Mother nature is beautiful.  Except she’s also kind of gross and at times, highly inconvenient.  And since cannabis is a plant, it is subject to pests and parasites.  Whether marijuana is grown indoors or outside, it cannot escape the circle of life, and apparently, humans aren’t the only ones interested in consuming cannabis.  Here is a list of the most common parasitic threats and what to do about them.

Continue Reading Below

Cannabis Pests and Parasites

Spider Mites

These guys are probably the most common of all pests and can cause the biggest headache.  Spider mites don’t play; they reproduce rapidly, reach full maturity in a matter of days, and binge on plant material until chlorophyll is depleted and the plant is dead.  It doesn’t take long for a spider mite spotting to turn into a full blown infestation and the demise of an entire cannabis harvest.


Easy to miss, aphids are tiny, quick, and devastating.  Like spider mites, they reproduce quickly and feast on the cannabis plant matter. They are especially damaging to indoor gardens that lack the natural aphid predators outdoor gardens can harness for protection.

Grasshoppers and Crickets

Pot lovers by nature, these insects will make the cannabis plant their primary food source without quick and effective intervention.  Crickets and grasshoppers typically feast at night and leave behind a whole lot of damage for growers to discover in the morning.  While birds love to eat these bugs, they must dig through the soil to get to them, and that can cause damage to root systems.


Plant Pests and ParasitesLike grasshoppers and crickets, caterpillars are very attracted to cannabis, and their insatiable appetites can destroy the crop.  Borer caterpillars go unnoticed because they burrow through the plant, hollowing it out and killing it before growers realize what’s happening.


They sound as lethal as they are.  Cutworms can destroy a harvest before it even has a chance to begin growing.  These night crawlers eviscerate cannabis seedlings and the tops of cannabis plants.

Leaf Miners

These insects are creepy and make me a little paranoid about eating anything leafy.  They burrow through the cannabis plant and mine the leaves of cells and nutrients.  In their wake, they leave behind brown or white streaks through the leaf tops.  The adults leave their larvae under the leaves, and those babies grow up to be just like their creepy, burrowing parents.  Unfortunately, the best remedy for these bugs are your hands since most pesticides that target leaf miners are more dangerous than they are beneficial.  Yep, that means you’ve got to find ‘em and squish ‘em.

Fungus Gnats

From their larval-hood to adulthood, these microscopic insects love to eat the cannabis plant.  They start by eating fungus near the plant’s base, but steadily eat through the roots.  This can be devastating for plant growth and soil drainage.

Slugs and Snails

Simultaneously cute and disgusting, these common garden pests eat cannabis plant matter and can eventually do a lot of damage.  They aren’t particularly discreet, though.  They leave streaks of shiny slime everywhere they go.  Like I said.  Cute and disgusting.


These tiny, flying insects love to chow down on cannabis.  They live beneath cannabis leaves, and, because of their size, are not easy to see.  Whiteflies can be particularly dangerous because of their ability to spread disease.  As fliers, they are extremely mobile, and once they show up, they can take down an entire harvest.


These tiny bugs thrive on the cannabis flower.  An infestation of them can ruin the crop’s ability to fully mature.  Like whiteflies, thrips are notorious for spreading diseases which can be even more detrimental to the plant than the thrips’ appetite.

Mealy Bugs

These insects are not a problem in small numbers, but an infestation could overrun a harvest.  Mealy bugs are small and live in the plant’s crevices.

They make their presence known by leaving behind gifts of cotton-like balls

These insect-hand-crafted gauze balls can cover a cannabis plant, and the presence of the mealy bugs can cause plant discoloration.


Rather than posing a direct threat to cannabis plants, ants are indicators of other problems since they are attracted to aphids or whiteflies.  Additionally, as burrowing insects, ants can damage the cannabis root systems.


Like ants, birds aren’t always bad.  In fact, they can be extremely helpful in eliminating other pests like caterpillars.  However, birds love seeds.  Birds are most hazardous to cannabis before the plant has even sprouted.

Cats and Dogs

We love our pets, but they aren’t the best for cannabis grows.  Although it isn’t likely that they will eat the cannabis, a cat’s ammonia-heavy urine and pet fecal matter are harmful for cannabis gardens.  The ammonia will wreak havoc on your plants and the feces attracts harmful pests.


Rudolph and Bambi love plants, and that includes young cannabis.  Deer Plant Pests and Parasiteswill eat an entire plant, destroying a harvest well before maturity.  Fortunately, a mature cannabis plant’s pungent aroma is a natural repellant for scent-sensitive deer.  Before maturity, however, cannabis plants must be vigilantly guarded against these large herbivores.   

Mice and Rats

While mice and rats are not particularly inclined to seek out cannabis, they will eat it if it’s there and nothing else seems better.  They are also the mammalian versions of roaches—they’re everywhere.  Even when you don’t see them, they see you, the insidious vermin.


Another rodent, gophers tunnel underground.  While burrowing alone isn’t always a bad thing—moles do it, too, but they aerate the soil and eat pesky insects for you—gophers also eat the cannabis roots, sometimes even pulling the entire plant down into their subterranean dwellings.

Natural Solutions to Pests and Parasites

Despite her inconvenience, mother nature is also a force of balance.  Ecosystems work to create and sustain life because each part of that system contributes to its overall wellbeing.  So here is a list of critters to welcome to a cannabis friendly ecosystem.  Keep in mind that these are pretty much exclusive to outdoor grows.

Amphibians are natural predators for snails and slugs.
Aphid midges are great natural predators for over 60 types of aphids.
Damsel bugs eat lots of pests including caterpillars, leafhoppers, thrips, and aphids.
Ground beetles binge eat on slugs, snails, and cutworms.
Lacewing larvae and adults thrive on caterpillars, mealybugs, thrips, whiteflies, and aphids.
Lady bug larvae and adults feast on mites, mealybugs, and aphids.
Birds of prey are natural predators for mice, rats, and gophers.
Sunflowers are pretty, covering, and natural repellants to cutworms.
Wasps and praying mantises are natural predators for caterpillars.

Environmentally Friendly Pest Control and Pesticides

Sometimes introducing natural predators to a cannabis grow isn’t an option or enough.  Here are safe ways to deter pests from your cannabis:

Neem oil has been regarded as an incredibly potent and versatile pesticide for centuries.  A spray containing this oil, organic soap, and warm water can ward off all kinds of insects.
Salt spray is an effective repellant for spider mites and other insects because it dehydrates the bugs and their larvae.
Citrus oil can be used in combination with cayenne pepper, soap, and/or water to create a natural pesticide for slugs and ants.
Onion and Garlic sprays are a natural repellant for most insects.
Scarecrows or reflective objects are good, reversible deterrents for birds.  Once the seeds have sprouted, you can remove these items so birds can help you get rid of other pests.
Fences are the best deterrent for large mammals including dogs, cats, deer, and humans.
Diluted dish liquid is a good way to get rid of grasshoppers and crickets.
Cornmeal is a safe way to deter ants from your plants. While ants are natural predators for whiteflies and aphids, they also threaten cannabis root systems, so apply cornmeal to the soil to keep them away.