2026 Final keeping quality forecast, news from the cranberry Pathology lab, news from the Physiology/Fruit Quality lab, news from the Weed/IPM and Entomology lab and Station news.
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2026 Final Keeping Quality Forecast (FKQF)
By Leela Uppala and Peter Jeranyama
The final forecast indicates VERY POOR keeping quality for the 2026 Massachusetts cranberry crop.
A total of 1 point out of a possible 16 points was obtained in the Keeping Quality Forecast assessment. Based on this score, the overall keeping quality forecast is classified as VERY POOR.
IMPLICATIONS
- Fruit rot risk is expected to be high without timely and effective disease management.
- Fruit quality may decline if fungicide programs are reduced or not implemented appropriately.
- Growers should exercise additional caution and take a conservative management approach, particularly:
- In beds intended for the fresh fruit market.
- In beds that received limited or no fungicide applications during the previous season.
- In beds with a history of high fruit rot incidence.
ADDITIONAL NOTES
- Carefully follow all fungicide label instructions, including application timing, rates, water-holding requirements, and pre-harvest intervals.
- Rotate fungicides with different modes of action to help manage fungicide resistance. FRAC (Fungicide Resistance Action Committee) codes listed on product labels can be used to identify fungicides with similar modes of action.
- Historically, above-average sunshine hours during June, July, and August—particularly in July—have been associated with better-than-predicted fruit quality and may partially offset some risk factors.
News from the Cranberry Pathology Lab
By Leela Uppala
CRANBERRY FRUIT ROT MANAGEMENT: TIMELY REMINDERSAs cranberry bloom progresses across Massachusetts, growers are entering the most critical period for fruit rot management. Decisions made during bloom and early fruit set can have a significant impact on fruit quality and fruit rot incidence at harvest. Here are several timely reminders, educational resources, and answers to common questions that may help inform fungicide application and disease management decisions this season.
Why bloom timing matters. Bloom through early fruit set is the most critical period for cranberry fruit rot management. Many fruit rot fungi infect flowers and young fruit long before symptoms become visible at harvest. Well-timed fungicide applications during this period provide the greatest opportunity to protect fruit quality and reduce fruit rot.
What are contact vs. translaminar fungicides?
Contact fungicides such as chlorothalonil (Bravo Weather Stik, Echo 720), mancozeb (ManzateMax, Dithane M-45), and copper products (Badge, Kocide 3000, Champ WG) remain on the plant surface and protect only tissues present at the time of application.
Translaminar (locally systemic) fungicides such as prothioconazole (Proline), fenbuconazole (Indar), azoxystrobin (Abound, Quadris), and difenoconazole (Quadris Top) penetrate plant tissues but are not extensively translocated throughout the plant. They generally provide strong preventive activity and may provide limited post-infection activity when applied shortly after infection.
What are broad spectrum vs. single-site fungicides?
Broad-spectrum (multi-site) fungicides such as chlorothalonil, mancozeb, and copper affect multiple biochemical processes within fungal cells, resulting in a lower risk of resistance development.
Single-site fungicides such as Proline, Indar, and Abound target a specific enzyme or metabolic pathway within the pathogen. These products generally provide strong disease control but have a greater risk of resistance development if used repeatedly.
In summary: Multi-site fungicides = broad-spectrum, lower resistance risk
Single-site fungicides = targeted activity, higher resistance risk
What is the Difference Between Protective and Limited Post-Infection Activity?
Protective (preventive) fungicides (chlorothalonil, mancozeb, copper fungicides) must be applied before infection occurs and prevent fungal establishment. Many fungicides used for cranberry fruit rot management provide limited post-infection activity (Proline, Indar, Abound, Quadris Top) but should not be considered truly curative. These fungicides provide strong preventive activity, may suppress fungal development shortly after infection occurs and may provide limited protection to developing tissues due to translaminar movement. These fungicides perform best when applied preventively as part of a well-timed fungicide program.
Copper Fungicides for Fruit Rot Management. Copper fungicides (FRAC M1) are broad-spectrum, multi-site protectants (Badge SC, Champ WG, Kocide 3000) that can serve as valuable rotational partners in cranberry fruit rot management programs. In our research trials, copper fungicides containing more than 20% metallic copper, when incorporated into a fungicide program, have consistently provided effective fruit rot suppression and ranked among the better-performing treatments in our fruit rot trials. Best timing to apply is late bloom through early fruit set.
