There are few experiences as devastating as cultivating an amazing cannabis crop only to have it destroyed by voracious insects and animals. You might be surprised to discover just how many different species love to munch on these plants! Below are some of the most insidious cannabis pests, and how to deal with them.
These tips can help your next cannabis crop to grow as pest-free as possible. Remember that prevention is the best medicine, but there are also many organic, earth-friendly pesticides and deterrents that you can use to keep your plants healthy.
Ask anyone who’s grown cannabis plants before and they’ll all have stories about animals that have obliterated some of their crops. These are some of the most common pests you’ll encounter, though species will be different depending on where you’re located.
While we don’t recommend allowing animals into your pot enclosure, chickens and ducks can be helpful at removing these cannabis pests right off the plants. Additionally, if you make little habitats that are attractive to snakes and toads, they’ll keep the slug population down exponentially.
While cannabis plants aren’t necessarily a deer’s first choice in salad greens, many species do develop a taste for them.
As you can imagine, keeping your plants behind a sturdy fence (or in a greenhouse) is the best way to keep them from being eaten by deer, elk, and other large herbivores. Alternatively… do you like venison?
Much like deer, rabbits can take a shine to the taste of cannabis leaves. They can trample young plants in search of leafy munchies, and inhale vast quantities of leaves and buds in a single visit.
Dig a fence at least a foot deep and curl it outwards so they can’t dig beneath. Then scatter predator poop like coyote, wolf, or dog droppings around the perimeter. The scent will put them on high alert and keep them at bay.
3. Marmots, Groundhogs, Woodchucks, Prairie Dogs, and Ground Squirrels
You’ll undoubtedly have to deal with some version of these ground dwellers depending on your locale. They differ in terms of their size, color, and eating habits, but they’re all voracious. There are different names for various species, but each of them can devour several pounds of vegetation every day.
That includes your pot plants.
Much like rabbits, these cannabis pests can be fended off with an outward-curving, deep perimeter fence, and some predator poop.
4. Mice and Rats
Although mice and rats don’t get high from eating cannabis, they do love to gnaw on stems and low branches. Maybe it’s because they’re sweet, or simply that they’re satisfying to chew on.
While there are few ways to keep small vermin out of your growing enclosures, there are a couple of options here. One of them is to grow your cannabis plants inside a greenhouse. If you’re diligent about keeping the doors closed, you’re less likely to get mice and rats in there.
The second option if you’re growing outdoors is to set traps around the enclosure with bait that’s much more appetizing than plant parts. Don’t use poison, as poisoned mice will also kill hawks, owls, foxes, and other predators that feed on them. Instead, go for quick-kill snap traps and check them daily.
Maybe befriend some owls and feral cats too, so they can keep rodent populations down.
These can wreak havoc on your plants by tearing through their root systems. If several of your plants seem to be keeling over and sickly for no apparent reason, look for mole holes and tunnels.
To deal with them, dig your enclosure’s perimeter fence a good 2 feet down, with the steel mesh turned outwards. Since moles can’t dig through this, they’ll find a way around or dig somewhere completely different.
You may not instinctively think of dogs as cannabis pests, but they’re some of the worst around.
A lot of homesteaders and farmers keep dogs around to protect their property, chickens, and such. And that’s great, provided that they aren’t allowed anywhere near the cannabis enclosure. This is because insects like mites love to hitch rides on dogs and will leap onto your pot plants at the first opportunity.
Keep dogs away from your medicinal plants at all costs, and don’t let neighbors who have dogs walk in amongst your plants either. Mites and other insects can jump from their dogs onto their clothing, and then onto your plants.
As a final insult, many dogs also really like the taste of cannabis. More than one grower has frothed and swore in all colors because their dogs decided to eat all their buds. Keep Fido away from your plants (and your drying/curing crop) and all should be well.
While cats aren’t quite as insidious as dogs when it comes to annihilating cannabis plants, they can still cause some damage. Some of them also develop a taste for trichome-rich nuggets, which can actually kill them if they eat large quantities. Cats can also carry mites and other insects, which you do not want on your plants.
