Vegetable Notes 2026 Vol. 38:12

Squash bug eggs were observed in tunnel cucumbers this week. Squash bugs may emerge slightly earlier in high tunnels due to the warmer temperatures, but now is around the time we typically see eggs laid on cucurbits in the field, in time for nymphs to hatch and begin feeding in the first or second week of July. Scout for clusters of bronze-colored eggs on the undersides of leaves, usually concentrated at the junctions of leaf veins. Early in the season, controls are warranted if you see more than one egg mass per plant. For young plants that are not yet flowering or vining, insecticides can be used when adult squash bugs are colonizing plants to prevent further egg-laying. Broad-spectrum pyrethroids or carbaryl are effective against adults, but should not be used on flowering cucurbits to avoid injury to pollinators. For flowering plants, apply products with lower toxicity to bees such as acetamiprid (Assail 30 SG), and time applications for when eggs are just beginning to hatch for the greatest efficacy. Organic growers can use a mixture of pyrethrin and azadirachtin at egg hatch, providing two modes of action. Any applications on flowering plants should be made late in the day while flowers are closed. Ensure good coverage of the underside of leaves where the bugs hide.

Nightshades

Colorado potato beetle larvae are continuing to feed in potato and eggplant crops. If you have not yet applied an insecticide, remember that insecticides are most effective against the smallest larvae. If possible, do not apply an insecticide from the same IRAC group as the insecticides you used last year to control CPB. See the eggplant or potato insect management sections of the New England Vegetable Management Guide for labeled materials. Treatment thresholds are below.

Potato aphids were observed in high tunnel tomatoes this week, with populations increasing from last week. Excessively high temperatures in tunnels can stress plants while favoring aphids, leading to outbreaks. Manage temperatures in tunnels as a first line of defense against infestation. Biological controls can effectively manage potato aphid populations in tunnels; aphid predators (lady beetles, the predatory midge Aphidoletes aphidimyza, and green lacewing larvae) are better at controlling high populations, while parasitoids (i.e. the parasitoid wasp Aphidius ervi) are more effective at controlling low populations. If an insecticide application is necessary, use selective or systemic insecticides in order to conserve natural enemies of aphids, which are abundant. Aphid outbreaks often begin as hotspots within the tunnel; spraying only these areas can further help to conserve natural enemies, especially if combined with releases of preventative biological control such as parasitoid wasps. 

Sweet Corn

European corn borer (ECB) moths continue to show up in traps in low numbers (Table 4). We have reports of limited ECB damage in tasseling sweet corn in Franklin Co. Continue to scout for flagged tassels and/or shot hole feeding damage in horizontal lines on leaves. See the Sweet Corn Insect Management Field Scouting Guide for instructions on sequential scouting and thresholds.

Corn earworm (CEW) moths are now being captured in fairly low numbers at most of our trapping locations (Table 4). Recommended spray intervals range from 5-6 days, with no sprays warranted in many locations. With low pressure, it is recommended to only spray silking corn for CEW unless other pests are present.

Multiple Crops

Potato leafhopper (PLH) nymphs were observed in low numbers in Bristol and Worcester Cos. this week. PLH feed on potato, eggplant, and bean plant sap with piercing-sucking mouthparts. Many cut flower growers are also reporting damage on dahlias. They inject a toxin while they feed which causes “hopperburn”—leaf yellowing and necrosis that starts at the margins. For effective chemical control, PLH must be managed when populations are still low. In potato and eggplant, some materials registered for Colorado potato beetle adults will also control leafhopper, including neonicotinoid foliar sprays such as Admire Pro or Assail. These and several other carbamate, pyrethroid, and organophosphate products are also registered for leafhopper control—refer to the New England Vegetable Management Guide for registered products in potato, eggplant, and beans. The new products Zivalgo (for potato) and Incipio (for eggplant) are labeled for PLH control. For organic growers, a mixture of pyrethrin (PyGanic) and azadirachtin (many trade names) is most effective. For more details, see the article in last week’s issue of Veg Notes.

