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Corn Earworm Alert: Aug. 30, 2018

Corn earworm feeding.
Photo: Hutchison Lab, University of Minnesota
By Bill Hutchison, Professor and Extension Entomologist

CEW adult, moth flights continue to be high near Blue Earth, and increased substantially this past week at Owatonna (now >70/night) and Rosemount (>175/night). As other crops continue to mature (e.g., tomato, peppers, green beans), late-planted or late-maturing sweet corn with fresh silks, will continue to be the #1 preferred host for CEW egg-lay. 

Recent flights have been supported by several recent weather systems, moving warm air from southern states, our way. Although we have observed various levels of CEW resistance to pyrethroid insecticides (bifenthrin, lambda-cyhalothrin) in recent years, our results so far this year have indicated good efficacy. 

If you are not finding good/excellent control, consider one of the diamide options (e.g., Coragen). See the VegEdge CEW page for moth flight updates at all locations: 

CEW egg-lay can continue throughout the next 4 weeks, as long as we maintain warm nights (>50F) and reasonable heat, or degree days through September. 

For more information regarding CEW thresholds, spray timing, review the CEW article published earlier this month in the Fruit and Vegetable News:

Thank again to all of our cooperators who are maintaining CEW traps this year!

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Author: Bill Hutchison, Professor and Extension Entomologist

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