Anyone who has spent time planting and caring for an outdoor vegetable garden has likely encountered the dreaded pest the cutworm. Though very common, and potentially quite devastating, there are numerous methods for controlling and curtailing the presence of cutworms in your garden. We will discuss the best methods here.
Cutworms are found worldwide, and are actually the larvae (or caterpillars) of numerous species of night flying moths from the Noctuide family. They were given the moniker “cutworm” because of their voracious appetite and subsequently, their ability to cut down young plants as they feed at the stem or below the surface. Typically, a young cutworm will begin feeding on the first part of a plant they encounter (usually the stem) and devour until the stem is felled or cut in half. Some cutworms will cut off a plant from underneath the soil, causing the rest of the plant to shrivel and die. Though some cutworms will remain eating the remaining fallen plant, most often the cutworm will move on to another stem rather quickly, thus causing a rather disproportionate amount of damage to crops when compared to the actual size of the pest or infestation.
Identification of cutworms:
Cutworms may vary in appearance, ranging in color from tan or green to even pink, gray or black, yet most often appear green, brown or gray. Like the moth they will eventually morph into, cutworms, may appear uniform in color, or spotted and striped. They are a soft bodied caterpillar, most often dull or greasy in appearance, (though they may appear in more bright and vivid forms as well). At it greatest length, a cut worm will reach up to two inches (40 mm) in length, and are most readily identified for their characteristic of curling into a “C” when disturbed.
In many climates, cutworms will winter just under the soil (typically within 1-2 inches of the surface) either as a final instar larvae, or as a pupae.
Damage caused by cutworms:
As mentioned above, because of its feeding habits, the cutworm is especially deadly for young crops.
Cutworms feed on a variety of plants, including asparagus, beans, cabbage, kale, rutabaga and other crucifers, as well as corn, celery, lettuce, peas, peppers, and tomatoes. Some species even feed on turfgrass.
Adult moths are nocturnal and will lay their eggs on vegetation, or on moist ground surrounding plants, and the cut worm caterpillar larvae will hatch anywhere from 3-24 days after being laid and begin feeding almost immediately on vegetation near the ground. After 10-14 days, the larvae will become noctural feeders, staying underground during the day, and feeding only at night.
- Methods of control:
- Eliminate Cutworms Using Natural Pest Control
- Eliminate Cutworms Using Natural Pest Control
- Tachinid Fly (Tachinidae family)
- Cutworm Control: How To Get Rid of Cutworms
- Key Takeaways
- Cutworm Control & Facts
- So… What are Cutworms?
- Reproduction Patterns of Cutworms
- Cutworm’s Habitat
- Symptoms of Cutworm Damage
- Results of a Cutworm Infestation
- Natural Predators
- How To Identify Cutworms
- How To Get Rid Of Cutworms
- How To Keep Cutworms Away
- Be Prepared
- How to Control Cutworms in Your Garden
- The who’s who
- VARIEGATED CUTWORM
- Life Cycle
- Quick Review
Methods of control:
There are several methods that can be utilized to control cutworm populations or to effectively eliminate their threat to ones crop.
1. Tilling: In some climates, as mentioned above, cutworms will winter under the soil. If this is the case, a farmer may control the pests by winter plowing or tilling. (or by tilling the soil 2-3 weeks before planting). Most farming sources recommend deep plowing or tilling in the fall, and again in early spring.
A winter plow will kill many of the cutworms in either the pupae/larvae or instar state, or bring them to the surface where they become subject to predators (chickens, moles, shrews, blackbirds, wasps, and parasitic nematodes). This method works exceptionally well for grain fields. (We utilize this method in our garden, and our chickens absolutely love this time of year, often spending hours eating the caterpillars that are turned over by the tiller).
2. Starvation and good weeding practices: Another less commonly used method of controlling cutworm populations is that of starving the caterpillars. If it is practical to keep weeds at a minimum before your planting and growing season, you can discourage cutworm moths from laying their eggs where your plants will be growing, and also depriving what larvae are present, the food they will need to grow. Along with this idea, many farmers make efforts to remove plant residue in their gardens, to reduce egg-laying sites.
3. Baits and poison: Secondary to successful starvation strategies, baits can also be utilized rather successfully. This is done by following up starvation methods with providing a sweetened bran mash containing a suitable stomach poison against the cutworm. Remember to use very small amounts, too crumbly and thinly scattered to be ingested by domestic animals or desirable wildlife.
