Corn earworm update

There are 3 blacklight traps monitored in Wilson County in the Fountain, Pender’s Cross Rds and Kenly areas. The corn earworm moth numbers are bouncing around.  Please click here to visit the webpage to view the Wilson County information as well as all blacklight trap monitorings in NC. Select a pest on the left hand side to view blacklight numbers.  Looking at blacklight traps from other areas is also a good indication to the CEW moth flight.   Please see the following article written by Dr. Dominic Reisig, NC State University Extension Entomologist, on an update on the  CEW in soybeans.

Corn earworm moths find flowering crops attractive to lay eggs, such as peanuts, soybeans (R4-R7 are at the greatest risk when pods are present), cotton and grain sorghum.  Even though we have Bt protection in cotton, it still needs to be scouted.  With a heavy moth flight, there maybe caterpillars that can get established cotton.  One female moth has the potential to lay 2,500 eggs.  It takes about 3-4 days for an egg to hatch and then several more days for caterpillar to grow.  So following a peak of CEW moths on the blacklight means you should be scouting had in about a week.

There is an online calculator for CEW thresholds in soybeans.  Enter information such as soybean row width, sampling method, price of soybeans per bushel, price of insecticide plus application per acre and the calculator will generate the CEW threshold. I have been getting questions on threshold levels in 30″ row soybeans and using a sweep net for sampling method.  Dominic comments that this is not the ideal method to scout for CEW in soybeans and that a beat cloth would be better.  IF you use the sweep net, 3 CEW in 15 sweeps would be considered threshold.

Norman Harrell
Extension Agent
North Carolina Cooperative Extension
Wilson County Center