For more information: https://z.umn.edu/bcw-reporting
May 14, 2024
Greetings:
In spite of periods of strong north winds, migrating black cutworm (BCW) moths continue to arrive in MN. Significant captures occurred in Martin, Nicollet, and Renville Counties. Most moths were found May 5-7 with May 7 seeing the most activity (Figure 1, Table 1).
Degree day predictions to help time scouting for 2024 moth captures can be found in Table 2. Recent warm weather moved projections ahead slightly. The larvae from moths arriving before May 7 should be hatched or hatching now. The larvae from moth arrivals before April 17 will be at, or near 2nd instar. Leaf feeding from these larvae should be increasingly visible and some of these larvae should be able to cut small corn by the last week of May. The larvae from later arriving moths will be earlier in development, and later in crop injury. Keep in mind, that these degree day projections are only guidelines and the temperatures the eggs and larvae are exposed to vary with solar radiation, crop residue and soil moisture. `
During the day, black cutworms hide under residue and dirt clods, often at the border between dry and moist soil. If you find a larva, you can estimate its age by measuring the cutworm’s length and width of the head (Table 3). You can find additional scouting information in black cutworm on corn.
True armyworm (TAW)
Armyworm moth migration increased although not yet at the levels that triggered problems in 2023A LeSueur County trap captured 21 moths this reporting period with a high of 11 moths on May 14. A Waseca trap captured 9 moths this trapping period. The rain has produced lush grass and small grains and arriving moths should find plenty of good egg-laying habitat - so stay tuned. For more information on armyworms see: https://extension.umn.edu/corn-pest-management/armyworm.
This project is supported, in part, by the farm families of Minnesota and their corn check-off investment.
Until next week,
Bruce Potter