Thrips or Spider Mites? How to tell the difference

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Are you dealing with spidermites or thrips?

The signs of thrips and spider mites are very similar, making it pretty difficult to see the difference between Thrips and spider mites. Since they both feed on the chlorophyll present in the leaves, they leave small white spots on them which is generally why they are confused.

Apart from that similarity they actually have nothing to do with one another, they’re not even in the same family! Thrips are insects and spider mites are part of the Arachnid family.

What are the difference between Thrips and Spider Mites?

The main difference within the symptoms of spider mites is the way the white (or grayish) marks appear. With mites the white marks appear mainly along the main-rib and veins of the leaves whereas with Thrips it will be randomly distributed.

This is due to the fact that the mites live under the leaf and the thrips move around (or fly around) on the top of the leaves.
Let’s get into the differences in detail:

Impact of Mites and Thrips on your plants




  • White bite marks are randomly spread out on the leaf
  • Live on top of the leaves. By looking closely you can see them crawling around.
  • Spreading can occur randomly across the plants.
  • White bite marks are centered along the main rib and veins of the leaves
  • Live under the leaves.
    The best way to see them is placing a white paper under an infested leaf and tapping on it.
    If you have spidermites you’ll see things (eggs and mites) fall on the paper.
  • Spreading occurs by touching leaves or nearest plants.
LOCATION ON THE LEAVESAbove the leaves. Once Thrips are big enough by looking close enough you will be able to see them crawling around.Below the leaves – Spider mites live under, lay eggs and die under the leaves. It’s very hard to see individual mites but by looking under the leaf you can notice the black dots.
WEBBINGNo.Yes – Webbing will appear under the leaf at first. Once the colony is well developed it will spread to the buds.
Here’s a step by step evolution
INFESTATION METHODWhen they can fly they will do so from one part of the room to the next.
If they are not able to fly than they will crawl from leaf to leaf or by going down one plant and up to then next.
From leaf to leaf or by crawling down the plant and up the next.
FLIGHT POSSIBILITYSometimes – Depending on the specie thrips are able to live.
Generally the one’s that invade Marijuana cultures have the ability to fly.
This is the main reason why you’ll notice random spreading making you think “how the hell did they get there”.
No – Spider mites being a part of the Arachnid family they cannot fly.

Thrips lay their eggs within the soft tissue of the plant.

This isn’t damaging to the plant itself but protects the eggs.

Mites lay their eggs within the webbing under the leaves or across the bugs, depending on the size of the colony
HATCHING PERIOD2 to 7 days, depending on the specie3 to 5 days, depending on the specie
LIFESPANDUp to 45 daysMost species live between 14 and 21 days
SIZEBetween 0.5 mm and 1.5 mmUnder 1.0 mm

What are the similarities between Thrips and Spider Mites?

Thrips and Spider mites actually have a couple things in common, whether it’s where they feed or the environment they live in.

Similarities between mites and thrips

 ENVIRONMENTThey both enjoy hot and dry environment. Over 25°C (77°F) and under 30% Humidity.
 FEEDINGSpider mites and Thrips feed on the chlorophyll within the leaves of the plant. That is the reason why you can see the white spots
HIBERNATION PHASESThrips born in late summer will go into diapause until spring time where the specie can thrive again.Spider mites eggs on their end can stay in hibernation mode for months until they are waken up. On top of that eggs can develop resistance to treatment methods, producing some super un-killable spider mites.
 TREATMENT METHODS As long as your spider mite colony hasn’t developed an immunity, all mainstream organic or chemical pesticides are effective on both (ex: neem oil).

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Spider Mites or Thrips – Which is worst?

If you’ve been following up on our grow journal you’re aware that we’ve been battling an infestation; At first we thought it was spider mites but now we’re positive it’s Thrips (How to tell the difference? Here’s our guide).

The signs of both these little suckers are actually extremely similar, showing small white marks on your leaves, some more impacted than others. Luckily the actions to get rid of both are pretty much the same, but we’ve covered all that in our guide linked above.

EASY TO KILLNo – Depending on the type they can develop resistances, making them so hard to killYes – A repeated treatment will do the trick
IMMUNITYYes – Very strong capability to develop resistance to any treatment.
To know more about spider mites check out our in depth guide
No – Thrips are not known to immunize themselves.
Barely – Since they live under the leaves and measure
between 0.5 mm and 1 mm they are very hard to see
A little easier – You can spot them moving around above
the leaf or flying around. They get up to 1.5 mm and white or
black depending on the stage of life making them easier to see.
Strong – Spider mites are know to be very resistant
to most organic or chemical treatments.
On top of that as we said further up they will develop an
immunity very quickly.
Low – Thrips will die on the first time you spray them. This issue
lies with the eggs, that’s why it is important to respray every 3 day
at least 3 times.
Very High – Spider mites are one (if not the) of the most
feared Marijuana Pests and for good reason.
They eat away the chlorophyll of the leaves
Medium/High – The direct danger to the plant is actually about the same
since Thrips attack and finish by killing you leaves. Furthermore once
they’ve developed enough they actually fly around from plant to plant.What really reduces their danger is the fact that you can treat the
infestation fairly easily. Remember to spray every 3 day at least 3 time
after the first application.
High – In optimal conditions and without and treatment
in a month there can be over 800 000 individuals!
Prevention and Early Action is key.

Medium/High – Once thrips have matured and are able to fly they will invade you grow space quickly.

Once they’ve hatched in the soil they will develop themselves on that plant. Once they’re
able to they will fly to the next plant, feed on it and then lay eggs in that soil.

With that we’ll let you make you mind, but honestly with experience on both, much rather thrips than spidermites (although thrips can be a head ache also)

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Alright folks that’s it for this one ! Hope it was useful and you now are able to spot the differences between both pests

Until next time, be safe and grow easy

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