In a nutshell, European corn borer (ECB) is a small nocturnal brown moth. Problem is, they may choose pepper plants as hosts for egg-laying and larval development. Since larvae feed and develop inside the pepper fruit, which is the marketable portion of your plants, it’s important to look for them.

This pest overwinters as fully-grown larvae in corn stubble or other plant material and complete development the following spring. When adults emerge, they take flight to look for mates and suitable hosts such as corn, wheat, potatoes, hemp and unfortunately greenhouse peppers to feed and reproduce.

Cara McCreary, Ontario greenhouse vegetable IPM specialist and Tracey Baute, Ontario entomologist for field crops, detail how to scout for European corn borer. They explain that a degree day model was validated to predict flight patterns of ECB in southwestern Ontario. This model predicts when ECB flight begins, peaks and ends based on moth catches and can be used to guide scouting and management decisions.

Pheromone traps or light traps will be attracting adult moths which are approximately 2 cm (0.8 in.) long, light-brown with dark wavy lines running across each forewing. Males are typically darker and smaller than females.  Pheromone traps only catch males (lure is the female sex pheromone) but there are other look-alike moths that can also end up in the traps. For more details on setting up pheromone traps and to view adult moths and their look-alikes click here.

Scouting for ECB should include close observations of pepper fruit, specifically looking for signs of larval entry. When larvae chew their way into the pepper fruit, they leave holes that may be hidden beneath the calyx or they could be entirely visible. They do leave some evidence in the form of frass (i.e., poop) near their entry point. Mature larvae are approximately 2.5 cm (1 in.) in length, creamy white to pale grey with two small spots on each abdominal segment, with a black head. If infested fruit are found, remove and discard properly (e.g. crush, freeze, or bury deep) to intercept the larvae from completing development.

For details, link here: https://ongreenhousevegetables.ca/2023/05/29/targeted-scouting-efforts-for-european-corn-borer/

Source: ONGreenhouseVeg May 29, 2023 blog