Berry Blast  

This week started off wet, which set the tone for berry growers. Wednesday and today look like they were/are the best window for scouting, harvesting, and catching up on spray applications if needed. We may see more showers or storms tonight and tomorrow, so use the rest of the dry period today wisely. The main message for this week is simple; stay ahead of harvest, protect fruit from secondary rot where needed, and do not stretch spray intervals too far in blocks with known disease pressure. We are now in the last stretch of the fertilizer window for most berry crops. For blueberries, brambles, and grapes, I do not recommend nitrogen applications after June 30. Late nitrogen can push soft late-season growth and increase the risk of winter injury. Liz Garofalo has mentioned the following multiple times and I will echo it: We are in a drought in many parts of the state. After this week’s rain passes, re-evaluate your soil moisture and plan to irrigate later in the season when needed. 

Strawberries are still the main crop on everyone’s mind. Harvest is moving fast across the state, and growers should continue to keep picking intervals tight. Last week’s heat, sun, and scattered heavy rain left some fields with soft fruit, sunburn, rain injury, and Botrytis on ripe berries. With more rain at the start of this week, those problems can build quickly if ripe or damaged fruit sits in the field. For strawberries, the best IPM tool right now is still harvest management. Pick clean, remove overripe or damaged fruit when practical, cool fruit quickly, and do not let soft fruit sit through another rain event. If you are seeing active Botrytis or fruit rot building after this rain, a short-PHI fungicide may be a good idea to protect those later season varieties. For insect pests, continue scouting for slugs in wetter blocks, and mites during hot, dry periods. Do not apply insecticides during bloom on late varieties.

Blueberries are moving through green fruit and putting on color. Early varieties are beginning to show what kind of crop we really have, while later varieties are still filling out. This week’s rain means you should be watching for fruit rot. Also, at this point in the season, symptoms of nutrient deficiencies will start to show. Take note of areas showing nutrient deficiencies and send in a tissue sample after harvest (not now). Wait till the fruit has been removed from the bush before removing green plant tissue. For insects, spotted wing drosophila (SWD) traps should be out before fruit colors. Don’t jump into a calendar SWD spray program too early, but once fruit starts to color and SWD is detected, the situation can change quickly. So continue to monitor, adjust your plan accordingly and re-evaluate after every spray. 

Grapes are at bloom to buckshot berries depending on variety and location. This is still a key window for disease prevention, so growers should stay on top of black rot, powdery mildew, downy mildew, Phomopsis, and Botrytis management. With wet weather in the forecast, black rot remains a major concern, especially on young berries, which are highly susceptible for the first several weeks after bloom. Canopy work should also continue. If shoot thinning is complete and shoots have started to lignify at the base, begin shoot positioning by tucking or combing vines, depending on the training system. Keeping the canopy open will reduce humidity, improve spray penetration, and make later-season canopy work easier. Be careful with spray timing during hot weather, since some products can cause injury when temperatures are high. Check labels and avoid applications when temperatures are expected to exceed 95°F. For insects, Japanese beetle adults are expected soon, usually around early July. Begin scouting vineyard edges and the tops of vines on warm, sunny days. Mature vines can tolerate some feeding, but young vines may need protection sooner. Japanese beetle traps are not recommended in vineyards because they can pull more beetles into the area. Spotted lanternfly nymphs should also continue to be monitored in and around vineyards. Scout trunks, posts, vine guards, vineyard edges, and nearby tree-of-heaven. At this point, I would not make major changes to the grape pesticide program unless populations are increasing or young vines are at risk. More detailed grape recommendations will be covered in Grape Notes (click here to subscribe).

For Brambles, b-ramble on!

Overall, this is a cleanup and protection week. The early-week rain will raise disease pressure, but the midweek drying window gives you a chance to catch up. Prioritize harvest, scout after the rain, protect high-risk blocks where needed, and keep an eye on PHIs as we move deeper into harvest season.

Be safe out there.

