not use LW if the winter has been unusually cold or abnormally warm (particularly if the fall was also warm).

Do not use LW in the spring following a fall flood. 

Inspect the bog after withdrawing the winter flood - if stress, winterkill or leaf-drop are apparent, do not use LW. Do not use LW if the bog was sanded the previous fall or winter. However, barge sanding in the LW flood has been reported successful. Experience has shown that in some years (on average, 1 in 10 years) LW bogs may produce significantly (>10%) lowered yields. However, this low yield may be offset by reduced cost of fungicide/fertilizer inputs during the year of LW and higher yields in subsequent years. If the bog holds a flood well, costs in the LW year should also be less, particularly if inputs are reduced due to reduced pest pressure, helping to offset any losses. All factors that contribute to these occasional lower yields are not entirely understood but avoiding LW in the conditions listed above should provide some insurance against a large crop loss.

Timing of LW flood

The flood should be applied in the spring prior to the breaking of bud dormancy. The leaves will be beginning to lose their dormant red color but the flower buds should still be red and tight. Historically, the 30-day LW flood will be initiated between April 10th and 15th. However, recent changes in climate have shifted bud development to be earlier in some areas. If temperatures in late March - early April are warm (5°F per day above normal) or the season is early due to warm winter temperatures, the flood may be applied earlier (up to one week). Do not apply the LW flood if the buds have broken dormancy. We recommend putting sprinkler heads in place prior to the flood. This ensures that you will be ready if a frost night occurs immediately after flood removal and facilitates the addition of algaecides if necessary.
 

Note: Choose actual application timing based on weather and bud dormancy, and hold for approximately 30 days.

Depth and temperature of LW flood

The flood depth should be maintained so that all vines are well covered by water. Shallow floods and/or flood temperatures consistently greater than 65°F (measured in the early morning) should be avoided to prevent injury and crop reduction. Flood water temperatures will generally be cooler if the flood is deep (> 12 inches above the vines). If temperatures are approaching 65°F, recirculation of the flood water may prevent having to abort the flood prior to 4 weeks. However, keeping the flood too cool using this technique may reduce efficacy in the suppression of cranberry fruitworm (see the insect section on the next page for more information).

Prevention and treatment of scum

Algae (scum) often forms in LW floods. Water temperature is a major factor in the development of scum; shallow floods and inland (warmer) locations may be more prone to this problem. If scum is severe, early withdrawal of the flood may be necessary. If heavy scum is present after the flood, it should be broken up mechanically so that light can reach the vines. Even so, crop reduction may occur when scum is severe. Barley straw may be used to clear the water; research indicates its efficacy can be variable, working well in many situations but failing in others.

A Special Local Needs (SLN or 24c) label is available for the use of Cutrine-Plus for the management of algae in LW flood for Massachusetts. Cutrine-Plus is a liquid copper-based formulation that is used to control a broad range of algae. If you have had scum problems in prior LW years, plan to treat 2 weeks into the flood period. Scout for algae and apply when growth is first visible on the water surface. Applications only prevent further growth (it does not eliminate existing algae), so prompt treatment is critical.

Cutrine-Plus is injected into the sprinkler system running at 20 psi (30-minute injection; you may continue running for 1-2 hours after injection to disperse the material). Rates are calculated using label information and the number of acre-feet to be treated. To calculate acre-feet, multiply the number of acres by the depth of the flood in feet. Multiply the desired rate (gallons per acre-feet based on the chart from the pesticide label) by the acre-feet of water (calculated as above) for the bed being treated.

Draining

Release the flood slowly over the top board to protect water resources. The date of flood removal will vary with location and date of flood initiation. If air temperatures are unseasonably warm and flood water temperature becomes too high, the LW flood may need to be removed prior to 30 days. If the flood is removed early, pest management benefits may be affected (see insect management, next page).

MANAGEMENT AFTER LATE WATER

Irrigation

There should be no need to irrigate (unless protecting for frost) for at least 2 weeks after the LW flood is withdrawn. However, we recommend that you schedule irrigation based on soil moisture status. Moisture sensors and tensiometers should be re-deployed soon after the flood is removed.

Frost protection

After removal of the LW flood, cranberry buds are sensitive to frost injury. During LW, the appearance of the terminal bud is arrested at the spring dormant stage. However, internal changes in the bud lead to a loss of frost tolerance despite appearances.  