Do Mancozeb (EBDC) fungicides affect cranberry color? Mancozeb is an important tool for fruit rot management. To maximize disease control while minimizing concerns about fruit color, I recommend applying Mancozeb during early to mid-bloom and avoiding unnecessary late-season applications.
Fungicide applications and rain events. Cranberry fungicides are often applied through chemigation using high water volumes (400–600 gallons per acre), which can increase drying time within the canopy.
General guidelines:
- Contact fungicides often require 12–24 hours before rainfall.
- Translaminar fungicides often require 4–6 hours before rainfall.
- Apply fungicides when no rainfall is expected for at least 24 hours whenever possible.
- A 48-hour rain-free period is even better.
These are general guidelines; actual time to be rainfast may vary among products, formulations, weather conditions, and application methods. Always consult the product label for specific information.
Does applying fruit rot fungicides after fruit set help? The benefit generally declines after bloom and early fruit set, when most fruit rot infections occur. However, applications slightly after fruit set may still be beneficial under prolonged favorable conditions for disease development, in bogs with a history of high fruit rot pressure, or when earlier applications were compromised by rainfall.
Contact fungicides protect only tissues present at the time of application and help prevent new infections. Flowers and fruit that develop after spraying receive little or no protection from contact fungicides. Translaminar fungicides may provide limited protection to developing tissues, but effectiveness depends on timing and product characteristics.
Bottom line: Fungicide applications during bloom and early fruit set provide the greatest benefit, while applications after fruit set may offer additional protection under high disease pressure.
KEY TAKE-HOME MESSAGES
- Many fruit rot infections occur during bloom and early fruit set, long before symptoms become visible at harvest.
- Thus, bloom through early fruit set remains the most critical period for fruit rot management.
- Rotate fungicides among FRAC groups to reduce the risk of fungicide resistance.
- Apply fungicides when at least 24 hours of dry weather is expected whenever possible.
- Copper fungicides may be useful as broad-spectrum protectants during late bloom and early fruit set.
- Protect pollinators by following bee-friendly pesticide application practices.
YOUTUBE EDUCATIONAL VIDEOS @DrLeelaUppala
Use the links below to watch timely and informative videos that may be helpful to you.
Cranberry Fruit Rot: Know Your Management Options
What is Critical Period of Infection for Cranberry Fruit Rot
How to Monitor Bloom for Cranberry Fruit Rot Spray?
When to Start Cranberry Fruit Rot Fungicides?
Should You Spray after Fruit Set?
Why is it important to Rotate Cranberry Fruit Rot Fungicides?
Do Mancozebs/EDBC’s impact Cranberry Color?
Coppers for Cranberry Fruit Rot?
How many fungicides should I Spray?
Questions? Please contact Leela Uppala (suppala[at]umass[dot]edu (suppala[at]umass[dot]edu) or 508-970-7644).
News from the Cranberry Physiology/Fruit Quality Lab
By Giverson Mupambi and Manu Priya
AGRIVOLTAICS RESEARCH UPDATE; PART 1 ECO-PHYSIOLOGICAL AND BIOCHEMICAL ATTRIBUTES
Agrivoltaics (also known as dual-use solar), the practice of installing solar panels directly over agricultural land that is active, offers a unique opportunity for dual land-use revenue.
However, because cranberries have evolved distinct growth habits and are managed as a continuous vine canopy, understanding how shading from solar panels affects the crop is crucial. We recently published a study evaluating the immediate "Year 1" impacts of agrivoltaics on a commercial 'Howes' cranberry bog. Solar panels were installed on steel poles 10 feet above the vine canopy in a North-to-South orientation. To study the effect of solar panel shading, we tested three row spacings corresponding to 30%, 35%, and 37% shading, along with an unshaded control area (Figure 1).
Results from the study show that moderate shading at 30% and 35% reduces environmental stress, as indicated by improved leaf water status and reduced electrolyte leakage. However, these treatments also suppress key physiological and metabolic processes, including photosynthesis, carbon storage, and the production of stress-related osmolytes and antioxidants (Figure 2). At 37% shading, these negative effects become even more pronounced, suggesting a threshold at which shading benefits are outweighed by reduced assimilate production and secondary metabolic activity.
This study highlights a balance between the benefits of stress reduction and the impacts on key physiological and metabolic processes in agrivoltaic systems. Optimizing row spacing is essential to minimize these trade-offs and preserve cranberry physiological health. We are currently processing the results on yield and fruit quality for publication and will share them when available.
