Have you ever woken up to find your lawn destroyed or your tomato crops ravished?
Cutworms, like vampires, come out at night to feast. They are voracious little pests and can do a great deal of damage in a very short space of time.
But we do have ways to thwart the little beasts – and we have been researching the best pesticides to kill the cutworms. So it’s good to know your enemy and how to get rid of cutworms before they destroy your crops.
Here are our five best pesticides for cutworms:
- Safer Brand 5163 Caterpillar Killer II Concentrate
- Monterey LG 6336 Bacillus Thuringiensis (B.t.) Worm & Caterpillar Killer Insecticide/Pesticide Treatment Concentrate
- Bio-advanced, Granules, 7007455 24 Hour Grub Killer Plus
- Bayer Dylox 6.2 Granular White Grub Insecticide
- Bonide (BND60360) – Insect and Grub Control, Outdoor Insecticide/Pesticide Granules
What exactly is a cutworm?
A cutworm is not a worm – it’s a caterpillar from the night moth. The moths are harmless, but their offspring lurks in the soil, creeping out at night to cut your plants, sometimes climbing them to ravage the upper part.
What a cutworm is not is a grub, though many gardeners confuse the two. Cutworms are the larvae of moths, but the grub is scarab beetle larvae – and they too can cause damage to your lawn and garden.
Cutworms come in various color schemes. There are black and brown ones, grey and beige, green and even pink varieties. Some have a pale stripe down their back, others sport spots or stripes or appear mottled, but when you pick a cutworm up, it curls round in your hand to make a C shape. You can see some pictures of cutworms on this YouTube video:
The Life Cycle of the cutworm
The moths lay their eggs which develop into the larvae. Over winter, the larvae, pupae, and cutworms rest in the soil or debris littering the ground. The mature cutworm comes back into the soil and digs a little chamber to pupate inside. In Spring, the moth comes out and flies off. The cutworm emerges from the larval form in the Spring. The young cutworms come out hungry and set to eating your lawn or crops.
Which plants does your cutworm enjoy?
Cutworms are not too fussy – here is a list of some of their preferred foodstuffs:
- Lawns – grass
- Tomato
- Potato
- Broccoli
- Corn
- Lettuce
- Cabbage
- Green beans
They can destroy 75% of your lawn or crop in just one season – unless you stop them!
Non-chemical prevention of cutworms
If you catch them early, and your garden is not very big, non-chemical methods can prevent them from becoming a huge problem. But once they get a grip, then you will need the help of pesticides. Here are some ways to prevent the cutworm from doing too much damage:
- Clear away debris and cultivate the ground to disturb them and deny them an overwinter retreat. The moths like to lay their eggs in weeds or uncut grass.
- Pick them off by hand and either squash them or drown them in soapy water.
- Make collars for your plants. Each plant needs a collar a few inched long to go into the ground around them and extending few inches above. The idea is to stop the cutworm from climbing over to eat your tender plant. Cardboard toilet rolls are easy to fix, and a plastic milk bottle can be practical – plus, the plastic surface can also help water the plant. This method could answer how to get rid of cutworms on tomato plants if there are not too many of them.
- One farmer swore by placing a large nail next to each plant.
- Delay planting for a week or two if you can; this will cut off their food supply when they first come out in the Spring.
- Sprinkle diatomaceous earth around the stems. This is a powder made from ground-up fossils. When insects walk over this natural product, it will kill them.
- Fireflies are predators that feed on cutworms. Attract them to your garden by switching off artificial lights and planting pine trees for them.
- Attract birds to your garden – they like a good cutworm for breakfast, too.
You cannot provide a collar for every blade of grass in your lawn or pick off every cutworm from a large crop – so you might need to consider a chemical insecticide. And if the infestation is heavy, then the only way to get rid of the cutworms is likely to be with a pesticide.
Cutworm chemical control
To find the best pesticide for cutworms, you have to balance the ecological effects with the best pesticide.
