The Worst Outdoor Cannabis Pests: 5 Bugs to Watch and How to Stop Them

The most troublesome pests in an outdoor cannabis grow are aphids, fungus gnats, leaf miners, mealybugs and spider mites, with spider mites usually topping the list of growers' nightmares. When you grow outdoors, you face a unique set of challenges, and these unwanted invaders can seriously threaten your plants' health and yield, especially out in nature where conditions are harder to control.

Spotting the worst outdoor cannabis pests early is key to preventing and controlling them. Below, you'll find the usual suspects, the damage they do and what you can do to protect your plants and maximize your harvest.

Pests on cannabis plants: protect your harvest

Whether you grow indoors or outdoors, every cannabis grower faces the same headache: pests. These intruders don't just love the taste of cannabis, they can turn into a real threat to your precious plants in no time. Prevention is your best defense, but if you spot them, you need to identify them, control them and get rid of them fast before they do irreversible damage.

Here are the most common pests that can infest your cannabis, indoors or out. Catching them early and taking the right preventive steps can keep the damage small, but ignoring them for too long can kill your plants.

Aphids: get rid of these annoying pests

Aphids are among the most common plant pests and some of the most irritating ones you can get. These tiny insects, often green, black or whitish, tend to go unnoticed because of their size, which makes them especially hard to control.

They mostly hang out on the undersides of leaves, where they suck up the plant's nutrients and reproduce fast. In controlled environments like indoor grows, aphids can multiply quickly and wreck an entire harvest in no time.

How to treat them

Prevention is everything with aphids. Check your plants regularly, and even if you only find a few, take them out right away. You can spray a natural insecticide like neem oil or any other organic insecticide that's safe to use.

Fungus gnats: keep your roots safe

Fungus gnats, small black flies that look a bit like winged ants, are another common problem in cannabis grows. In their larval stage, these little bugs can do serious damage to your plants' roots, hurting growth and the drainage of your growing medium.

They start their feast at the base of the plant and eventually work their way into the root system. Overwatering is what draws them in, and they can be a real pain for growers.

How to treat them

To control fungus gnats, avoid constantly wet soil. Letting the top layer dry out helps cut their numbers. You can also use yellow sticky traps, neem oil or diatomaceous earth to get rid of them effectively.

Leaf miners: spot and treat this threat in time

Leaf miners are insect larvae that can be the bane of any cannabis grower. These little pests, which can be flies, beetles or moths, make themselves at home inside your plant's leaves, tunneling through them and damaging cells as they feed.

The signs of a leaf miner infestation are pretty obvious: white, brown or yellow squiggly lines snaking across the tops of the leaves. The adult, which looks like a housefly or a winged ant, lays its eggs under the leaves, and once they hatch, the larvae start burrowing inside.

How to treat them

Leaf miners are especially hard to fight because they live inside the leaves and are shielded from many insecticides. The best strategy is to remove the affected leaves entirely. If you'd rather not toss the whole leaf, you can squish the larvae by hand wherever you see their trails.

Mealybugs: keep this white pest in check

Mealybugs are small white insects that hide in the nooks and crannies of your cannabis plant. If there are only a few, they're usually not a big deal, but they can turn into a real nuisance if they multiply out of control.

How to treat them

If there are only a few mealybugs, you can pick them off by hand. If the infestation is severe, though, neem oil or a lemon juice and water solution can help you knock them out.

SPIDER MITES: every grower's nightmare

Spider mites are one of the worst nightmares for cannabis growers. These tiny arachnids reproduce fast and can damage your plants in no time. They feed on the sap in the leaves, weakening the plant and cutting its ability to produce quality flowers.

How to treat them

Spider mites thrive in hot, dry, still air and hate humidity and wind. Bring the temperature down, keep humidity in a healthy range and set up a fan so air keeps moving around your plants. After removing as many as you can by hand, you can use a miticide, ideally organic and safe for people and plants.