When using LW, frost management should be based on the actual duration of the flood, rather than relying on the appearance of the buds. After more than one week of LW flooding, the appearance of the buds will not be an accurate predictor of tolerance. A 1-week LW flood has no impact on frost tolerance -- protect the buds based on appearance. After LW of longer than 1-week, protect the bogs for 27°F (flood duration = 2 weeks) or 30°F (any duration longer than 2 weeks) regardless of how buds look.

Fertilizer use

LW bogs respond readily to fertilizer: N dose should be reduced to avoid overgrowth. A 30-40% reduction of N can be achieved by eliminating the spring application and/or reducing the fruit set dose. Further reductions may have an impact on bud development for the following year. Remember, fertilizer applied in the current season has the greatest impact on the following season's crop. The best tactic for a LW bog is to add no fertilizer for at least 2 weeks after flood withdrawal and then add small amounts with close monitoring of response. Generally, no fertilizer should be needed until bloom. Time your applications by the plant’s development. This is especially crucial when development has been temporally shifted by the use of LW. If the LW flood was terminated early (3 weeks or less), standard fertilizer regimens may be followed.

Disease management

LW can be an excellent cultural control strategy against fruit rot.

• Fresh fruit Howes and all processed fruit bogs in the year of the LW flood - Use reduced rates (never use less than the recommended rate listed on the fungicide label) and number of applications of fungicides. Fungicide application intervals may be extended to every 10 or 14 days depending on bloom. Fungicides may be eliminated on processed-fruit beds if the final keeping quality is forecast to be good. If one application is to be made, apply at 50% bloom. If two fungicide applications are made, apply the first at 10% bloom and the second two weeks later. Reduced fungicide rates should be employed, especially for Howes, which has greater resistance to rot. Scientific literature focusing on the effects of LW in the newer cultivars/hybrids is limited.
• First year after LW has been held - Fungicide applications and rates can still be reduced without sacrificing fruit quality.
• Second year after LW has been held - Fungicide applications and rates should be increased to a normal schedule. Otherwise, fungal inoculum will increase and may cause significant field and storage rot losses.
• New Plantings - LW held in a newly planted (one- or two-year-old) bog will help reduce inoculum buildup, as well as helping the vines spread over the surface of the soil. Thus, LW contributes to minimizing rot during the initial two crop seasons. LW may also slow down weeds on new bogs (see next page).

Insect and mite management

Many insects are affected by LW. Emergence is delayed, and when a type of insect does appear, emergence is often synchronous, permitting better management. LW can be used to manage several pest insects:

• Early season insects - False armyworm and Spongy (Gypsy) moth may be suppressed.  Pre-bloom sprays are seldom needed but sweep net scouting should still be carried out. Spanworms (other than winter moth) have sometimes been found on LW bogs.  Winter moth hatches from late April into early May, so on-bog populations of this insect should be suppressed by LW.  BHF is not impacted by LW.
• Cranberry weevil - is not impacted by LW.

• Cranberry fruitworm - Cranberry fruitworms, which overwinter in the bog in hibernacula (cocoons), have been shown to be greatly reduced by LW, particularly when held for the full duration of 4 weeks. Mortality is higher when the flood is warm (approx. 60°F) and is significantly lower if the flood water is cool throughout the 4 weeks. Shorter duration (2.5-3 weeks) LW floods appear to have little effect on mortality in the hibernacula; populations are suppressed very little, compared to those on unflooded beds and significantly less than those on beds receiving a 4-week flood (see table below). A 4-week flood with water temperatures that rise to the 60°F level provides the best chance for fruitworm suppression. Therefore, growers should closely monitor flood temperature. While 60°F provides the best fruitworm suppression, greater than 65°F increases the potential for crop reduction. Monitoring for infestation is important (see the insect section for scouting practice after LW). Fruitworm sprays may be eliminated on LW bogs. Second and third sprays are seldom needed but scouting for eggs should continue as populations may move in from surrounding beds. 

  Effects of LW (Late Water) duration on cranberry fruitworm (CFW) mortality. Data is based on the failure of insects to emerge from hibernacula following a flood.

  Site	Flood Length	CFW Mortality
  		Flooded	No Flood
  1	2.5 weeks	50%	28%
  2	2.5 weeks	45%	13%
  3	2.5 weeks	40%	34%
  	4 weeks	98%	20%
  4	3 weeks	41%	37%
  	4 weeks	94%	71%

• Scale - LW suppresses scale.
• Sparganothis fruitworm  - is not controlled by LW but flight is synchronized, making management easier.
• Southern red mite - Mites can be severely impacted by holding LW. Intense infestations can be essentially eliminated in the year of LW.  The mites begin to increase in the second year following the flood, but even then, may stay much below the original infestation level prior to the flood. Generally, LW affords 2 years of control for this pest.

