Arthropod predator community associated with soybean gall midge, Resseliella maxima (Diptera: Cecidomyiidae), in Minnesotan soybean fields.

The soybean gall midge, Resseliella maxima Gagné (Diptera: Cecidomyiidae), is a pest that injures soybeans in the Midwest United States. Little is known about the natural enemies of R. maxima or the potential for biological control. Therefore, we performed a 2-yr survey in Minnesota to examine the predator community associated with R. maxima infestations. We found that Orius insidiosus (Say) (Heteroptera: Anthocoridae) and Pterostichus melanarius (Illiger) (Coleoptera: Carabidae) were the most common foliar- and ground-foraging predators, respectively. Some of the commonly encountered predator species were tested in laboratory predation experiments. Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) and O. insidiosus represented the foliar-foraging predators tested, and H. axyridis consumed significantly more R. maxima larvae than O. insidiosus. Among the ground-foraging predators, 4 carabids were tested. Poecilus lucublandus (Say) (Coleoptera: Carabidae) and Pt. melanarius consumed significantly more R. maxima larvae than Poecilus chalcites (Say) (Coleoptera: Carabidae) and Bembidion quadrimaculatum oppositum (Say) (Coleoptera: Carabidae). We conclude that Pt. melanarius should receive further attention as a potential biological control agent of R. maxima, due to its high abundance in the soybean fields in this study, temporal overlap with the pest, and high propensity to feed on the pest.