D3090: Soybean gall midge: Estimating spatial severity of plant injury and yield loss

< ![if !vml] >< ![endif] >Soybean gall midge (SGM) was recently identified as a new species causing injury to soybean. Over the past three years, SGM larvae have been documented in 114 counties across five midwestern states. The SGM larval stage can cause significant injury to soybean with infestation starting at V2 stage when fissures form at the base of the stem. The most significant injury and yield loss from SGM occurs at the field border, however, studies have evaluated yield loss with distance into the field. As a result, a field study is being conducted in Lancaster County, NE during the 2021 season to evaluate SGM injury to soybean with distance from the field edge through larval presence, plant injury, and soybean yield components. In 2020, a field efficacy study found that Thimet treated soybean yields were 98% and 54% greater than untreated plots at 3 and 12 meters from the field edge, respectively. In 2021, treatments consist of Thimet (9 oz per 1000 ft/row) treated and untreated, soybean plots planted parallel to the field border at set distances from the field edge to 150 meters in a randomized completed block design with three replications. Each plot will be evaluated for the frequency of infested plants and the number of larvae per plant at three times during the season. This study will provide clientele with the critical information on the area from the edge of the field where current and future management tactics should be applied.