Jim Jensen, extension field specialist in crops, reports finding grasshopper nymphs in soybean fields in southeastern Iowa. I also have seen them in central Iowa. No economic damage has been reported, but their appearance in soybeans should serve as an early warning to scout soybean fields during the next couple of weeks.
Iowa State University
Rice, Marlin E., "Scout soybeans for grasshoppers" (1999). Integrated Crop Management News. 2175.