The number of capture Japanese beetles in southern Illinois skyrocketed shortly after a warning from the University of Illinois Extension department.

Ron Hines, senior research specialist at the Dixon Springs Agricultural Center, reported that from June 16 to June 20, approximately 1,000 to 3,000 Japanese beetles were captured per day.

Due to the potentially large number of Japanese beetles in southern Illinois, Kevin Steffey, entomologist for the University of Illinois, notes that the potential for economic damage is real. Since most cornfields are not tasseling, silking and pollinating, the only threat to corn is defoliation, which, if severe, could warrant control. That same concern about defoliation applies to soybeans.

Steffey adds that since most people have had bad experiences with Japanese beetles when corn is pollinating, some producer may be considering ‘pulling the trigger’ on this pest sooner rather than later. However, Steffey encourages people to fight the urge to spray insecticides to control Japanese beetles before pollination, unless defoliation is excessive. He notes that an insecticide applied too early may not have enough residual to control Japanese beetle adults that may fly into cornfields at a late date.