Keep your crop protected using cat-proof fencing. The easiest way to do this is to create an overhang that faces outwards, so cats can’t hook over to pull themselves into the enclosure.
Insect Cannabis Pests
While the animals mentioned above can certainly be a nuisance to deal with, it’s insects that’ll cause the most (and worst) damage to your cannabis crop. Below are the major players that you may come across in your growing endeavors.
Depending on where you are, you may encounter a number of different mite species. These can include red spider mites, broad mites, etc. They like to eat leaf sap, and will leave white, yellow, or black spots on leaves where they’ve fed. You might even find a fabric-like film on some of the leaves.
Mites love dry environments, so the best way to fend them off is to make the area less attractive to them. If you’re growing indoors, raise the greenhouse’s humidity levels. Whether you’re growing indoors or outside, spray your plants down with diluted neem oil, or a water wash that has some Ecotenona added to it.
9. Leaf Miners
These little jerks leave white or brown lines all over the leaves they’ve feasted upon. They have big appetites and multiply often, and can munch their way through your entire crop.
The best way to deal with them is hand removal. Look underneath leaves and squish them when you find them. Additionally, since they crawl around rather than flying or hopping, you can trap them. Get some double-sided tape and wrap it around your plants’ stems. Do this at the bottom, a few inches above soil level, and in a few places higher up as well.
These will trap adults and young alike, thus keeping them from feeding or reproducing further.
If you find silver drops and markings on brittle, dried-out leaves, you may be dealing with thrips. These insects are tiny, and some species can have wings.
Much like with leaf miners, the best way to catch and deter them is with sticky tape. Diluted neem oil foliar sprays can work wonders, as can potassium soap. Since these bastards like to suck all the chlorophyll out of leaves, make the leaves wholly unappetizing to them!
A number of different caterpillar species can wreak havoc on your plants. These will differ by location, of course, but there are generally two different types. Borers will burrow into your plants’ stems and devour them from the inside out, while others eat all the foliage.
Plant yarrow and Queen Anne’s lace around the outside of your enclosure to encourage braconid wasps. These are predators that will destroy caterpillars. Additionally, if you find some praying mantids, bring those into the enclosure. They’ll eat the caterpillars and make excellent companions to hang out with.
There aren’t many plants that aphids won’t attack, and cannabis plants are no exception. These cannabis pests like to feed on leaf sap, and leave sticky residue behind. If you find that your plants are suddenly covered with ants (who love this sticky “honeydew”), then look for aphids as well.
These can be controlled by introducing lacewings and ladybugs, or by hosing the plants with the aforementioned neem oil.
Anyone who has dealt with a massive wave of grasshoppers can understand why their locust cousins were among the Biblical plagues of Egypt. They can completely annihilate an entire cannabis crop—literally overnight! Seriously, these critters are night feeders, so they’ll eat everything under cover of darkness, leaving you crying into your coffee when you wake up.
Letting chickens and ducks at the plants can reduce the grasshopper population, but chickens are likely to scratch up the soil and disturb plant roots in search of them. Your best bet is to make the leaves unappealing.
Dress this tasty cannabis salad with a diluted dish soap wash, and these cannabis pests will seek dinner elsewhere. Our guide has more info on controlling these pests.
If clouds of little white flies puff off your plants when you shake or nudge them, then yeah, you have a whitefly issue to deal with.
Prevention can be effective for keeping these at bay, so plant plenty of basil, nasturtiums, and calendula around the perimeter. To actually deal with established whiteflies, alternate between hosing your plants down with diluted neem oil, and diluted Castile soap (like Dr. Bronner’s). Just don’t use a scented soap like peppermint or it’ll affect the final buds’ fragrance and flavor.
15. Slugs and Snails
These are pretty much the easiest of all to get rid of. If you’re dealing with large slugs, check your plants around dawn and dusk and peel the slugs off by hand. You can then drop them into a bucket and feed them to your chickens and ducks, or drown them.
Additionally, you can create slug traps and barriers around your enclosure. Eggshells, wood pellets, and copper have been proven to be ineffective, but pellets and nematodes work. If you want to get mean about it, then put down a thick layer of salt and diatomaceous earth around the enclosure: that’ll keep them away or slow them down.