4. Plant Collars or barriers: Perhaps the most widely known treatment for cutworms is the use of plant collars. This should be done right at the time of transplanting. It is a bit time consuming, but definitely works. You can use aluminum foil, plastic soda bottles, tuna fish cans, or a cardboard collar around the plant stem approximately 4 inches tall. The collar should fully encircle the the plant stem, and be pressed at least an inch deep into the soil. This creates a barrier to keep cutworm larvae from feeding on plants. Some growers use toilet paper or paper towel tubes cut at 3 inch intervals filled with potting soil, and standing in a tray for planting seeds, and when the seeds have matured sufficient for transplanting, plant them together, with the tube, in your garden.
5. Hand picking: Nothing beats an excuse to roll up your sleeves and get on your hands and knees in the garden, and the existence of cutworms is a great excuse. It is best to go looking for cut worms at night, or in early evening, with a flashlight while they are out and actively feeding. You will find the cutworms on the stems and foliage of your plants eating away. Simply pluck them off of the plant, and crush them, or drop them into a bucket of soapy water. Personally, we place them in a ziplock or sealable bag and feed them to our chickens the next day.
6. Capsaicin sprays and powders, extracts of pineapple weed or sagebrush: There are various organic treatments that are recommended for use against cutworms, including sprays or powders made from either ground red pepper (cayanne) or red pepper spray. These types of sprays are recommended by “Rodale’s Ultimate Encyclopedia of Organic Gradening” as a repellent for numerous garden pests, including the cutworm. To repel cutworms, it is suggested that cayanne pepper be dusted around the base of the plant stems. It is also suggested by numerous sources, that coffee grounds, extracts of pineapple weed, and sagebrush may act as a deterrent to the cutworm larvae.
7. Oak leaves, vulcanite sand, damp wood ash, egg shells, or diatomaceous earth: Some folks choose to mulch their plants with oak leaves, vulcanite sand, damp wood ash, egg shells, or diatomaceous earth to deter cutworms. These components may act as irritating physical barriers against the cut worm larvae. Personally, we do not use diatomaceous earth because we also raise bees, and some studies suggest that diatomaceous earth can be harmful to bees.
8. Bacillus Thuringiensis: Bacillus thuringiensis (Bt) is a naturally occurring soil borne bacteria that is widely available and has been used since the 1950’s for caterpillar and insect control. It can be applied via spray to young plants, (and in other ways), and is a very effective control against climbing cutworms or stem eaters. Beware however that Bacillus thuringiensis is also harmful to butterflies, which are powerful and important pollinators.
9. Cornmeal: Another effective method for killing cutworms is sprinkling cornmeal around your plants. Though we have not tried this in our own garden, it is reported by the farmers almanac and other sources that the cutworm larvae will eat the cornmeal but not be able to digest it, thus causing them to bloat and die.
As you can see, there are many methods to combat the cutworm, and good reasons to do so. Though there are a large variety of garden pests that can affect the growth of your garden or crop, most (like the cutworm) can be combated rather easily. Do not let the presence of cutworms deter you from growing fantastic plants. You will likely find out that deterrents for one pest may also deter others. For more information regarding garden pests, you may wish to research 1. common garden pests, 2. beneficial insects for gardens, and 3. organic treatment for garden pests.
Eliminate Cutworms Using Natural Pest Control
The second issue of American Country, MOTHER’s new sister magazine, contains an indispensable field guide to natural pest control. This brief excerpt will help you keep cutworms from your crops.
Eliminate Cutworms Using Natural Pest Control
Range: Throughout North America
Description: 1 inch grayish brown caterpillars, some with spots or stripes. Nocturnal-rarely seen in daytime. Curl up when disturbed. Adult “Miller’s moth” is gray or brown with paler hind wings and 1 inch to 1-1/2 inch wingspan.
The name cutworm is justifiably ominous. You won’t know you’ve got cutworms in your garden until they’ve performed their guillotine act and decapitated several of your plants. There are approximately 20,000 kinds of cutworms, including tunneling, subterranean, and climbing species (such as the armyworm), but the surface feeders are the most common. These spend two summers as destructive larvae (overwintering in the soil) before they mature into harmless moths.
Modus operandi: Fells young plants by cutting off stems at or just below soil surface. Favorite victims: Your carefully nurtured garden seedlings.