--Written by J. Galvan, UMass Fruit Program

Resources:

• Fact Sheets: Spotted Wing Drosophila
• Fact Sheet: Spotted Lanternfly
• News: Spotted Lanternfly Egg Mass Hatch Has Begun in Massachusetts
• New England Small Fruit Management Guide

Onion Thrips

We have been seeing thrips in allium crops for about a month and are now seeing their population numbers increase quickly as temperatures rise. Onion thrips are common pests on alliums as well as a broad range of other crops including beans and brassicas. They are tiny insects, only up to 1/16” in length, that spend the winter as adults in crop remnants, alfalfa, wheat, greenhouses, and weeds along the borders of crop fields. Adults lay eggs singly in the epidermis, nymphs feed on leaves, and pupation occurs in the soil. All life stages may be present by early- to mid-spring and there are at least three generations per year in the Northeast. Populations are favored by hot, dry weather. Heavy rain or overhead irrigation can lower populations.

In onions, thrips feeding occurs in protected, succulent areas where new leaves are emerging, deep between the leaf blades. Adults and nymphs have rasping mouthparts, which they use to pierce the plant epidermis and cell walls and feed on plant juices. Damage may appear as silver lines, white patches, tip dieback, curling and twisting of leaves, slowed growth, reduced bulb size and yields, or if severe enough, can result in plant death. The irregular and blotchy whitening of the plants is known as 'blast'. Plants are most sensitive when bulbs are forming. Scallions are particularly sensitive because the whole plant is marketed. Healthy, vigorous plants can tolerate moderate populations.

Onion thrips damage may also occur on brassicas including cabbage, broccoli, kale, and collards, especially fall plantings near a maturing onion crop. On cabbage, thrips feed on inner leaves of the head, which are difficult to reach with sprays. Damage appears as rough, golden or brown scars on the undersides of open leaves, scars and discolored layers within cabbage heads, and generally reduced vigor in plants. Thrips damage can be confused with oedema, a physiological disorder that causes small, bump-like protrusions to form on leaf surfaces.

In addition to direct feeding damage, onion thrips can damage crops by vectoring viral pathogens such as tomato spotted wilt virus, impatiens necrotic spot virus, and iris yellow spot virus. Wounds caused by thrips feeding can also create pathways for infection by fungal and bacterial pathogens, leading to increased occurrence of diseases such as purple blotch (Alternaria porri) and bacterial bulb rots.

Monitoring & Thresholds:

Scout across susceptible fields weekly, starting in late-May, to determine if populations are increasing, especially on plants along field margins where infestations build early. In allium crops, gently part the leaves of each plant and look closely between the leaves to find the light-yellow nymphs or darker-colored adults. Though tiny, they can be seen moving on leaf surfaces when leaves are parted. Count the number of adults plus nymphs per plant and note the number of leaves per plant to determine the average number of thrips per leaf. A pesticide application is warranted if thrips numbers reach 1 to 3 per leaf. Thrips feeding that occurs during the period of rapid bulb expansion causes the greatest loss in yield. Use the lower 1 thrips/leaf threshold during this period, or if expected efficacy of the insecticide to be used is low, water availability is limited, or other conditions reduce the overall health of the plants. Growers using OMRI-listed materials should also use the lower threshold.

Cultural Controls & Prevention:

• Practice good field sanitation at the end of the season.
• Avoid using last year’s onions for sets.
• Avoid imported transplants from southern areas that may be infested with thrips or their eggs.
• Eliminate volunteer allium crops.
• Use straw or reflective mulch to deter thrips. Reflective silver mulch can lead to substantially lower thrips pressure. 
• Avoid planting onions and fall brassica crops near each other or near alfalfa, wheat or clover, as these crops can harbor large populations of thrips. Thrips may migrate to onions when these crops are cut or harvested.

Tolerant varieties are the most cost-effective means of controlling thrips in cabbage but are generally not available in other brassicas or onions. Cabbage varieties that have shown tolerance in trials (see here for a summary of 2009 Cornell trial data) and are still available include Capture, Celebrate, Benelli, Cairo, Bravo, Cheers, Huron, and the various Vantage varieties. The Cornell Organic Production and IPM Guide for Cole Crops has an extensive list of cabbage varieties and their thrips tolerance.

