Caterpillars

It's time to start scouting for podworms (Helicoverpa zea) in double-crop soybeans. There have been reports of high numbers of small and young pod worms and soybean loopers in double-crop soybean on the Delmarva. Podworms prefer fields that are flowering, open canopy, and stressed and have been recently sprayed with a non-selective insecticide. Their population can be spotty, so one field can be high while the field next to it is low, so the only way to know what is happening in a particular field is to sample it. You can sample for podworms using either a sweep net or drop cloth.

Eastern tent caterpillar and moth photos

August IPM insect scouting tips on soybean, field corn, and sorghum.

IPM Threshold Guide for Vegetable Crops

Soybean: Scout for the usual defoliators, including bean leaf beetle, Japanese beetle, and caterpillars. The treatment threshold is 15-20% defoliation for bloom to pod fill. Note that defoliation percentages should be based on the entire soybean plant or canopy, not just the top leaves or worst leaves. University of Nebraska Extension has a nice guide for defoliating insects in soybeans (https://croptechcafe.org/defoliating-insects-in-soybeans-thresholds-training-and-tools/). Adult Dectes Stem Borer will be emerging over the next several weeks. Chemical control is not recommended since it would require multiple applications to reduce larval infestations, which is not economical. However, if a high number of adults are found, harvesting that field as soon as it matures will reduce losses associated with lodged plants.

Over the last 4-5 years I have received calls and emails from growers about insect pests that they cannot seem to control as well as they had in the past. This presentation is going to look at some of the top vegetable pests that growers in the mid-Atlantic have had problems with and some ways to mitigate those problems.