D3128: Evaluating the Impact and Interactions of soybean gall midge, Dectes stem borer, and plant diseases in soybean

Insect pests and plant diseases can directly or indirectly impact crop yields, necessitating a comprehensive understanding of their effects to enhance crop protection. Of these pests, soybean gall midge (SGM) has been a significant threat to soybean production in the Midwest since its discovery in 2019 as a new species. SGM infestation on soybean is typically confined to the base of the plant. In 2023, SGM larvae were found in the upper canopy of soybean and were associated with oviposition sites from Dectes stem borer. The co-infestation and utilization of other parts of the soybean raise concerns about an increased impact from SGM on soybean. The infestation and feeding from these two pests also increase the potential for plant disease. To understand these interactions, a study was conducted at several sites in central and eastern Nebraska using unconventional tactics such as hilling to target SGM, fipronil seed treatment for Dectes stem borer, and multiple fungicide applications with the goal of selectively reducing the presence of one of these organisms. Treatments were evaluated for the presence and abundance of these organisms through the season, as well as total yield and yield components, to determine the impact and potential for interactions. The results of this study will provide growers with an understanding of the interactions between key pests in the system to understand the risk and potential for management of these organisms if they co-occur in a field.