Injury severity to yield loss relationship for soybean gall midge

Soybean gall midge, Resseliella maxima Gagné (Diptera: Cecidomyiidae), is a new soybean pest in Nebraska, Iowa, South Dakota, Minnesota, and Missouri. In 2018 and 2019, severe economic loss occurred in commercial fields and therefore our research focused on the biology and management of this pest. An injury rating system (0-3) was developed to measure the severity of plant injury from soybean gall midge. Insecticide efficacy evaluation plots from 2019-2020 from Iowa and Nebraska were evaluated for injury throughout the growing season and yield was measured. A nonlinear regression model was developed to validate our injury rating system for soybean gall midge. This model expresses the relationship between season long injury severity and yield loss caused from soybean gall midge infestations. Results from our analysis indicate that the injury rating system developed correlates well with yield loss caused by soybean gall midge and may be an important tool for understanding the economic impact of this emergent pest of soybean.