Weed management

While LW may delay weed development and suppress the growth of some perennial weeds, this technique alone does not result in control of most established weeds. LW does not control dodder.

• Dewberries (running bramble) - Some success in retarding the growth of dewberries by holding LW has been shown. Fall flooding also suppresses dewberries. However, severe crop loss resulted when LW was used in the spring following a fall flood. Do NOT combine these practices. Sawbrier (Smilax glauca) was less affected. LW suppression of dewberries should be followed up with other controls such as hand-wiping, clipping, flame cultivation or glyphosate. Dodder (seeds or seedlings) are not known to be controlled by LW.
• Herbicide use:
  • Do not apply preemergence herbicides prior to a Late Water (LW) flood.
  • Casoron may be applied after the LW flood is withdrawn for the control of dodder. Apply herbicide as soon as possible after the withdrawal of the flood (ensuring vines are dry and the soil has drained).

  • Use caution if considering the application of other preemergence herbicides after the flood is withdrawn.

    • Evital use should be avoided.
    • Sulfentrazone (Zeus/Spartan) can cause stress to cranberry plants; adding this after the stress of late water increases the risk of injury and is not recommended.
    • Herbicides such as napropamide (Devrinol) and mesotrione (Callisto) are likely safe after the soil has drained, though research evidence is limited.

    Recommendation: If the bed shows signs of stress (high temperatures, excessive leaf drop, etc.), avoid preemergence herbicides. Contact the Station with questions.

  • POST herbicides can be applied when weeds have emerged, according to the label.

Bees

Bees for pollination may be more important on LW beds due to the fact that the period of flowering is of shorter duration than that for early water bogs. Protect bees from pesticide exposure.

Prepared by Peter Jeranyama and Carolyn J. DeMoranville

Cranberry vines may be injured or killed by severe winter weather.  The most common injury is classified as a ‘physiological drought’ when moisture lost from the vines due to wind and evaporation cannot be replaced due to freezing in the root zone. That injury is known as 'winterkill'.  The symptoms are leaf discoloration and eventual drop.  Such injury can occur within 3 days if the root zone is frozen to a depth of 4 inches, air temperature is below freezing, and strong winds (10 mph or greater) occur.  Injury is prevented by a winter flood that should be in place when winterkill conditions exist.  It is likely that 2-3 days with temperatures below 20°F will be enough to freeze the soil.  New plantings (first year) are less susceptible to winterkill but should still be protected in severe conditions.

If crop elimination by mowing or flooding is planned for the following season, the winter flood may be eliminated.

General winter flood management

The winter flood may be applied as early as December 1 and should remain on the bog as long as winterkill conditions are present or forecast. The flood may be delayed if winterkill conditions are not forecast if the plants are dormant. Exposure to moderately cold temperatures will encourage deeper dormancy leading to lower oxygen and carbohydrate demand and greater cold tolerance. However, an early cold snap following a warm fall could lead to actual cold injury in the plants (like frost injury). Under such conditions, the winter flood should be in place even before winterkill conditions are reached.  Generally, the flood should not need to be held any later than March 15. However, holding the flood for a few days past that date will not harm the bog.

To be effective, the flood should cover the plants entirely (no vine tips sticking out). It is particularly important to maintain a sufficiently deep flood on new plantings to prevent heaving of the plants during freeze/thaw cycles during the winter.

Cold acclimation which occurs in the fall is a gradual process that enables plants to survive increasingly lower temperatures until they reach maximum hardiness. The process is genetically controlled and varies among cultivars in the Vaccinium genus (Rowland et al., 2013). In cranberry, floral buds for the following year are initiated in the summer, continue to develop into the fall, and must become cold hardy to survive the winter. Although frost protection of the buds in the spring is routinely required and practiced in commercial cranberry production, limited knowledge regarding the progression of cold acclimation in the fall raises questions regarding the need to implement bud frost protection in the fall.

