In February, University of Minnesota Extension hosted a two-part Midwest soybean gall midge webinar series. Several university experts from Nebraska, Iowa State, Minnesota and South Dakota were involved in discussing the latest research developments. The recordings can be found via the University of Minnesota’s website. Iowa State entomologist and ISRC affiliate Erin Hodgson and University of Nebraska Crop Protection and Cropping Systems Specialist Justin McMechan helped moderate the series.

Session one covered “Insights on soybean gall midge distribution, scouting, ecology and chemical control.” Highlights included an overview of soybean gall midge, which can now be found in several states along the Missouri River. However, the heaviest infestations are still found in eastern Nebraska with infestations typically occurring around field edges in the V2 soybean growth stage or later and it is common to see different life cycles at the same time. Researchers commented that just because a field may have gall midge, it does not necessarily mean the field will incur a lot of damage, so using insecticides may be more harmful than helpful.

Session two covered “What's in the toolbox? Updates on cultural, biological, and host plant resistance tactics.” Researchers continue to study a variety of management strategies. Interestingly, hilling (bringing soil up around the base of a plant) appeared to reduce the number of larvae. And, while seed treatments didn’t seem to make a difference, time of planting may. Later planted soybeans seemed less infested, but dry weather conditions may have also played a role. Of particular interest was a discussion with George Graef, a professor of plant breeding and genetics at the University of Nebraska, who observed significant resistance in elite soybean germplasm, which could be good news for soybean farmers and agriculture companies. He believes there is a way to screen elite soybean germplasm to identify the best lines to use in infested areas and in breeding programs, and management of the pest may be related to variety choice. Another interesting development is that the gall midge appears to have natural enemies. Studies showed that once gall midge larvae fell to the ground in the process of becoming an adult that they were eaten by brown beetles and parasitic wasps.

Stay tuned as researchers continue to observe this relatively new pest. If you think you may have soybean gall midge in your fields or to learn more, visit the Soybean Gall Midge Alert Network website.