For more about this research, you can read the following article: Impact of shading following installation of agrivoltaic systems on eco-physiological and biochemical attributes of ‘Howes’ cranberry in Massachusetts.
*This material is based upon work supported by the U.S. Department of Energy Office of Energy Efficiency and Renewable Energy (EERE) under the Solar Energy Technologies Office Award Number DE-EE0009374.
News from the Cranberry Weed/IPM and Entomology Labs
By Katie Ghantous and Marty Sylvia
Kerb use was approved as an Emergency Exemption for 2026 in MA (Section 18) for dodder control. This label expires on June 30, 2026. If you used or are planning to use Kerb, you must report the use to the MDAR. The Kerb Applicator Reporting Form 2026 can be found on our website under Special Labels.
Unfortunately, most poison ivy (PI) growing on cranberry bogs is not upright enough that it can be wiped with glyphosate. At this time, the best tool we have to suppress PI is with spot-treatment applications of concentrated Callisto. Our research shows that by mid-June, PI has invested stored resources on growing full-sized leaves, and this was an ideal time to knock it back with a spot-treatment of concentrated Callisto (see Chart Book or contact Katie for more details). It is most effective to treat twice in each year. The second application should occur several weeks later after the PI recovers from the first treatment and spends more resources on making new leaves. This tactic forces the PI to deplete resources that are stored in the roots, as well as prevents it from having a long growing season to store more resources and spread. If patches are large and well established, it may take multiple years to eradicate the PI.
The Special Local Needs (24c; SLN) that permits the use the concentrated solution for spot treatment is only available for Callisto; the other generic mesotrione products do NOT have this special labeling and cannot be used in this fashion. You are limited to two applications of mesotrione per year (whether that is made as a broadcast or spot treatment).
Review of grass control with herbicides. There are two herbicides active ingredients that are registered for grass control in cranberry. Sethoxydim (Poast) and clethodim (Select Max, Intensity, Intensity One, etc.) are both HRAC Group 1 herbicides and are similar to each other. These herbicides are most effective on actively growing grasses BEFORE they flower. These herbicides injure grasses by interfering with an enzyme that grass plants need to make cell membranes. They work best when the grass is in the process of adding new cells and increasing in size. So, while some grasses may remain green through the winter (like the center of a poverty grass tussock), which shows the grass is living, it is not in a state of active growth. Simply being green/alive is not a good indicator for when to use these herbicides. Target a time when the grass is increasing in size.
Grasses, sedges, and rushes can be hard to distinguish from one another. To make matters more confusing, the common names can be deceptive. What we call “Wool grass” is actually a sedge and not a grass at all! Clethodim and sethoxydim only work on true grasses, so while you don’t need to know the exact species you are trying to manage you do need to confirm that it is actually a grass. Looking at some key characteristics can help you differentiate the three types of plants.
- Sedges have edges. Their stems are triangular, especially at the base.
- Rushes are round. Their stems are not hollow. If you cut them, the centers usually look white and have pith (soft spongy tissue).
- Grasses have nodes/joints where the leaf sheaths attach, and stems are hollow.
Various grass species are at different growth stages now. Some have already flowered, while others are still not actively growing. If you missed the window and the grass you want to manage has already flowered, you might still get some control with an herbicide application, but it may not be very effective.
Intensity One is the ONLY grass herbicide that can be chemigated. Be sure to get a copy of the SLN (or 24c) label to make a legal application. The SLN also allows applications throughout hook and fruit set, but again, this is only for Intensity One. All the grass herbicides need adjuvant to work well, and all of the labels call for NIS or crop oil to be included. Read the label to determine the proper adjuvant for the product you are using. They have little to no soil activity and can only enter the plant through the leaves. Avoid run-off to keep as much material on the grass leaves as possible. ONLY Intensity One can be applied through the chemigation system (SLN label for MA).
BLOOM PROGRESSION TERMINOLOGY AND CALCULATIONS
Bloom progression is used to time fungicide (percent through-bloom), insecticide (percent out-of-bloom), and fertilizer applications (75% through-bloom aka “early set” and 75% out-of-bloom aka “late set”). People in different growing regions can use different terms to talk about the same phenology stages (or the same words to talk about different things), and this can cause confusion for both growers and researchers – especially when comparing recommendations across regions. Ocean Spray Ag Scientists Lindsay Wells-Hansen and Dave Jones have created and published an informative guide to Bloom and Fruit Set Terminology and Calculations for Cranberry Production and Research.