For bogs that cannot maintain a winter flood

On bogs that cannot maintain a winter flood, additional winter protection may be gained by the application of an antitranspirant. These waxy or resin-based materials reduce the amount of water loss from the leaves by providing an additional physical layer on the leaf surface. Research with Vapor Gard has shown that one application, made prior to the onset of winterkill conditions, may offer some protection against winter injury. Vapor Gard should be applied at the rate of 1 gal/A. Since the material becomes quite thick at low temperatures, application is best when done at temperatures above 45°F (above 50°F is much preferable). It may be combined with hot water to facilitate mixing.  It can be applied through the irrigation system, by boom sprayer or tank spray apparatus. Vapor Gard needs at least 1 hour of sunny conditions after application to ensure proper set of the material on the leaf surface. Vapor Gard will persist on the plant for several months, so application should be planned for the fall (November typically has favorable conditions). Other products such as Wilt-Pruf or Moisturin are available, but we do not have much experience with these.

Oxygen deficiency injury

Historic research by Bergman indicated that a lack of dissolved oxygen in the winter flood water was the cause of injury to cranberry plants, resulting in leaf drop and reduced yield potential. Plants, like animals, use oxygen in respiration so lack of oxygen could lead to plant injury. Bergman stated that oxygen deficiency injury may occur when oxygen levels in the winter flood water drop below 4 mg/l (full oxygenation = 10+ mg/l). Bergman further stated that lack of light penetration led to poor photosynthesis, and it was the lack of photosynthesis that led to poor oxygenation in the water. The recommended remedy was to remove water from under the iced-over flood if light penetration was poor.  

Removal of water from beneath the ice is standard practice in WI and in cold conditions in MA. In WI, the removal of remaining water is done as soon as a thick ice layer forms on the surface. Air then penetrates along edges and through cracks in the ice so that the vines are exposed to atmospheric oxygen. If the flood remains unfrozen as is often the case in MA and NJ, oxygen readily mixes into the water from the surrounding air with the possible exception of very deep (3+ feet) areas in out-of-grade bogs. If plants are encased in ice for a prolonged period, they may be smothered by metabolic byproducts [e.g., CO2, ethanol (C2H5OH), and methanol (CH3OH)] or injured when exposed to cold air due to the relatively low insulation value of ice (Durling et al., 1995). In contrast, snow can be highly beneficial to overwintering crops such as cranberry, providing effective insulation from extreme cold conditions and fluctuating temperatures (Leep, et al., 2001). The insulating properties of snow are generally the result of trapped air (low thermal matrix and the high reflectance of incident radiation on a snow-covered surface; these two factors in turn depend on the depth of the snow, its age, and its density (McComb, et al. 1992).

Research in both MA and WI has caused us to re-examine Bergman's theories and recommendations.  Research by Justine Vanden Heuvel and Teryl Roper showed that cranberries require very little light for photosynthesis and the light that penetrates snow or sand may be sufficient for this purpose. Further, in a bog with a full layer of water beneath ice, even with 9 inches of snow on the ice, oxygen in the water beneath remained at 8 mg/l or greater. In WI, covering ice with black cloth, sand, or snow did not lead to leaf drop or crop reduction in the plants below the treatments. In MA, plants held flooded in darkness and low oxygen did not show reduced carbohydrate (the product of photosynthesis) or leaf drop.

So what is the cause of the leaf drop that is observed after the winter at certain bogs? Definitely, loss of leaves is a sign of some sort of stress on the plants. It is unlikely that lack of light is the cause. Lack of oxygen remains a possibility if the levels actually become severely depleted. A likely scenario for this would be pulling the water from beneath the ice and leaving a shallow layer of water in low spots. The smaller volume of water could become oxygen depleted where a large volume had not.  

As wetland plants, cranberries can survive periods of poor oxygenation during flooded conditions. In particular, the plants can tolerate low oxygen levels in saturated soil. However, survival under these conditions requires using up carbohydrate (food) reserves.  Plants with poor carbohydrate reserves due to large crops, poor sunshine the previous fall, or other stresses may have less ability to tolerate low oxygen stress and may show injury the next spring. In those cases, failure to prevent oxygen deficiency can result in leaf drop, inability of blossoms to set fruit, and crop reduction.  

Certainly, any risk associated with using a winter flood is far outweighed by the benefit of protection from winterkill injury.

To assure that leaf drop potential is minimized:

• Remove the water from beneath a frozen flood as soon as is practical – this also minimizes mobilization of soil phosphorus into the flood water due to soil anoxia.
• If water is being held beneath ice, monitor oxygen levels in the underlying flood. Do not allow water with <3 mg/l oxygen to remain beneath the ice. Consider pulling water at a reading of 5 mg/l on a standard color kit.
• Try to avoid shallow layers of water beneath ice; they may lose oxygen more readily than deeper layers of water.
• If you pull the water from beneath the ice -- make sure that you leave no puddles behind. Vines trapped in these puddles under the ice are particularly susceptible to leaf drop in the spring.
• Manage plantings during the season so that stress is minimized, particularly through proper irrigation.

