Doug Johnson, Extension Entomologist
The most recent capture number for armyworm moths in the UK-REC trap shows a decided decrease, down to 87 moths/trap-week. This is an overall good sign that no large population is in the offing. This does NOT mean that any specific field will not have a problem population, only that there is unlikely to be a widespread large problem. Fields should still be scouted.
|Fig. 1. Armyworm caterpillar|
Armyworms tend to feed at night and damage small grains and corn by stripping the leaves. They feed from the margin in toward the mid rib. In small grains, whole leaves will be consumed, but in corn they tend to leave the center portion of the leaf. Also in corn, they may feed in the whorl and destroy the bud.
The economic threshold for small grains is 16, ½-3/4” larvae per four-feet2. In corn, the guidelines are 35% or more of plants infested AND 50% or more defoliation and larvae averaging ½” – ¾” in length.
Armyworms are not hard to control. Losses are usually associated with lack of detection. Insecticides for use against this pest may be found on line at:
http://pest.ca.uky.edu/EXT/Recs/ENT47-SmallGrain.pdf for field corn and
http://pest.ca.uky.edu/EXT/Recs/ENT16-Field%20corn.pdf for small grains, or at your local county extension office.