IPMP3.0, Oregon State University, Copyright 2000

Bertha Armyworm



Development Model

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

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Registered Insecticides


[Insect Management]


Link to large image (127K) of bertha armyworm larva Link to large image (148K) of bertha armyworm adult
Bertha Armyworm Larva Bertha Armyworm Adult
Link to large image (108K) of bertha armyworm pupa Mature larvae are about 40 mm long. The head is pale brown with or without markings. The color of the larva varies from green to gray, brown, or nearly black. The area above the spiracles is marked with brownish or orange. Spiracles are white with black rims. The stripe below the spiracles is yellow or orange, and the bottom area is mottled gray or greenish.  Adults are greenish-gray with a large "kidney-shaped" white or gray spot on the middle of the wing, and a whitish band near the fringe of the wing. This insect overwinters as a pupa in the soil.   Adults emerge in April and lay eggs. Larvae are present in June and July. There are two overlapping generations each year.

Bertha Armyworm Pupa

View the Fact Sheet for More Information

This section contains information on the management of bertha armyworm in peppermint.  The Fact Sheet contains specific information on identifcation and biology of this pest (requires Acrobat Reader).  Bertha armyworm often occurs during the same period as variegated cutworm and beet armyworm. Refer to information on these two insects for management of bertha armyworm.