Cutworms

There are several species of cutworms, all with a wide host range, including soybean. Most cutworms overwinter as pupae in the soil or as young larvae, however, some move into the Midwest as moths from southern latitudes. Late-planted and/or weedy fields are at higher risk for cutworm infestation. Young cutworm larvae feed above-ground at night or on cloudy days. Older, larger worms tend to remain below the soil surface, and often cut plants above, at, or below ground level.

Cutworm Identification
Cutworms are similar in general appearance. They are smooth with very few hairs and are about two inches long when fully grown. They typically curl into a tight ‘C’ shape when disturbed.

Different species can look different from one another and they can range in colors including brown, tan, pink, green, gray or black. Some cutworms are a uniform color while others are spotted or striped. Some larvae are dull and others appear glossy or shiny.

Black Cutworm (Agrostis ipsilon)

Photo Credit: Adam Sisson, Iowa State University, Bugwood.org 

• Range in size between one sixth to one and one half inches
• Color varies from greasy gray to black. A broad light gray band runs down the middle of the back
• Unequally sized, paired tubercles (small rounded projections or protuberances) run along the upper side of the body

Claybacked Cutworm (Agrotis gladiaria)

Photo Credit: James Kalisch, University of Nebraska, Bugwood.org 

• Larvae are pale-gray and translucent with a gray-brown head
• There are bars on the front of the face and a broad yellow-brown stripe on the back

Dingy Cutworm (Feltia jaculifera)

Photo Credit: Canadian National Collection, The Canadian National Collection (CNC) of Insects, Arachnids and Nematodes, Bugwood.org 

• Larvae have a light gray back and have four black dots on each segment
• The underside of the larvae is a pale yellow

Variegated Cutworm (Peridroma saucia)

Photo Credit: James Kalisch, University of Nebraska, Bugwood.org 

• Larvae are gray, mottled and have distinctive yellow dots at the top of the front abdominal segments
• Some larvae may have a yellow-orange stripe along the body