As Wisconsin fields enter dormancy, it’s time to analyze the past season’s pest pressures to inform planting and management strategies for 2026. While 2025 was largely an “uneventful insect year,” one pest, armyworm, caused significant problems during its second generational flight.
Emily Bick, an entomologist and Extension Specialist for field and forage crops, notes that the initial true armyworm flight from the south was minor because crops were not yet established. However, the subsequent generation found ideal conditions.
“We were really hit with a massive, massive true armyworm population,” she tells Mid-West Farm Report.
These outbreaks were most common in fields with higher levels of weeds or grassy margins where the moths prefer to lay eggs, Bick explains.
Since true armyworms do not overwinter in Wisconsin, Bick and her team have successfully used early warnings from their regional network. This information is now being disseminated to growers via a modern tool: the Insect Pest Text Alert Service. The service, which sends texts only when there is an active threat in the subscriber’s region, helped growers manage the armyworm spike.
“For the folks that were involved in that pest text alert, they got a bit of an early warning, so they knew when to scout, and then they knew when to spray for those true armyworms,” Bick says.
The service, which covers most field and forage crops, had nearly 400 active users by the end of the season. Interested growers can sign up for the 2026 season through UW-Madison Extension: https://cropsandsoils.extension.wisc.edu/pest-management/insect-pest-alerts/
Emerging Threats
Looking ahead to 2026, Bick highlights two major pest issues that growers need to monitor:
Soybean Gall Midge: The pest was detected in a border county in Minnesota, sparking concern that it may enter Wisconsin next year. SGM remains a major issue for which effective management strategies are still being developed.
Pyrethroid Resistance: Researchers found a high level of resistance to pyrethroids in corn earworm populations in southern Wisconsin. Since pyrethroids are a main management tool for this pest, new strategies will be necessary.
European Corn Borer: Resistance to common Bt traits in ECB has been reported in Wisconsin. While populations are not high yet, Bick warns, “I’m getting a little bit nervous that that one is going to reemerge as a pest due to these resistance issues.”
Dr. Bick’s lab is also recruiting volunteers for on-farm research next season to address the lack of data on slug pressure, especially in fields using conservation cropping practices. Reach out to be a part of the research: https://cropsandsoils.extension.wisc.edu/people-2/#topic-crops-and-soils-all-staff/person/62c5d3bf342622001e7849a7/
