July 11th, 2025

Highlights

• Soybean gall midge larvae and wilting and dead plants found in two new counties in eastern Iowa. 

• Increased in plant injury and adult emergence in eastern Nebraska over the past week.

• Larvae detected in southeastern South Dakota.

• Important to scout fields especially in counties were soybean gall midge has not been found.

• Scouting resources can be found at Scouting Resources

Iowa

Wilting and dead plants were observed in Dallas, Tama, Marion, and Poweshiek (Fig. 1). The occurrence of wilting and dead plants in newly identified counties (Tama and Poweshiek) suggests that soybean gall midge might be more widespread in eastern Iowa. If you are in that area, now is a good time to scout field edges next to last year’s soybean.

Figure 1. Wilting and dead plants in Poweshiek County in eastern Iowa taken in July 2025. (Photo: Matt Vandehaar)

Nebraska

A significant increase in adult emergence was observed at several locations from the current year’s soybean field over the last 7-10 days. Larval counts between plants vary considerably but we are seeing several plants with numbers exceeding 30 per plant. Plant death along field edges have also increased significantly over the past week from 1-2% to 10-30% at research sites (Fig. 2) spanning several eastern Nebraska counties.

Management Recommendations

Past studies have shown that peak larval numbers for the season typically occur in late July and early August. These large numbers of larvae often raise questions about management at this point in the season. Managing soybean gall midge this late in the season isn’t recommended for several reasons. First, adult emergence cages in the current year’s soybean field in east-central Nebraska have shown that adults are emerging almost daily from now until late-August. Second, the larvae are hidden within the stem, and as a result, foliar insecticide applications are unlikely to reach them. Lastly, a field study conducted at the Eastern Nebraska Research and Extension Center over the last couple of years showed that soybean gall midge was unable to cause a significant impact on soybean yields when infestations on plants at the R2 (full flower) that were not previously infested.

Although management isn’t recommended, the next few weeks are a good time to scout soybean fields for the presence of larvae. Soybean fields do not have to show signs of wilting or dead plants to have a significant infestation of soybean gall midge. To scout a field, you should look at the base of a soybean plant between the first two rows that are adjacent to a field that was soybean the previous year. There are several videos on the “Scouting for Soybean Gall Midge” webpage.

Thank you to the USDA NIFA, North Central Soybean Research Program, Nebraska Soybean Board, Minnesota Rapid Response Agricultural Fund, Minnesota Soybean Research and Promotion Council, and our Industry Partners for funding soybean gall midge research.

Grower Survey of Soybean Gall Midge and Dectes Stem Borer

Dr. Doug Golick from the University of Nebraska is conducting a survey on the opinion of soybean producers on emerging pests. As a subscriber of the soybean gall midge alert network website, I would like to inform you that a link to this survey is available for you to provide your opinions on emerging soybean pests in Nebraska. Participation in this survey will take about 15 minutes to complete. If you are interested in participating in this study, follow the link to the survey here:

https://go.unl.edu/soybeanpestsurvey2024

There are no known risks involved in this research. If you have any questions regarding this research, please let me know. You can reach Doug at dgolick2@unl.edu. For questions concerning your rights or concerns about the research, please contact the UNL Institutional Review Board (IRB) at 402-472-6965 or irb@unl.edu.