IPMP3.0, Oregon State University, Copyright 2000

Western Yellowstriped Armyworm



Fact Sheet (requires Acrobat Reader 3.x or above to read and print. Click below to download the free "Reader".)

Download Acrobat Reader Software

Registered Insecticides


[Insect Management]


Link to large image (159K) of western yellowstriped armyworm larva Link to large image (136K) of western yellowstriped armyworm adult
Western Yellowstriped Armyworm Larva Western Yellowstriped Armyworm Adult
Link to large image (147K) of western yellowstriped armyworm eggs Mature larvae are about 40 mm long, with a faint white or red mid-line stripe on the top of the body.  Black triangular marks are present on each side of the mid-line on each segment, except the prothorax.  These are bordered below by a white stripe on each side.  There is a prominent black stripe along each side bordered below by an orange- brown strip.  Larvae have an inverted white "Y" on the front of the head. Adults have a wingspan of 35 to 40 mm. The forewings are gray or brown with slate or buff-colored markings.  This insect overwinters as a pupa in the soil.   Adults emerge in March or April. Larvae feed for 6 to 8 weeks during May, June, and early July, then pupate in the soil. Adults emerge in mid-August and early September.  Larvae feed during the fall before entering the pupa stage to overwinter.  There are two overlapping generations each year.

Western Yellowstriped Armyworm Eggs

View the Fact Sheet for More Information

This section contains information on the management of western yellowstriped armyworm in peppermint.  The Fact Sheet contains specific information on identifcation and biology of this pest (requires Acrobat Reader).  Western yellowstriped armyworm often occurs during the same time as variegated cutworm. Refer to information on variegated cutworm for information on management of western yellowstriped armyworm.