2020 UMN Cooperative Black Cutworm Trapping Network Report #2

Report #2 Week of April 4 - 10, 2020

For more information: Black Cutworm Reporting Network

April 16, 2020


The 2020 black cutworm (BCW) trapping season has just completed week three and most cooperators pheromone traps are operating and reporting. 

Along with the warm southerly winds last week, we had a few visitors from the south. These arrivals were scattered and low numbers (Figure 1).   A Cottonwood trap captured a moth on 4/6, one of the Waseca County traps had a moth on 4/6 and another on 4/7, traps in Jackson and Kandiyohi Counties caught single moths on 4/7 and a Pope County trap had a single moth on 4/10. These single moth/night captures are well below the eight moths/2 nights that could indicate a migration event large enough for increased concern for crop damage. These immigrants may be wishing they had stayed south as black cutworm moths and eggs do not tolerate freezing well.

We have a tentative ID on some of the moths that have been showing up in some armyworm pheromone traps. I received a couple of specimens in from Stephan Melson in this morning’s mail. I did not key these out but suspect they are Bethune's pinion (Lithophane bethunei). The adults overwinter and larvae feed on broadleaf trees. See https://www.butterfliesandmoths.org/species/Lithophane-bethunei for more pictures and biology.  I have always enjoyed moth ID and in this case especially challenging when the specimen under examination realizes it is alive and capable of flight.

Next week, I’ll discuss factors that help black cutworm migrations. In the meantime, look for sustained southerly winds, particularly those associated with thunderstorms, to bring more moths to Minnesota.

If you have not yet placed your traps, please do so as soon as possible. Also remember to report your captures to Travis Vollmer each Friday. We start analyzing the results Monday mornings. Because we are trying to determine where flight occurred, it is important to report both positive and negative captures each week. Finally, a quick email if a trap captures 8 or more moths over a 2-night period will be appreciated.

Until next week, 

Bruce Potter and Travis Vollmer

This project is supported, in part, by the farm families of Minnesota and their corn check-off investment.