What to be on the lookout for…
Fungal Diseases in Tomatoes
Extended periods of wetness from fog or dew as nighttime temperatures begin to drop is creating an opportune environment for fungal infections.
Alternaria, also referred to as Early Blight of tomato, can cause lesions to form on tomato leaves. They first appear as small brown to black lesions on older foliage, and the tissue surrounding the lesion may become yellow. As the number of lesions grows, the entire leaf can become chlorotic. As the lesions themselves grow, they often develop concentric rings like a bull’s eye or target-spot. In addition to reducing plant vitality, fruits can also be infected by causing them to rot.
Septoria leaf spot is one of the most destructive diseases of tomato foliage, causing defoliation and reducing crop yield. Symptoms can be found on the leaves and other green parts of the tomato plant. Small, round, yellowish spots appear first, later becoming brown or grayish. Heavily infected leaves will fall off. Unlike early blight, however, fruit infection is rare.
Anthracnose ripe rot also favors long periods of wetness. This disease causes ripe fruit to rot, creating losses both in the field and during storage. Fruit spots are round, slightly sunken, and up to 1/2" in diameter. The center of anthracnose spots darkens as the fungus begins producing spores.
Healthy plants with adequate nutrition are less susceptible to disease. Removing infected leaves may slow disease spread. Apply fungicides preventatively when history of fungal diseases are present. See the New England Vegetable Management Guide for an up-to-date list of disease control products for tomatoes.
Allium Leafminer
The Allium Leafminer (ALM) is an invasive pest, targeting allium crops like leeks, onions, garlic, and scallions. It has two generations per year, active in spring and fall, with the fall being more damaging. Adult flies emerge from the summer pupa beginning in early to mid-September through the end of October. ALM causes economic damage primarily in leeks and scallions by feeding on leaves and potentially introducing bacterial rot. Proper timing for control is critical during egg-laying periods.
Row covers are the most effective control, while conventional insecticides like Exirel and Radiant offer strong protection. For organic management of this pest, spinosad-based products like Entrust are effective. Neembased insecticides (Azadirachtin) and pyrethrin-based sprays (e.g., PyGanic) offer some control but require more frequent applications.
Monitor the presence of adult flies using sticky traps or observe for feeding damage. Begin sprays when adult flies are active to target them before they lay eggs. Reapply according to the product's label instructions to maintain protection during peak activity.
For detailed management strategies in controlling allium leafminer, visit Cornell's ALM factsheet.
Weeds going to seed - act now to prevent long-term issues!
It can be tempting to avoid spending extra hours in fields with poor crops or where you have finished harvesting. However, preventing weeds from reaching seed maturation is crucial for long-term success. Weeds like pigweed, lambsquarters, and ragweed produce large quantities of seeds that can remain viable in the soil for many years. Allowing these weeds to mature and shed seeds can lead to significant problems in the future, as the seeds contribute to the weed seed bank in the soil. Taking the time now to mow down or remove these weeds before they seed will save you considerable hours and effort in the coming years. Investing in weed control today is a proactive step toward more manageable and productive fields in the future.
Do you leave ripe pumpkins in the field or bring them indoors?
- Pumpkins should ideally be harvested when fully mature, with a deep orange color (or any color they turn when fully mature) and a hardened rind. However, when there is high pest (disease or insect) pressure in the field or poor canopy coverage, it is better to harvest pumpkins that have started to turn color, as they can ripen off the vine under proper conditions (#3 below), rather than leaving them exposed to pests and sun.
- Pumpkins can be stored in the field (even after they are ready to harvest) if vines and fruit are healthy. But field storage should last only a few weeks. Scouting for insect damage is important, particularly for squash bugs and cucumber beetles. Field storage may increase problems like Phytophthora blight, Fusarium fruit rot, or black rot, especially after wet weather or storms.
- Ripening can be done in a well-ventilated barn or greenhouse.
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- Ideal temperatures for ripening: 80-85°F with 80-85% relative humidity.
- Night temperatures should not drop below 60°F.
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- Curing in temp 70-80°F for about 7-10 days helps harden the rind, heal wounds, and ripen immature fruit.
- Pumpkins should be stored in a cool, dry place (after curing):
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- Ideal storage temperatures: 50-60°F. Green rind squashes should be stored at 50-55°F because 59°F or higher temperature may cause de-greening, undesirable yellowing, and texture loss.
- Ideal relative humidity: 50-70%.
- Higher humidity can cause condensation and risk of disease.
- Lower humidity can lead to dehydration.
- Higher temperatures increase respiration and cause weight loss. For example, mature Kabocha squash lose 1.0 and 1.5% of their fresh weight per week of storage at 59°F and 68°F, respectively. Weight loss of butternut squash stored at 55°F and 68°F is 2.5% and 5.5% per month, respectively.
- Temperatures below 50°F cause chilling injury.
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Winter Squash Maturity, Harvest, and Storage
There is a daunting list of diseases, insects, and weather events that threaten the quality of pumpkins and winter squash as we patiently await their maturity. Ideally the plants will stay healthy and the weather will cooperate all the way until the end, but that’s not always the case. Chuck Bornt, Vegetable Specialist at Cornell Cooperative Extension in Eastern New York, highlights what to keep in mind if you have winter squash and pumpkins in your field: Winter Squash and Pumpkin Maturity, Harvesting and Storage Tips.
