Stephen B. Bambara & Rick Brandenburg, Extension Specialists
CAUTION- This information was developed for North Carolina and may not apply to other areas.
Cutworms are caterpillars that feed on the stems and leaves of young plants
and often cut them off near the soil line, hence their common name. Although
there are many important species of cutworms, the black, granulate, and variegated
cutworms are the ones most commonly encountered on North Carolina turfgrass.
Distribution -- Cutworms are found throughout the United States.
Host Plants -- Besides turf, cutworms attack many field and vegetable crops.
Damage -- Many cutworms prefer wilted plant material and sever the plants sometime prior to feeding. Cutworms in turf often burrow in the thatch or ground. At night they emerge and chew stems and blades near the soil. The damage may appear as circular spots of dead grass, finger-sized brown crescents or ball marks on a golf green. Bronzed cutworms are active in Spring and Fall and may strip large areas of turf at ground level.
Adult -- When resting, cutworm
moths hold their wings back in a triangular position. The moths are generally
stocky and have a wingspan of about 1.5 inches (40 mm). The forewings are dark
brown and mottled or streaked; the hindwings are lightly colored and unmarked.
Egg -- The eggs are usually white (becoming darker prior to hatching), round, and smaller than a pin head (0.5 to 0.75 mm) in diameter.
Larva -- If disturbed, the larvae usually curl into a C-shaped ball. Cutworms are plump, smooth, dull-colored caterpillars that measure about 1.75 inches (45 mm) when fully grown.
Pupa -- Pupae are brown and 15 to 22 mm long.
Each cutworm species differs slightly from the others in details of habits and appearance, but their life histories are generally similar. Adults and larvae are nocturnal and hide during the day but may also become active on cloudy days. Larvae are very active and may crawl 60 feet or more during the night. Cutworms overwinter in the soil either as pupae or mature larvae. In the spring, the hibernating larvae pupate. Adults begin to appear in the middle of March. Female moths deposit eggs singly or in clusters, and each female can lay as many as 500 eggs. Under optimum conditions, the eggs hatch in 3 to 5 days, and larvae develop in 3 to 4 weeks passing through 6 instars. Pupae mature in 2 weeks during the summer and as many as 9 weeks in the fall. Some of the cutworms can produce as many as four generations each year in North Carolina.
Since cutworms may be difficult to detect, soap flushing solutions can be helpful for detection. Use 1 oz of lemon-scented liquid dishwashing detergent in 2 gal of water. Dispense with a watering can within a 3ft x 3ft grid. Larvae should appear in five to ten minutes. Treatment threshold is five to ten larvae per square yard. Threshold may be lower on finer turf such as golf greens. Irrigate the grid with plain water afterwards. Commercial pheromone traps that attract male moths can be used to determine treatment timing but are not indicators of larval densities in the turf. Damage can be expected 2 weeks after peak flight so time pesticide applications accordingly.
Nonchemical Control Strategies
Kentucky bluegrass is a non-preferred host, for black cutworm, compared to creeping bentgrass and perennial rye and may reduce infestation. This may be used in mixed turf or in border areas. The nematode, Steinernema carpocapsae is moderately effective against black cutworm. Follow label instructions exactly. Bacillus thuringiensis products work best while larvae are young. Collection and removal of clippings from the area may be helpful.
Chemical Control- For chemical control, liquid formulations
should be used, applied as late in the day as possible, and not watered in for
at least 24 h. Treating a 20-30 ft buffer zone aroundgreens and tees will
reduce migration from outlying areas. Preceed chemical treatments with mowing
24 hours prior to treatment. Apply chemicals in the evening for optimal night
Recommendations for insecticides approved for control of these insects in home lawns can be found under "cutworms & armyworm" in the Insect Control in the Home Lawns section of the NC Agricultural Chemicals Manual. Follow all label directions.
Bacillus thuringiensis var. kurstaki (various products); spinosad (Conserve); carbaryl (various Sevin products); cyfluthrin; azadirachtin are some examples. Lawn care professionals may have additional chemical choices not available to the home owner applicators.
Chemical Recommendations for Professional Turf-
Recommendations for insecticides approved for the control of cutworms on sod farms, recreational areas, golf courses and other commercial sites can be found in the Commercial Turf Insect Control section of the NC Agricultural Chemicals Manual. Please note the formulation, application, and site restrictions for some products. Follow all label directions. Spinosad, deltamethrin, halofenazide, bifenthrin, lambda-cyhalothrin, carbaryl, trichlorfon and azadirachtin are examples.
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Link to: Ohio State Note on Cutworms
Because environmental conditions, methods of application by growers, and performance of the chemicals may vary widely, control results may also vary.
Recommendations for the use of chemicals are included in this publication as a convenience to the reader. The use of brand names and any mention or listing of commercial products or services in this publication does not imply endorsement by the North Carolina Cooperative Extension Service nor discrimination against similar products or services not mentioned. Individuals who use chemicals are responsible for ensuring that the intended use complies with current regulations and conforms to the product label. Be sure to obtain current information about usage and examine a current product label before applying any chemical.
Published by North Carolina Cooperative Extension ServiceDistributed in furtherance of the Acts of Congress of May 8 and June 30, 1914. Employment and program opportunities are offered to all people regardless of race, color, national origin, sex, age, or disability. North Carolina State University at Raleigh, North Carolina A&T State University, U.S. Department of Agriculture, and local governments cooperating.
Stephen B. Bambara & Rick L. Brandenburg, Extension Specialists
ENT/ort-130 June, 2003
Web page last reviewed January, 2011 by the webperson .