How to Get Rid of Cutworms on Cannabis?

Many growers visit their seedlings one morning and find them lying on the soil — as if they have been beheaded. It's one of the most disastrous things that can happen, especially if you've spent a lot of money on seeds. 

However, it's not due to some jealous neighbor or your mischievous pet. It's more likely due to cutworms — a pest that loves to eat young seedlings. 

What are cutworms, how can they damage your plant, and how to get rid of them — find out everything in this article, and you'll be better equipped to handle them. 

What are Cutworms?

Cutworms refer to the larvae of various moth species. These moths, of course, are unlike the other gorgeous moths you might find in your garden. On the other hand, cutworms don't look so pretty. 

Cutworms aren't exactly worms. They are caterpillars that feed on plants. Since they look similar to grubs, people get confused and take different measures to control them. 

If anything, cutworms are notorious for damaging seedlings and young plants all over the world. Their favorite pastime is to terrorize growers by nipping off their young, favorite seedlings. 

Cutworms like to chew grass at the crown, where the roots meet the shoot. It's not that they love cannabis specifically. But, unfortunately, they can confuse your cannabis seedlings with grass and attack them too. And they can gnaw at the stem until it is completely severed — a compelling reason why they are called cutworms.

A single cutworm can kill your seedling within a night, so they are a serious problem for cannabis growers everywhere. 

You will most probably experience a cutworm problem in your garden during the start of the season, which is when they emerge from their slumber and start feasting on grass or seedlings.

Generally, cutworms are 1 to 2 inches in length. Most cutworms look brown or gray and slimy, but you might notice other colors too. And some subspecies also display spots or stripes over their body. Here are the two most common subspecies of cutworms:

• Black cutworms: Also known as Agrotis ipsilon, black cutworms are the most common kind of cutworms growers encounter, and they are identifiable by the dark spots on their bodies. Once they mature, they turn into dark sword-grass moths.
• Variegated cutworms: Also known as Peridroma saucia, this subspecies is also quite common, and you can identify them with their mottled brown color and a faint white stripe running down their back.

When disturbed or threatened, they try to curl up into a ball, resembling a ‘C’ shape, making it easy to spot them.

How to Identify a Cutworm Infestation?

Cutworms can be troublesome for your garden, but they are quite easy to identify and deal with. 

The first dead-giveaway of a cutworm problem is if you find some of your seedlings cut and lying on the soil. Not many pests damage plants in such a way. This is also the reason cutworms are a serious problem because they can kill young plants within a few hours with no hope of recovery.  

If you find cut-up seedlings, you should grab a flashlight and inspect your garden during the wee hours of the night. Go just after the sun has set, when the worms come out to make their rounds. Cutworms are sensitive to light so they tend to sneak around the plants when it is dark. 

Inspect the base of your seedlings and the surrounding soil. Their dark color may work as camouflage on the soil, so be watchful, and look out for curled-up ones.

You can even shuffle the top layer of loose soil around your seedling or plant. If you see tiny rolls in the soil, they are most likely cutworms. 

While they mostly affect seedlings, it is not uncommon for them to attack young plants. So, if your plant is wilting or tilting over, you should check for cutworms in the soil.

Cutworms or caterpillars also like to chew the leaves, so if you see holes in your cannabis plants, it's likely due to these pests.

How to Eliminate Cutworms?

Fortunately, dealing with cutworms is quite easy. All it takes is a little effort and around an hour of your time to eliminate them from your garden. Here are some techniques you can use:

Remove Them by Hand

Cutworms are a nuisance for your plant but they are completely harmless and easy to spot. So, the simplest way of eliminating them is by simply picking them by hand. 

Granted, it's kinda gross to touch them. The best way is to wear gloves so you don't have to touch their slimy bodies. Remember, keep a flashlight handy and only go looking for them during the dark hours. 

Once you pick them off from the soil, place them in a container with soapy water, which will kill them. 

Sprinkle Cornmeal or Diatomaceous Earth on the Soil

If you don’t want to go around digging your soil, you can also sprinkle some cornmeal or diatomaceous earth on the soil around your plant. 

Cornmeal is appetizing to cutworms, along with fleas and ants, but their bodies are not capable of digesting them. So, when they eat it, their bodies will swell up and they will die.

