Corn earworm report for July 12, 2018

Corn earworm moth numbers have been low in local black light traps. Watson Lawrence reported 1.4 per night in Chesapeake; Livvy Preisser averaged 0.6 per night in Isle of Wight; Mary Beahm had zero in Warsaw; we had 0.9 per night in Suffolk this week.

Virginia Cooperative Extension Agents and Virginia Tech employees will be scouting field corn for corn earworm larvae this month as part of Dr. Taylor’s annual survey. They examine ears in five corn fields per county and calculate the average percent infested ears. Corn is a nursery crop for corn earworm–the percent of infested ears can be a useful indicator of the pressure to expect in other crops such as soybean, cotton, peanut, etc. when moths emerge and migrate out of corn. We’ll provide results of the survey in the first week of August.

We have tested 80 corn earworm moths in our cypermethrin vial tests this season, with only 8% surviving the 24-hour exposure to 5 micrograms/vial of cypermethrin. It would be great to see moth survival remain that low, but we need to continue testing to see what happens when we get the flight out of corn and later into the season.