Soybean Gall Midge (Diptera: Cecidomyiidae), a New Species Causing Injury to Soybean in the United States

Abstract The soybean gall midge (Resseliella maxima Gagné) was recently identified as a new species causing injury to soybean in the Midwestern United States. Although this insect was only recently identified, it has likely been present in soybean fields for at least the last 8 yr based on anecdotal reports. The soybean gall midge has historically been observed late in the season on soybean plants that were believed to have been previously compromised by a plant pathogen or mechanical damage with little to no concern for economic losses. In late June 2018, dead and dying plants were found to be associated with the soybean gall midge across four midwestern states. The distribution of plant injury in the field, larval feeding within the stem, and timing of infestation indicate that it is likely an important pest of soybean. Yield losses in soybean gall midge infested fields can be up to 100% for the first 30 meters from the field edge, with losses of 17–31% further into the field. The rapid development of the soybean gall midge as an important pest of soybean has left large gaps in the knowledge necessary to develop an integrated pest management program.