Biological Controls:

Lacewing larvae, minute pirate bugs and predatory thrips and mites are important natural enemies of onion thrips. To conserve natural enemies, avoid use of broad-spectrum insecticides. Intercropping onions with barley has also been shown to suppress numbers of onion thrips by increasing numbers of hover flies whose larvae feed on both cereal aphids and thrips.  

--written by UMass Extension Vegetable Program

Produce Safety and Public Water Supplies

The FSMA Produce Safety Rule (PSR) requires that growers assess the microbial quality of the water they use on their farms. If water is intended or likely to contact fresh produce or food contact surfaces, it must be safe and of adequate sanitary quality for its intended use (Produce Safety Rule, Subpart E §112.41). For preharvest water, PSR-covered farms must conduct an annual written risk assessment, and for postharvest water, they have to test the water to show that it has no detectable generic E. coli in a 100 ml sample.

An exception is if the water is obtained from a public water system. Farms are exempt from the preharvest ag water assessment requirement for municipal water sources, as long as the quality of the water is not likely to change prior to its use. And water testing is not required for municipal water used postharvest. Municipal water is treated to be safe for drinking and other human uses. Among agricultural water sources, it is the safest water to use because the supplier is required to ensure that it is free of E. coli and other contaminants. If you’ve attended a PSA grower training or met with an auditor or inspector from the MDAR Produce Safety Program, you may have heard one of us say, “if you use municipal water, you just need to show the documentation you get from your town”. But what if the documentation you get from your town says that the water might not be safe?

Water Main Breaks

Water main breaks are becoming more common in New England’s cities and towns. Treated drinking water runs to our homes and farms through thousands of miles of sometimes very old pipes. A news search for water main breaks in Massachusetts will result in a long list of results, including a series of 19 water main failures that affected the city of Worcester earlier this year due to corroded pipes that were installed between 1915 and 1970. Of the nearly 600 miles of pipe that supply the Springfield area with water, 25% of them are over 100 years old. This week, a water main break in Somerville, where about 90% of the pipes are over 50 years old and 70% are over 100 years old, created a geyser of water through a hole in the street and forced the city to shut off the water supply to some residents while repairs were made. 

While the Northeast’s water supply is largely safe and reliable, these incidents are important reminders for agricultural users of public water supplies to stay alert to potential problems and develop contingency plans to help avoid introducing risk to produce and keep operations moving. 

When a water main breaks, users may lose access to water until the mains are repaired. Breaks also introduce the possibility that contaminants can enter the drinking water system. Outward pressure from the break, as well as precautions taken by water departments such as disinfecting tools and equipment during repairs, help reduce risks to the system, but occasionally large breaks can result in negative pressure that can pull contaminants into the lines. When E. coli is detected in the water, either through routine sampling or after a break, or when there is a likelihood of contamination, the municipality will issue a boil water or other public health order.

Public Health Orders 

The Massachusetts Department of Environmental Protection (MassDEP) Drinking Water program (DWP) issues public health orders as a preventive measure when they determine that there may be contamination in a public water system. There are 3 types of orders, depending on the type and severity of the issue:

• Boil Water Order (excess levels of bacteria or other contamination)
• Do Not Drink Order (contamination for which boiling the water may not be enough treatment, e.g., lead or PFAS)
• Do Not Use Order (unknown or high-risk contaminants)

The water supplier is required to notify its customers about any orders and keep them updated about the status of repairs and termination of the order. Notifications may come through news outlets, social media sites, town websites, or other sources.  More information about the types of orders and precautions to take when an order is in effect can be found on the MassDEP website, Drinking water boil orders and public-health orders. This site also has a link to a database of all water orders issued in the state, dating back to 2009.

Example – Abington-Rockland Joint Water Works

On May 15, 2025, The Abington-Rockland Joint Water Works detected positive samples for both total coliforms and generic E. coli through routine sampling of treated water. The water supplier issued a boil water notice that affected residents in 5 Massachusetts towns: Abington, Rockland, Pembroke, Hanson, and Whitman. Residents were notified via reverse 911 and Code Red calls, Notify Me texts, website, social media posts, Town Hall signs, and postings in local newspapers and on television. The town performed repairs and cleaned storage tanks, retested the system, and lifted the order on May 18. 

