Missouri corn and soybean growers are reporting growing numbers of Japanese beetles in crops in recent weeks, according to University of Missouri Extension state entomologist Ivair Valmorbida.
Valmorbida uses numbers from MU Extension’s Pest Monitoring Network, which gathers information from across the state. The highest numbers are reported in northwestern Missouri’s Gentry County. Numbers are also growing in northeastern Missouri. Japanese beetle adults are highly mobile, so Valmorbida recommends regular scouting of fields. Adult Japanese beetles primarily feed on the upper canopy leaves, causing defoliation in soybeans.
Leaves become skeletonized with veins still intact. In soybeans, insecticide treatment decisions are based on growth stage and amount of defoliation, including injury from other defoliators because it is difficult to distinguish among the types of feeding injury.
Japanese beetles are also considered a pest in corn crops. They focus on clipping corn silks necessary for pollination, which can lead to some yield reductions, Valmorbida said.
MU Extension’s pest monitoring website offers an alert system for Japanese beetles and other pests. Subscribe to alerts at https://ipm.missouri.edu/pestMonitoring or email [email protected].