SCALE PROBLEMS
Unfortunately, as of 6/12/26, it is still too early to spray for scale! In the infested sites where we see the big females, they have just started to produce eggs, so crawlers will be another week away. The scale are not vulnerable to insecticides until the crawlers are released. Hold off on sprays until that time. This continues to put us in a very hard place regarding timing and bees.
Many growers believe they have scale problems, but unless you see orange colored dieback and evidence of scale on the uprights, there is NOT active feeding or an active infestation. Not all dead spots are scale. Not all dead spots from scale are active and need management. If there is no orange dieback area, or tiny orange blob under the covers (the females), then it is likely NOT scale. Do not consider treating unless you can confirm you have an ACTIVE scale issue. You can bring a sample to the Station for help assessing the problem areas. Ask for Marty or Krystal to check your sample!
Start by searching for weak, red, or dead circles or swaths of vines in spring, and determine if it is not caused by low spots, Phytophthora root rot, or drought. Do not sample upright where the scales have died on vines that are dried up or dead. Carefully check for live scales on vines with some green leaves that are on the edge of the dying vine area. Collect 10-20 uprights (all the way down to the duff layer) that can be examined under the scope to see if there are viable females that warrant treatment.
Remember, late water in the spring is an excellent option to slow down populations.
SOME GENERAL OBSERVATIONS
Some growers have been seeing unusual vine development. There seem to be more and more reports of “unhappy Stevens”. The cause is unclear! There is a lot of speculation about various contributing factors. Winter injury the previous year caused some people to back off fertilizer in 2025 and may have left their plants a little hungry or perhaps should have backed off and ended up over-fertilizing vines that had low production. Our region has been in a drought for multiple years which can compound with other environmental stressors. One grower felt that the heavy snow cover and lack of light could have negatively impacted the plants. We have a had a cold spring with many frost nights, and Stevens notoriously hate “wet feet”. Many possibilities! Please let us know what you are seeing out there.
Station News
INTRODUCING DR. LUIS MARQUEZ, DIRECTOR OF THE UMASS CRANBERRY STATION
Please help us welcome Dr. Luis Marquez to the Cranberry Station! Luis brings 20+ of experience in both academia and agricultural biotech and has strong ties to Massachusetts. As Lynne McLandsborough stated, “What stands out most about Dr. Marquez is his ability to connect cutting-edge research with real-world needs of agriculture communities. His collaborative and extension-oriented approach, combined with strong ties to the regional innovation ecosystem, positions the Cranberry Station to strengthen partnerships while remaining grounded in its core mission of supporting Massachusetts growers.”
We are looking forward to working with Luis and his vision for the Cranberry Station.
You can reach Luis at luismarquez[at]umass[dot]edu (luismarquez[at]umass[dot]edu) or 814-769-6136.
AND THE AWARD GOES TO MARTY SYLVIA!
The annual CNS Outstanding Achievement Awards recognize colleagues for excellence, and honor members of the community whose work has contributed to the success of their department and the University. This year Marty Sylvia, who has worked as an entomologist and Extension Educator at the Cranberry Station for nearly four decades was recognized with an Outreach and Engagement Award. Congratulations to Marty, on your strong contributions to the Cranberry Station, CAFE and your work areas. We are proud to have you as a colleague.
BOGSIDE WORKSHOPS
Mark your calendars! The Cranberry Station has 3 Bogside Workshops scheduled, 2 in June and 1 in July. Join us bogside (weather permitting) at the Cranberry Station, 1 State Bog Road, East Wareham. Please see details below.
Thursday, June 18, 2026 (1 credit) Free
8:00-9:00 AM
Bloom count calculations for timing applications of fertilizer, fungicides, and insecticides.
Thursday, June 25, 2026 (1 credit) Free
8:00-9:00 AM
Backpack sprayer calibration for spot treatment sprays.
Thursday, July 2, 2026 (1 credit) Free
8:00-9:00 AM
Weed ID (Bring in your weeds)
For more information contact Krystal DeMoranville krystald[at]umass[dot]edu (krystald[at]umass[dot]edu) or 508-542-2605.
REMINDER! WEEKLY IPM MESSAGE
Regular IPM messages are sent out on Fridays. You can receive the weekly message by email, checking our website (right hand side of page “Quick Links”, IPM Message) or by calling 617-928-4000 to listen to our recorded message. If you would like to receive the IPM message, please contact Robyn Hardy rmhardy[at]umass[dot]edu (rmhardy[at]umass[dot]edu) or 508-970-7635 and she can assist you.
