Soybean Gall Midge in Minnesota Soybeans

There is a new pest that has been identified in Minnesota soybean fields this summer. Soybean Gall Midge was found in southwestern Minnesota and in Faribault County. David Key who is Research Director for Minnesota Soybean said there is a lot we do not know about the Soybean Gall Midge. The species in Minnesota has never been identified before. That means there is nothing in the literature that researchers can find to learn more about Soybean Gall Midge.

Entomologists think the larvae overwinter inside cocoons with pupation and adult emergence in the spring. The adults begin to emerge in June and can be extended into July. Researchers think the adult flies lay eggs near the base of the soybean plant. Cracks in the stem epidermis and other wounds any provide the larval to enter the soybean stem. Larval feeding causes blackened areas at the base of the stem. Heavy infestations can cause deformed and necrotic areas on the stem.

Infected soybean plants can be stunted, show wilting or they can lodge or break off. Significant yield reductions have been reported especially on field edges. So, if you see some of these symptoms or dark discolorations at the base of the soybean plant contact Bruce Potter at bpotter@umn.edu or Robert Koch at koch0125@umn.edu.