Many species of cutworms from the night-flying moth family Noctuidae are found in home gardens across the United States. The larvae commonly feed on plant stems at or below ground, eventually cutting them down. Cutworms attack a wide variety of plants including beets, cabbage, broccoli, kale and cauliflower.

Cutworm caterpillars (larvae) are stout, soft-bodied, gray or dull brown caterpillars (1-2 inch long) that curl up when at rest or disturbed. They feed at night and burrow into the soil during the day. Adults are dark gray or brown, night-flying moths (1-1/2 inch wingspan) with ragged blotches or stripes on their wings. They do not damage plants.

Note: Pest populations vary greatly from year to year. When numerous, cutworms can destroy up to 75% of a crop.

Life Cycle

Most species pass the winter in soil or under garden waste as young larvae. In the spring, as temperatures warm, they become active and begin feeding on plants at night remaining hidden during the day. The larvae molt several times and when fully grown pupate in the soil (late spring). Within one week moths emerge and begin laying hundreds of eggs mostly on stems and leaves. One to five generations per year, depending upon the species.

Note: Overwintering larvae and the first generation in the spring are the most damaging. A few species pass the winter as pupae or hibernating moths.

Damage

Damage occurs at night when caterpillars feed by clipping off seedling stems and young plants near or just below the soil surface. Often, an entire row of newly planted garden vegetables will be cut off during the night.

Different cutworm species will climb plants doing damage to foliage, buds and shoots. Cutworms are also known to gouge potato tubers. Late season cutworms will tunnel in fruit.

Cut worms, like their close cousins armyworms, will also frequently attack turf grass. The damage they inflict on grass — cutting off blades at the crown — is usually more dispersed than damage from army worms. Cutworms favor golf courses where they cause “ballmark” pockets of dead and missing turf both on fairways and putting greens.

Cutworm Control

Losing precious transplants once to cutworms is all most people require to implement preventive measures as part of an Integrated Pest Management plan. There’s little more heart-breaking than coming out to the garden one morning to find the seedlings you started months ago indoors have been severed at the root.

Tempted to spray chemicals after losing young plants to the slow-moving eating machines? Despite the fact that it will endanger your pets, your children and the environment, pesticide use against cutworm, reports Michigan State University Extension, is “often unsuccessful.”

Preventive Measures

  • Before planting a new garden remove weeds and plant debris that might feed and shelter developing larvae.
  • Turn the soil after fall clean up then give birds and other predators a chance to pick off the expose larvae and pupae.
  • Mow as closely as possible to the edge of your garden to give cutworms less to feed on and less shelter near your plants.
  • A three-foot wide (or more) bare-soil strip between your lawn and your garden plants makes it harder for larvae to reach your plants. It also gives you more of a chance to spot them.
  • Wait as late as possible before setting out starts. Cutworms go on the move early in the growing season. Give them a chance to starve before you put out dinner.
  • Place cardboard collars (or milk containers with the bottom cut out) around transplant stems at planting time. Be sure to work the collar into the soil at least an inch or two.
  • Plant sunflowers along the edge of your garden. Sunflowers are a favorite target of cutworms. The plants will attract the larvae giving you a chance to pick them from the ground before they head to your corn.

Dealing with Infestations

  • The presence of many birds feeding in the yard may indicate cutworms in your turf.
  • Handpick caterpillars after dark. This is often most productive following a rain or thorough watering.
  • Slow the progress of worms, who don’t like navigating dry soil, by watering in the morning then cultivating your garden’s walkways lightly to a depth of an inch or so. This cultivated soil will dry quickly while trapping moisture beneath it. Do not use mulch which gives the worms shelter.
  • Beneficial nematodes released in moist, spring soil will attack and destroy cutworms living underground. They’re especially beneficial to apply the season after cutworms have been a problem.
  • At the first sign of moths, release trichogramma wasps weekly for three consecutive weeks to parasitize cutworm eggs.
  • Spreading a line of diatomaceous earth around the base of plants sets up a barrier to larvae. Diatomaceous earth, the fossilized, abrasive remains of prehistoric sea life, literally lets you draw a line in the dirt that’s deadly to any larvae that pass over.
  • Scatter bran or corn meal mixed with Monterey Bt (Bt-kurstaki) and molasses on the soil surface to attract and kill caterpillars. Eco-Bran will also kill caterpillars that feed on it.

Note: Gardens that were covered in grass or weeds the previous season are especially attractive to this pest.

VARIEGATED CUTWORM

Cutworm is a general term referring to the larval stage of many night-flying miller (Noctuid) moths. Nationally the most economically important ones for potato are the variegated cutworm (Peridroma saucia), black cutworm (Agrotis ipsilon) and spotted cutworm (Amathes c-nigrum). They all have similar habits and appearance; therefore, variegated cutworm is used as the model.

Description

Adults are called miller moths and are usually drab gray or brown but also can be somber yellow and tan.

Larvae are the cutworm which is the damaging stage. Cutworms are caterpillars that when disturbed curl their body into a tight ‘C’ appearance. They have a smooth skin and a wet or greasy texture; their body is plump. The variegated cutworm is grayish brown and lightly speckled with darker brown; it has a single row of pale yellow dots along each side of its body. The black cutworm is greasy gray or brown with faint lighter stripes and granular appearance. The spotted cutworm has a dark stripe along each side of its body and several pairs of triangular-shaped black dashes at the rear of its back. Full grown cutworms are two inches long.

Eggs are small and hemispherical laid under debris, in the soil or on leaves and stem depending on geography.

Pupae are tiny and form in the soil.

