–by Dr. Jeff Whitworth and Dr. Holly Schwarting
Many beans have passed the stage that is attractive for bean leaf beetle adult pod feeding. However, later planted beans are still tender enough to attract these beetles and they are feeding on the pods.
This can reduce yield quickly so monitoring needs to continue until the last pods have turned yellow. Please refer to the 2016 Soybean Insect Management Guide available at: https://www.bookstore.ksre.ksu.edu/pubs/MF743.pdf for management recommendations.
— by Dr. Jeff Whitworth and Dr. Holly Schwarting
Green Cloverworms in Soybeans
Remember a few weeks ago when there was considerable concern relative to all the green cloverworms causing irregular holes in leaves? Even skeletonizing some areas of some fields until treated with an insecticide and/or and entomopathogenic fungus started decimating the larval populations? Well, the surviving larvae pupated and now are annoying little aerodynamically shaped dark brown moths flying around lights at night or trying to get in through doors and windows.
These moths will mate and then begin ovipositing in soybean and/or alfalfa fields. Eggs hatch in approximately 10-14 days and the larvae will again start feeding on leaves of either crop. By this time of year, the larval feeding is usually of little consequence relative to yield. However, really late planted soybeans, and all alfalfa fields, should be closely monitored to ensure leaf feeding in either crop does not affect pod fill in soybeans or leaf area in alfalfa.
These insect pests seem to be on about the same developmental schedule as green cloverworms. So, late planted soybeans may be at risk for bean feeding within the pods.
Adult bean leaf beetles, while probably not as numerous as in past years, may still be feeding on the pods themselves. This can cause yield reductions. For more information on bean leaf beetle biology and control, please visit: https://www.bookstore.ksre.ksu.edu/pubs/MF2824.pdf
Another leaf feeder that can cause concern this time of year is woollybear caterpillars. There are several different species but all are foliage feeders although they rarely cause any economic problems.
Hopefully, most soybeans are past the stages that are succulent enough for stink bugs to be feeding on. However, there are still some late planted beans setting pods with seeds that may be vulnerable to stink bug feeding. So, until pods are turning yellow or brown, fields probably should continue to be monitored for soybean podworms, adult bean leaf beetles, and stink bugs.