Most Common Pests in Cannabis Plants

Like all plants, cannabis can suffer from pests, they can be easily treated early but can ultimately be deadly.
21 May 2020
6 min read
Most Common Pests in Cannabis Plants

  • 1. Pests in cannabis
  • 2. Aphids
  • 3. Fungus gnats
  • 4. Leaf miners
  • 5. Mealy bugs
  • 6. Spider mites
  • 7. Thrips
  • 8. Whiteflies
  • 9. Ants
  • 10. Broad mites
  • 11. In conclusion

As it happens in nature, there are numerous pests that can attack your cannabis plant. These pests can be easy or impossible to deal with, depending on the amount and gravity of the situations.

Here is some information that can help you deal with them.

1. Pests In Cannabis

Humans aren’t the only ones who enjoy the unique taste of cannabis. Unfortunately, many of the bugs that also enjoy it can ruin your cannabis plant extremely quickly.

Prevention is the most important thing when dealing with any of them. If we haven’t managed to prevent their attack, we must identify, control, and eliminate it very quickly. It is very important to deal with them very quickly to avoid the consequences because sometimes they can be irreversible.

The following are the most commonly found pests either indoors or outdoors. All of them can be detected and treated early with small or zero consequences but if left untreated for a long time can be deadly to your cannabis plants.

2. Aphids

Aphids are tiny white bugs and one of the most irritating pests you will encounter. A big part of the problem is their small size as they're easy to miss.


Most Common Pests in Cannabis Plants: Aphids on Cannabis Plant

Aphids on Cannabis plant.

They stay in the undersides of the leaves, draining out nutrients and reproducing very quickly. Indoors, in a controlled environment, aphids can ruin an entire crop super quickly. 

How to Deal?

The best way is to prevent them. Check regularly for aphids and if you see even a couple, remove them and spray a natural insecticide like Neem Oil or any other Organic and safe-to-use insecticide.

3. Fungus Gnats

Fungus gnats look like black ants with wings. The adults love to hang around the cannabis plants and the larvae can cause a lot of damage to the roots of your plants.


Most Common Pests in Cannabis Plants: Fungus Gnats on Cannabis

Fungus Gnats on Cannabis plant.

They start out eating at the base of the plant and then eat their way into the root system, slowing growth and affecting the drainage of the medium.

How to Deal?

The most important thing to know is that fungus gnats need wet soil to grow. The most common reason they appear is overwatering.

Even though there are ways to get rid of them, they will go away if you let the top part of your soil dry. 

But if you already have them, you can use yellow sticky cards, neem oil or diatomaceous earth to get rid of them.

4. Leaf Miners

Leaf miners refer to the larva of any bug (flies, beetles, moths) that live inside of the cannabis leaves. They will dig through the top of your cannabis leaves, damaging the cells and draining out nutrients.


Most Common Pests in Cannabis Plants: Leaf Miners on Cannabis plant

Leaf Miners on Cannabis plant.

The symptoms are usually very easy to recognize: white, brown, or yellow traces running along the top of the leaves. The adult leaf miner resembles a house-fly or an ant with wings, it plants the larvae under the leaves and after they hatch, they burrow into the interior.

How to Deal?

Leaf miners are really hard to deal with and because they live inside the leaves, insecticides won’t kill them. The only way to effectively treat this is to completely remove the affected leaves.  

If you don’t want to remove the whole leaf, you can crush the larva with your fingers where you see the trails.

5. Mealy Bugs

Mealybugs are soft little white bugs that live in the corner and gaps of your cannabis plant. Usually, if there isn’t a lot of them it won’t be a problem. It can get serious if their population gets out of control. 


Most Common Pests in Cannabis Plants: Mealy Bugs on Cannabis Plant

Mealy bugs on Cannabis plant.

The symptom of a mealybug population becomes a problem when white balls start to appear on the foliage.

How to Deal?

