–by Dr. Jeff Whitworth and Dr. Holly Davis
Not much defoliation in soybeans in north central Kansas, so far. Bean leaf beetle adults are emerging and feeding on leaves. Photo: Both color phases of the bean leaf beetle and the 12-spotted cucumber beetle or the southern corn rootworm, which is commonly mistaken for a bean leaf beetle.
These adults may start feeding on pods when the plants get to that developmental stage. All the soybeans we examined this week were still in the late vegetative to early R1 stages. But, when plants do start setting pods, bean leaf beetle adults need to be closely monitored.
Potato leafhoppers were also very numerous in soybean fields. They do not seem to be problematic in soybeans yet in KS. However, these increasing populations will also be in alfalfa.
Dectes stem borers continue to be active in soybeans throughout north central KS, depositing eggs in stems.
For more information on these and other soybean insects, please see the 2018 Soybean Insect Management Guide: https://www.bookstore.ksre.ksu.edu/pubs/mf743.pdf