Management after a mid-winter thaw

Once the water has been removed from beneath the ice, the remaining ice may melt during a mid-winter thaw, leaving the vines exposed. Bogs may be left exposed if winterkill conditions are not present (see above). However, long exposures to abnormally warm temperatures (>55°F) may lead to loss of chilling. The result could be a reduction in hardiness and greater susceptibility to spring frost. Depending on the conditions prior to the winter flood, loss of chilling during a mid-winter thaw could also lead to reduction in bud break and flowering the following season. This is especially true if the previous fall was warmer than usual, leading to lack of chilling accumulation. To guard against these possibilities, reflood the bog if a long warm spell is forecast during mid-winter. The water will cool at night and re-warm slowly during the day, buffering against the warm daytime temperatures. Environmental factors may have a profound effect on the susceptibility of buds to winter injury. Cranberry buds can be injured due to repeated freezing and thawing.

Management after the winter flood

Once the flood has been removed, the cranberry buds will break dormancy in response to exposure to warm temperatures. The earlier the flood is removed, the sooner the plants will experience enough heat units to break dormancy. To avoid the need for frost protection during the first half of April, hold the winter flood until March 10-15. In the early spring, cranberry buds will survive exposure to at least 18ºF.  As the buds lose their dormant color and begin to expand, they must be protected from frost damage. The tolerance varies by variety and growth stage.  Refer to the "Frost protection guide for Massachusetts cranberry production", the Frost Management BMP, and Frost Tolerance Reports on the Station’s website for further information: 

References

Durling, J.C., O.B. Hesterman, and C.A. Rotz. 1995. Predicting first-cut alfalfa yields from preceeding winter weather. J. Prod. Agric.8:254–259.

Leep, R H., J.A. Andresen, and P. Jeranyama. 2001. Fall dormancy and snow depth effects on winterkill of alfalfa. Agronomy J. 93:1142-1148.

McComb, T.J.L., A.B. Rimmer, M.L.B. Rogers, K.E. Turver, and A.F. Vickers. 1992. A mathematical model for the prediction of temperature in a dry snow layer. Cold Reg. Sci. Technol. 20:247–259.

Rowland, L., E. Ogden, F. Takeda, D. Glenn, and M. Ehlenfeldt. 2013. Variation among highbush blueberry cultivars for frost tolerance of open flowers. Hortscience 48:692-695.

Prepared by Martha M. Sylvia

The Massachusetts Department of Agricultural Resources (MDAR) is charged with maintaining clean groundwater.  To this end, they have issued Groundwater Protection Regulations.  These Regulations are intended to prevent contamination of public drinking water supply wells through regulating the application of pesticide products on the Groundwater Protection List within primary recharge areas. A primary recharge area is either an “Interim Wellhead Protection Area (IWPA)” or a “Zone II”.  In this publication, we refer to all primary recharge areas including IWPAs as Zone IIs.  The Zone IIs are updated yearly.  The pesticide groundwater protection regulations ONLY apply to public drinking water wells that pump greater than 100,000 gallons of water per day (gpd).

Some products registered for use on cranberry (listed below) have the potential to leach through the soil and as a result have been placed on the Groundwater Protection List.  If your bog is in a Zone II, you should review the particulars for each compound to determine if you can use it in your situation.  If you are able to use a compound, you must follow these rules:

• MDAR notification within 10 days of the end of the month for each application. You may use one form to report multiple applications that occurred in the same month. Forms are available at the Cranberry Station, CCCGA, points of purchase, or online: www.mass.gov/forms/groundwater-protection-program-notification-form

  Note: This reporting form must be filed in addition to the Pesticide Applicator Form that reports annual use to the state.

• Confirmation of 50% foliar cover. Assume an established working bog has at least 50% foliar cover but a new planting likely does not.
• An approved IPM program (use of Cranberry Chart Book) and an acreage-specific IPM plan.
• A support letter from UMass Extension and/or a copy of this Chart Book showing you have confirmed that your conditions allow the application.
• Proper documentation showing failure of alternatives. Generally, IPM records will suffice.

Guidelines provided by Massachusetts Department of Agricultural Resources (MDAR)

Greater detail is provided on the MDAR website or from the Cape Cod Cranberry Growers’ Association website under “Grower Advisories”.