Natural Pest Control Methods for Cutworms:
• The traditional-and very effective natural pest control method is to set a small 2 inch to 3 inch collar, pressed 1 inch into the soil, around each vulnerable plant. Collars can be made of paper, cardboard, PVC, metal cans, paper cups, or toilet tissue tubes.
• Bacillus thuringiensis, a widely available caterpillar-killing bacterium,is a very effective control for climbing cutworms as well as for the surface feeders.
• Handpick larvae at night by flashlight.
• Mulch plants with oak leaves, crushed eggshells, damp wood ashes, or other skin irritating physical barriers.
• Deep plowing, digging, or tilling in fall and again in spring will expose and kill soillaid eggs and overwintering larvae. Chickens let into the plot after these cultivations will help improve the effectiveness of this technique.
• Tachinid flies, trichogramma wasps, braconid wasps, and insect-killing nematodes parasitize cutworms.
• Toads, moles, shrews, blackbirds, meadowlarks, and firefly larvae are all natural predators.
• The adult moths can be attracted to, and killed by, electronic bug zappers.
• Sprinkle cornmeal around your garden. Cutworms love it but can’t digest it. Some will die from overeating the treat.
• Make a mixture of molasses (another vice), water, wheat bran, and hardwood sawdust. Circle plants with this glop. It dries on the cutworms’ bodies and immobilizes them.
• It’s said that if you push a small twig, nail, or toothpick into the earth right next to a seedling, the cutworm cannot wrap around the stem and fell the plant.
• According to University of British Columbia student Greg Salloum, cutworms would rather starve than eat plants treated with extracts of pineapple weed or sagebrush.
Tachinid Fly (Tachinidae family)
Range: Throughout North America
Description: Looks like a common housefly, about the same size (1/8 inch to 1/2 inch) and color (gray-brown). There is one significant distinction: Houseflies don’t have the prominent abdominal bristles that tachinids do. But these are hard to spot on a fly in flight, and tachinids are very active and quick fliers.
Modus operandi: Adult tachinids are fond of nectar and insect honeydew and are therefore often found on flowers or foliage. It’s the tiny yellow larvae that prey on garden pests. These maggots eat the flesh of cutworms, sawflies, Japanese beetles, Mexican bean beetles, gypsy moths, grasshoppers, corn borers, and many caterpillars.
Tachinid larvae feed mostly on muscle tissue and fat, allowing their host to remain alive, though sickly, for a good while. Sometimes a host caterpillar will even live long enough to spin a cocoon or chrysalis before it dies. No moth or butterfly emerges from that tomb, though-just more tachinid flies!
A tachinid larva also has a remarkable way of assuring its respiration. It either attaches its rear end, which contains its respiratory organs, to the victim’s tracheal system, of makes sure its bottom pokes out from the prey’s body.
A tachinid mother means business. She has three ways of assuring meal tickets for her offspring. First, she may glue her eggs to the victim’s skin, being careful to place them out of reach-right behind the victim’s head. Second, she may lay them on foliage near host insects. The larvae will then hatch near their prey or even be ingested by the unwitting victim. Third, some tachinids (there are over 1,300 species) can hatch the young within their own bodies and then attach the larvae to a host. This tactic can backfire, though. If the mother doesn’t find a good host, her offspring may devour her.
Sources: Tachinid flies are native to most areas of the U.S., so try not to spray your garden with any all-purpose pesticides. And never swat a fly in your vegetable plot unless you know for sure what it is.
Cutworm Control: How To Get Rid of Cutworms
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.
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.
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.
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.
- 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.)
Cutworm Control & Facts
Found throughout North America, these destructive eating machines may not be easy to see in your garden or fields since they tend to remain hidden under debris, preferring to come out at night to feed.
Holes in leaves and fallen plantings are prime symptoms of cutworm activity. Some cutworms of the climbing variety will leave holes in tree and vine fruits and buds as well.
So… What are Cutworms?
Cutworms are the larval or caterpillar stage of certain moths. There are numerous species of cutworms, each affecting certain parts of plants in specific ways.
Cutworms can vary in color from brown to gray to black as well as green and pink. Some species may have more than one color and some may have stripes or spots. Cutworm caterpillar or larvae are generally 1″-2″ in length. When they emerge as adults, they will be gray or brown in color with dark or light markings on their wings.
Reproduction Patterns of Cutworms
Cutworms may spend the winter as pupae or they may overwinter in a partly grown larval state. If they are partly grown larvae, they will be particularly destructive when they emerge since they are hungry and ready to eat when the garden or field crops are being planted.
