Cutworms

How to Identify and Get Rid of Cutworms

black-cutworm-control-prevention

Black cutworms can wreak havoc on your garden, so learn these tips for identification and control.

GrowVeg.com/Sam Droege on Flickr Creative Commons

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Here are tips on how to identify, control, and get rid of cutworms in the garden.

What are Cutworms?

Cutworm is the name used for the larvae of a number of species of adult moths. Eggs that hatch in the fall can produce larvae capable of overwintering in the soil or a woodpile. They do the most damage early in the gardening season, when they emerge from hibernation. Cutworms are caterpillars, but they are often mistaken for grubs.

Identification

How to Identify Cutworms

Cutworms are common on a wide variety of vegetables and any fresh seedlings. To identify them, try patrolling your garden in dusk and evening hours, when cutworms will begin to feed. They are also partial to cloudy days.

Different species range in color from grey to pink, green and black and can be as long as two inches. They can be solid, spotted, or striped. They tend be curled up when they are not on the move. Cutworms are stealthy, and tend to feed only at night, while hiding in daylight hours.

Black cutworms, also known as Agrotis ipsilon, are some of the most common cutworms. They have small dark spots on their bodies and mature into the dark sword-grass moth. Variegated cutworms, another common species, are mottled brown and have a faint white stripe down their backs.

Adult cutworms are moths of dark wing colors. They are usually brown or gray, and they are about 1 ½ inches long with a 1 ½-inch wing length. You should keep an eye out for them, because the females will lay eggs in dry soil after they mate.

brown-cutworm-moth-identification.jpg
Photo Credit: GrowVeg.com/gailhampshire on Flickr Creative Commons. The adult moth of the brown cutworm is an indicator that cutworm eggs could be in your soil.

Cutworm Damage

Cutworms chew through plant stems at the base. They primarily feed on roots and foliage of young plants, and will even cut off the plant from underneath the soil. In most cases, entire plants will be destroyed; they do a lot of damage in no time at all. Even if only the bottom of the plant is destroyed, the top will often shrivel and die.

In the summer, cutworms sometimes crawl to the tops of plants and do damage there. Be careful not to mistake this damage for slug damage.

prevent-cutworm-damage.jpg
Photo Credit: John Obermeyer, Purdue University. Black cutworms can cause severe injury to the base of plants, often killing them.

Control and Prevention

How to Get Rid of Cutworms

  • Make plant collars. Put a 4-inch piece of cardboard around each plant stem to help stop cutworms from reaching tender stems, especially right at transplanting. This time-consuming task works, though it is only efficient for a smaller garden.
    • Or, try this method: Save toilet paper tubes, cut them in half, fill with potting soil, and stand up in a tray. Use for planting seeds. When young plants are ready, plant them, tube and all. 
  • Hand pick. Go out at night with a flashlight and gloves. Pick off the cutworms and drop into soapy water; repeating this every few nights.
  • Sprinkle used coffee grounds or egg shells around your plants.
  • Circle stems with diatomaceous earth, a natural powder made from ground up fossils which kills insects when they walk over it.
  • Apply an insecticide late in the afternoon for best control. Some readers use Bacillus thuringiensis, a natural way to kill cutworms. However, note that this bacterium may harm butterflies, an important pollinator.
  • Try this folk advice from The 1963 Old Farmer’s Almanac: A mulch of oak leaves is useful against cutworms. Tansy planted near cabbages keeps them free of cutworms. A hog turned into a garden in early spring will root up cutworms.

How to Prevent Cutworms

  • 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. The 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.
  • Fireflies are a fun insect to have around the garden, plus they are a natural predator to cutworms. Check out these tips to attract fireflies to your garden.
  • Birds are another natural predator to cutworms. Learn how to make your garden bird-friendly.

Plants Affected

Reader Comments

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Cutworms killing our lawn in patches

We have sections of our lawn with roots eaten by cutworms. I have been removing these sections. If I did not remove would the grass reroot? I have been putting on different cutworm killers but not sure they are working. I have also had Terminex put granular poison on lawn.

cutworms or grubs?

This sounds more like the work of grubs, which can resemble cutworms (see above). Grubs are Japanese beetle larvae that live underground and feed on the roots of lawn grass. We have more information and some organic/non-chemical ideas for eliminating there here: https://www.almanac.com/pest/japanese-beetles And keep this in mind: If you see birds, skunks, armadillos, raccoons, or moles poking around your lawn, don’t be in a hurry to shoo them away: they are probably eating your grubs.

Rhubarb and cut worms?

My rhubarb had finally taken off. I checked it in the morning and it was fine, I came back and walked through the garden around 9 pm and the stalks were cut off at the ground. Could this be cut work? Will my plants produce next year?

Damage to Meyer lemons

The outer peal and pulpy layer of several of my Meyer lemons have been eaten. The damaged lemons are interspersed along the entire tree. The damage does not go into the fruit. What would cause such damage?