Records of the incident can be found in news outlets, the Abington-Rockland water works website, and the MassDEP database of public health orders. The annual water quality report—this is the documentation you get from your town that you need to show for FSMA purposes—noted the positive E. coli sample and included a description of the violation and the supplier’s response. These reports are mailed to all residents who use the water and are also generally available on the town or city’s website.

Examples of aforementioned boil water notifications. Click on images to expand.

In the event of a public health order, note the type of order issued and any related guidance provided by the water supplier. Under a boil water notice, the guidance may say that water is safe to use for some activities, including watering plants or gardens. Under FSMA rules, there is no specific threshold for generic E. coli in preharvest water and the water may still be appropriate to use for these applications (e.g., irrigation or crop sprays), though if the extent of potential contamination is not known, it may be safest to avoid applying the water to food crops.

Under a boil water or other type of order, the water should not be used for any postharvest applications until testing shows that there is no detectable E. coli or other contaminants above the allowed threshold in the water and the order is lifted. 

Other risks to municipal water

Even outside of boil water notices or other system-wide issues, there can still be risks to municipal water under normal conditions. Once public water gets to a farm, contamination can be introduced through the farm’s own distribution lines or storage containers. 

A requirement of the FSMA Produce Safety Rule for all agricultural water, both pre- and postharvest, is to conduct an annual inspection of the whole distribution system from source to outlets, including municipal water sources. While the inspection will likely be focused on risks from ground or surface water sources, it may also bring to light issues that may result in municipal water contamination.

Do you store water? Some farms fill tanks with municipal water and bring it out to fields for irrigation, handwashing, or produce cooling. Remember, the exemption from the preharvest water assessment only applies if the water quality isn’t likely to change before you use it. And postharvest water needs to be maintained to ensure that it’s safe. If you store municipal water for farm use, make sure you have a system for maintaining the water quality—keeping the system closed and cleaning and sanitizing any tanks, hoses, or other surfaces.

Even though testing is not required for municipal sources, consider testing occasionally to confirm that quality is being maintained.

What should you do? 

If your farm relies on a public water supply for some or all of your agricultural water, be aware that while contamination in the water is unlikely, it can happen. Here is some guidance for maintaining adequate sanitary quality of your municipal water sources (with thanks to Carol Allen from the University of Maryland Plant Science Food Safety Group for informing this section).

• Have a contingency plan in place in case of an emergency. This may include having a back-up water source for irrigation, produce washing, and handwashing, or having protocols for how to avoid water use, if necessary, such as not washing harvested produce.
• Become familiar with your distribution system. From Carol Allen, “Where does your domestic water pipe attach to the city’s main line? Where does it go from there? Are there other lines that go to outbuildings or beds? Where are your hose bibs and or field stanchions? Do you have backflow prevention devices at every point of use or on the main line?” If a boil water order is made, lines will need to be flushed when the order is lifted. 
• Note conditions that would increase the risk of contamination of your water. Repair or replace leaking hoses or other water use devices. If water can get out, then contamination can get in. If using a hose to fill sinks or wash tubs, or for cleaning food contact surfaces, hose ends or sprayers should never touch the ground. Always provide an aboveground hook where the hose can be hung. 
• If storing municipal water, have and implement a cleaning and sanitation plan for the storage container, as well as any filters or pumps. Record cleaning and maintenance events. 
• Know how your municipality notifies residents of a boil water alert. Stay alert to any announcements and have a plan! 
• Keep documents of the dates that a public health order was in effect and any measures you took on your own farm to reduce risk (E.g., we didn’t wash produce or use the water for cleaning and sanitizing during the boil water order; we had a backup cistern and this is how we maintain water quality in the cistern, …) 

--Written by Lisa McKeag, UMass Extension

Sources & Resources

• MassDEP, Drinking water boil orders and public-health orders
• UMD Extension, Precautions Fruit and Vegetable Growers Should Take During a Boil Water Advisory
• Recommendations above are informed by the University of Maryland Plant Science Food Safety Group newsletter articles, Have a Backup Water Source, 6/9/26 and On Municipal Water? Do You Need a Risk Assessment?, 12/9/24). Subscribe to the University of Maryland Extension Plant Science Food Safety Group Newsletter This newsletter is intended primarily for Maryland farmers, but has timely information that might be relevant to any Northeast produce grower. 

