Report #8 May 17-23, 2025
This issue was prepared by:
Dr. Fei Yang – Extension Corn Entomologist, University of Minnesota Department of Entomology
Bruce Potter – Potter Bros., LLC
May 27, 2025
Greetings,
Black cutworms
A reduced number of traps were operating May 17-23. A Renville County trap reported 8 moths the mornings of May 20 and 21, but there were no other significant captures reported in week 8 (Table 1, Figure 1).
Scouting for leaf feeding and possibly cutting of small corn should be underway in high-risk fields.
Larvae from most April moth arrivals should now be able or soon able to cut corn hybrids without the Cry1F or Viptera traits if they are less than 5-leaf stage. These larvae should cease feeding and being to pupate in mid-June (Table 2). Early planted corn may be able to outgrow larvae from moths arriving in May.
This was a relatively active year for black cutworm moth migration. Figure 2 shows the highest 2-night capture for reporting counties. Because of the widespread significant captures, keep black cutworms in mind when scouting any southern MN counties.
Armyworms
While there were no large captures of armyworm moths this week, Steele County reported 3 moths on April 23 and 15 on April 24. This is the only pheromone trap site that has captured large numbers of armyworm moths.
Historically, economic infestations of armyworm larvae correlate with large trap captures. However, the infestations may not be in the same geographic area as the trap capture. As the season progresses, pay attention to late terminated rye cover crops or dense grass weeds, and to areas where small grain cereal crops and other grasses are dense and lodged.
This is the last report for 2025. We are grateful for the help of cooperators (Table 3) for running pheromone traps this spring and to Gretchen Thillen and the University of Minnesota Southwest Research and Outreach Center for hosting the website for this project.
Please let me or Dr. Fei Yang know if you run across any cutworm or armyworm infestations this year.
For more information: bcw-reporting
This network is supported, in part, by the farm families of Minnesota and their corn check-off investment.
Products are mentioned for illustrative purposes only. Their inclusion does not mean endorsement and their absence does not imply disapproval.
Contact me with any questions and Happy trails,
Bruce Potter
[email protected]
(507) 276-1184