In certain species, adults emerge in the spring and lay eggs in the soil or grass. Within a week, these eggs will hatch and the larvae will feed on the nearby plantings. After several weeks, the larvae will penetrate the soil and pupate. They will emerge as adults by late summer.
In other species, eggs are able to survive the winter and hatch in the spring, where the emerging larvae will feast on early plantings and seedlings, and then go through pupation and emerge as adults. In all of these species, there is usually only one generation of cutworms produced in a year.
Found throughout North America, these destructive eating machines may not be easy to see in your garden or fields since they tend to remain hidden under debris, preferring to come out at night to feed.
Whether as eggs or in a larval or pupal stage, the cutworm almost always hides under old crop debris, trash, grass clumps or any other form of protection it finds suitable.
Symptoms of Cutworm Damage
Holes in leaves and fallen plantings are prime symptoms of cutworm activity. Some cutworms of the climbing variety will leave holes in tree and vine fruits and buds as well. You will not see the cutworms during the day since they are only active at night.
Results of a Cutworm Infestation
Young plantings may be destroyed at the soil level, causing them to fall over in the garden or field. Seedlings may be completely devoured by the cutworms.
For the gardener, loss of crops are a source of frustration for time and care spent in growing the plantings. For the farmer, total loss of the plantings/crops can occur, resulting in a serious financial loss.
Catching toads and placing them in the garden is an inexpensive natural way to control cutworms. Both you and the toads benefit from this arrangement since they will have plenty of food and you will have fewer cutworms.
Parasitic nematodes (non-segmented round worms) are another natural control that won’t harm the environment, your family, or wildlife.
Toads will feast on the cutworms in your garden. Place parasitic nematodes on the soil where they will attack the cutworms.
Catch the toads when the cutworms first appear and they will help control any other cutworms as they continue to appear. Read the directions for the nematodes to find out when to spread or spray them.
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One of my worst gardening experiences entailed going out to what had been a healthy, vibrant garden, only to find those healthy plants literally cut through and lying on the ground. For the home gardener and the farmer alike, pests are one of the biggest impediments to healthy plants and high yields.
There are countless pests and threats to your garden, but one of the most pernicious is the cutworm. They can be found on any number of common garden plants, and if not addressed, can wreak real havoc on a garden.
How To Identify Cutworms
So how do you know if what you have eating your plants are actually cutworms and not some other pest? Let’s take a look at how to identify these hungry caterpillars.
What Are Cutworms?
Cutworms are a type of caterpillar that will eventually turn into a moth – this is the larvae stage of many types of moths. There are a number of varieties of cutworm, but black cutworms are the most common.
They are a difficult pest in that when eggs are laid in the fall, the cutworms can actually survive the winter, hatching in the early spring to take advantage of seedlings and other young plants. They will literally cut through a stem of a seedling, killing the plant and causing a huge amount of damage to an otherwise healthy garden.
It’s incredibly the amount of havoc these little critters can have on your gorgeous garden.
It is easiest to look for cutworms around dusk. They tend to chew through plants near ground level, so this is where to look for them. Cutworms are often mistaken for grubs, and how you treat them is a little different, so make sure that when you are diagnosing your pest problem, you are sure that what you are dealing with is a cutworm.
Unfortunately, cutworms come in a range of appearances. They can be just a few centimeters long to a few inches long. They can be spotted, plain colored, or striped. Cutworms range in color from gray to pink to black. As noted above, black cutworms are among the most common variety and they can be identified by the small dark spots that appear across their bodies. When fully fledged, these cutworms turn into one of the more common types of moths we are all familiar with.
How To Get Rid Of Cutworms
There are a number of methods for getting rid of cutworms that have varying degrees of effectiveness. Which method will work best for the problem at hand will have to do with the severity of the problem. When I find them, my thoughts immediately go to how to kill cutworms, as one generally indicates more and they can quickly take their toll on even the healthiest garden.
What follows are a number of effective means of getting rid of cutworms – I have used all of them at one time or another and they are all effective ways at treating the problem, whether it is a large or small one.
Make cutworm collars for your plants
Cutworm cup – Image Source
If the problem isn’t too out of hand and the garden space is of a manageable size, homemade collars are often a really great solution to cutworms. These can be made from a range of household materials including foil, paper, and cardboard.
Basically what you need to do is to create a tube that can be slid over the stem of the plant that touches the ground and goes a few inches up the stem. It is even more effective if you push the collar a bit underground as well.
