Source: University of Missouri
Several regions of Missouri are experiencing high numbers of small grasshoppers. Historically wet years have not favored grasshopper populations as high moisture levels tend to allow bacterial and fungal pathogens to attack developing grasshopper nymphs. This has changed in the past five years as grasshopper populations tend to build whether wet conditions are present or not.
The economic thresholds for grasshoppers vary depending on the commodity or non-cropland area requiring insecticide applications for effective grasshopper management. In Missouri, there are approximately 100 species of grasshoppers although only five to seven species are common in field crops.