Cutworm larvae — variegated and black

Life Cycle

Developing larvae, cutworms, and pupae overwinter in the soil especially from previously grassy areas. Cutworms emerge in the spring. Mature cutworms return into the soil where they will dig a small chamber in which they pupate. Adult moths emerge from overwintered pupae or early-season pupae. Causing no damage, they fly around at night (attracted to electric lights), mate and lay eggs late in the afternoon or at night. Some species lay a single egg or small groups of eggs while others like the variegated cutworm lay closely-packed rows of over 600 eggs. The incubation period ranges from two to 14 days depending on species and temperature. The eggs hatch as cutworms. All cutworms have the same general life cycle; the length of stages varies somewhat. All stages of the variegated cutworm develop rapidly and three or four generations per season are possible. Others may have only one generation per season.

Damage

Initially, spring-emerged cutworms do slight damage by cutting into young stems while eating only a little bit. Unlike, armyworms, cutworms are loners; they do not travel in hordes and are not as prolific. Most cutworms only attack the stems of a few small, often weak, plants. However, the variegated cutworm and a few others will climb up the plant and eat leaves. Feeding is only at night and cooler times of the day. During the day, they hide in soil cracks, or under debris and clods at the soil surface. Their leaf feeding appears as ragged holes or cut-outs in the leaflets. On rare occasions, cutworm feeding on an exposed tuber, leaving shallow holes, has been observed. Economic damage occurs only when there is a high population with intense feeding in the middle of the season during early to mid bulking when plants tolerate up to 10% defoliation. Most foliar damage usually occurs late in the season after bulking when there is little if any effect. Since cabbage and other loopers and armyworms are seen during the day, they may be blamed for cutworm damage.

Management

Biological — Grassland which will be rotated to potato, should be plowed in late summer of early fall thereby reducing the number of eggs deposited. Early fall plowing and clean cultivation will remove debris on which they feed. Cutworms will die of winter starvation or even cannibalism. Do not plant immediately after stubble, grass or sod. In general, cutworms are naturally controlled by parasitic wasps and tachnid flies, and are prone to various diseases.

Chemical — Special chemical treatment for cutworms is discouraged. Soil-applied systemic insecticides used for other pests work well. Since their damage seldom appears until late in the season, it is not economical to treat.

Quick Review

Appearance:
Adult – night-flying miller moths, usually gray or brown
Larva – smooth-skinned caterpillars, cutworms, up to two inches

Life Cycle:
Overwinter as cutworms or pupa
Up to four generation per season depending on species and climate

Damage:
Foliar feeding causing ragged holes usually late in season

Management:
Fall-plowing especially of grassland
Insecticides used against other, more important, pests

  • Defoliating Insects
  • Colorado Potato Beetle
  • European Corn Borer
  • False Chinch Bug
  • Cutworm
  • Grasshopper

Cutworms

Cutworms are destructive pests that damage many different types of plants. The larval forms of several species of moths, cutworms plague lawns and gardens from early spring through fall. Some cutworm species prefer vegetables, including cabbage, lettuces, peppers and carrots. Others go after lawn grasses first. In warm climates, several generations of cutworms are born each season. Their damage builds by fall.

Identification: Depending on the species, cutworms vary in color from pink, green or brown to black, usually with muted stripes running lengthwise along their bodies. When disturbed, they curl up into a “C.” One of the most common types is the black cutworm, which affects lawns and vegetable gardens. The plump, grayish brown, greasy-looking larvae grow up to two inches in length.

Signs/Damage: Cutworms spend their days in soil, coming out to feed at night. You may notice plants wilt under the sun’s heat. Closer inspection reveals stems damaged or cut in two as the name implies. Seedlings and young transplants are hardest hit. In lawns, cutworms feed at the base of grass, cutting off the blade and often dragging it back to nearby burrows. Check lawn thatch for small tunneling holes lined with green excrement. Lawn damage peaks during hot summer months.

Control: Unless days are cloudy, cutworm damage happens at night. To maximize your impact, apply cutworm treatments in evening hours. GardenTech® brand offers several highly effective products that kill cutworms by contact and keep protecting for up to three months*.

  • Sevin® Insect Killer Granules reach cutworms above and below the soil line. Apply the ready-to-use granules with a regular lawn spreader. Then water the treated area to release the active ingredients and reach cutworms where they hide. In garden areas with known cutworm problems, be proactive. Work the granules into the top 4 to 6 inches of soil before planting or as soon as plants emerge.
  • Sevin® Insect Killer Ready to Use is ideal for treating targeted plants or smaller garden areas. Just shake the bottle, adjust the nozzle to spray narrow or wide, and you’re ready to treat and protect.
  • Sevin® Insect Killer Concentrate, used with a pump-style sprayer, or Sevin® Insect Killer Ready to Spray, used with a regular garden hose, simplify treating larger areas where you see or expect cutworm damage. Spray to cover all plant surfaces thoroughly, including stems and undersides of leaves.

Tip: Cutworms overwinter in the larval stage in soil. Till your garden in fall and spring to expose and kill overwintering larvae.

Always read product labels and follow the instructions carefully, including guidelines for pre-harvest intervals on edible crops.

*These products provide up to 3 month control on all listed insects except ticks.

GardenTech is a registered trademark of Gulfstream Home and Garden, Inc.

Sevin is a registered trademark of Tessenderlo Kerley, Inc.

