Cutworm

Agrotis ipsilon (black cutworm), Peridroma saucia (variegated cutworm)

Brown cutworm moth
Brown cutworm moth [Credit: Gail Hampshire]
Brown cutworm moth [Credit: Gail Hampshire]
Black cutworm
Black cutworm [Credit: Sam Droege]
Black cutworm [Credit: Sam Droege]
Larval cutworm in its characteristic c-shape
Larval cutworm in its characteristic c-shape [Credit: Sterling Southern]
Larval cutworm in its characteristic c-shape [Credit: Sterling Southern]
Dorsal view of the larva of a black cutworm
Dorsal view of the larva of a black cutworm
Dorsal view of the larva of a black cutworm
Adult black cutworm
Adult black cutworm
Adult black cutworm
Lateral view of the larva of a black cutworm
Lateral view of the larva of a black cutworm
Lateral view of the larva of a black cutworm


Host Plants:

On Crops: Beans, cabbage, corn, greens, lettuce, any fresh seedlings

Where Found:

Common wherever vegetables are grown

Description:

These are blackish-gray to brown smooth-skinned caterpillars that hide in the soil during the day and feed at night. Black cutworms have small black dots on their bodies, while variegated cutworms are mottled brown with a faint white stripe down their backs.

Damage:

Larvae feed on roots and foliage of young plants, often girdling them at the soil line. The top of the plant is left to shrivel and die. In the summer, cutworms can crawl up plants and chew holes in the foliage that look like damage done by slugs.

Preventing Problems:

Cutworm collars, which are 2- to 3-inch rounds pressed one inch into the soil around vulnerable plants, are usually effective. They can be made of cardboard, metal cans, or plastic drink cups cut into rounds. Bt (a biological pesticide) also be mixed with oatmeal or cornmeal and placed in mounds on the soil’s surface to catch foraging cutworms. Including perches in your garden for insect-eating birds can help prevent problems with cutworms.

Managing Outbreaks:

As soon as you suspect cutworm damage, use a fork and flashlight to find the culprit at night; one individual cutworm can do significant damage. Check at hourly intervals at night and you can catch them as they show themselves. Bt solution can also be helpful in managing outbreaks.

Tips:

Frequent shallow cultivation can expose and kill cutworms. Attract insect eating birds by providing convenient perches nearby. You can passively trap the adult moths with solar landscape lights set above broad pails of soapy water. Be especially vigilant when growing veggies in new garden beds that were previously covered with grass and weeds.

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