In late June 2018, entomologists in Nebraska, Iowa, South Dakota, and Minnesota began receiving reports of soybean fields with visible signs of dead or dying plants that were found to be associated with soybean gall midge. The presence and injury from soybean gall midge were most significant in fields adjacent to a field that was soybean the previous year.

Since its discovery and designation as a new species in 2019, soybean gall midge has expanded its range in eastern Nebraska from 24 counties in 2018 to 39 total counties as of 2020, with continued expansion west each year. Of the newly infested counties in 2020, all showed low larval presence and no significant signs of wilting or dead plants. In contrast, some counties that were first observed as infested in 2019 have seen elevated levels of plant injury. Efforts to document the distribution and severity of soybean gall midge were funded by a one-year objective from the North Central Soybean Research Program. Survey results documented several counties in Nebraska with severe injury, identified eight newly infested counties, and noted the presence of orange larvae on other hosts (sweet clover) in the state.

With soybean gall midge rapidly emerging as a new pest of soybean, it is critical to systematically track and scout for its presence in uninfested counties and document the level of injury in infested counties. This information in combination with its presence on other plant hosts are critical for estimating the risk and loss from soybean gall midge each year.

Collecting detailed spatial and temporal information would allow for greater understanding of the factors (e.g., landscape, weather, agronomic factors, etc.) that lead to Figure 1. 2020 survey of soybean significant loss, and if its potential as a pest is increasing. It is also critical to alert soybean farmers and clientele in new areas to the pests’ presence and to connect them with information on management and scouting. (Year 2 of 3 Year Project)

Determine the presence the severity of soybean gall midge in new and previously reported counties in eastern Nebraska.

Obtain geographic information on the frequency of soybean, landscape characteristics, and weather patterns such as rainfall and temperature to determine there are any correlations with plant injury and larval number at each site.

Collect and process a subset of representative samples for DNA sequencing for identification and to compare sequences between hosts and samples from different geographic areas.

Each year of the project will have a similar milestone with collections beginning in mid-July end ending in late August. Within seven days of the last collection, all larval counts on samples would be completed. This portion of the project would allow for the development and release of maps with areas of significant pressure to be used by extension, industry, and farmers. During the winter, sequencing of samples would provide continued detailed information on the proper identification of soybean gall midge. Information at each site on the frequency of soybean, weather, and other parameters would be added to determine what potential factors contribute to field injury from soybean gall midge.

Resulting data from this project would be presented at a number of Nebraska outreach extension efforts such as Soybean Management Field Days, Nebraska Crop Management Conference, Midwest Crop Production Clinic, Crop Production Clinics, and Nebraska Soybean Expo. Updates on research progress would be presented through Blackboard Connect Alert System, soybeangallmidge . org, Twitter, Market Journal interviews, and UNL Cropwatch articles. We would expect that at least one peer-reviewed publications will result from this work.

The proposed project, although not traditional, would provide the foundational information necessary to not only document the production losses but isolate factors for increased risk. In addition, such efforts would provide Nebraska farmers as well as researchers with a proactive approach to mitigate and manage soybean gall midge as new tactics emerge through current and ongoing research projects. The goals of this project are closely aligned with a USDA NIFA Foundation project planned for submission in 2021. Funding from the Nebraska Soybean Board would greatly enhance this effort and keep Nebraska as a national leader on soybean gall midge research.