Greetings from the Veg IPM team! Read more for the latest pest and disease updates.
Sweet Corn
Pressure in the north is beginning to increase as we are seeing more storms moving in from the south. 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 and Central Jersey, the pressure is quite high (3-4 day spray intervals), and North Jersey pressure is lower, but increasing. Remember, when the average maximum temperature for the next 3 days is above 80 degrees, shorten the spray interval by one day. 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 are 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. We have been seeing sporadic fall armyworm infestations at various levels throughout the state. Young larvae cause “window paning” damage, in which the top surface of the leaf is eaten away, leaving behind thin, white, membranous-looking scratch marks (A). As the larvae get bigger, these feeding marks become ragged holes (B). The damage can look similar to European corn borer feeding, but FAW damage will be more severe and will lead down into the whorl. The caterpillars have a dark head capsule with a distinct, inverted Y-shaped suture (C). They can also be identified by four dark dots arranged in a square on their last segments (D). We use a treatment threshold of 12% fresh feeding damage in pre-tassel corn. Below this level, treatments for FAW are unlikely to pay off and can flare up aphids. For treatment, we recommend using products other than diamides (IRAC Group 28), as diamides are important to save for silk protection. Effective products include Lannate (Group 1A), Radiant (Group 5), Intrepid (Group 18), Intrepid Edge (5+18), and Avaunt (Group 22). Note that Avaunt can only be used through tassel push.
Fall armyworm identification: A) Windowpane damage, B) ragged holes, C) larva with inverted “Y” on head capsule, and D) larva with 4 dots arranged in a square. Pictures by Maria Cramer.
Aphids. We’re seeing aphid infestations in corn tassels. We are beginning to scout corn silks for heavy aphid pressure, like in the picture below. Aphids don’t hurt the edible ear of corn, but in large numbers they can cause honeydew and sooty mold that reduce marketability. If you’re seeing a lot of aphids on corn tassels, you can start your CEW spray rotation with Lannate (group 1A), which has some efficacy for aphids. Come back a week later and check ear tips for aphid populations. If they are high, as in the below picture, use a product more targeted for aphids, such as Assail 30SG or 30 SC (group 4A), Transform WG (group 4C), or Sivanto Prime (group 4D). Keep in mind that Transform WG and Sivanto Prime have 7 day PHIs.
Corn leaf aphids on the tip of an ear. Note blue-green color with dark tail pipes (also called cornicles), legs, and antennae. Picture by Maria Cramer.
Tomatoes and Peppers
Thrips and TSWV. Thrips and tomato spotted wilt virus (TSWV) continue to be the main issue in tomatoes. The worst problems are in south Jersey, but isolated cases have been found in throughout the state in peppers and tomatoes. Growers should scout regularly for TSWV (see figure below for an example of a plant with TSWV) and rogue out affected plants to reduce risk of secondary spread. Often multiple plants will be affected and symptoms will appear over a couple of days or weeks, so keep checking the planting for plants that need to be rogued. If you need help identifying TSWV, please contact us with the form at the end of this post.
TSWV symptoms: A) Stunting of infected planted compared to healthy plants, and B) closeup of affected foliage showing curling and brown lesions. Pictures by Maria Cramer.
Second, scout plants for thrips. This is important before and after insecticide applications, because you need to know how well treatments worked. There is no established treatment threshold for thrips, especially when TSWV is a risk, although one adult western flower thrips (the TSWV vector) per flower has been suggested. In the veg IPM program, we typically scout foliage for thrips, as these are most likely to be western flower thrips, but at this point most of the thrips we are finding are western flower thrips, so we advise monitoring both flowers and foliage to get a sense of thrips pressure in a planting.
Thrips on a tomato leaf. Picture by Maria Cramer.
In cases where TSWV is scattered throughout a planting and thrips are present in high numbers in flowers, weekly sprays can help slow TSWV spread, but will not stop it. If you are spraying regularly for thrips, make sure to use effective products (see our previous article for a chart listing products and efficacy) and always rotate modes of action and follow seasonal limits.
