Most Common Pests In Cannabis: White Flies

White flies are tiny moths that hide on the underside of the leaves, sucking nutrients and leaving white spots behind.
16 June 2020
3 min read
Most Common Pests In Cannabis: White Flies

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

White flies affect all plants, including cannabis. They hide on the underside of the leaves, where they reproduce and suck on the nutrients your plant has.

1. What Are White Flies?

White-flies are sap-sucking aphids that hide on the underside of the cannabis leaves. These white moth-looking bugs feed on the contents of your plant's leaves, draining out its energy. Lucky for you, they can be easily controlled and eliminated with insecticidal soaps, yellow sticky and a good airflow.

These tiny white moths feed on the nutrients your plant holds and glue their eggs to your plant, making it difficult to remove them without damaging it.

They can reproduce super fast, being able to lay up to 300 eggs that will hatch in around 24hs.

Note: Even though they're called flies, they're not flies at all. White flies are related to sap-sucking aphids.

2. What Do White Flies Look Like?

These bugs looks like a tiny white moth, they can grow up to 2mm long, have wings, antennae and can easily be spotted flying around your plant if you shake it a little bit.


Most Common Pests In Cannabis: White flies

These bugs looks like tiny white moths, they can grow up to 2mm long, have wings and antennae.

They usually have fluffy-looking legs and depending on where you live, they can have red eyes and a yellowish head.

3. Where Are They Found?

White flies can be found on any part of the plant, although they usually hide on the underside of the leaves, where they lay their eggs.

It can be fairly easy to spot them, because they will fly if you shake your plant.

So if you shake it and look closely, you will be able to see them, despite their small size.

4. What Do White Flies Do?

White flies feed on the nutrients your plant contains, just like spider mites, they bite the leaves and suck out their content.

They can lay up to 300 eggs, which can hatch in a day and completely mature in around four weeks, making it a pest that spreads fast.


Most Common Pests In Cannabis: White flies eggs

When a white fly population is increasing, you'll start to see small white eggs glued to the underside of the fan leaves.

The eggs will hatch and the new born white flies will start feeding on your plant, this is super dangerous because white flies can carry diseases that can gravely affect your plant.

5. White Flies Symptoms

You can find signs of white flies since the beginning, although the yellow spots they leave when feeding on your plant can be confused for other things, there is a way to be sure white flies are attacking your plants.

To spot them, you need to shake your plant, this will cause them to fly off and you will clearly see them.

Another way is to check the underside of fan leaves for eggs, you should be able to see small white eggs glued under your leaves.

Signs that a white flies infestation is getting serious is the yellowing and drying of the leaves.

At this stage, leaves will start to die and fall off, and you will start to see a reduced growth and overall development.

6. How To Prevent Them?

There’s not much you can do to prevent white flies, it is crucial to have a good air flow because this will cause them to not feel safe and look for another place to lay their eggs.

Other than that, you should check your plants thoroughly everyday.


Most Common Pests In Cannabis: White flies under leaves

You'll most likely find white flies on the underside of your plant's leaves.

You can also place yellow sticky traps all throughout your growing space, although this won’t exactly prevent them but you will see when they start to appear.

7. How To Deal With Them?

If you happen to get white flies you should spray your plant with organic insecticides and only move on to more aggressive insecticides if they’re not working.

You can deal with them with Neem Oil or insecticidal soaps.

Remember everything you spray on your plant can affect its growth, especially in the flowering stage, where it can affect the smell, flavor and effect your buds will have.

8. In conclusion

White flies won’t risk your harvest unless you let them be for a long time. 

Even though they reproduce quite fast, it will take a lot of white flies to kill your plant.

Your plant will go through a process of slowly running out of nutrients, yellow and the leaves falling off before it starts dying, so you have a fair amount of time to deal with them.

As always, remember the best way to avoid having any problems is growing in a good environment and checking for any kind of bugs everyday.

16 June 2020