David Owens, Extension Entomologist, owensd@udel.edu
Cole Crops
We have finally picked up a couple of cabbage looper. Most worms present in cabbage plantings are diamondback moth and imported cabbageworm. We are finding occasional beet armyworm. Remember beet armyworm are not susceptible to pyrethroids. Pay attention to the size of worm present. For instance, we visited one field of cabbage earlier this week in which all the diamondbacks were beginning to pupate. Barring another flight into the field from outside, it should take 7-10 days for those pupae to emerge as adult moths. Pay attention to aphids. Many, but not all, worm materials have aphid activity. Broad spectrum insecticides may limit aphid natural enemies, potentially resulting in elevated numbers of aphids. In 2020, our fall cabbage in Georgetown was so infested many plants did not make a head. Remember to use a spreader type adjuvant, high water rates, and multiple nozzles to achieve good coverage.
Lima Bean
Scout late lima bean for soybean looper and stink bugs. Soybean looper activity has been increasing in Virginia, though with nighttime temperatures dropping into the low 50s, looper activity should start to decline. Loopers can feed on lima bean pods, and they can be a contaminant issue. In 2021 trials, the most effective material for soybean looper was indoxacarb. Lannate can also be used to knock them down but pay attention to its preharvest intervals.