Events

Sprayer Calibration Workshop

When: Thursday, July 9th, 2026, 4:30 – 7:30pm

Where: Gove Farm, Leominster, MA

Registration: Free, but please register in advance. Space is limited! Click here to register.

George Hamilton, of Hillside Meadows Ag Consulting and previously with University of New Hampshire Extension, will lead us through the calibration of a boom sprayer, teaching us along the way. We will experience how speed, pressure, nozzles, and boom height interact, and will then test to see if we’ve achieved the desired coverage. You’ll then use those concepts yourselves as you calibrate a backpack sprayer. This event is the first of our “From Tip to Tank: Pesticide Applicator Laboratory Series” events, funded by the Northeast Risk Management 

Click here for full event description.

Questions? Contact Maria Gannett, mgannett[at]mass[dot]edu (mgannett[at]mass[dot]edu)  

All About Peppers – Twilight Meeting at Kitchen Garden Farm

When: Tuesday, July 21, 2026, 4-6 pm, followed by refreshments 

Where: Kitchen Garden Farm, 131 S. Silver Lane, Sunderland, MA 01375

Registration: Free! Please register in advance. Click here to register.

Kitchen Garden Farm is a 65-acre specialty vegetable operation and value added business in Sunderland, MA.  The farm grows a variety of crops to process into a line of hot sauces, salsas, pickles, and dried spices/herbs, including peppers, tomatoes, onions, cauliflower, celery, carrots, oregano, thyme, sage, as well as a diverse array of crops for niche regional and local wholesale markets.

This meeting will focus on their pepper production and some of their related challenges, including Phytophthora and pepper maggot, and work they're doing in collaboration with UMass Extension to try to improve management. The farmers will also share their experiences with learning about the risk management options available to their farm through crop insurance and the FSA's Non-Insured Disaster Assistance program (NAP). 

41st Massachusetts Tomato Contest

When: Thursday, August 20

Where: Boston Public Market

Please join MDAR and the New England Vegetable and Berry Growers Association for the 41st Massachusetts Tomato Contest! Tomatoes will be judged by a panel of experts on flavor, firmness/slicing quality, exterior color, and shape. Always a lively and fun event, the day is designed to increase awareness of locally grown produce.

Open to commercial farmers in Massachusetts, growers can bring tomatoes to the market between 8:45am and 10:45am on August 20 or drop their entries off with a registration form at one of the regional drop-off locations on Wednesday, August 19. Drop off locations include sites in South Deerfield, Southboro, North Easton and West Newbury. These tomatoes will be brought to Boston on Thursday.

Details, including drop off locations, contest criteria, and registration form here. *Be sure to include the registration form with all entries.

The 41st Tomato Contest is sponsored by the MDAR and New England Vegetable and Berry Growers Association, in cooperation with the Boston Public Market. Please consider participating to showcase one of the season’s most anticipated crops!

Questions? Contact Rose Arruda, rose[dot]arruda[at]mass[dot]gov (rose[dot]arruda[at]mass[dot]gov). 

Save the Dates!

• 2026 MA Fruit Growers' Association Summer Meeting: Wednesday, July 15, 9:30am-2:30pm, UMass Cold Spring Orchard, Belchertown, MA
• UMass Agronomy Farm Research Field Day: Wednesday, August 5, 9:30am-1pm, South Deerfield, MA
• Food Safety Farm Tour at Red Shirt Farm: Monday, August 31, Lanesborough, MA
• Temporary Fence Installation & Maintenance: Thursday, September 17, 5-7pm, Heart Beets Farm, Berkley, MA