Research HighlightsFinding Answers to Strengthen the Fight Against Soybean Pests
In this article, you’ll find details on:
- Findings from a multi-state research project sheds light on different aspects of insect pest management
- Entomologists are improving ways to scout fields for stink bugs, learning more about two newly discovered soybean pests, and exploring aphid control through new insecticides and resistant soybean varieties
- The 3-year project is funded by the North Central Soybean Research Program
By Carol Brown
Once soybeans are planted, they must fight to survive a plethora of combatants. Insect pests are in a unique category on the soybean enemy list. Insect lifecycles and insecticide resistance are varied and these variations make it difficult to control pests with blanket methods.
Researchers across the North Central U.S. have been collaborating for years to find effective solutions for insect control. A project supported through checkoff funding by the North Central Soybean Research Program (NCSRP) is enabling entomologists to compare and contrast their findings across the region.
The three-year project covers several areas: improving scouting methods for stink bugs, testing insecticide resistance of the soybean aphid and soybean varieties that are resistant to them, expanding knowledge of the soybean gall midge, and gaining information on the newly discovered soybean tentiform leafminer.
The project also provides continued support for the midwestern aphid Suction Trap Network, which began in 2005. The network comprises 28 suction traps across the Midwest that capture winged insects. Data is gathered on these insects for population counts for infestation levels.
“Of the recent outcomes from this work, I’m excited about the new monitoring tool for stink bug,” says Kelley Tilmon, entomology professor at Ohio State University and past project leader. “The soybean gall midge results also have been quite impactful.”
Stink Bug Pheromone Traps
Sampling for insects in soybeans during the height of summer can be a problem, Tilmon says. By August, soybean vegetation is dense, making it difficult to sweep a net through the rows to catch insects. Once a specified area is swept, the insects caught in the net are identified and counted to determine insect levels in the field.
“We have found that pheromone baits paired with a sticky card mounted at the edge of a field have proven to be as effective as using sweep nets when field scouting for stink bugs,” Tilmon says.
A team of entomologists across 12 states compared the pheromone-laden sticky traps with stink bug counts from field sweep nets. They saw similar results between the two systems, especially for the brown marmorated sting bug, which means the pheromone lures are an accurate monitoring tool for this species.
“This tool will be good for where the brown marmorated stink bug is the main stink bug species, which is basically the eastern half of the corn–soybean belt,” Tilmon comments. “We are in the process of publishing a scientific journal paper on the results. Once published, we’ll develop extension materials for farmer use.”
They also updated the field guide Stink Bugs of Soybean in the North Central Region, which can be viewed on the SRIN site.
Learning About New and Old Pests
The entomologists continue to research soybean aphid control methods, which were a large problem in the entire Midwest years ago. They prevail as an issue mainly in the western part of the North Central region. The insect has become generally resistant to some commonly used insecticides, Tilmon says, and team members have been diagnosing aphid resistance to these and the new insecticides on the market. They have also done extensive work on resistant soybean varieties, documenting the value of resistance and how aphids can overcome host plant resistance.
Another component of this project is advancing the knowledge about two new insect species: the soybean gall midge, which was first discovered in Nebraska and Iowa in 2018, and the soybean tentiform leafminer, found in Minnesota in 2021.
Although these newly found insects are concentrated in a relatively small geographic area, they are inhabiting some of the highest soybean producing areas in the country. This is concerning to farmers as well as scientists, so it is important to know how to stop their spread. Entomologists have been steadfast in their education of these pests to reduce soybean yield damage.
The soybean gall midge research is led by Justin McMechan, a University of Nebraska entomologist and cropping systems specialist. The team is exploring tillage and mowing as control strategies, testing for midge-resistant soybean varieties as well as resistant germplasm for future variety development. McMechan conducts an annual survey to track the gall midge’s geographic spread and maintains the Soybean Gall Midge Alert Network, which informs farmers of emergence.
The soybean tentiform leafminer is the most recent discovery in midwestern soybean fields. University of Minnesota Extension Entomologist Robert Koch is leading the research on this pest. He first identified the soybean tentiform leafminer in Minnesota and South Dakota, and now it is also in North Dakota and Nebraska soybean fields. The team is also surveying the pest’s spread as well as testing insecticide effectiveness. Additionally, Koch is looking at biological control, which consists of nearly 20 species of parasitic wasps that feed on the leafminer’s larvae.
Other Key Outcomes
In addition to these important research areas, Tilmon cites a few other effective outcomes of this project.
“One of the more popular tools is the 3D-printed keychain set for soybean defoliation,” Tilmon says. “The set contains three plastic leaves with different defoliation levels that can be used for comparison when field scouting. This can help farmers or crop scouts be more accurate when diagnosing defoliations for more informed management decisions.”
Lastly, Tilmon has been pleased with the number of students who were supported by this research project and the iterations prior to the current funding.
“In just the last three years, 12 graduate students were supported through this project and at least 49 undergraduate summer students have been trained in soybean field research,” she remarks. “Training that many students in how agricultural science is done, I think is a powerful impact.”
Additional Resources
Stink Bugs of Soybean in the North Central Region – field guide
Developing a New Method to Monitor Sink Bugs in Soybeans – SRIN article
Soybean Gall Midge Alert Network – website with survey details and sign-up
Suction Trap Network – website
Meet the researchers: Kelley Tilmon, Robert Koch
Published: Jun 23, 2025
The materials on SRIN were funded with checkoff dollars from United Soybean Board and the North Central Soybean Research Program. To find checkoff funded research related to this research highlight or to see other checkoff research projects, please visit the National Soybean Checkoff Research Database.
