image used as white space
MSUcares header Link to home page
Logos of MSU, Extension Service, and MAFES Links to home page of website.

Cotton Insect Pest

photo of fall armywormFall Armyworm

Fall armyworms attack both corn and cotton, as well as a variety of other crops. They are distinguished from the other armyworms found in cotton by the presence of stiff body hairs, but beginning scouts often confuse them with bollworm/tobacco budworm. However, a distinct inverted white "Y" shape on the head capsule of larger fall armyworm larvae helps readily distinguish them from bollworm and tobacco budworm (note that this "Y" shaped area is present on all caterpillars, but it stands out distinctly on fall armyworm because it is colored white). Fall armyworm moths are dimorphic. Female moths are grey and unmarked, while male moths have more distinct markings. Eggs are deposited in masses. In cotton egg masses are usually deposited on the undersides of leaves in the lower portion of the canopy, and larvae disperse from the site soon after hatching. Small larvae are most commonly found feeding on the insides of the bracts of large bolls and this is one of the most important sites to check when scouting for this pest. Older larvae may be found feeding or resting in open blooms, but the primary damage is inflicted by older larvae feeding in large bolls.