Citrus Cutworms

Citrus cutworms are the most likely culprit. Does the damage look fresh or does it look like the fruit has had time to develop a scar? Citrus cutworms feed on the rind of developing fruit, which leaves scars when the fruit eventually matures. They are also known to eat only some of each fruit before moving on to the next, which is why you see damaged fruits throughout your tree. The good news is that their damage should not have affected the quality of the inside of the fruit, so you can still use them. Cut off the affected areas, if you like.

Citrus cutworms do their damage from late spring to early summer. In spring, you can apply Bacillus thuringiensis (Bt) to your tree to help keep them at bay. Bt is non-toxic to humans and must be ingested by insects to be effective, meaning pollinators like bees and butterflies are not harmed.

Cutworm eggs

So I found three of these worms in my garden boxes in my green house used btk, I sprayed Finn my garden boxes after that the next day I found the worms one was dead the other fell out of the plants I killed it the other went into the plastic cup of beer I put out not sure if there are more haven't noticed Amy more plants being eaten or poop anynwhere, but I noticed these little balls when I squish them there is liquid in it, searched they are eggs I'm guessing from the cutworms they are everywhere I smoothed I couldn't tell u how many but there are tons, how do I kill the eggs before they hatch, or did spraying btk in my garden box help with the egg to? What can I do I don't want them to hatch and get more cutworms. Like imsaid only caught out three not sure if there is more or not but want to get rid of the eggs.

Cutworm Eggs

Bt will have no effect on cutworm eggs—only the larvae themselves—as it must be ingested. You could try spraying the eggs with a mixture of equal parts rubbing alcohol and water, which will dry them out. Test this on a single area of the plant before applying it to the whole thing, just to make sure there are no adverse effects. Other potential solutions include insecticidal soaps, neem oil, and compounds containing pyrethrins—all of which should be available at your local hardware store or garden center. Most insecticides target pests after they have already hatched, so you may be better off waiting until the eggs hatch, at which point Bt will be effective.

iris cutworms

well, I had a good laugh at your solutions to stop cutworms on iris. I have over 1,000 CLUMPS.not about to handpick,do collars or use Bt on that many.besides the fact that I am disabled.so...any ideas on a larger scale than a handful of iris? like a spray or something?

hundreds of cutworms

Well, at least you’re laughing, Sheryl. There are a variety of chemical treatments on the market—too many to mention and not a category from which we can make recommendations with experience. Visit your local garden/lawn supply stores. Some sources suggest that tilling your garden before planting helps to expose and kill overwintering larvae, as well as remove plant residue which helps to discourage egg laying. Make a plan to till your garden in the fall, too, for the same effects. You might also inquire at your local cooperative extension service. Folks there have some creative ideas. Click on your state to find the one nearest you: http://www.almanac.com/search/site/cooperative%20extension

We hope this helps!

Cutworms

I accidentally found a way to locate and then remove cutworms. I was drying a black plastic tarpaulin on my lawn and when I went to roll it up I noticed quite a few cut worms on the tarp trying to escape the heat I think. I also found heaps of cut worms on the top of the lawn driven out by the heat of the sun. I presume this would work better on a sunny day. I collected several hundred in a few 15 minute searches on a 4 square metre lawn.

Cut worm

I have a tunnel with raised beds enclosed by shade cloth. Had several years of fantastic veg until a month ago when cutworm destroyed most of the veg. Would clearing the beds which are not too long, then pouring boiling water over them several times get rid of the cut worm??

boiling water on cutworms

We’ve heard of baking soil but not soaking it with boiling water. You may be on to something, as the cutworms lay eggs in the soil. We can not comment on the idea because we have never done it, but we can advise removing weeds and plant residue, Til the garden before planting to help expose and kill overwintering larvae (if your beds are covered, perhaps the lack of exposure to cold enables the cutworms/larvae to thrive?), and avoid green manure; instead use compost. To that point, have you considered replacing your soil?? If you still think there are larvae in the soil, collar the plants with aluminum foil. Cutworms have many natural enemies but none can really eliminate them. We hope this helps.

Chemical control cutworm

Hello dear
Plz gave me information about chemical
control cutworm. There are alat of cutworms in khost afghanistan.
Tank

Cutworms inside

I believe we have cutworms in our house! Pics match, they are only found at night, they curl up when touched. The only thing is the floor we find them on has no plants. We are wondering where they may be coming from? Thoughts?