PHOTO CREDIT:

“Black cutworm, curled” by USGS Bee Inventory and Monitoring Lab (Public domain)

“Black cutworm, side” by USGS Bee Inventory and Monitoring Lab (Public domain)

“Black cutworm (Agrotis ipsilon)” by W.M. Hantsbarger (Bugwood.org) licensed under CC BY 3.0 US

“Black cutworm (Agrotis ipsilon)” by David Jones at University of Georgia (Bugwood.org) licensed under CC BY 3.0 US

“Black cutworm, face, straight on” by USGS Bee Inventory and Monitoring Lab (Public domain)

Turfgrass Insects

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HOW TO USE THIS PUBLICATION

This publication provides turfgrass management professionals and golf course superintendents in Indiana and throughout the Midwest with information to help them 1) properly identify the black cutworm, 2) understand black cutworm biology, 3) recognize black cutworm damage, and 4) formulate safe and effective black cutworm management strategies. For information on turfgrass identification, weed, disease, and fertility management, visit the Purdue Turfgrass Science Website (https://turf.purdue.edu) or call Purdue Extension (765-494-8491).

DISTRIBUTION

The moth species Agrotis ipsilon is commonly known as the black cutworm, but is sometimes referred to as the Dark sword-grass (larvae) or the Ipsilon dart (adult). The black cutworm’s range encompasses the entire continental United States but varies seasonally, as this species does not tolerate colder temperatures. The black cutworm has four to five generations in the southern-most states, three to four in the transition zone, and 2 to 3 generations in the most northern parts of its range.

Larvae are the damaging stage; adults feed only on nectar. The species is a well-known pest of corn, cutting the stalks at the base without consuming the rest of the plant. However, the larvae also feed on turfgrasses, causing notable damage on closely mowed turf. This feeding makes it a common pest of golf course putting greens and tees.

IDENTIFICATION AND SEASONAL BIOLOGY

Adult

The black cutworm moth is a mottled brown. There is a dagger-shaped marking on the adult’s wings (Figure 1). The marking can also be described as a dart below a kidney-shaped spot. The wingspan of the forewing can range between 1.25- 2 inches (32-51mm).

Egg

The egg is yellow-cream in color. The shell is smooth and bears no visible markings. Egg are attached singly to the tip of a blade of grass (Figure 2).

Figure 1. Black cutworm adults have distinctive dagger-shaped markings on each wing.

Figure 2. Black cutworm eggs are usually laid singly and toward the tips of grass blades making them easy to remove by mowing.

Larva

The black cutworm caterpillar’s body appears greengray to almost black, with a lighter gray underside and a broad stripe of lighter gray or brown down the middle of the back (Figure 3). The body is also hairless, excluding a few bristles. The head capsule is dark with a triangle-shaped marking. When full grown, the larva is about 2 inches (50 mm) in length.

Figure 3. Black cutworm larvae are green-gray to almost black, with a lighter gray underside and a broad stripe of lighter gray or brown down the middle of the back.

Black cutworms overwinter in the southern most states as pupae and adults. Adult moths travel northward from southern states on weather fronts during April and through May. The adults mate upon arrival and begin laying eggs. Eggs are laid singly on the tips of grass blades, but one female can lay as many as 1600 eggs. The eggs hatch into caterpillars a few days later and the caterpillars burrow into the thatch and soil, emerging to feed at night. As the larvae grow, they able to travel into more sensitive turfgrass areas. Larvae generally pupate in late May and emerge as adults by early June. A second generation of larvae appears throughout July and a third generation of larvae are often present through September. Cooler temperatures during October, usually kill remaining adults and pupae.

DAMAGE AND DIAGNOSIS

Black cutworm damage can initially be misdiagnosed as a ball marks or other depressions in highly manicured turf. These pockmarks become more irregular as the caterpillar continues to feed. This kind of damage may interfere with play on golf courses and can be unsightly when large numbers of caterpillars are present (Figure 4).

Figure 4. Over time, pock marks caused by blackworm larval feeding become more irregular in shape.

Detection and Monitoring

Black cutworms only come out to feed during the night and generally hide during the day. This feeding behavior means extra effort is needed to find evidence of the caterpillar’s presence before damage occurs. The presence of birds, especially the European starling, foraging on turf can indicate the presence of black cutworms or other caterpillars like sod webworms. Birds will leave probe marks when searching for cutworm pupae or larvae in the grass. Tufts of loose grass around probe markings can indicate where birds have pulled up larvae or pupa from the thatch or soil.

A more direct approach to monitoring for black cutworms is to apply a soapy water flushing solution. Adding two tablespoons of liquid detergent to two gallons of water will create a solution that can be applied to one square yard of turf using a watering can. The best detergent for soap flushing is lemon-scented Joy, but Ultra Dawn and Ivory Clear also do not damage turf when used. Avoid using Palmolive. A few minutes after application, larvae irritated by the soap flush will rise to the surface, largest to smallest, and can be collected for identification. Applications should occur in the morning when the larvae are still close to the surface. Turf should be well-irrigated for best results. Soap flushing can also be performed after insecticide applications to assess efficacy.

BLACK CUTWORM MANAGEMENT

Black cutworm management relies on a combination of cultural, biological, and chemical tools aimed at keeping populations below damaging levels. Although observation of the migrating adults may forecast a potential future problem, only management of the larvae will reduce damage.

Cultural Tools

The primary challenge for turfgrass managers is striking a balance between the functional and aesthetic requirements of the turf and maintaining an environment that is suitable for beneficial organisms and the services they provide. Sound cultural practices that include 1) selection of turfgrass species and cultivars that are well adapted for a specific site or use and 2) proper mowing, fertilization, irrigation, thatch management and cultivation to promote healthy vigorous turf. Such turf is capable of tolerating or quickly recovering from insect feeding and serves as the foundation of “integrated pest management” (IPM).