Are you applying a product that is listed on the Groundwater Protection List within a regulated primary recharge area?

The pesticide groundwater protection regulations ONLY apply to public drinking water wells that pump greater than 100,000 gallons of water per day (gpd). The primary recharge area is designated as a Zone II or an Interim Wellhead Protection Area (IWPA) by the Massachusetts Department of Environmental Protection (DEP). Listed below are several ways to establish if you are in a regulated primary recharge area.

Determining the location of a Regulated Primary Recharge Area - Zone II or IWPA

To determine if the application site falls within a Zone II or IWPA, you can use the following options:

• Internet Option: Visit the Mass GIS system MassMapper at https://maps.massgis.digital.mass.gov/MassMapper/MassMapper.html. After advancing into your bog area, on the right side of the page click on the plus sign next to “Regulated Areas”, then within that group “Wellhead Protection Area” and then click on “Zone IIs”. The Zone II areas will be highlighted in pink hatch.
• Other Options: Check with the DEP Southeast Regional Office: 508-946-2700.

Are you applying pesticides in an area that has less than a 50% foliar cover?

If your area of application is located within the primary recharge area, you must determine if you are applying to an area with less than or greater than 50% foliar ground cover.

Assume an established, harvestable bog has at least 50% foliar cover.

If your bog is a new planting or it has not vined in to at least 50% foliar cover, and you wish to apply a pesticide listed on the groundwater protection list within a Zone II or IWPA, then the applicator must submit a Pesticide Management Plan (PMP) to MDAR for that use pattern and have it approved prior to the application. If this is the case, contact CCCGA or MDAR to develop this plan.

What is an Integrated Pest Management Program?

Pesticides on the groundwater list must be applied as part of an Integrated Pest Management (IPM) program from an MDAR approved source. These include:

• Use of the current "Cranberry Chart Book" published by the UMass Cranberry Station.
• UMass Extension generated fact sheets that outline IPM practices specific to the pest problem.
• IPM Programs specifically developed to meet the requirements of the Groundwater Protection Regulations.

The Department does not require the submission of IPM plans for approval. Instead, the applicator should maintain a copy of their IPM program in their records. The plan should be specific to the pest problem requiring management with the Zone II chemical and include:

• The name of the applicator.
• The location (Zone II and property) and dates of the application.
• A problem statement that outlines the reason for using the pesticide product on the Groundwater Protection List.
• An account of the method used by the applicator to identify the problem. Any laboratory diagnosis of the pest problem must also be maintained.
• An account of the IPM measures that have been taken to manage the problem.
• A letter or statement from the appropriate UMass Cranberry Station personnel stating that there is no viable alternative to the use of the product on the Groundwater Protection List to control the particular pest problem.

CONDITIONS TO ALLOW APPLICATION OF COMPOUND

Chlorothalonil - Bravo, Chlorothalonil, Echo, Equus, Initiate

If your cranberry bog is located in Zone II and you wish to apply a chlorothalonil product, you must consider the following conditions and select the most appropriate scenario that applies to your situation:

• If you have traditionally had good fruit quality (less than 3% rot at delivery): You should use any of the fungicides that do not have chlorothalonil as the active ingredient. It is advisable to keep records of fungicide performance to provide evidence if you need to use chlorothalonil in the future.
• If you have previously used non-chlorothalonil fungicides and can show they performed poorly or failed: You can use the chlorothalonil fungicides because you have no other viable option. Documentation (scouting reports, IPM notes, delivery records with >3% rot) is required.
• If you have previously used non-chlorothalonil fungicides and can NOT show failure: You must continue to use non-chlorothalonil fungicides. You cannot use chlorothalonil products until you can document that alternatives do not work.
• Significant upright dieback: If significant dieback occurred during the previous growing season and a pre-bloom application is warranted, Champ can be used instead of chlorothalonil. If Champ does not provide adequate control, a chlorothalonil fungicide can be used in the subsequent season.

General Information

Chlorothalonil fungicides are considered a necessary component of an integrated approach to control fruit rot. Field testing in MA has proven they are the best registered fungicides for fruit rot and upright dieback control. Their sticking agents help the fungicide adhere to tissue, resisting degradation by sunlight and washoff by rainfall. They are especially critical for fresh fruit production where high quality is required for storage.

