True Armyworm (aka Common armyworm) 
Armyworm moths are long-range migrants that arrive on the spring storms from their southern
overwintering locations. Armyworm moth migrations are somewhat sporadic, cyclic from year to
year and difficult to predict. True armyworms are primarily a pest of
plants in the grass family: forage / pasture /grasses (& lawns), wheat, corn and small grains.
Note: Under hunger stress true armyworms will also attack some legumes and other plants.
Moths lay their eggs on weeds and/or grasses along field margins, on leaves of corn, or on small
grains. Larvae hatch about a week later and develop over approximately a 3 week period, feeding
mostly at night.
Fields at most risk for armyworms feeding are:
1) grass or mostly grass hayfields, pastures. (Armyworms will also feed on grass lawns.)
2) wheat and other small grain fields and cut hay fields
3) corn fields that:
a. were planted into a small grain cover crop (such as rye grass)
b. have grassy weeds, quackgrass, crabgrass and bluegrass and other perennials
c. were planted into burned down sods, have grass weed issues, no-till or reduced tillage
fields, fields with crop residue
d. fields near severely infested small grain and cut hay fields, and in no-tillage corn
established in grain stubble or on grassy land. 

Field Crops Specialist, Josh Putman, is getting ready to set traps in SWNY with hopes to capture armyworm moths to better help predict potential infestations on your farm. Contact Josh at jap473@cornell.edu or 716-490-5572 for updates on these timely pests.