David Owens, Extension Entomologist, owensd@udel.edu and Bill Cissel, Extension Agent – Integrated Pest Management; bcissel@udel.edu
Continue to scout for corn earworm and soybean looper. Last weekend’s storm activity from the south could have brought up more loopers from that region. I have received a couple of reports of pockets of loopers in fields. They often show up in localized sections, typically in drier, less robust parts of fields. Defoliation thresholds prior to R6 are 15%, at R6, plants can tolerate greater defoliation. R7 beans are safe. Also, be sure to check the lower canopy if you do see significant looper activity, they sometimes start first in the lower canopy unlike our other defoliators that concentrate in the upper canopy. NC only recommends Intrepid Edge, VA recommends Intrepid Edge and Steward. Both products are ‘worm’ products and will clean up corn earworm. Steward has some, but not great activity on bean leaf beetle, and neither has stink bug activity. We also had a report of armyworm activity in some isolated fields. Armyworms can feed on pods, but are not as aggressive as corn earworm. There doesn’t seem to be much consensus in different states’ recommendations; some combine them with corn earworm thresholds, others treat them as defoliators, and others use a threshold in between.