If you need to get rid of them, there are easy ways to do so. If you have a small number of mealy bugs you can just remove them manually. But if you are suffering from a real infestation, you can use Neem Oil or lemon juice mixed with a little bit of water to get rid of them.

6. Spider Mites

Spider mites are little bugs that look like ticks and are the most common problem for cannabis growers, they reproduce extremely quickly and reach full maturity in less than a week.

Their fast reproduction rate and maturity means it is extremely easy and quick to be completely infected by these tiny creatures in a short amount of time. 

This bugs feed on your plants, feeding on valuable nutrients and chlorophyll until the plant dies, and can quickly ruin your entire crop if not dealt with quickly.

How to Deal?

Spider mites hate wind and heat. The best thing to do is adjust the temperature, have the fan blow directly onto your plants, and kill every spider mite you can. After removing most of them (or as much as you can) you can start treating with insecticide for mites (preferably organic and safe to humans and plants).

7. Thrips

Although thrips are very small insects, they can be a huge problem. They are worm-like bugs that have legs and may have wings depending on their age.


Most Common Pests in Cannabis Plants: Thrips on Cannabis Plant

Thrips on Cannabis plant.

Their primary source of food is the flower itself, which means your plant won’t mature properly and the open wounds may cause diseases to your plant.

How to Deal?

As with most pests, the best way to deal with thrips is preventative action, check every couple of days to make sure there’s no sign of them. However, if you already have thrips, you can spray your plant with a mix of water and neem oil to get rid of them.

8. Whiteflies

Whiteflies are really small insects that have the ability to fly because of this they can infect surrounding plants easily.


Most Common Pests in Cannabis Plants: Whiteflies on Cannabis Plant

Whiteflies on Cannabis plant.

They live on the undersides of cannabis leaves and feed on the plant matter, because of this, they can infect your plant with diseases and leave open wounds that can become infected with fungus.

How to Deal?

Like with other pests, best would be to prevent from having them by maintaining a clean growing environment and always be on the lookout for bugs.

If your plants are already suffering from whiteflies, you can create a mix of water and garlic to spray your plants with. This will discourage whiteflies from staying on your plant. If this doesn’t work then you will have to use more aggressive sprays like Neem Oil or Natural (or organic) insecticides.

9. Ants

Ants don’t actually affect your cannabis but they can feed off other pests, making them a sign that something is wrong. If you see ants on your plants, search for other pests that may be damaging your cannabis.


Most Common Pests in Cannabis Plants: Ants on Cannabis Plant

Ants on Cannabis plant.

Also, ants may want to dig tunnels in your medium, this can damage the root system and make it difficult to get good water circulation among the roots.

How to Deal?

Dealing with ants can be surprisingly easy. By eliminating the other pests affecting your plant they will naturally go away. If they don’t, spraying your plants with Neem Oil or other natural insecticides will do the trick.

10. Broad Mites

Broad Mites are so tiny they are practically impossible to spot with the naked eye, and can even be difficult to see under a microscope. When broad mites are attacking your plants, the new growth may be twisted and “wet” looking. If your plant is attacked while flowering, the buds may turn brown and die.

The main way to spot them is the damage they leave behind because the mites themselves are too small to see. Their symptoms can be confused with overwatering, nutrient deficiency, or heat damage.

How to Deal?

With broad mites, the best way is to throw out the whole plant. If you want to try and treat them, you can apply Neem Oil every couple of days for 5 or more weeks until they’re gone. Even applying insecticides heavily, these bugs are really hard to kill, and still, the best way is to dispose of the affected plants.

11. In Conclusion

When talking about pests and bugs, size has nothing to do with the damage they can do. When dealing with any of them, prevention is the best way to go, check your plants daily, and try to deal with pests as soon as you can.

Leaving them on your plants for as little as 5 days can be the difference between being able to recover your plants and the death of them. We recommend always using natural and/or organic pesticides so you don’t affect your plant as much.

21 May 2020