By Ron Hammond and Andy Michel, The Ohio State University Extension
With many soybean fields starting to yellow and mature, our concern needs to turn to late maturing fields that are, and will remain, green for the next few weeks. As fields mature, bean leaf beetle adults will leave and look for soybean fields that are still green to continue their feeding prior to overwintering.
Because of very high numbers that can come into green fields, the soybeans remain susceptible to pod feeding. Growers are urged to monitor any field that is still green for their presence and feeding activity. Treatment is warranted if feeding injury is reaching 10-15% of the pods and beetles are still actively feeding. Remember that if treatment becomes necessary, growers should note the preharvest interval on the insecticide label so that they can still harvest on time.
Late maturing fields could be those late planted, including those doubled or intercropped. Special concern should include soybeans grown for seed or as food grade soybeans.