–by Dr. Jeff Whitworth and Dr. Holly Schwarting
Double cropped soybeans are still very much in the reproductive stages throughout north central Kansas. Thus, they are still vulnerable to a variety of pests – and pest populations seem to be increasing. Green cloverworms (see pic) have been feeding on leaves for the past couple of weeks but are starting to cease feeding to begin pupating. They rarely cause actual yield loss but usually cause concern because of the amount of defoliation they often cause. While green cloverworms don’t feed on the pods or seeds, adult bean leaf beetles and corn earworm larvae (a.k.a. soybean podworms) do (see pics). Both species, bean leaf beetles and corn earworms, seem to be increasing throughout south central and north central parts of the state. The corn earworm larvae will usually feed on the seed within the pod and will only feed for about 10-14 days. However, bean leaf beetles will continue to feed until harvest, or they disperse to overwintering sites.
There are still a few soybean aphid populations in north central Kansas, however there are more winged adults present which probably means they are mostly finished feeding and preparing to migrate to overwintering sites (they probably do not overwinter successfully in Kansas – we hope).
We have received several calls this week relative to these “interesting little green worms” in soybeans. These are silver spotted skipper larvae and will feed on leaves but should not defoliate enough, on a field-wide basis, to impact yield.