Proper mowing is essential for controlling black cutworms on high maintenance turfgrass. Mowing tees and putting greens every morning removes the majority of the eggs laid the previous night. The clippings should be collected and disposed of accordingly, at a fair distance away from susceptible playing surfaces to avoid re-infestation. Cutworm larvae will also readily inhabit aerification holes, so filling these openings with sand or other top-dressing material soon after aerification may reduce their attractiveness to the larvae.

Resistant Turfgrasses

Certain turfgrass varieties play an important role in black cutworm management because they are less likely to suffer damage and recover quickly if damage should occur. When complemented by proper mowing, irrigation, and fertilization, planting resistant varieties can reduce the need for chemical insecticides.

Endophyte-Enhanced varieties

The endophyte-enhanced (E+) cultivars of perennial ryegrass, tall fescue, and creeping red fescue provide some resistance to black cutworms. These grasses harbor symbiotic fungi (Neotyphodium spp.). However, the effects of E+ turfgrasses on black cutworm larvae are generally sublethal and have they not been shown to stop black cutworm feeding.

Resistant Kentucky Bluegrasses

Kentucky bluegrass is generally resistant to black cutworm larvae. When planted in Collars, Aprons, and Approaches surrounding more sensitive areas such as putting greens, Kentucky bluegrass may reduce the reservoir of black cutworms that could move onto these sensitive areas when they become larger and more mobile.

Biological Controls

Although a host of pathogens, predators, and parasites will attack and kill black cutworm larvae, commercially-available biological controls are limited primarily to the insectparasitic nematode Steinernema carpocapsae. When used properly, this nematode can provide good control and is generally safer than chemical insecticides. However, special considerations must be made when using insect-parasitic nematodes. Nematode products should be refrigerated upon arrival and stored as briefly as possible. Nematode viability should be checked prior to application. After mixing, nematodes should be applied immediately. Applications should be made in the evening and irrigation should immediately follow. Screens should be removed from spray nozzles and spray equipment should be pressurized to a maximum of 50 psi. CO2 should not be used to pressurize spray equipment as nematodes may be asphyxiated. Steinernema carpocapsae is available under the trade names Millennium® (BASF), NemAttack™ (Arbico Organics) and others.

The black cutworm has several natural enemies and while they are not commercially available, they can assist in management. Ants will attack any caterpillars they come across, but are killed by insecticides in the organophosphate class. Tachinid flies will lay their eggs on caterpillars, where their larvae will hatch and then excavate the host’s body. As mentioned previously, birds eat black cutworm caterpillars, but cause minor damage by pulling up turf in the process. The baculovirus virus (AgipMNPV) infects and kills black cutworms by liquefying them without any danger to humans or wildlife. The virus can be spread through ingestion, mating, and egg-laying. However, outbreaks usually only occur in high population densities which is contradictory to IPM. Finally, two species of entomophagous fungi, Beauveria bassiana and Metarhizium anisopliae can also infect larvae, but they may not perform well on turf treated with fungicides.

Chemical Insecticides

A curative strategy is the most efficient strategy for achieving control of black cutworms using chemical insecticides. This strategy relies on careful monitoring to identify black cutworm larval activity, followed by timely application of an effective insecticide. Black cutworm larvae can be managed with a wide assortment of insecticides and Table 1 provides a list of insecticides recommended for black cutworm management. Black cutworm larvae are typically exposed to the insecticides through both physical contact and ingestion of treated plant material. Applications should ideally be made in the late afternoon or evening, due to the black cutworm’s nocturnal feeding behavior. When liquid materials are used, post-application irrigation should be avoided for 24 hours in order to ensure that the insecticide deposit remains in target zone of the turf canopy and thatch as long as possible. Granular materials should always be lightly irrigated after application to release the active ingredient from the carrier granule.

Due to their extended residual activities, some insecticide products may also provide protection against infestations for an extended period after application. When used at appropriate rates, products containing the active ingredients clothianidin, chlorantraniliprole, cyantraniliprole or thiamethoxam may also be useful as part of a preventive strategy.

Table 1. Active ingredients of insecticide products recommended for black cutworm control using curative and/or preventive strategies.

Insecticide* (Trade Name/Manufacturer) Insecticide Class Curative Strategy Preventative Strategy

SYNTHETIC INSECTICIDES

Beta-cyfluthrin (Tempo/Bayer) Pyrethroid X
Bifenthrin (Talstar/FMC) Pyrethroid X
Carbaryl (Sevin/Bayer) Carbamate

X

Chlorantraniliprole (Acelepryn/Syngenta; Others) Diaminde X X
Chlorpyrifosa (Dursban/Dow) Organophosphate X
Clothianidin (Arena/Nufarm; Others) Neonicotinoid X X
Cyantraniliprole (Ference/Syngenta) Diaminde X X
Deltamethrin (DeltaGard/Bayer; Others) Pyrethroid X
Dinotefuran (Zylam/PBI-Gordon) Neonicotinoid X
Indoacarb (Provaunt/Syngenta; Others) Oxadiazine X
Lambda-cyhalothrin (Scimitar/Syngenta; Others) Pyrethroid X
Permethrin (Astro/FMC) Pyrethroid X
Thiamethoxam (Meridian/Syngenta) Neonicotinoid X X
Trichlorfon (Dylox/Bayer) Organophosphate X
Zeta-cypermethrin (Talstar Xtra/FMC) Pyrethroid X

BIOLOGICAL/BIORATIONAL INSECTICIDES

Spinosad (Conserve/Dow AgroSciences) Spinosyn X
Steinernema carpocapsae (Millenium/BASF, Others) Parasitic Nematode X
*Always consult label directions for specific timing and application recommendations.
aLabeled only for use on turfgrass grown for sod or seed.