Preparing for Cold
Most cool season crops will tolearate temperatures as low as 28 °F. Cooler temperatures actually enhance the flavor of many cool season crops. Kale, collards, cabbage, Brussels sprouts, spinach, Swiss chard, carrots, onions, garlic, and leeks are among the hardiest of cool season crops. However, warm season crops such as tomato, pepper, eggplant, squash can be injured when temperatures are below 36 °F. Cold temperatures or frost can damage the surface of fruit vegetables. Light weight covers offer a few degrees of protection while the heavier grades protect plants from lower temperatures. PVC plumbing tubing or metal electrical conduit bent over beds can be used to make hoops.
End of Summer Season Reminders
- Field clean-up for pest management: At the end of the season, field clean-up and removal or soil-incorporation of crop debris are important tasks that will help reduce diseases and insect carrier over to the subsequent season. There are many pests of vegetable crops that can overwinter in New England. This article (see pages 8-9) published in a previous Crop Talk features a table describing overwintering stage and recommendations focused on cultural control of major insect pests of vegetable crops.
- Cover crops: A fundamental goal of cover cropping is to avoid bare soil between cash crop plantings. This not only protects soil, but captures sunlight and produces biomass that enhances soil quality. Other benefits include improved trafficability of fields and reduced compaction, enhance aesthetics, and potential for animal feed production. See the New England Vegetable Management Guide to get information about late summer-seeded and fall-seeded cover crops.
- Soil test: Fall is also a good time of year to perform soil tests on your fields. It provides you time to add lime if needed and be ready for spring fertilizer bulk orders. Instructions to collect soil samples and other relevant resources are available online for the Soil Nutrient Analysis Laboratory.
Sweet Corn Pests - Trap Count Update
We’ve started to notice a decline in sweet corn pests, likely due to the cooler nightly temperatures. This week our Glastonbury B traps only recorded 3 fall army worms. Keep monitoring until all generations of corn have finished silking. Regular trap updates and additional resources can be found on our website.
Ornamental & Turf Short Course
Biological Control Conference for Ornamental Growers
Thursday, September 18, 2025
Jones Auditorium, The Connecticut Agricultural Experiment Station,
123 Huntington Street, New Haven, CT
Rosa Raudales and Charles Krasnow from UConn's Greenhouse Extension Team are hosting a day-long workshop for ornamental growers. It will be a great opportunity to learn how to properly implement a biocontrol program from the practical experience of a grower and industry leaders, what are the new tools and products in the biocontrol industry, and how to train staff to seek and find pests and insects.
Registration: $70 per person. Registration includes a boxed lunch and six pesticide recertification credits for Connecticut and New England states for presentations marked with ♣.
Space is limited. Registration will be open until September 11th at 5pm.
See program details: greenhouse.uconn.edu/biocontrolworkshop/
Participate in UMN/UNH High Tunnel Cover Crop Trial
Becky Sideman at University of New Hampshire is once again putting the call out to recruit organic high tunnel growers as part of an OREI funded high tunnel cover crops project. This Fall 2025 trial will look similar to last year’s: growers will get sent seed, a free soil test and help interpreting it, and will be asked to complete a couple of short surveys to let the researchers known how it went. A biomass sample from the following spring would be ideal as well, but is not required.
These on-farm trials are meant to evaluate how legume cover crops perform in active farming systems. Farmers will not be asked to plant replicated arrangements of the trial plots on their farms. Instead, researchers will plant all of the cover crop options in replicated plots on a research station, while each participating farmer plants one plot of each of the cover crop options that they select. Farmers can select between two levels of participation and compensation, depending on the amount of time and effort they are willing to commit.
- Read the full trial instructions, detailed species and timing menu, and farmer expectations for each level here.
- Watch the recording of the High Tunnel Cover Crop Trial Webinar
- Sign up to participate by telling the team which species you’d like to grow and how much seed to send.
Contact the research team at hightunnel-cc@umn.edu with any questions.
Stay in touch with us
- Share what you see: We're here to assist with identification, management strategies, and guidance on best practices. Send us a photo/message via iMessage at 959-929-1031.
- Facebook Group: UConn Extension moderates a private Facebook group specifically for commercial vegetable producers. It is a space to share photos of insects and diseases you find in your fields, ask questions, share ideas, and stay engaged with growers across the state. Join the "UConn Extension - Vegetable IPM" Facebook Group
- Schedule a consultation: Would you benefit from meeting with an Extension Specialist at your farm to provide insight on pest or disease identification, management strategies, and more? If so, please contact our Vegetable Extension Specialist, Shuresh Ghimire, to setup a farm visit. Contact him at shuresh.ghimire@uconn.edu or 860-870-6933.
Contact Information
Shuresh Ghimire, Vegetable Extension Specialist: shuresh.ghimire@uconn.edu
Nicole Davidow, Vegetable Extension Outreach Assistant: nicole.davidow@uconn.edu
Vegetable IPM Office Phone Number:
860-870-6933
Vegetable IPM Cell Phone Number:
959-929-1031 (feel free to text/iMessage photos)
Vegetable IPM Pest Alert Audio Recording:
860-870-6954
Thank you for reading!
This report was prepared by Nicole Davidow, Outreach Assistant, and Shuresh Ghimire, Commercial Vegetable Specialist, UConn Extension.
The information in this document is for educational purposes only. Any reference to commercial products, trade or brand names is for information only, and no endorsement or approval is intended. Always read the label before using any pesticide. The label is the legal document for product use. Disregard any information in this report if it is in conflict with the label. UConn Extension does not guarantee or warrant the standard of any product referenced or imply approval of the product to the exclusion of others which also may be available. The University of Connecticut, UConn Extension, College of Agriculture, Health and Natural Resources is an equal opportunity program provider.