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Cutworms

Quick facts

  • Cutworms get their name because they cut down young plants as they feed on stems.
  • There are climbing cutworms that move up plants and feed on foliage, buds and shoots.
  • Seedlings are most susceptible to cutworm feeding.
  • Physical removal is effective in many cases.
  • There are pesticide options if cutworm problems are severe. 
Black cutworm (with black bumps) curled up in a ‘C’ shape
Black cutworm (with black bumps) curled up in a ‘C’ shape

How to identify cutworms

Cutworms are similar in general appearance. They are smooth with very few hairs and are about two inches 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 color from brown or tan to pink, green or gray and black.

  • Some cutworms are a uniform color while others are spotted or striped.
  • Some larvae are dull and others appear glossy or shiny.

Common cutworm species in Minnesota

The most common species of cutworm occurring in Minnesota gardens are the bronzed cutworm, variegated cutworm, black cutworm, dingy cutworm, glassy cutworm and army cutworm.

Adult moths are moderate sized, brown or black insects showing various splotches, or stripes in shades of gray, brown, black or white.

  • They generally have a body length of about one inch with wingspans up to 1 1/2 inches across.
  • Typically, the front wings are darker than the hind wings and are patterned.
Dull brownish caterpillar on green stems
Black cutworm
 Brown caterpillar with white vertical stripes over the body
Bronzed cutworm
Dull gray cutworm on green leaves
Dingy cutworm
Shiny whitish cutworm with a red head
Glassy cutworm
Blackish green cutworm with an orange stripe along the side, found in plant debris
Variegated cutworm
Brown moth with patches of white markings
Black cutworm moth
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Damage caused by cutworms

Cutworms are general feeders that can attack a wide range of plants. Common vegetables they like to feed on include asparagus, beans, cabbage and other crucifers, carrots, celery, corn, lettuce, peas, peppers, potatoes and tomatoes.  A few species feed on turfgrass.

Cutworms curl their bodies around the stem and feed on it. This feeding causes the plant to be cut off just above the soil surface. The number of cutworms found can vary a lot each year. When their numbers are high, there can be severe damage to a garden.

    • Black, bronzed and army cutworms can cause serious injuries, attacking and cutting new plants nightly.
    • The variegated cutworm can climb the stem of trees, shrubs, vines and garden plants and eat the leaves, buds and fruit.
    • Species such as glassy cutworms remain in the soil and feed upon roots and underground parts of the plant.
    • Cutworms feed in the evening or night and hide in plant debris during the day.
    • New transplants or young plants have more chances of injury because their stems are more tender.  
    • Damage is most severe in the early season when plants are small and have tender tissue.
    • Cutworms are active throughout the summer but are rarely a problem after spring.
    • Adult moths do not damage plants. 
    A curled up black cutworm next to a corn stem cut in two
    Black cutworm damage to a young corn plant
    Green stems, cut at the base, bending over in the soil
    Cutworm damage on potato

    How to protect your plants from cutworms

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    Cutworms can cause serious damage to crops. Specific pest management information for black cutworms on corn and soy is available in the Crop Production section of this website.

    Jeffrey Hahn, Extension entomologist; Suzanne Wold-Burkness, College of Food, Agricultural and Natural Resource Sciences

    Reviewed in 2019

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