Most Common Pests In Cannabis: Thrips

Thrips are little bugs that bite your plant to suck out their contents, leaving a shiny spot on them.
17 June 2020
4 min read
Most Common Pests In Cannabis: Thrips

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

Thrips are small long bugs that attack all kinds of plants. In cannabis, they reproduce in the tissue of the plants and also feed on the sap, leaving white shiny spots on the leaves.

1. What Are Thrips?

Thrips (also known as tobacco thrips) are tiny elongated insects that feed on the liquid inside plants, they can be found all over the world and attack almost all plants, not only cannabis.

They’re a big worry for growers because they carry viruses that can be transmitted to plants.

2. What Do Thrips Look Like?

Thrips are 0.6mm long when in the early stages and can reach up to 1.5mm when adults. 

Adults can also grow wings and antennae. Their color can also change, depending on where you live and in which stage of their life cycle they’re in.


Adult thrips have antennae and also can have wings.

They can be white or yellowish when young and will change into a darker color, turning brown or black as they grow.

It actually is kinda hard of spotting them unless they’re adults, at this stage, you will be able to see them walking on your plants.

3. Where Are They Found?

These bugs will try to hide anywhere they can, especially under the fan leaves, crevices and anywhere they get cover from direct sunlight and from you.

It can be hard to spot the actual thrips but before they become adults you will clearly see symptoms all over your plant.

4. What Do Thrips Do?

Thrips use their tiny mouths to puncture the cannabis plant in different spots, this allows them to suck out the liquid.

This will cause the leaves to start yellowing and with time they’ll be completely brown and dried up, although this is not a huge deal (if dealt with early). 


Thrips use their tiny mouths tomake holes on the leaves, this allows them to suck out the liquid.

Thrips can carry viruses that affect plants. Considering they puncture the plant multiple times, your plant can easily get infected, get sick, and die.

On top of this, thrips reproduce in the tissue of the stems, leaves, or flowers, damaging every part of your cannabis plant, including the precious flowers.

5. Thrips Symptoms

When your plant gets attacked by thrips, you’ll start to see small black dots on the leaves and stems, these are their excrements. 


When thrips bite your plants, they leave silver spots behind.

You’ll also start to see silver or bronzes spots all over your plant which is where they are feeding on, this is a sign of the leaves starting to dry out, after some time, they will be completely dry and will brown and become extremely brittle.

6. How To Prevent Them?

The best way to prevent thrips is to disinfect your growing space after each cycle and renewing the soil in case you have them in your soil.

A good way to prevent them is to use yellow or blue sticky cards in your grow room, thrips are attracted to them and will get stuck and die before they can reproduce.


Blue or yellow sticky cards will help reduce the population of thrips in your growing space.

Another good tip is to avoid overwatering and overfeeding, especially nitrogen, which these bugs love.

7. How To Deal With Them?

As with all other bugs and pests, thrips can be dealt with Neem Oil, insecticidal soaps, organic insecticides, or a mix of 90% water and 10% alcohol.

As usual, follow the instructions on the product you're using and always make sure you start applying the organic insecticides before you move on to the stronger products. This way you avoid damaging or shocking your plant.

8. In Conclusion

Even though thrips are relatively harmless to your plant if caught early, the viruses they carry can seriously hurt your plant. 

Also, a combination of good genetics, a good growing environment, and happy and healthy plants is a good way to prevent pests.

If you’re looking for a resilient strain, we recommend our new Gorilla Cookies Auto. 

Gorilla Cookies Auto
Gorilla Cookies Auto
Sativa 45%/Indica 55%
Gorilla Cookies Auto
10 weeks
500 – 600 gr/m2
90 – 100 cm
Up to 27%
< 1%
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2 fem
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3 fem
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5 fem
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10 fem
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100 fem
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500 fem
1 950,00 €
1000 fem
3 400,00 €
3 fem
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36,00 €

She is extremely resistant to harsh climates and pests.

As we always say, the best way to prevent bugs is by checking the underside of the leaves and soil every day.

17 June 2020