Greetings from the Veg IPM team! This week we are sharing our first CEW pheromone map of the season, and we have also included some useful information about other early sweet corn pests.
Sweet Corn
Pheromone traps for corn earworm (CEW) have been deployed throughout the state. If your corn is close to silking, it’s time to start thinking about your spray program. Sprays should be initiated at 10% green silks, and continued in intervals as determined by your local CEW pheromone trap counts. Refer to the map below to see this week’s CEW pressure. In South Jersey, the pressure is quite high (3-4 day spray intervals) while North Jersey pressure is lower (5-6 day spray intervals). Rotation is important for avoiding resistance, and there are four IRAC groups that are registered in silking sweet corn: 1 (carbamates), 3 (pyrethroids), 5 (spinosyns), and 28 (diamides). Corn earworm is at least partly resistant to several pyrethroids, so a spray program should not rely solely on pyrethroids, although they can be useful in tank-mixes or as pre-mixed products, such as Besiege or Elevest (Group 28 + Group 3). For detailed information about resistance and potential spray programs, the University of Delaware has an excellent resource on corn earworm management.
Spray intervals based on nightly pheromone moth captures for the southern part of New Jersey. Note that not all locations in the IPM program are currently trapping. This map is based on the following thresholds: 0 moths = 6-7 day schedule, 1 moth = 5 day spray schedule, 2-20 moths = 4 day spray schedule, 20+ moths = 3 day spray schedule.
Caterpillar pests in the whorl and tassel stage. Fall army worm have not arrived in New Jersey yet, so the main caterpillars that might occur in sweet corn are corn earworm and European corn borer. Historically, European corn borer (ECB) was an important pre-silk pest, but populations have declined drastically in the last 2+ decades since the introduction of Bt corn; in the IPM program, we rarely see more than one or two affected plants in a scouted sweet corn field if we see them at all. We also rarely see ECB occurring in other crops they historically damaged, such as peppers. Because of this, we do not recommend making a routine tassel spray unless you have known pest pressure. It’s important to remember that tasseling corn hosts a wide range of natural enemies (including lady beetles, minute pirate bugs, and syrphid flies) that help suppress secondary pests like corn aphids, as well as pollinators that visit during pollen shed.
If you have historically treated for ECB, we recommend scouting for ECB prior to spraying tassels. ECB feeding damage has a characteristic “shot hole” appearance (photo A below) with distinctly circular feeding holes, whereas CEW damage can appear in more elongated/ragged patches. If you follow the feeding damage down into the whorl, you may spot frass (caterpillar waste), and often the larva. ECB are small, smooth, tan-colored caterpillars with a black head (A and B). CEW larvae grow larger than ECB, come in a variety of different colors, and have speckles and hairs. Unlike ECB, they will have a light, tan-colored head capsule.
European corn borer surrounded by characteristic “shot hole” feeding damage (A) and an ECB feeding in a tassel (B). Photos by Amanda Quadrel.
Corn earworm caterpillars in corn tassels. Note light-colored head capsules, colorful bodies with dots and hairs. Pictures by Maria Cramer.
If you are scouting your own sweet corn for larva, choose ten random locations in the field and check five consecutive plants at each location. If 12% or more of the plants show signs of fresh caterpillar feeding, an early spray may be warranted. We haven’t seen caterpillar feeding above threshold levels at any of our scouted sites, so there’s been no need for sprays before the onset of silking. If you do find that larval pressure in your sweet corn is above threshold and your corn is nearing/in the tasseling stage, we recommend starting with a diamide like Coragen (IRAC Group 28). These products tend have lower toxicity to bees compared with other IRAC groups, which helps protecting bees that may be visiting during pollen shed.
Cole Crops
Flea beetle surrounded by feeding damage. Picture by Maria Cramer.
Flea beetles have still proven to be troublesome in various cole crops. This year, they have been especially prevalent in Napa cabbage, Tuscan kale, and bok choy. Young plants are especially vulnerable to attack from flea beetles. For all growth stages of heading cole crops, the threshold is 50% plants with flea beetles present before sprays will pay off.
Left: Diamondback moth caterpillar, showing characteristic tapering at each end. Right: Imported cabbageworm caterpillar showing characteristic fuzziness. Pictures by Maria Cramer.
We’re also seeing caterpillar activity (imported cabbageworm and diamondback moth) in cabbage and other cole crops. Treatment thresholds vary between crops and growth stage, but for heading cole crops between early vegetative and cupping, the treatment threshold is 30%. At this stage, sprayable Bt products (IRAC 11A) such as Dipel, Xentari, or Javelin can be effective on young caterpillars and will also be gentle on natural enemies that control other cole crop pests. Other materials approved for caterpillar control include Entrust/Radiant (IRAC 5), Proclaim (IRAC 6), Torac (IRAC 21A), Exirel (IRAC 28), and the new product Incipio (IRAC 30). These additional products may work better for diamondback moth or larger larvae. For Bt products and contact insecticides, coverage on the undersides the leaves is essential.
