Dr. Fei Yang – Extension Corn Entomologist, University of Minnesota Department of Entomology, and Bruce Potter – Potter Bros., LLC
No significant black cutworm captures were reported between May 10 and 16 in week 7 (Figure 1). Black cutworm trapping will wind down on May 24 although some trappers may continue for a bit longer based on the agronomic situations in their areas.
Warm temperatures led to predicted development of black cutworm larvae faster by two or three days. Scouting for leaf feeding and possibly cutting of small corn should be underway in high-risk fields. The recent cool temperatures will slow the development of both corn and soybeans.
Larvae from the earliest mid-April moth arrivals may be able to cut small corn now. These larvae should cease feeding and being to pupate in mid-June.
This is now a race in development stage between cutworm larva and corn stage. Remember, corn plants that are 5 leaves and less are most susceptible to being killed by 4th stage and larger larvae feeding below the growing point.
There were still no large captures of armyworm moths this week. Steele County had the only notable capture trap capture so far this spring (12 moths on April 22). The Polk County trap sites indicate that both black cutworms and armyworms have both made their way into NW Minnesota. Historically, most armyworm issues in Minnesota occur in late June and early July so there is still time for problematic moths to arrive.
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| Figure 1. Black cutworm moth captures May 10 –16 2025. Color shading represents the maximum two-night captures for trap(s) in the county. |
No significant black cutworm captures were reported between May 10 and 16 in week 7 (Figure 1). Black cutworm trapping will wind down on May 24 although some trappers may continue for a bit longer based on the agronomic situations in their areas.
Warm temperatures led to predicted development of black cutworm larvae faster by two or three days. Scouting for leaf feeding and possibly cutting of small corn should be underway in high-risk fields. The recent cool temperatures will slow the development of both corn and soybeans.
Larvae from the earliest mid-April moth arrivals may be able to cut small corn now. These larvae should cease feeding and being to pupate in mid-June.
This is now a race in development stage between cutworm larva and corn stage. Remember, corn plants that are 5 leaves and less are most susceptible to being killed by 4th stage and larger larvae feeding below the growing point.
There were still no large captures of armyworm moths this week. Steele County had the only notable capture trap capture so far this spring (12 moths on April 22). The Polk County trap sites indicate that both black cutworms and armyworms have both made their way into NW Minnesota. Historically, most armyworm issues in Minnesota occur in late June and early July so there is still time for problematic moths to arrive.
Report #7 includes BCW leaf feeding and cutting projections, economic thresholds and recommended management strategies.
Read this week's full report
Information on moth arrivals earlier this spring can be found in previous 2025 UMN Cooperative Black Cutworm Trapping Network Reports. These along with previous year's reports and other black cutworm information are on the Black Cutworm Reporting Network.
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