Evaluating biological control of the soybean gall midge (Resseliella maxima Gagné) in Minnesota

Abstract

The soybean gall midge, Resseliella maxima Gagné (Diptera: Cecidomyiidae), poses a threat to soybean crops in the Midwest US. However, little is known regarding its natural enemies and the potential for biological control. Therefore, this thesis aims to fill this knowledge gap by focusing on evaluating biological control for R. maxima. To achieve this, we conducted a two-year survey to investigate the parasitoid and predator communities associated with R. maxima infestations in Minnesota. Our findings confirmed parasitism of R. maxima larvae by the wasp Synopeas maximum Awad & Talamas (Hymenoptera: Platygastridae) and examined the spatial-temporal dynamics of parasitism within fields. Additionally, our observations showed that the predator Pterostichus melanarius (Illiger) (Coleoptera: Carabidae) was the most prevalent species in the soybean fields in this study, presented temporal overlap with the pest, and had a high propensity to feed on R. maxima larvae. We concluded that further research should evaluate how parasitism rates by S. maximum could be promoted in production fields and that Pt. melanarius should receive further attention as a potential biological control agent of R. maxima.