Cutworms in my home

Trish I have the same problem and also wondering where they are coming from and how to get rid of them. Don't like it at all.

cutworm conundrum

Are they found near an outside door, or near something that has been brought in from outside? Do you have any potted plants in the house (perhaps not in that particular room) or anything that has soil? It is rare to find cutworms inside the home, although it does sometimes occur. They are not a house pest. Perhaps a moth may have gotten inside and laid eggs in the soil of a potted plant? The larvae may then have hatched and are roaming to look for food. Or, some may come inside if the door is open (or they may hitch a ride on the door edge), seeking warmth to pupate.

cutworms

My 87 year old aunt says she covers her garden with a thin layer of lime and then has it worked in. Claims she doesn't have any cutworms.
Are there any harmful side effects to putting lime in the soil?

Lime in Soil

Repeated applications of lime can disturb your soil’s pH balance, which can affect nutrient availability for plants. Too much lime can also be detrimental to the health of beneficial microbes in the soil. Applications should be made based on recommendations that might come out of a soil test.

Caterpillar larvae and Lime

Every year the caterpillar eat half my tomatoes and I am sick of it.I think I will try the lime.Can you tell me when is the best time to put it and how much to put.I was even thinking about putting DE in the soil Help!!!!

cutworm collars

First of all, we recommend the cutworm collars (above) when the seedlings are first set up. Once your tomato plants’ stem is the thickness of a pencil, you can throw the collars out. 

Yes, you can use DE, too.  Just scatter it around the plant.  If cutworms are a big problem, consider a Wall O’ Water. Search on Amazon.com.

Lawn cutworm

How do I get rid of cutworm in my lawn? I also have tiny white butterflies laying around my lawn, I have used Ortho bug be gone spray and the seven crystal bug killer and none of them has worked. Can you help me? Thank you.

Killing Cutworm Alternatives

Multiple chemical applications negatively impacts the health of your soil, which is key to a healthy lawn. After a good rain, go out after dark with a flashlight and handpick as many of the cutworms as you can (drown them in soapy water). They don’t like dry soils, so water well in the mornings. Release beneficial nematodes, which will attack the cutworms (given your soil is likely not biologically rich, it may take some time and a few releases to start to establish a healthy population). The moths should be dealt with as soon as you see them: release tricogramma wasps weekly for three consecutive weeks–they will parasitize cutworm eggs. Apply Eco-bran on the lawn surface to attract (and kill) catapillars.

cutworms

I've read through your contents on cutworms, I believe that is what I have. We came home after being gone 4 days....early July so all my broccoli heads have produced, a few of my cauliflower, but still have the broccoli, remaining cauliflower and Brussel sprout plants growing. But these are full grown plants, no young seedlings. There were holes all through these leaves....and we plucked several dozen "green cutworms". But this was not at night...6 pm, plenty of daylight here in WY. I'll continue to look every day, but what can I do to protect my remaining plants? Fels Naptha soap solution?

how to control cutworms

Try the following: Sprinkle used coffee grounds or egg shells around your plants. Also you can circle plants with diatomaceous earth, a natural powder made from ground up fossils which kills insects when they walk/crawl over it.

'Cutworms' on cauliflower and broccoli

These aren't cutworms. I think what you had there were the caterpillars of the Cabbage White butterfly which are an extremely common pest of Brassicas. The eggs are laid by the adult butterflies on the underside of the leaves. When they hatch, the green caterpillars can quickly turn an entire plant into a skeleton.

The tops of our tomatoes

The tops of our tomatoes keep getting eaten off. It looks a lot like the work of a cutworm, but they are eaten off just below the foliage. The main stems are mostly affected, but the some of the side leaf stems were eaten off as well.I wrapped the whole stem up in tin foil right up to about an inch below the main foliage, but I went out the next day and one was eaten just above the foil. I have had cut worms before and they only ate near the bottom, but this is all the way up to under the main foliage where the blossoms start. The stem just gets bitten off, and the top is left lying there. What do you think is going on? I'd appreciate any tips to help!

cut worms

This is heartbreaking. It certainly sounds like cut worms. Are you smoothing the aluminum? You want to create a surface that has sharp edges, a surface on which the worms will cut themselves as they attempt to cross or climb it. So crinkle the aluminum around the stem. Or sprinkle crushed egg shells at the base of the plant. Even sharp pebbles. Some people cut the bottom out of paper/plastic cups and sink the cups around vulnerable seedlings. Half-gallon milk jugs from which the bottom and tops/necks are removed fit easily over larger plants. Others use (paperless) toilet rolls, but plants have to be small for those to fit.

We hope that helps!

Moringa tree and corn seed

My moringa tree has ten pods and no leaves. It is about six feet tall. Why won't leaves grow? Now my corn seeds need help.

Cutworms and our lawn

We live just south of Ocala and recently began to see our lawn start to die out. I found what looks to be a cutworm in the grass while raking the dead grass out of the yard. Could these worms be doing this kind of damage to our yard? If so, I will give these remedies a try.

Cutworms and army worms can

Cutworms and army worms can damage a lawn. If you identified the worm (or worms) as cutworms you can try some of these remedies. It’s important to keep your lawn healthy. A healthy lawn will withstand a cutworm attack.

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