Two main ways of applying pesticides to cutworms are sprays or granules. There is also dust you can sprinkle around. The sprays usually come as concentrates, so you need to mix them accurately according to the instructions on the package. You will also need an applicator to spray your crop.
Utilizing a broadcast or rotary spreader, you can distribute the granules effectively. If you are treating your lawn, make sure the lines overlap to cover all of the grass. It is suggested you start at the edges and then fill in the center part to kill all the cutworms. You probably need to apply the granules when the ground is dry then water them in.
When you treat the area in the late afternoon or evening, you can catch the little cutworms before they emerge later in the night. When you use a pesticide, you have to check how safe it is for children and pets. The best pesticide will have clear instructions and be targeted to cutworms and other harmful pests. If you are using granules, once you have watered them in and the ground has dried out again, it is safe for the pets to venture out – but always read the labels and check with the manufacturer if in doubt.
Pesticides commonly used might contain permethrin, carbaryl, or cyfluthrin. You may prefer to use an organic insecticide containing Bacillus Thuringiensis, a natural cutworm killer. If your pesticide has been granted Organic Materials Review Institute (OMRI) status, you can be sure it is safe for organic gardening.
We have looked at different pesticides and what follows is a review of the top five best pesticides for cutworms in our opinion:
Reviews
Safer Brand 5163 Caterpillar Killer II Concentrate
The environmentally safe, organic pesticide.
This organic cutworm killer contains 98.35% Bacillus Thuringiensis var. Kurstaki (B.t. for short). Once the cutworm ingests this, it stops eating your plants straight away. It kills other plant-eaters like caterpillars, cabbage loopers, the tomato hornworm, and gypsy moth larvae as well, but your earthworms are safe. It does not harm other beneficial insects, your bees are safe, and it is environmentally friendly.
This insecticide is OMRI listed, so you can be confident that it is safe for organic gardening. Birds, bees, and ladybugs will not be harmed, provided you follow the manufacturer’s instructions. Bacillus Thuringiensis breaks down in sunlight after 24 – 36 hours, so it’s best to use it on a cloudy day if possible and near dusk time. Safer Brand is an effective insecticide, but you might get the best results by two applications a couple of days apart.
There is also a Sevin dust containing the bacillus Thuringiensis that is easy to use.
Pros
- Natural cutworm killer
- Safe for birds and earthworms
- Effective – stops the cutworm from eating
- Safe for the environment
Cons
- Bacillus thuringiensis degrades after 24-36 hours
Monterey LG 6336 Bacillus Thuringiensis (B.t.) Worm & Caterpillar Killer Insecticide/Pesticide Treatment Concentrate
A biologically safe and effective cutworm killer.
Monterey LG is the ideal pesticide for cutworms. It contains Bacillus Thuringiensis, specific for “worms” like creatures such as bagworms, fall cankerworm, the elm spanworm, and others – but the earthworm is safe!
Specially designed with foliage in mind, the Monterey Worm Killer is suitable for broccoli, cabbage, celery, lettuce, tomato plant, and more. It has the OMRI qualification, so you know that it can be used for organic farming. You can use this right up to the day of harvest and feel good about the environment!
Provided you follow the instruction this pesticide is safe for bees, earthworms, birds, and ladybugs. It is easy to apply when you mix it with water and use a trigger spray bottle or a pressure tank sprayer. This is another best pesticide for cutworms.
Pros
- Biological cutworm killer
- Safe for birds and earthworms
- Effective – stops the cutworm from eating
- Safe for foliage
Cons
- Bacillus thuringiensis degrades after 24-36 hours
Bio-advanced, Granules, 7007455 24 Hour Grub Killer Plus
An over-night and all-season effective bug killer.
Bio-advanced granules kill cutworms overnight, and the protection remains for the season if you apply it in Spring and again in the Summer. It also kills ticks, chinch bugs, earwigs, and more. Use it as soon as your notice your lawn is suffering for the best effects. This bug killer contains Dylox, the trade name for trichlorfon. This is a contact killer and also kills the cutworm when eaten. To eliminate all the cutworms, you may need two applications several days apart since this insecticide is only effective for about 48 hours.