Pay attention to fertility: over-fertilized plants are more attractive to thrips.
Thrips can move from older plantings to younger ones, carrying TSWV with them, so destroy older plantings as soon as harvest is done or if management becomes non-economical in order to prevent spread to younger plantings.
Spider mites. We have seen elevated spider mite counts in some tunnel and field tomatoes and peppers. Otherwise, tomatoes and peppers have been relatively free of aphids, stinkbugs, and caterpillars. When sampling spider mites on tomatoes, check 10 upper leaflets in at least 5 sites per field. Typically, the treatment threshold is 2 mites per leaflet on average (one of the individual leaves that makes up the compound tomato leaf). Keep in mind that in 2025 we saw miticide resistance on farms where crop rotation was limited and the same miticides were used for multiple years — If you apply a miticide, check whether the application has decreased mite populations, and if it did not work well, do not keep using it. Rotate between miticides and only treat when above threshold. Some products for spider mites in tomatoes include:
- Nealta (group 25)
- Oberon (group 23)
- Portal (group 21A)
- Agri-Mek (group 6) *7 day PHI
- Kanemite (group 20B)
- Acramite (group 20D) *3 day PHI
- Incipio is also considered a very good miticide that also has activity against thrips. In cases where thrips and spidermites are both high, this may be a good choice.
Spider mite stippling on the top of tomato leaves. If you turn the leaf over, you will often see spidermites on the lower surface. When spidermite infestations are large they may be on both surfaces of the leaves. Picture by Maria Cramer.
Beet armyworm. We track beet armyworm with pheromone traps deployed in south Jersey. Beet armyworm is an occasional pest of peppers, swiss chard, and beets and can cause serious damage and crop loss if outbreaks occur unexpectedly. Our traps indicate that beet armyworm flights have remained low this week, with captures in Atlantic County below 2 moths per night for the last week, and captures in Salem County below 10 moths per night.
Cucurbits
Powdery mildew has been detected at low levels in most scouted fields. If you detect more than 1 leaf with lesions out of a 50 leaf sample, you should initiate your fungicide program. Anthracnose continues to be present in fields as well. Fungicides that control powdery mildew should also aid in controlling anthracnose.
Powdery mildew on pumpkin leaf. Photo by Amanda Quadrel.
Bacterial Diseases: Bacterial diseases are still present at low levels in many fields. Bacterial diseases can be difficult to manage, and heavy rainfall will encourage spread of the disease. Regular copper sprays plus mancozeb may help reduce spread in the field. If possible, try to avoid overhead irrigation or working in the plants when they are wet.
Squash Bugs: We are still regularly seeing squash bug eggs and nymphs in many locations. If you are scouting your pumpkins and find that your plants have more than one egg mass or nymph cluster per plant on average, it may warrant treatment. Materials for squash bug treatment include Sivanto Prime (IRAC 4D), Cormoran (IRAC15+4A), Incipio (IRAC 30), and various neonicotinoids and pyrethroids. Treatments should target the nymphs, and coverage of the undersides of the leaves is essential.
Squash bug eggs (A), newly hatched nymphs (B), and an adult (C). Photos by Amanda Quadrel
Cucurbit Downy Mildew (CDM) Status: There still haven’t been any reports of downy mildew in New Jersey, however, with the recent storms coming up from the south, we are expecting to see it arrive on cucumbers and cantaloupes soon. We still have not detected CDM in our sentinel plots at the Snyder Farm in Pittstown and RAREC in Bridgeton. These plots contains two varieties of cucumber (a susceptible and resistant variety), watermelons, cantaloupe, and various types of winter squash. If we detect CDM, either in our sentinel plots or elsewhere in the state, we will send out an alert immediately, but the CDM IPM Pipe site can be used to see the most recent sightings of the disease throughout the country.
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: James Johnson, Shayne Miller, and Cassandra Dougherty
South NJ: Alex White, Renee Carter, Peter Combs, and Kris Szymanski
Authors: Amanda Quadrel (Northern NJ Veg IPM coordinator) and Maria Cramer (Southern NJ Veg IPM coordinator)
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