READ AND FOLLOW ALL LABEL INSTRUCTIONS. THIS INCLUDES DIRECTIONS FOR USE, PRECAUTIONARY STATEMENTS (HAZARDS TO HUMANS, DOMESTIC ANIMALS, AND ENDANGERED SPECIES), ENVIRONMENTAL HAZARDS, RATES OF APPLICATION, NUMBER OF APPLICATIONS, REENTRY INTERVALS, HARVEST RESTRICTIONS, STORAGE AND DISPOSAL, AND ANY SPECIFIC WARNINGS AND/OR PRECAUTIONS FOR SAFE HANDLING OF THE PESTICIDE.

May 2016

It is the policy of the Purdue University Cooperative Extension Service that all persons have equal opportunity and access to its educational programs, services, activities, and facilities without regard to race, religion, color, sex, age, national origin or ancestry, marital status, parental status, sexual orientation, disability or status as a veteran. Purdue University is an Affirmative Action institution. This material may be available in alternative formats.
This work is supported in part by Extension Implementation Grant 2017-70006-27140/ IND011460G4-1013877 from the USDA National Institute of Food and Agriculture.

765-494-8491

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How to Manage Pests

Identification
Adults are dull brown or grayish, relatively large, up to 1-1/2 inches (3.8 cm) long, night-active moths. Larvae are caterpillars that are up to 2 inches (5 cm) long at maturity and often curl up and lie still when disturbed. The large size and behavior of larvae distinguish them from lawn moth caterpillars.

Hosts

All turfgrass species

Damage

Cutworm and armyworm larvae chew and cut leaves around the crown. Damage begins in small, irregular spots and spreads to patches extending many feet in width. Armyworms, especially, prefer moist areas.

Monitoring information

Cutworms and armyworms are active from early spring through the fall. Look for fat, dull gray, green, or brownish larvae up to 2 inches (5 cm) long with a drench test. Inspect outdoor lights around dawn for 1-1/4 inch (3.2 cm) brownish to gray moths.

Management

Reduce thatch and eliminate soggy areas. Larvae have some natural enemies, such as braconid wasps and tachinid flies. If more than 5 larvae per square yard are present, you may need to treat. Beneficial nematodes or an application of Bacillus thuringiensis (Bt) may be effective against young caterpillars. Other safe products are available.

Life cycle

For more information on lawn insects, refer to:
Pest Notes: Lawn Insects

Cutworm Control: How To Get Rid of Cutworms

Identification

Cutworms are caterpillars which can be identified via the way they curl their body into a tight ‘C’ when they are disturbed. They have a plump body and smooth skin which appears to have a wet or greasy texture. The variegated cutworm is grayish brown and lightly speckled with darker brown and when observed closely you will notice a single row of pale yellow dots along each side of its body. When they grow into adulthood, they become moths.

Use the image and description above to help you identify cutworms on your lawn. If you are having trouble confirming that the pest on your property is a cutworm, you contact us with a quality close-up photo and we will be happy to respond back to you with the pest ID as well as offer you some suggestions and products recommendations to eliminate the pest.

Inspection

When to Inspect

Most of the damage inflicted by cutworms is done early in the growing season when they come out from hibernation. Cutworms are caterpillars, but they are often mistaken for grubs. Around summertime, cutworms will often crawl to the tops of plants and damage the area. It’s not uncommon to mistake the damage they cause with the damage of other turf and garden insects like slugs and grubs.

What to look for

Check the damage of your garden plant and if there are any eggs in high grass or weeds. Reducing weeds and clutter around your garden can help to not only expose cutworms but discourage them from staying in the area. Timing is important when treating cutworms as they are known to lay a lot of eggs and it would be best to control them before they hatch and add to the damage.

Treatment

Cutworms can be easy to find where they are established. To find them, what you’re going to want to do is root around in the soil around the base and you may be able to dig one up. If you don’t locate the cutworms quickly, they will move from plant to plant dealing more damage. If you only have a few you can go ahead and smash them by hand, but for more severe infestations it would be best to apply an insecticide.

Before conducting chemical applications, you should make sure that you are wearing protective equipment when handling pesticides, even organic pesticides, for any chance of skin or facial contact which can be irritating or uncomfortable. Our top pesticide suggestion for cutworms is Dominion 2L. Mix and utilize the product according to the set instructions on the label.

Step 1 – Mix and Apply Dominion to Lawn

Mix water in a handpump sprayer with Dominion 2L and agitate the sprayer. Follow label instructions for specific application rates then broadcast the solution over your entire lawn.

Apply late in the afternoon for best control as that is when cutworms are most active. Reapplications may be necessary until you see no further damage to your garden or the presence of cutworms has been eradicated.

Prevention

After eliminating the cutworm infestation, you will need to work to prevent the infestation from returning. In the spring, emerging cutworms will be waiting to feast on your garden. Cut off their food supply by delaying transplanting or planting by a couple weeks if possible. Keep up with cultivation. Cutworm moths prefer to lay eggs in high grass and weeds. At the end of the season, plow or till the garden and mow surrounding areas to expose cutworms and destroy their winter habitat.

Key Takeaways

  • Cutworms is a catch-all term describing the larvae stage of various moth species found developing on lawn turf. Cutworms can often cause a lot of damage to a garden in a short amount of time.
  • Our top recommendation for controlling a cutworm invasion is Dominion 2L. Mix the insecticide with water into a pump sprayer and do a full broadcast on your lawn and garden for best results.
  • Prevent cutworm reinfestation by closely monitoring your lawn and garden and conducting cultural practices which discourage cutworm activity (tilling, mowing, etc.)

