Black Cutworm and Its Allies

Cutworms are the larval stage of several moths in the insect Order Lepidoptera: Family Noctuidae (the Owlet Moths) which includes cutworms and armyworms.  Several species of cutworm occur in Ohio.  Typically they have 1-2 generations per year depending on the species and adult flights occur at different times through the growing season.  All have 4 stages in their life cycles: eggs, larvae (caterpillars = cutworms), pupae and adults.  Again, depending on the species, some overwinter as partially grown caterpillars, others as prepupae in the soil, and others do not overwinter in Ohio and must migrate into the state every year.  Recognizing these caterpillars for who they are will again be important this year because of the amount of early weed growth on many agricultural fields which is very attractive to adults for egg laying or good cover for overwintered larvae.

The black cutworm, Agrotis ipsilon, is probably the best known of the cutworms, but several others are fairly common in agricultural fields.  Although they may be less significant to the success of the crops, they could be confused with black cutworms.  Some of these additional cutworms include the dingy cutworm, clay-backed cutworm, sandhill cutworm, and variegated cutworm.

The dingy cutworm, Feltia jaculifera, are very common in Ohio.  They are frequently mistaken for black cutworms.  However, they primarily feed on weed species in agricultural fields and rarely cause much damage to crops.  Dingy cutworms overwinter as partially grown larvae, so relatively large caterpillars can be present in cornfields at planting time, particularly in weedy fields.  Dingy cutworm larvae are pale gray to brown, tinged with red.  A faint, dark V-shaped marking appears on the back of each abdominal segment.  The head is pale brown-gray.  Tubercles (raised bumps on the skin) along the top of the abdominal segments are equal in size (on the same segment), in contrast to the unequal-sized tubercles on the back of the black cutworm.  A full-grown larva is 1 1/3 inches long.

The clay-backed cutworm, Agrotis gladiaria, can be just as destructive as black cutworms.  Its range covers much of the eastern US, but is not observed in Ohio often or it is mistaken for black cutworm activity.  It overwinters as partially-grown larva and can cause significant damage early in the spring. Their feeding habits are similar to those of black cutworms.  The cutworm has a broad, yellow-brown stripe on the back.  The rest of the body is pale gray and translucent, and the head is gray-brown with bars on the front of the face.  A full-grown larva is 1 1/3 inches long.

The sandhill cutworm, Euxoa deters, is somewhat a specialist to fields with sandy soils or sandy knolls in the middle of clay-soiled fields.  They can be very destructive on these sandy knolls.  Some may miss this cutworm chalking up thin stands to poor soil conditions.  Sandhill cutworms construct subterranean burrows to feed on underground portions of host plants.  It is another cutworm that overwinters as a partially grown larva.  The larva is white to pale gray.  Faint, chalky-white stripes are evident on the back and sides, and the head is dull red-brown.  A full-grown larva is about 1 1/3 inches long.

The variegated cutworm, Peridroma saucia, is a pest of numerous different crops including soybean, corn, fruits, and many vegetables.  Variegated cutworms do not overwinter in Ohio.  The moths fly into the Midwest during the spring.  Females deposit eggs in pastures, edge of field grasses, densely growing weeds, and debris in fields that have not been tilled.  The caterpillar's color varies considerably. However, a narrow line of pale yellow dots along the middle of the back is almost always present.  A full-grown larva is 1 1/2 inches long.

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About the C.O.R.N. Newsletter

C.O.R.N. Newsletter is a summary of crop observations, related information, and appropriate recommendations for Ohio crop producers and industry. C.O.R.N. Newsletter is produced by the Ohio State University Extension Agronomy Team, state specialists at The Ohio State University and the Ohio Agricultural Research and Development Center (OARDC). C.O.R.N. Newsletter questions are directed to Extension and OARDC state specialists and associates at Ohio State.