2016 University of Minnesota Cooperative Black Cutworm Trapping Network Report #7

Week of April 30-May 6, 2016

This newsletter is also available in a print-friendly pdf format: 2016 Black Cutworm Network Issue 7

BCW 2016 07

Last week's weather systems brought additional black cutworms into the state. Eleven trap locations reported moth captures from April 30-May 6, with most occurring May 5-6 in western locations and May 2-4 in the east. Fortunately, none were significant.

The southwest corner of the state continues to receive rain and moths. Rock had 7 moths May 5-6 and Nobles had 6 from 5/4-5.

One of the systems dropped moths into the Renville through Rice Steele County area.  The Blue Earth County trap had a weekly total of 13. Most corn was planted in this area, but there were enough moths captured that sweet corn should be watched.

The rainfall events on May 9-11 may hold some interesting trap results.

Leaf feeding from the early flights may be visible on weeds and emerged corn. Eggs hatch at 90 degree-days after the biofix (flight) so leaf feeding from later flights should be just beginning. (Table 1).

Date* of significant trap capture Trap location Degree-days/Estimated development stage Projected date to corn cutting
28-Mar Swift Co. 264 DD/leaf feeding 23-May
12-Apr Rock Co. 242 DD/leaf feeding 24-May
19-Apr Murray Co. 152 DD/leaf feeding 1-Jun
20-Apr Sibley Co. 151 DD/leaf feeding 1-Jun
24-Apr Rock Co. 138 DD/start leaf feeding 31-May
24-Apr Meeker Co. 120 DD/start leaf feeding 4-Jun
* first date if two night significant flight
Degree-day accumulations to 5/12/16
Table 1. Dates and locations of significant 2016 captures of black cutworm moths in 2015. The estimate of projected cutting date is based on accumulating 300 Degree Days (base 50ºF) after a significant capture. It uses 30-year historical temperature data for projecting future degree-days. Projections run with temperature data current to May 12, 2016. Source: https://mygeohub.org/groups/u2u/gdd.

I have not yet heard of any field observations of black cutworm larvae this spring. We will know the success of this year's migrants’ offspring soon.

-Bruce and Travis