Most Common Pests In Cannabis: Spider Mites

Spider mites are tiny spiders, they're the very common in cannabis and their webbing can be a growers worst nightmare.
11 June 2020
4 min read
Most Common Pests In Cannabis: Spider Mites

  • 1. What are spider mites?
  • 2. What do spider mites look like?
  • 3. Where are they found?
  • 4. What do spider mites do?
  • 5. Spider mites symptoms
  • 6. How to prevent them?
  • 7. How to deal with them?
  • 8. In conclusion

Spider mites are the most common pest in cannabis. These bugs live in dirty indoor and outdoor grow spaces where they feed on chlorophyll and sap, webbing all over your precious plants.

1. What Are Spider Mites?

Spider mites are common in cannabis, these small mites hide inside the buds, sucking the liquid in your plants and leaving webs all over. It's fairly easy to eliminate them but make sure you spot them early because they can rot the buds, ruining your entire harvest really fast.

These tiny mites are related to spiders, ticks,  and other small tetranychidae. They are a very common bug that attacks cannabis, seeking dark places in plants where they can lay eggs and continue to reproduce.

2. What Do Spider Mites Look Like?

These bugs are actually super tiny (around 0.5mm). They can be red or black and have 8 legs.


Most Common Pests In Cannabis: Red Spider Mite

Red spider mite.

Because they’re so tiny, you’ll only be able to see tiny dots walking around your plant unless you have a 10x microscope available.

3. Where Are They Found?

Spider mites can be found walking all over the plant but you’ll usually find them on the underside of the fan leaves.

That’s where they lay their eggs, protecting them from the sun and other elements that may affect them.

4. What Do Spider Mites Do?

These mites feed not only on sap but also on chlorophyll, damaging the plant. Even though this can have a toll on your plant, this is not the worst they can do.

Spider mites can reproduce super fast and will use their web to protect their eggs. This means they will completely cover your plant in spider web if you don’t deal with them early.

They can even lay eggs inside the buds and when the eggs hatch, they will start eating the inside of your bud, causing bud rot.


Most Common Pests In Cannabis: Spider Mite Bites on Cannabis Leaf

Spider mites feed not only on sap but also on chlorophyll, damaging the leaves.

Even though the webbing won’t kill your plant, it will be impossible to remove it if you’re in the flowering stage as it can get stuck in the flowers.

So although it doesn’t kill your plant, you will have to throw it away if you get seriously infested when flowering.

5. Spider Mites Symptoms

The symptoms you’ll see with spider mites are just signs of their presence. The first thing you see is tiny yellow or white spots, these are mites' bite marks and they are a sign that they are feeding on your plant.

After that, you will start to see small transparent eggs stuck under the stems and leaves, this is a sign that the infestation is starting to grow.


Most Common Pests In Cannabis: Spider mites infestation

Spider mite infestation during the preflowering stage.

If left untreated for around a week, you’ll see what they can do. You will start to see webbing all around your plant and you’ll be able to see the mites walking all over your plant.

6. How To Prevent Them?

Although like with other pests like Mealy bugs, there is nothing you can do to avoid them 100% other than keeping a good growing environment. Keeping your growing space clean and quarantine clones (or other plants) before bringing them in with your plants is a good way to prevent them.

Because spider mites don’t like wind, keeping a well ventilated growing room can be an effective way to prevent them also.

If you want to do everything you can to prevent them, you could slightly spray insecticides to prevent their appearance but this can affect your plant.

But the best way really is to keep your space clean, with the appropriate temperature, humidity and ventilation.

7. How To Deal With Them?

If spotted in the early stages, it can be fairly easy to remove the eggs manually or with a high-pressure sprayer to knock them down. After you remove the excess, you can apply Neem oil or a mix of alcohol and water to eliminate the rest.

Now if your plant is being taken over, it can be difficult, because they can cause bud rot and can hide inside the buds.


Most Common Pests In Cannabis: Neem Oil against Spider mites

After knocking them down, Neem oil is a good way to deal with spider mites.

You will have to make the hard decision of completely eliminating them by applying harsher chemical products, with the risk of damaging your plant or applying organic and safer-to-use insecticides daily, with the risk of losing your plant to spider mites.

If your plant is severely affected, the best thing to do is throw the plant out to avoid them spreading to your other plants.

8. In Conclusion

Spider mites are the worst bugs that can attack your plant. Even though they don’t feed on the roots or something more serious like Fungus gnats, they can lay eggs inside the buds, being able to compromise the entire main cola.

Their webbing can also get stuck to the trichomes on the buds and it will be impossible to remove them completely, affecting yields and quality.

As with all other pests, we recommend checking your plants every day and take action as soon as you see any sign of bugs.

11 June 2020