Tomatoes and Peppers
Last week, we saw a few different diseases show up in tomatoes and peppers. Botrytis, or gray mold is a fungal disease that has been prevalent in tunnel tomatoes. Refer to the photos below to identify foliar symptoms of the disease. To prevent the spread of Botrytis, good air flow and reducing humidity in your tunnels is key. Make sure that your tunnels are properly ventilated, avoid crowding your tomato plants, and lightly prune your plants to facilitate better airflow or to remove infected material (make sure to sanitize your pruning tools frequently). If disease pressure is high, fungicide applications can help; see table E-14 in the 2026/2027 Mid-Atlantic Production Guide for a list of materials approved for Botrytis control in greenhouses/tunnels. For more information on Botrytis and its management, see the Botrytis Fact Sheet from our vegetable pathologist, Andy Wyenandt.
Botrytis symptoms on tomato foliage. Notice the tan lesions with concentric rings (B). Photos by Amanda Quadrel.
Regarding bacterial diseases on tomatoes, symptoms first appear on leaves as dark brown lesions surrounded by a yellow halo. These can coalesce into larger lesions over time. On the undersides of the leaves, the lesions will often have a “greasy” or water-soaked appearance (see photos below). In the case of bacterial canker, the leaves are more likely to develop a “scorched” appearance, with the margins of the leaves turning yellow, and then eventually brown. If left untreated, the bacteria will also infect the fruit, resulting in numerous unsightly blemishes. It is often difficult to tell bacterial spot, speck, or canker apart, as symptoms can overlap. We encourage you to send a sample to the Rutgers Plant Diagnostic Laboratory to identify exactly which bacteria you are dealing with, as management for these diseases can differ slightly.
Symptoms of bacterial diseases on a tomato plant (A), lesions on the upper surface of a leaf (B), and appearance of lesions on the undersides of the leaves (C). Photos by Amanda Quadrel.
Bacterial leaf spot on peppers has similar symptoms to those seen on tomatoes, but the lesions may develop a tan center. The lesions will have a similar greasy or water-soaked appearance on the undersides of the leaf (see photos below).
Bacterial leaf spot symptoms on the upper (A) and lower (B) surface of pepper leaves. Photos by Amanda Quadrel.
While there are seldom curative measures for bacterial diseases, there are ways to suppress symptoms and prevent the disease from spreading throughout the field. Remove and destroy symptomatic plants, avoid working with plants in wet conditions, and frequently sanitize any tools or equipment that are used when handling tomatoes and peppers. If your farm has a history of bacterial issues, or you suspect your plants may be showing early symptoms of disease, regular applications of copper-containing products can slow the spread of the disease. However, keep in mind that in some areas, the causal bacteria may be resistant to copper. More info on bacterial diseases and copper resistance can be found here.
We have identified several tomato spotted wilt virus cases in south Jersey greenhouses and tunnels (see below). It’s important to identify and remove infected plants to prevent the spread of the virus, in combination with monitoring and managing western flower thrips populations. Thrips management is challenging due to insecticide resistance, multiple overlapping generations, and the fact thrips are often in protected areas, such as the flowers or the soil. In order to plan a strategy refer to our earlier PPA post on managing thrips, or contact us through the form at the bottom of the post. If you need help identifying tomato spotted wilt virus, please also contact us.
Tomato spotted wilt virus symptoms on a greenhouse tomato. Picture by Maria Cramer.
Insect/mite pest pressure is still reasonably low in both tunnel and field tomatoes. We’ve been seeing limited thrips (A), aphid (B) and spider mite (C) activity, although thrips populations are increasing steadily. As we see small grains drying down and cover crops terminated, thrips are moving to vegetable crops. At this stage, especially for aphids and spider mites, we recommend avoiding broad spectrum products that can flare up secondary pests unless absolutely necessary, so be sure to base interventions on seeing threshold-level pest problems. Consider spot treatments for aphids and spider mites. Additionally, biological control agents can be used in tunnels to help suppress pest populations. If primarily dealing with aphids or thrips, products such as Beleaf (IRAC 29) are recommended, especially if plants have reached the flowering stage. Keep in mind that only two applications of Beleaf can be made on a crop per season.
From left to right: (A) an adult thrips with feeding injury, (B) aphids, and (C) a two-spotted spider mite. Photos by Amanda Quadrel.
As a reminder, the new 2026/2027 Mid-Atlantic Commercial Vegetable Production Guide is now available for free online (click here) or as spiral-bound hard copies that can be purchased at your local county extension office. Consult this guide for a more comprehensive list of materials that are labeled for specific crops and pests.
We want to give a huge thanks to our scouting team for keeping an eye on things for us throughout the season!
North NJ: Connor Colonese, Shayne Miller, and Cassandra Dougherty
South NJ: Alex White, Renee Carter, and Peter Combs
Authors: Amanda Quadrel (Northern NJ Veg IPM coordinator) and Maria Cramer (Southern NJ Veg IPM coordinator)
Questions or comments? Contact us below:
