Vegetable IPM Update 5/08/26

Greetings from the Veg IPM team! We hope everyone is doing alright despite the tough spring weather. In this post, we’ll discuss what we’ve been seeing as we’ve begun scouting cole crops and high tunnel tomatoes.

Cole Crops 

Flea beetle surrounded by feeding damage. Picture by Maria Cramer.

In some parts of NJ we are detecting flea beetles in various cole crops. This year, they have been especially prevalent in Napa cabbage 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

In high tunnel tomatoes, we’re seeing limited aphid, thrips, and spider mite activity. At this stage, 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. For thrips and spider mites, below is a table of some products that are labeled for tunnel use for each pest, including a column for products that are labeled for control of both thrips and spider mites. Note that this is not an exhaustive list.

When using pesticides, the label is the law. Always make sure the product you use is registered in your state and for your crop(s). Follow all application restrictions.

Additionally, please note that most thrips control products are labeled for suppression only. Be sure to consult the label for specific application instructions and limitations. More information on managing thrips.

Sweet Corn

We’ve put out a few corn earworm pheromone traps throughout the state. While silking corn is the main target of CEW activity, we set the traps early to detect overwintering moths, which have become more common with warmer winters. Official maps with statewide CEW activity will be shared starting in June.

On the last note, the new 2026/2027 Mid-Atlantic Commercial Vegetable Production Guide is now available both online (click here) and as spiral-bound hard copies in county extension offices. Consult this guide for a comprehensive list of materials that are labeled for specific crops and pests. Always check the label for rates and application instructions.

Authors: Amanda Quadrel (Northern NJ Veg IPM coordinator) and Maria Cramer (Southern NJ Veg IPM coordinator)

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