ProCrop

Armyworms

Armyworms are olive-green or greenish-brown with dark stripes running the length of the back along with two orange stripes on each side of the body. Larvae range in size from 1/4 to 1/2 inch long. The adult moths are light brownish gray with a white spot on each front wing. When spread out, the wings are about 1 1/2 inches across. Eggs of armyworms are laid at night in folded leaves or under leaf sheaths and on small grain plants. The eggs look like small white beads and are in masses. Eggs hatch in about eight to ten days.

During the day, armyworms can be found under plant trash, clods of soil and in soil cracks. They feed at night. Smaller worms will feed on lower leaves. As they increase in size, they tend to feed higher up on the plant. They feed for about three to four weeks.

Sampling for armyworms should include inspections at a minimum of five locations using an X pattern to spread the sample sites out across the field. In small grains, treatment for armyworms is advised when four to five or more larvae are found per square foot. In corn, treatments should be applied when two or more larvae occur per plant on 25 to 30 percent of the stand or there is one per plant on 75 percent of the stand.

*Small grains = wheat, barley and oats

For more information see the Insect Guide at http://www.ext.nodak.edu/extpubs/plantsci/pests/e1143w1.htm

Back to Armyworms - Insects Menu
Back to Insects Menu
Back to Main ProCrop Index

Further contact information