Prepared by Martha M. Sylvia and Katherine M. Ghantous

Always check the specific label of the product you are applying for adjuvant requirements and recommendations.  In general, adjuvant rates are based on the volume of water used for application or on an amount per acre, and are not related to the rate of pesticide being used.  Depending on the type of adjuvant, they can help pesticides be more effective by giving better coverage, better penetration, or better adhesion. Some products suggest using an adjuvant to improve efficacy, while others may not work at all without an adjuvant included! Contact UMass Extension and/or your Ag Supplier for further guidance on which products to use for your particular situation.

FUNGICIDES

• Abound: Adjuvants may be added.
  • Do not use adjuvants that contain silicone (aka organosilicone).
• Chlorothalonil: Bravo already has Spreader-Sticker in it! Using extra could cause more run-off, reduce retention, and cause injury. The other formulations generally also have an adjuvant added.
• Indar: Adjuvants may be added.
  • Do not use penetrants.
  • For NIS, 0.25% v:v (or 1 pt/A if chemigating) is sufficient.
  • For organosilicones, a spray mix concentration of 0.05% v:v (or approx. 1.5 pt/A if chemigating) or less is sufficient.
• Indar + Abound Mixtures: Adjuvants may be added.
  • Do not use adjuvants that contain silicone (aka organosilicone).
• Mancozeb products: Adjuvants may be added.
  • Use a spreader-sticker to improve deposition / durability.
• Proline: It is recommended to use a non-ionic surfactant (NIS) at the “lowest recommended rate” for the adjuvant product. For most NIS products, 1 pt/A is typically the lowest rate. Check your product label for details.
• QuadrisTop: Adjuvants may be added.
  • Do not use high rates of silicone/organosilicone-based or oil containing adjuvants at high temperatures.
  • Do not exceed 0.125% v:v adjuvant (4 pt/A if chemigating).

INSECTICIDES 

Adjuvants are recommended with

• Intrepid, Confirm, and DiPel
  • A spray adjuvant should be used.
  • Improves: deposition, redistribution, and weatherability.
• Delegate, Altacor, and Avaunt
  • Recommended to improved performance due to cranberry’s dense canopy and waxy leaves.

HERBICIDES

In general, adjuvants are not needed for PREemergence (soil-active) herbicide applications, and adjuvants are recommended or required for use with POSTemergence herbicide applications.

COC = crop oil concentrate, NIS = Nonionic surfactant

• Callisto (mesotrione)
  • Chemigation postemergence: 1 – 4 pt/A NIS or COC
  • Spot-treatments postemergence:
    • NIS (0.25% finished spray volume) = 2 tsp or 0.3 oz/gal
    • COC (1% finished spray volume) = 2.5 Tbsp or 1.3 oz/gal
• QuinStar (quinclorac): Chemigating postemergence
  • 2 pt/A COC
• Poast (sethoxydim): (grass herbicides don’t have and preemergence activity) 
  It is highly recommended to use an adjuvant with grass herbicides.
  • Boom or aerial applications: 2 pt/A COC
  • Spot-treatment COC (1% finished spray volume) = 1.3 oz or 2.5 Tbsp/gal
• **Intensity One (clethodim) is the ONLY grass herbicide that has 24C for chemigation! 
  It is highly recommended to use an adjuvant.  If not included, you will have poor efficacy!
  Chemigation postemergence: 1 – 4 pt/A NIS

• Select Max, Intensity, and others (clethodim) – NOT for chemigation

  It is highly recommended to use an adjuvant with grass herbicides!

  • SelectMax and Intensity One:
    Spot-treatment/Boom/Mist blower/Aerial, etc. postemergence: NIS at 0.25% v:v
  • Intensity:
    Spot-treatment/Boom/Mist blower/Aerial, etc

Prepared by Hilary A. Sandler

Liquid Measures

1 oz = 2 tablespoons = 6 teaspoons = 29.6 ml
1 cup = 8 oz        
1 pint = 2 cups = 16 oz        
1 quart = 2 pints = 4 cups = 32 oz        
1 gallon = 4 quarts = 8 pints = 16 cups = 128 oz    
1 cup = 237 ml        
1 pint = 473 ml = 0.473 liters            
1 quart = 946 ml = 0.946 liters 
1 gallon = 3.78 liters = 3,785 ml    
1 acre-foot water = 326,000 gallons        
0.1 inch water per acre = 2717 gallons
1 fl. oz/gal = 7.81 ml/liter        

Mass Conversions

1 oz = 28.4 grams        
1 lb = 454 g = 0.454 kg        
1 kg = 2.2 lb = 35.2 oz
1 oz/gal = 7.49 g/liter