Cutworms

Multiple Species

Appearance and Life History

Dingy Cutworm
Photo by B. Christine

Cutworms can attack crops virtually anywhere in the Midwest. The importance of a particular species of cutworm varies with how and when it damages corn. Some species feed much like the black cutworm and can cause extensive crop damage, others are more like armyworms that climb the plant to feed on foliage. Often an infested field will have a mixed population of several species of cutworms. Because they vary in their feeding habits, early diagnosis of cutworm infestations are essential.

Variegated cutworm
Photo by Purdue University

The bodies of cutworms are cylindrical and may vary in length from 1/8 to 1-1/2 inches (3.2 to 38.1 mm), depending on the species. Often, 3 or 4 different sizes of cutworm will be noted in a typical field collection. Cutworms may lack any visible markings or may be distinctly marked with spots or stripes. Color may range from black, gray, and brown to nearly white or translucent.

Claybacked cutworm
Photo by J. Obermeyer

Most cutworms overwinter as pupae in the soil or as young larvae. After mating, moths deposit eggs on soil, weeds, and/or cultivated plants, if present. Feeding begins in the spring. This may occur before or after planting.

The larvae hatch in 2 days to 2 weeks, molt several times and mature in 2 weeks to 5 months. Most cutworms have one generation per year, while some species have 2 to 4.

Sandy knoll with sandhill cutworm damage
Photo by Purdue University

Early cutworm feeding may include holes chewed in leaves. Leaf margins may appear ragged. This above ground injury occurs early in the cutworm’s developmental stages. At this time, young worms feed above ground at night or on cloudy days. Older larger worms often cut plants at or below ground level. Cutworms often pull cut plants into their burrows to feed on at their leisure. Larger worms tend to remain below the soil surface, especially if the weather is dry and a surface crust has formed.

Sampling Method

Cutworms remain hidden in the soil or under crop residue during the day. To find them, examine the top several inches of soil or under plant residues around damaged plants. If most residue is between the rows, the cutworms may be found there instead. Since the color of some cutworms blends with the soil, they may be easily overlooked.

To monitor for cutworm damage, walk fields as plants emerge. Randomly check 20 plants in each of 5 areas of a field (100 total plants). Record the number of cut or damaged plants for each area and the field as a whole. Make a note of leaf feeding that may be due to young cutworms. Record the average number of fully unrolled leaves for the field. Check fields again in 24 to 48 hours. Be sure to monitor those areas of the field where cutworms are most likely to be found (wet, weedy areas).

Also, look for live cutworms around damaged plants. Collect 2 cutworms from each sample set for a total of 10 and record the body length of each. Determine the average length and species of cutworm causing the damage.

Management Guidelines

Corn Insect Control Recommendations: E-series 219-W (PDF)

No management guidelines have been established for cutworms other than black cutworm in corn.

If control is necessary, contact your state Cooperative Extension Service or click here for control materials and rates.

Vegetable crop pests-Cutworm

Includes

Black cutworm (Agotis ipsilon)
Variegated cutworm (Peridroma saucia)

Pest description and crop damage The black cutworm moth is a uniform dark brown with a lighter irregular band near the wing tips and a distinct black dash. It has a wingspan of 1.5 to 2.12 inches long. Eggs are white at first, later turning brown. Larvae are a uniform gray to nearly black, lighter underneath, ranging in size from 0.18 inch to 2 inches as they pass through up to nine instars. The pupa is dark brown and about 0.75 inch long. Most feeding is at ground level. In the Willamette Valley, black cutworm is considered to be the most damaging cutworm species to vegetable crops. The last instar does by far the most feeding, though middle instars can cut down seedlings.

Variegated cutworm moths are approximately 1 inch long with a wingspan of 1.25 to 2 inches. They vary widely in coloration. Eggs are white to dull or off-white in color, and ribbed. They generally are deposited in massed rows on crop foliage but frequently are found on weeds. Larvae are brownish gray to grayish black and up to 1.75 inches long when fully grown. Pupae are mahogany brown and about 0.75 inch long. The variegated cutworm feeds readily on a wide variety of crops and climbs into the host plant to feed. Cutworms are most active and cause the most damage during spring and early summer months.

Biology and life history During mild winters, the black cutworm overwinters in field debris and brush as a pupa. Otherwise, it flies in from warmer climates in late spring. The variegated cutworm overwinters in the soil or under trash as a partially mature larvae.

Larvae begin feeding in early spring and may damage seedlings. They mature in late April and May and pupate in earthen cells in the soil. Adults emerge in late May and June. Black cutworm moths scatter their eggs across the field. Variegated cutworm lays eggs in clusters on the undersides of leaves. Eggs hatch in 4 to 7 days, and larvae begin to feed on plant foliage. Larvae feed for 4 to 6 weeks, then pupate in the soil. The next generation of adults emerges in late August and lays eggs. These hatch into larvae which form the overwintering stage for the variegated cutworm. There are two generations each year.

Identifying soil beetle pests

African black beetle (Heteronychus arator)

Description

Adults:

  • about 12mm long
  • shiny black
  • slow moving
  • usually found on or under the soil surface.

African black beetle adult

Larvae:

  • about 35mm long and 10mm wide when fully grown
  • soil dwelling
  • three pairs of legs on the thorax
  • prominent brown head with black jaws
  • body forming a C-shape with the end of the abdomen slightly enlarged
  • distinguished from other species with the naked eye, as their anal opening and associated spines are horizontal (see figure below).

