For the upper Midwest Region, we currently have "Moderate Risk" of significant Corn Earworm flights northward. Corn earworm migrates on weather fronts from southern/southeastern regions of the U.S. to the Midwest Region during late summer.
Corn Earworm Risk Forecast, Midwest Region
Eileen Cullen, Extension Entomologist
For the upper Midwest Region, we currently have "Moderate Risk" of significant Corn Earworm flights northward. Corn earworm migrates on weather fronts from southern/southeastern regions of the U.S. to the Midwest Region during late summer.
Corn earworm information, digital images, and management recommendations are available at my program website (Field and Forage Crop Entomology):
http://www.entomology.wisc.edu/cullenlab/insects/info/cew.html#Info
UWEX Publication A3655 The Corn Earworm provides identification, life cycle, corn ear damage, scouting and integrated pest management control options. A link to the UWEX fact sheet is available at http://learningstore.uwex.edu/pdf/A3655.pdf
Figure 1. Corn earworm moth. Photo: Eric Birschbach, CCA, AgSite Crop Consulting
Extension entomologist, Dr. Bill Hutchison, University of Minnesota Entomology Department, forwarded the following timely corn earworm alert information for the Midwest Region.
Although field corn in the northern states can be attractive this time of year (if silking), this forecast applies primarily to processing and fresh market sweet corn and seed corn growers. Watch your corn earworm pheromone traps carefully. For any corn that is in silk stage; trap catches of 5-10 moths/night are generally high enough to indicate female moth activity and significant egg-lay on silks (most eggs are laid directly on silks). However, for those who have field scouts/employees available (or a 15X hand lens) to check silks directly for corn earworm eggs (laid singly), this is the best way to verify an infestation.
For several weeks, the South-Central U.S. states have been dealing with very high corn earworm flights (> 300/night in some areas) and larval infestations near 100% in field corn (ears) in some areas (e.g., Arkansas; Dr. Randy Luttrell). So, the Southern source areas, typically involved with late summer northern migrations, are producing moths.
High Pressure systems, and cool air from Canada, have thus far dominated in Wisconsin and prevented the risk of northward flights. Wisconsin continues to have Low Risk. However, with new Low Pressure action from the south, the Midwest Region has the first "Moderate Risk" of significant Corn Earworm flights northward.
The latest edition of the Insect Migration Risk Forecast for Wednesday, August 12, 2009 is now available online at the link below, provided by Mike Sandstrom and Dave Changnon, Northern Illinois University:
NOTE: A MODERATE risk of insect migration has been issued for the Day 4 period across a portion of the Plains and Midwest. Please view the risk maps and forecast text for more details on this increased insect migration risk.
http://www.agweather.niu.edu/IMRFForecast.html
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