Since Dylox comes in granules, it is not likely to contact the edible tomato part of the plant, so it can be used on this crop if applied safely. The granules are easy to apply using a rotary or drop spreader.
Although Dylox is a potent pesticide, it is not so toxic for people and pets. Once it is adequately watered in, you can allow pets back into the treated area. However, it can kill earthworms and is toxic to birds and fish.
Pros
- Fast action works overnight
- Easy to use granules
- Probably safe for pets once watered in properly
Cons
- Toxic to wildlife
- Run-off must not be into rivers or ponds where fish or other wildlife may live
- Moderately toxic to earthworms
Bayer Dylox 6.2 Granular White Grub Insecticide
An overnight, rapid cutworm killer with dual action Dylox.
No products found.Bayer Dylox is a granular cutworm killer that works overnight when the cutworm is most active. It stops the depravations to your lawn and protects your crops from cutworms and other destructive insects. You can use it around your tomato plants and shrubs, your grounds, and landscapes. Dylox (trichlorfon) is the active ingredient and is effective against a host of bugs, including cutworms, white grubs, and chinch bugs.
Dylox has a dual-action and kills both on contact and by ingestion. Once watered in, the cutworms are at risk, but pets can be allowed back into the area – but do read and follow the manufacturer’s instructions since Dylox is a potent pesticide. Unfortunately, earthworms are not safe.
Pros
- Strong, effective cutworm killer
- Easy to apply granules
Cons
- Toxic to wildlife
- Run-off must not contaminate other water sources
- Bees and earthworms might be killed
Bonide (BND60360) – Insect and Grub Control, Outdoor Insecticide/Pesticide Granules
Granules for fast, effective action against cutworms and other insects.
Bonide has produced a very effective bug killer. It contains imidacloprid which acts systemically, and the fast-acting Lamba-Cyhalothrin. Once treated, your cutworms and other species will die within 24 hours, and the protection continues for up to 3 months. It kills insects below and above the soil. While this product isn’t suitable for indoor use, it can make a very effective barrier to protect your home from invasion if necessary.
Like most chemical pesticides, this one is very effective, but your earthworms are not safe from Lamda-Cyhalothrin, and you need to keep your cats in when you apply it. Cats have a specific enzyme deficiency that makes them vulnerable. As far as dogs and humans are concerned, the low levels needed to eradicate insects make it unlikely to affect them once the granules are watered in, and the ground is dry again. But you must follow the instructions on the label. The imidacloprid part is safe when used correctly.
Pros
- Dual-action so fast and long-lasting effects
- Easy to apply granules
- Kills many pests
- Effective barrier
Cons
- Cats are vulnerable
- Kills earthworms
- It smells “pretty evil”
Conclusion
All these cutworm killers are effective and safe for people and pets as long as you follow the manufacturer’s instructions. They can all be used on a wide variety of plants and lawns, although the Lamda-Cyhalothrin contained in the Bonide granules is very toxic to cats (although on the whole, cats don’t tend to dig, and these are granules, well-watered into the ground). For that reason, we have placed it in fifth place.
Bayer and the bio-advanced granules use Dylox – which is moderately toxic but reasonably safe cutworm killer but needs care in controlling the run-off after watering.
- Kills caterpillars, gypsy moth larvae, worms and cabbage loopers
- Effective method of eliminating your garden or field of the tomato hornworm without environmental concerns or harm to beneficial insects
- Can be used up until day of harvest
- OMRI Listed and compliant for use in organic gardening
- Contains bacillus thuringiensis var Kurstaki 98.35 percent
It is difficult to choose between the Safer Brand Caterpillar Killer and the Monterey LG Worm & Caterpillar Killer. Either could rate as our best pesticide for cutworms. Both use Bacillus Thuringiensis as the active ingredient, which is safe for beneficial insects and wildlife. Both come as a concentrate that needs mixing appropriately. But, we’ll go for Safer Brand 5163 Caterpillar Killer II Concentrate, 16 Oz For Insects as our “winner for our top favorite cutworm killer.”