The horizontal opening on the tip of the abdomen of African black beetle larvae is a distinguishing feature that separates this species from other cockchafer larvae. Line drawing courtesy Clive Thornton, University Pretoria African black beetle larva

Adults:

  • strong fliers – mass flights sometimes occur in late summer-autumn and they are attracted to light
  • feed on stems of plants near ground level killing them
  • chew grass stems causing fraying. They also chew holes in potato tubers.

Larvae:

  • damage grasses by root pruning.

Little pasture cockchafer (Aphodius frenchi)

Adults:

  • about 3mm long
  • small, black, shiny beetle
  • similar in shape to African black beetle.

Small pasture cockchafer

Larvae:

  • similar to African black beetle but much smaller.

Adult and larvae:

  • are often found in pasture, but not considered to be pests
  • adults very occasionally recorded damaging emerging onion seedlings.

Vegetable beetle (Gonocephalum missellum)

Adults:

  • about 9mm long
  • matte grey, sometimes encrusted with soil on their back.

Vegetable beetle adult

Larvae:

  • about 18mm long and 2mm wide when fully grown
  • three pairs of legs on thorax
  • shiny, hard skin
  • worm-like shape (‘false wireworm’).

Vegetable beetle larva

Adults:

  • often present in clusters and found under debris or vegetation
  • feed on decaying vegetation, but known to attack seedlings
  • more active than African black beetle.

Larvae:

  • soil dwelling and feed on organic matter
  • can be pests of summer grown crops
  • if present as large larvae when potatoes are near harvest can chew holes in them.

Bronzed field beetle (Adelium brevicorne)

Adults:

  • about 10mm long
  • shiny, black beetles.

Bronzed field beetle adults

Larvae

  • dark brown larvae up to 12mm long
  • have upturned spines on the end of the body
  • commonly known as ‘false wireworms’ (the same common name as larvae of vegetable beetle).

Bronzed field beetle larvae are known as false wireworms

Adults:

  • not crop pests
  • feed on dead, decaying plant matter
  • sometimes seen feeding on damaged crop leaves.

Larvae:

  • chew through stems of seedlings at ground level
  • most destructive when they have reached half size, before the crop emerges.

White fringed weevil (Gnaphognathus leucoloma)

Adults:

  • large grey weevil, 15mm long
  • white stripe along each side and a hairy back
  • when wet it is black.

Whitefringed weevil adult

Larvae:

  • white-headed weevil larva, about 12mm long when fully grown
  • soil inhabiting
  • prominent black jaws, legless.

See: Differences in morphology of adults and larvae, weevil larvae for picture.

Adults:

  • often seen feeding on sunny days
  • slow moving and nibbles edges of leaves causing scalloped effect
  • found in many situations, for example, gardens, orchards and pasture.

Larvae:

  • soil inhabiting and can damage potato tubers, root systems of tomato, kiwi fruit and cauliflower seedlings and lucerne.

Vegetable weevil (Listoderes difficilis)

Adults:

  • medium sized grey weevil, 10mm long
  • two short white stripes at an angle on each side of the back and a central white line on the back of its head
  • this weevil can fly.

Vegetable weevil adult

Larvae:

  • about 10mm long and 3mm wide when fully grown
  • brown head with brown plate behind the head
  • legless
  • yellow to green.

Vegetable weevil larva

Adults:

  • usually hide under vegetation during the day
  • often more noticeable at edges of crops
  • feed on leaves, especially brassicas.

Larvae:

  • feed on above ground foliage
  • can be found on brassicas, though rarely found on canola
  • seek shelter during the day.

Sub-clover weevil (Listoderes delaguei)

Adults:

  • slightly smaller than vegetable weevil, about 7mm long
  • brightly coloured with a smooth appearance to its body
  • has a prominent white spine on each side of the back
  • two angled short white stripes like vegetable weevil
  • prominent white stripe running down the centre of the body just behind the head.

Sub-clover weevil adult

Larvae:

  • similar to vegetable weevil larvae with brown head with brown plate behind the head
  • legless
  • yellow to green.

See: Vegetable weevil section for picture.

  • similar habit to vegetable weevil, but little is known of its biology and pest status.

Small lucerne weevil (Atrichonotus taeniatulus)

Adults:

  • small to medium size weevil very similar in colour to whitefringed weevil, but much smaller, about 7mm long
  • white stripe down the side not obvious as in white fringed weevils
  • hairs on the back are less obvious also.

Small lucerne weevil adult

Larvae:

  • white headed weevil larva
  • prominent black jaws, legless
  • soil inhabiting
  • not easily distinguished from Fuller’s rose weevil or white fringed weevil.

See: Differences in morphology of adults and larvae, weevil larvae for picture.

Adults:

  • may be seen on foliage during the day, or hides under debris
  • feeds on leaves, especially braissicas including canola; can damage established clover.

Larvae:

  • will debilitate mature lucerne stands and damage potato tubers.

Fuller’s rose weevil (Asynonychus cervinus)

Adults:

  • medium size weevil, about 8mm long, elongated body form
  • grey with yellow stripe running across the side on first two body segments and a lateral yellow stripe on each side of the abdomen.

Fuller’s rose weevil adult

Larvae:

  • white headed weevil larva; when fully grown, smaller than whitefringed weevil and similar size to apple weevil and garden weevil larvae
  • prominent black jaws, legless
  • soil inhabiting
  • not easily distinguished from whitefringed weevil or small lucerne weevil.

Adults:

  • seen on foliage during the day
  • feed on leaves
  • egg laying blocks mini-sprinklers.

Larvae:

  • inhabit the soil and have damaged potato tubers.

