UConn’s Sweet Corn IPM Action Thresholds

European Corn Borer (ECB)

  • 30% infested whorl-stage plants
  • 15% infested pretassel-stage plants
  • treat early-season, fresh-silking corn if 35 or more ECB moths/week are captured in pheromone traps

Fall Armywarm (FAW)

  • 10% infested whorl or pretassel-stage plants
  • treat fresh-silking corn if 50 or more FAW moths/week are captured in pheromone traps


  • 15% infested whorl or pre-tassel-stage plants

Corn Earworm (CEW)

Average number of CEW moths captured per trap each night Spray interval for silking corn
0.0 – 0.2 no spray
0.2 – 0.5 6 days
0.5 – 1.0 5 days
1.0 – 13.0 4 days
over 13.0 3 days
Less than 5 days until harvest no spray
Note: CEW spray intervals should be lengthened by a day if daily maximum temperatures were less than 80 degrees F for the previous 2-3 day period.

This information was developed for conditions in the Northeast. Use in other geographical areas may be inappropriate.

Reviewed by: T. Jude Boucher, IPM, University of Connecticut. 2012

The information in this document is for educational purposes only.  The recommendations contained are based on the best available knowledge at the time of publication.  Any reference to commercial products, trade or brand names is for information only, and no endorsement or approval is intended. The Cooperative Extension System does not guarantee or warrant the standard of any product referenced or imply approval of the product to the exclusion of others which also may be available.  The University of Connecticut, Cooperative Extension System, College of Agriculture and Natural Resources is an equal opportunity program provider and employer.