David Owens, Extension Entomologist, owensd@udel.edu
Soybeans
We started surveying full season soybean for stink bug this week. Defoliator populations appear to be low. The greatest populations of stink bugs we found were in the Greenwood area. Pay attention to field edges bordered by woods, field corn, or woody shrubs/small trees. One field we visited near Greenwood was 3-4 times over the 5 bugs per 15 sweep thresholds along the woody edge. However, stink bug populations dropped below threshold about 150 feet from the woody edge. Thus, a large field might not need to be completely treated.
Sorghum
begin scouting for white sugarcane aphids (now also referred to as sorghum aphid). This aphid typically arrives in our area between late July and early August and can cause yield loss as late as soft dough. Thresholds from flowering to dough stage are 30% infested plants with localized areas of honeydew and established aphid colonies. If a field needs to be treated for aphids, Sivanto Prime and Transform are the best materials.