If the problem is really bad and you have an infestation of cutworms, chemical solutions may be the best way to deal with the problem. The best pesticide for cutworms will depend on a few different factors.
There are a number of natural solutions that, while they do have their own set of concerns, are not environmental contaminants like traditional pesticides.
It should be noted that BT (Bacillus thuringiensis), one of the more common natural remedies for cutworms and other pests has been shown to cause damage to butterfly populations.
This is another good solution for minor problems with cutworms. To do this, all one needs is a flashlight and some soapy water.
After dark, using the flashlight, manually remove the cutworms and place them in soapy water. You may need to repeat this every few days until the problem is curtailed.
Old fashioned remedies
There are a number of tried and true methods that can be fairly effective against small numbers of cutworms.
- Sprinkling eggshells or coffee grounds can be an effective deterrent
- Oak leaf mulch is another deterrent.
- You can also try what is often called “companion cropping” by planting certain crops (in this case cabbage), which can also help reduce issues with cutworms. Not to mention, you get bonus cabbage!
How To Keep Cutworms Away
One way to help avoid cutworms, to begin with, is to make sure that you clear all leaf litter and other organic debris away from your garden beds. This is a prime spot where eggs are laid and removing this material is a good way to help prevent problems before they begin. But even taking these steps to avoid the problem is often not enough, they will still show up in your garden, but it does make sense to do what you can to try to avoid the problem as much as possible.
No matter how large or small the area one is cultivating, pests are always going to be part of the proverbial equation. With foresight and planning, it is pretty easy to keep these problems under control so they do not cause untold amounts of damage to your garden.
Cutworms are a common problem for gardeners, particularly early in the growing season, and if left untreated, they can devastate a garden very quickly. Knowing how to identify, prevent, and manage these pests is part and parcel to a successful garden.
With a bit of knowhow, you can beat the bugs!
By Rasbak , from Wikimedia Commons
How to Control Cutworms in Your Garden
The who’s who
There are three types of cutworm moth that are especially common in North America. The number of generations they have depends on location of the pest. North Carolina, for example, can see as many as 4 generations/year, while in Florida there may be 5 – 6 generation/year. In the warmer climate zones of Canada, gardeners can see 2-3 generations of cutworms per year.
- The Black Cutworm Agrotis ipsilon is a serious pest of corn and does not overwinter in the colder climes of the U.S. The adult moths arrive in these locations via the strong southerly winds from the Gulf states and Mexico travelling a few hundred miles in just a couple of nights. The adults will lay their eggs on the leaves of weeds or crop residue prior to late corn being planted. They will feed on the leaves of host weeds until corn shoots emerge at which time they will move to the crop and eventually burrow into the soil to tunnel into the stalk. Early detection is the best defense. Keep an eye out in springtime for the adults arriving on the wind and inspect corn plants for wilt or damage. In small gardens it is very helpful to pick the cutworms by hand if you find them.
- The Variegated Cutworm (Pearly Underwing) Peridroma saucia has the widest distribution in North America. Their range includes southern Canada from coast to coast, the entire US, and all the way south into Mexico. Variegated cutworms overwinter as grubs in the soil and are most distinguishable by the 5 yellow dots along the center of their back. They emerge in early spring for the newly emerging first growth. They will initially feed on weed hosts until the plants they favor emerge. Vegetable hosts include asparagus, bean, cabbage and other crucifers, carrot, celery, corn, lettuce, pea, pepper, potato, rhubarb, and tomato. As with the Black Cutworm, early detection is essential because they arrive so early. If you see a freshly fallen starter, dig an inch or so into the nearby soil and you’ll likely find the culprit.
- The Spotted Cutworm is most common in the Gulf States and scattered as far north as North Carolina, and has recently been discovered as a pest of mint crops in Oregon. The spotted cutworm only has 2 generations per year throughout the US.
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.
“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)
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.
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 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.
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.”
- 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.
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.
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
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.
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.
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.
Adult – night-flying miller moths, usually gray or brown
Larva – smooth-skinned caterpillars, cutworms, up to two inches
Overwinter as cutworms or pupa
Up to four generation per season depending on species and climate
Foliar feeding causing ragged holes usually late in season
Fall-plowing especially of grassland
Insecticides used against other, more important, pests
- Defoliating Insects
- Colorado Potato Beetle
- European Corn Borer
- False Chinch Bug