BCW 2026 Report 8

2026 University of Minnesota Cooperative Black Cutworm Trapping Network 

Report # 8 May 9- May 15, 2026

This report was prepared May 19, 2026 

Dr. Fei Yang - Extension Corn Entomologist, University of Minnesota Department of Entomology

Bruce Potter - Potter Bros, LLC

Greetings, 

Black Cutworm 

MN captures rpt8
Figure 1. Black cutworm moth captures May 9 – May 15, 2026. Color shading represents the maximum two-night captures for trap(s) in the county. 

Very few moths arrived this week, again with no significant captures. (Table 1, Figure 1). Some Northerly winds were not for migration.

Early planted corn is at most risk from April 12-14 flight egg laying. They should be large enough to cut 4-leaf and smaller corn by May 23 and begin to cease feeding and pupate by June 21 

Based on projected temperatures, black cutworm larvae from the late-April flights will not be large enough to cut until the 1st week of June (Table 2). Early planted corn, less than 6 leaves may still be susceptible to cutting from these moth arrivals. 

Keep in mind, the recent cold snap will slow both cutworm and corn development.

Fortunately, to this point, we have seen relatively few black cutworm flights.  Scout efficiently over the next few weeks.

positive captures rpt 8

 

Table projections report 8

 

Armyworm

Low trap captures again this week.  Dakota, Freeborn, Houston, Martin, Olmsted and Steele had captures below levels indicating an increased threat. Because we did have a couple large captures earlier, keep an eye open for larvae when you check fields with late-terminated cover crops, weedy fields, or lodged grasses and small grains.

Volunteers Rpt 8
Table 3: Many thanks to the volunteers in the 2026 MN Cooperative Moth Trapping Network! Thanks to Grethen Thillen UMN SWROC for her help posting articles to the SWROC website.

This will be the last planned issue for 2026.  If you do find any fields with cutworm or armyworm problems, please contact Dr. Fei Yang ([email protected]).  We’ll try to keep everyone updated if any problems arise.

This and previous reports can be found at  bcw-reporting This network is supported, in part, by the farm families of Minnesota and their corn check-off investment. 

Contact me with any questions and Happy trails, 
Bruce Potter
[email protected]
(507) 276-1184