Source: Iowa State University
An insect never before seen in Iowa was found in a field feeding on soybeans, according to Iowa State University. The pest was confirmed as the threecornered alfalfa hopper, Spissistilus festinus (Hemiptera: Membracidae), which is native to the southern U.S. and South America and can be an economic pest of soybean in southern growing regions. ISU entomologists cannot recall a previous detection in Iowa.
Although this hopper rarely causes economic damage because soybean plants can compensate greatly, reduced tillage areas and late planted fields are more likely to get infested. When plants are less than 12 inches tall, visually look for hoppers and initial girdling symptoms. As plants get larger, use a sweep net to capture adults and nymphs. Consider making a foliar insecticide application if 10 percent of plants (less than 12 inches tall) are infested or if 50 percent of plants are girdled. For reproductive soybean, consider treating when an average of one hopper per sweep is reached.