Pictured: Black cutworm moths. Photo by K. Hamilton DATCP
Ahead of spring corn planting, DATCP’s Pest Survey Program and many volunteers have been tracking the northward migration of black cutworm and true armyworm moths into Wisconsin using pheromone traps.
The annual trap networks include 151 traps supported by 47 cooperators, including agronomists, crop consultants, farmers, UW-Extension specialists, and DATCP field staff. As migratory moths continue arriving in the state, the traps are supplying data on local moth flights that will be useful in forecasting optimal scouting windows next month.
As of April 29, the black cutworm network has collected a cumulative total of 2,085 moths in 93 traps, or an average of 21 per trap. Thirty-six of the trap sites have reported intense flights and a forecast of the peak black cutworm seedling corn damage window for Wisconsin will be issued May 7.
True armyworm network traps have registered larger flights this month, which is normal and expected for this pest. Five trap sites reported 250 or more moths in the past week and the highest individual catch was 550 moths at Brodhead in Green County. The cumulative total true armyworm count is 7,173 moths in 58 traps as of April 29, or an average of 124 per trap.
While black cutworm trap counts can confirm a biofix (or intense flight) to start counting degree days until a peak seeding corn damage window, true armyworm traps provide only general information on moth arrival and flight trends, but there is no specific trap catch threshold for true armyworm that corresponds to the onset of field damage or predicts an armyworm outbreak. In addition, heavy armyworm and black cutworm flights do not inevitably lead to damaging larval populations. Last season’s astonishing July armyworm outbreaks will not influence this season’s armyworm outlook since this pest does not overwinter in Wisconsin.
Current trap network maps and weekly moth count data tables are available on DATCP’s Crop Pest Trap Networks web page: https://datcp.wi.gov/Pages/Programs_Services/TrapNetworks.aspx
Sign up for DATCP’s Field Notes: https://datcp.wi.gov/Pages/Programs_Services/FieldNotesNewsletter.aspx