On the other hand, diatomaceous earth is a fine powder, completely harmless to humans, but deadly to insects. The fine powder is razor-sharp on a microscopic level, making it lethal for insects. The powder punctures their bodies and dehydrates them, eventually killing them.

You can buy both cornmeal and diatomaceous earth at your local gardening store or online stores easily.

Use Chemical Insecticides

If you are looking for a more potent solution, you can also consider chemical insecticides. Insecticides like Bug Blaster work wonders in eliminating all kinds of invasive pests from your garden. 

Just remember to choose a cannabis-specific insecticide, so it does not contain anything that may harm your plant. Plus, read the labels and instructions carefully for the best results. 

Some growers prefer not to use chemical insecticides in their garden, but if you pick the right one, it won’t harm your plant. But ultimately, the decision is yours.

Use Biological Control Agents

On the other hand, for a more eco-friendly and safer approach, you can use biological control agents, too. 

The University of California Integrated pest Management Program recommends using Bacillus thuringiensis (BT) against cutworms and armyworms. BT is a soil-dwelling bacterium capable of naturally producing toxins that are fatal to various insects like cutworms. 

BT is most effective on young, larval cutworms, but it can still eliminate older ones, too. Just remember to read the instructions carefully, as recommended by the manufacturer. And ideally, avoid irrigating your soil for a couple of days for the best results, unless recommended otherwise.

Introduce Some Friendly-Neighbourhood Pests 

Imagine having a constantly patrolling security detail around your precious cannabis plants! That’s exactly what you get with some friendly beneficial pests. Insects like parasitic wasps, spiders, or beetles (and even frogs) love hunting cutworms (and many other harmful pests).

So, just visit your local gardening supply store and introduce some beneficial pests to your garden. They are cheap and a good way to deter harmful pests and improve your garden’s ecosystem. 

How to Prevent Cutworms in the Future?

Now, you have eliminated cutworms from your garden, but you have to also prevent them from coming back. Use the following techniques:

Inspect Your Garden Regularly

The first thing you must do is inspect your garden regularly. The best time to do this is during the dark hours, dusk, or dawn when the sunlight isn’t too bright. You can also till or shuffle your soil lightly to find any cutworms lying under the soil. Doing so frequently will allow you to catch them before they multiply too much. 

Prevent Grass or Weeds Around Your Plant

Cutworms primarily attack grass and moths prefer to lay their eggs in weeds. So, by preventing grass and weeds in your garden, you reduce the chances of them lurking in your garden.

Plant Sunflowers Around Your Garden

Sunflower plants work as a decoy for cannabis plants, so if you plant them on the perimeter of your garden, cutworms will go there first instead of coming to your cannabis plants. And when you spot any cutworms around your sunflower plants, just eliminate them using some soapy water.

Also, sunflowers look pretty — another reason why they should be in your garden!

Make a Cutworm Border

As a last-resort measure, you can make a small fence around your plant’s stem to prevent any intruding cutworms from reaching your plant.

To make the fence, all you need is an empty toilet paper roll or 4 to 5 inches long PVC pipe. Push the roll or pipe an inch into the soil, surrounding the plant’s stem. This will stop cutworms from reaching the stem.

If you find it difficult to place PVC or toilet paper rolls around the stem, you can even use aluminum foil, but you will have to keep checking the foil regularly.

Summary: How to Get Rid of Cutworms on Cannabis?

Cutworms are a subspecies of moth larvae that can do significant damage to your seedlings and young plants in no time. But they are easy to spot and eradicate. If you spot any seedlings cut up in your garden, you should search for cutworms. 

If you find them, the easiest way to eliminate them is to toss them in soapy water. If there are many, you can use other methods, too. You can sprinkle diatomaceous earth or cornmeal, use chemical insecticides or BT, or introduce some beneficial pests into your garden.

Additionally, you should never underestimate the chance of them coming to your garden. You must take some precautions to prevent cutworms. You can do so by regularly inspecting your garden, preventing grass and weeds there, planting sunflowers, or making a small fence for the stems. 

Many pests pay a visit to your cannabis plants. Most are harmless, but some pests can significantly affect your plant’s health and even kill plants.