Soybean gall midge is no longer just a curiosity or annoyance for many Midwest farmers. The pest is chewing into yield and profitability for soybean growers across parts of at least seven states – Kansas, Iowa, Minnesota, Missouri, Nebraska, North Dakota, South Dakota.
Iowa State University Entomologist Erin Hodgson reports the pest’s footprint is significant, present in at least 42% of the 45.4 million acres of soybeans farmers harvested across the seven states in 2025.
“At least 19 million soybean acres are potentially impacted by this pest,” Hodgson says, noting that the pest continues to spread. Eight new counties were confirmed in 2025, with five of those being in Iowa.
According to a recent farmer survey led by University of Nebraska Entomologist Doug Golick, the pest has become a major threat in parts of Nebraska. “In the last year or two, soybean gall midge is approaching as near high of concern as herbicide-resistant weeds for survey respondents,” Golick says.
Look For Small Orange Or White Larvae
Damage from the insect starts at the base of the soybean plants, largely out of sight. Adult midges emerge from the ground in May and June, then seek out tiny fissures in young soybean plants near the soil line to lay eggs, according to Thales Rodrigues da Silva, a master’s student at the University of Nebraska–Lincoln.
The larvae cause severe, localized yield losses from 20% to 100% loss along field edges and 17% to 50% reductions in entire fields average under heavy infestation, according to University of Nebraska-Lincoln (UNL) Extension. The larvae – small, orange worm-like pests – feed inside the base of the stem, causing plants to wither, die, and lodge (break), with damages sometimes extending 100+ feet into fields. Scouting for the pest should occur after the second trifoliate (V2) growth stage, according to the Crop Protection Network.
Because the pest often feeds along field edges, the damage in affected plants is often mistaken for issues caused by compaction or herbicide injury, according to Stine Seed Company.
To confirm the pest’s presence, Stine agronomists recommend digging up compromised soybean plants and splitting open the stem. If white or orange larvae are found feeding within the inner layers, growers should check the Soybean Gall Midge Alert Network tracking system to determine whether the pest has been reported in their area. Next, they should contact their local Extension specialist to help confirm the diagnosis and report the finding if their county is not yet documented in their area.
Cultural Practices Show Promise
Unfortunately, there are few strategies to manage and control soybean gall midge, according to Tony Lenz, Stine technical agronomist.
With no labeled, consistently effective in-season insecticide program and no established treatment threshold, researchers are testing cultural and mechanical tactics that might give farmers at least partial relief.
Tillage ahead of planting — a tough sell in no-till systems — shows some promise in reducing early infestations in current-year soybean fields.
“Turns out that disking alone, at least in (our) study… did reduce infestation,” says Justin McMechan an entomologist and associate professor at UNL.
“There’s a significant reduction as we move from no-till to that… where it’s just disked and planted into, and then disking and hilling (a practice used in growing potatoes), which really is effective, because you’re covering up the infestation site,” McMechan adds.
He notes that even subtle changes in seedbed shape may help by covering fissures or altering microclimates at the stem base.
On planters running row cleaners, McMechan says adjustments at field edges might be one of the more accessible tools.
“There are not huge differences, but they are statistically significant,” he adds.
Field edge management has been another area of experimentation, including mowing or managing dense vegetation next to infested fields. Results are mixed, but McMechan says there are situations where mowing modestly cuts pressure.
“Nebraska saw on occasion where mowing would reduce infestation and lead to marginal yield benefit… we’re talking like 6-bushel differences,” he says, adding that weather and nearby corn canopy can override those gains.
Scientists Evaluate ‘Out-Of-The-Box’ Practices
Other work by researchers is pushing even further outside the box to find control measures. At UNL, graduate research assistant Kristin Heinrichs Stark is testing whether a biodegradable surface barrier called BioWrap can physically trap larvae in the soil and prevent emergence.
The work is early-stage and raises reasonable questions about cost and field-scale application rates, but it points to the kind of layered, non-chemical tactics Extension researchers say will likely be needed to address the pest.
Even as these cultural and physical strategies are developed, Hodgson reminds farmers that the ag industry still lacks any clear control option once larvae are inside the soybean stem.
“We really don’t have a treatment threshold, or a rescue treatment option at this time,” she says. “We know that the soybean gall midge certainly can cause yield losses, plant death, and that directly relates to yield. But we don’t really have great answers on like, how many plants does it take? How many larvae per plant (causes yield loss)?”
For now, farmers dealing with soybean gall midge are being asked to combine careful field scouting, crop rotation, and targeted cultural tactics to address the pest as the research community races to find answers and close those gaps.
Specialists from three Midwest universities provided the latest updates on soybean gall midge (SGM) this spring in a webinar, available at the link below:
