Corn Earworm Alert – Southern Minnesota

Bill Hutchison, Eric Burkness & Suzanne Burkness, MN Extension IPM Program, UMN

August 4, 2016

CEW larvaeGiven recent trends in recent trap catches of CEW moths in pheromone traps, sweet corn now silking (early, peak and early brown silk) may be at risk to egg-lay, and should be scouted, and/or traps checked more frequently this week.  If CEW moth catch is averaging >5 moths/night, growers should consider treating silking fields at least twice (e.g., 6-day interval), to control CEW.  All trap locations in the MN IPM Network are updated at the following web site:

The primary concern this week is that since many of the cooperators submitted their data on Monday, we found a substantial increase to an average of 21 moths/night –as of today, at the Rosemount Agric. Expt. Stn. (UMORE Park, Dakota Co.) where the traps are adjacent to a 100-ac sweet corn field. It’s noteworthy that the CEW increase in these traps is greater than the catch near our small plot experimental sweet corn.  Clearly, CEW moth catches are well known for high variability among locations, within a 5 mile radius, or across a county wide production area.  Ideally, we therefore recommend that each grower maintain a trap at their production sites, placed near silking corn. For more information on CEW traps, and management, see:

Checking a CEW Hartstack Trap
CEW moth

Monitoring for CEW moths using a Hartstack Trap (top), and closeup of a CEW moth (bottom).