Major Migration of Corn Earworm Moths in Progress
Eileen Cullen, Extension Entomologist
Reprinted from August 16, 2012 Wisconsin Pest Bulletin courtesy of Krista Hamilton, DATCP Entomologist.
A major migration of corn earworm moths is in progress. Counts at the Ripon trapping sites increased to 271 and 503 moths per trap last week, while counts at four of five Dane County sites escalated to 81-250 per trap this week. Larvae of various maturities can be found statewide. Examination of field corn in Buffalo, Chippewa, Eau Claire, Jackson and Trempealeau counties found minor infestations of 2-6%. Most earworms were in the intermediate to late instars, although a few were very small.
Sweet corn growers should continue to monitor fields for egg laying as long as moth activity persists and green silks are present. Counts this week were: Aztalan 130, Chippewa Falls 10, Columbus 81, Coon Valley 38, Janesville 10, Manitowoc 0, Marshfield 2, Oregon 36, Ripona 146, Riponb 206, Sun Prairie 130, Wausau 0 and Westport 250.
–Krista Hamilton, DATCP Entomologist