Spotted vegetable (desiantha) weevil (Steriphus diversipes)

Adults:

  • small weevil, about 5mm long
  • dark coloured sometimes with grey flecking on the back.

Spotted vegetable weevil adult

Larvae:

  • brown-headed weevil larva smaller than apple weevil and garden weevil larvae when mature
  • soil inhabiting
  • small larvae are difficult to distiguish from garden weevil, apple weevil and sitona weevil.

Spotted vegetable weevil larvae

Adults:

  • may be seen on foliage during the day
  • found in many situations, from domestic gardens to pastures.

Larvae:

  • soil inhabiting and can attack vegetables, but most serious damage is to cereal seedlings.

Sitona weevil (Sitona discoideus)

Adults:

  • small greyish-brown weevil, about 5mm long, with three white stripes on the thorax
  • strong flier.

Sitona weevil adult

Larvae:

  • brown headed weevil larvae
  • inhabit soil
  • similar to garden weevil, apple weevil and spotted vegetable weevil larvae.

Sitona weevil larva

Adults:

  • feed on leaves
  • minor pest of pastures and rarely causes damage to canola.

Larvae:

  • feed on grass roots
  • not known to be a pest.

Apple weevil (Otiorhynchus cribricollis)

Adults:

  • medium size weevil, about 8mm long with a slightly bulbous abdomen
  • uniform brown colouring
  • rows of short hairs along its back.

Apple weevil adult

Larvae:

  • brown-headed weevil larva, about 10mm long and 4mm wide when mature
  • bulbous abdomen
  • soil inhabiting
  • small larvae are difficult to distiguish from garden weevil, spotted vegetable (desiantha) weevil and sitona weevil.

See: Differences in morphology of adults and larvae, weevil larvae for picture.

Adults:

  • feed at night
  • found in orchards
  • descends trees during the day and hides under the bark or debris and crawls back up at night
  • feed on leaves and pedicels of fruit.

Larvae:

  • inhabit the soil and have damaged potato tubers.

Garden weevil (Phylyctinus callosus)

Adults:

  • medium size weevil, about 7mm long with a bulbous abdomen
  • has a prominent lighter coloured strip running across the back
  • usually grey-brown colour.

Garden weevil adult

Larvae:

  • brown-headed weevil larva, similar in size to apple weevil
  • soil inhabiting
  • small larvae are difficult to distiguish from apple weevil, spotted vegetable (desiantha) weevil and sitona weevil.

See: Differences in morphology of adults and larvae, weevil larvae for picture.

Adults:

  • hide during the day
  • cluster in curled leaves, below deciduous trees and in crevices
  • feed on leaves and fruits.

Larvae:

  • damage potato tubers, asparagus and strawberry roots and crowns.

Cooperative Extension: Insect Pests, Ticks and Plant Diseases


Clay A. Kirby, Insect Diagnostician

For information about UMaine Extension programs and resources, visit extension.umaine.edu.
Find more of our publications and books at extensionpubs.umext.maine.edu.

Description & Biology

The following are the most significant soil insects attacking home garden plants:

Wireworms are the immature stage (larva) of the click beetle. Wireworms are cylindrical, about 1-1/2 inches long, brownish to yellow and are rather hard-bodied. These insects eat seeds, cut into small shoots and often bore into stems, roots, and tubers. They attack many vegetables including potatoes, onion, corn, carrots, peas, beans, and melons.

Wireworm (Larva)Wireworm Feeding on PotatoClick Beetle

White grubs are cream colored, C-shaped larvae with brown heads. They include the immature stage of European chafer, Japanese beetle, and beetles from the genus Phyllophaga (May beetles/June bugs). They stay in the soil and feed on the roots of corn, beans, peas and other vegetables. They are most likely to damage plants in or near ground that was recently sod covered.

White GrubAdult European Chafer BeetleAdult Japanese BeetleAdult May Beetle/June Bug
Cutworm Feeding on Potato Stem

Cutworms are the larval, or immature, stage of certain moths. They can often destroy a stand of plants in a garden. Cutworms are night feeders and are seldom seen during the day. These insects cut off small plants at or near the ground level and feed on the tender stem. Some types climb up the stem and feed on foliage. Many plants are attacked by cutworms, but they are especially damaging to corn, beans, tomatoes and peppers.

Cabbage Maggots and Pupae

Cabbage maggots are also the larvae of small flies. They feed on fine roots, eventually tunneling into the taproot. They attack cabbage, broccoli, turnips and similar crops. Other maggots which attack vegetable crops are the carrot rust fly and the onion maggot.

Seed corn maggots are the larvae of small flies. They develop in the soil and feed on seed and seedlings of corn, beans, peas, potatoes, cabbage, melons and other crops. Cool wet springs and soil with a high concentration of organic matter favor the development of this pest. (No pictures available at this time).

Management

Beneficial nematodes can be used for controlling the soil-dwelling larval stages of the above pests. Cardboard plant collars, spinosad, Bt (Bacillus thuringiensis), and carbaryl (Sevin) sprays and baits can be used to control cutworms. Row covers can be used to prevent maggot problems.

When Using Pesticides

ALWAYS FOLLOW LABEL DIRECTIONS!

Pest Management Unit
Cooperative Extension Diagnostic and Research Laboratory
17 Godfrey Drive, Orono, ME 04473-1295
1.800.287.0279 (in Maine)

Information in this publication is provided purely for educational purposes. No responsibility is assumed for any problems associated with the use of products or services mentioned. No endorsement of products or companies is intended, nor is criticism of unnamed products or companies implied.

© 2016, 2018 | Reviewed: 2020

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