Temperature Conversions

°F = (9/5 °C) + 32 (guesstimate: double °C, add 30)    
°C = 5/9 (°F-32) (guesstimate: subtract 30 and halve)

Length and Area Conversions

1 acre = 43,560 sq. ft = 0.405 hectares
1 hectare = 2.47 acres
1 meter = 1.09 yards = 3.28 feet = 39.4 inches
1 yard = 3 feet = 36 inches = 0.914 meters
1 cm = 0.39 inches
1 inch = 2.54 cm
1 rod = 16.5 ft
1 sq. rod = 272.2 ft2
1 square meter = 10.76 ft2
1 cubic meter = 35.29 cubic feet = 1.30 cubic yards
1 inch layer of sand per acre = 134 cubic yards

Other Conversions

pt/A * 0.473 = liters/A
pt/A * 1.167 = liters/ha
lb/A * 0.454 = kg/A
lb/A * 1.12 = kg/ha
gal/A * 3.78 = liter/A
gal/A * 9.35 = liter/ha
ton/A * 2,242 = kg/ha
bbl/A * 0.112 = Mg/ha
g/ft2 * 0.958= bbl/A
1 fl. oz/A *73.1 = ml/ha

Prepared by Hilary A. Sandler

Read and follow the pesticide label; it contains information concerning directions for use, application site and rate, storage and disposal, active ingredients, protective equipment needs, etc. Pesticides should always be stored in their original containers, according to label requirements, with the label intact.

Avoid carry-over of pesticides; buy only what you will need for the current season.  In selecting an area for storing/handling pesticides, human and environmental safety should be foremost considerations. In particular, the area should be evaluated for potential risks to human health due to accidental spills, fires or contamination of drinking water supplies. Pesticides should not be stored over soil that is coarse or sandy or over surfaces that drain easily such as gravel because the pesticide can then easily move through the soil into the ground water.

A well-designed storage facility has four components: 1) a storage cabinet, room or building, 2) a mixing area,  3) an area for loading and rinsing spray equipment, and 4) a place to store and secure equipment and records.  Depending on the size of your operation, you should have the appropriately sized storage facility.  It should be large enough to accommodate new chemicals, opened containers, and unused material awaiting disposal but small enough to discourage significant carry-over from year to year.  A pesticide storage facility should be on the ground floor with direct access to the outside. The storage area should be locked at all times and legibly and prominently identified as a place of pesticide storage. The area should be well ventilated either by windows or a fan to avoid the build-up of fumes.

Pesticides and fertilizers should be stored separately. Pesticides should be separated by type (insecticides, herbicides, fungicides) to avoid cross contamination and possible accidental misuse.  Flammable and non-flammable pesticides should be stored in separate areas. Pesticides should never be stored alongside food, feed or seed. Pesticides in containers that can be damaged by moisture should be kept off the floor.

Dry pesticides (e.g., granular, powder) should be stored in a cool, dry place.  Liquid or emulsified products may have restricted temperature ranges at which they should be stored.  CHECK THE LABEL!  In general, liquid or emulsified materials should not be stored at temperatures below 45°F or at temperatures that frequently exceed 100°F.  These pesticides may form crystals at the lower temperatures.  If crystals form, bring the pesticide into a warm place and gently agitate the pesticide container to re-dissolve the pesticide.  

Affix fire extinguishers on the outside and the inside of the building.  Be sure to inform your local Fire Department which buildings on your property are pesticide storage facilities. Post a list of materials outside of the building if possible and/or give a list to your local fire department so they know what is inside.

Disposal Resources. Some pesticides (but not all) are regulated as hazardous waste when disposed.  The Department of Transportation (DOT) regulates the transport of hazardous materials.  The Department of Environmental Protection (MassDEP) regulates and provides guidance on hazardous waste disposal.  Properly dispose of used containers.  Check with your local supplier for any available recycling programs.  For further information, contact Steve Antunes-Kenyon, MDAR Pesticide Program Operations Coordinator at (857) 278 8318 or Hotze Wijnja at (857) 972-4670.

For more information

MA Energy and Environmental Affairs, Pesticide Storage and Disposal
MassDEP 
Southeast office: 20 Riverside Drive, Lakeville, MA.  (508) 946-2700 (main office)

U.S. DOT
Hazardous Materials Information Center: 1-800-467-4922
Eastern Region Contact (Trenton, NJ): (609) 771-7890