Japanese beetle is an invasive insect capable of feeding on corn and soybean. This pest has been in Iowa since 1994 but its distribution in field crops is sporadic around the state. Statewide populations have been low since 2014 and it is unclear if pressure will be significant this year. Japanese beetle adults need about 1,030 growing degree days (base 50°F) to complete development and will continue emergence until around 2,150 degree days. Based on accumulating degree day temperatures in 2017, Japanese beetle adults should be active in some areas of southern Iowa this week (Figure 1).
Iowa State University
Hodgson, Erin, "Japanese Beetles Emerging in Southern Iowa" (2017). Integrated Crop Management News. 2444.
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