Thrips or Spider Mites? How to tell the difference

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Are you dealing with spidermites or thrips?

Signs of thrips and spider mites are similar and it can be difficult to see the difference.
They both feed on the chlorophyll in the leaf leaving white spots on them. This can can create a confusion when identifying what’s going on.

Apart from that 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.

Thankfully, there are also clear differences to tell the difference.

How to quickly tell the difference

Before getting into the all the differences between thrips and spider mites, here’s a quick list that can help you get your answer quickly.
All these aspects are in regards to the leaves showing signs of an infestation.

When you look under an affected leaf, do you see small dots, and maybe some webbing?
Yes? You have Spidermite
Do you see small, long, brown-ish inspects crawling around the veins, or stems, of the leaves?
Or small white larvae in the same locations?
If so, it’s most likely Thrips
Are the signs appearing on leaves near each other, or does the spreading seem to be “a bit everywhere”
In the first case, it’s probably spidermites and the second, thrips

You’re not sure? Keep reading, we go in depth on the differences and how to tell who you’re dealing with

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 marks will mainly appear along the main-rib and veins of the leaves. They also feed “from leaf to leaf”, generally your they will move “bottom up”,. Your top & middle leaves may be totally fine, bottom ones covered in white spots.

In the case of thrips the marks will be randomly distributed along your foliage.

This is due to the fact mites living under the leaf, colonizing it before moving on to the next.
Thrips move around much more. They crawl, or fly, around the foliage, above or under the leaves, feeding when they feel like it.

Let’s get into the differences in detail:

Impact of Mites and Thrips on your plants

	THRIPS	SPIDER MITES
VISIBLE DIFFERENCES	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 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 LEAVES	Above the leaves. You can see adult Thrips by looking closely on the leaves. You will see a small, long, brown thing 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.
WEBBING	No.	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 METHOD	When 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 POSSIBILITY	Sometimes – 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.
EGG LOCATION	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 PERIOD	2 to 7 days, depending on the specie	3 to 5 days, depending on the specie
LIFESPAND	Up to 45 days	Most species live between 14 and 21 days
SIZE	Between 0.5 mm and 1.5 mm	Under 1.0 mm

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What are the similarities between Thrips and Spider Mites?

Thrips and Spider mites actually have some things in common. Mainly their feed and environment they live in.

Similarities between mites and thrips

SIMILARITIES	SPIDER MITES AND THRIPS
ENVIRONMENT	They both enjoy hot and dry environment. Over 25°C (77°F) and under 30% Humidity.
FEEDING	Spider 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 PHASES	Thrips 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 treatments. This can produce some super un-killable spider mites.
TREATMENT METHODS	Most organic or chemical pesticides will be effective, as long as they haven’t developed an immunity. That said, we recommend using many different methods to get rid of them, they’re sooo resistant!

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Spider Mites or Thrips – Which is worst?

The short, and very biased, answer is for us.. spider mites by far !

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 extremely similar, small white marks appearing on your leaves. Luckily the actions to get rid of both are pretty much the same, but we’ve covered all that in our guide linked above.

	SPIDER MITES	THRIPS
EASY TO KILL	No – Depending on the type they can develop resistances, making them so hard to kill	Yes – A repeated treatment will do the trick
IMMUNITY	Yes – 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.
VISIBLE BY THE NAKED EYE	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.
RESISTANCE TO TREATMENT	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.
THREAT LEVEL TO MARIJUANA	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 are eating up the sap in the leaves. Furthermore once they’ve grown, they fly around from plant to plant. What really reduces their danger is the fact that you can treat the infestation fairly easily. The other aspect that reduces their danger is the fact that they reproduce much slower. Your plant has less individuals to deal with with over the same period of time Remember to spray every 3 day at least 3 time after the first application.
SPEED OF SPREADING	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)

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

About the author

plant-lover

Plant Lover is Free the Tree's founder and a passionate grower of plants. Mostly from the city, I work on my computer all day so about 4 years ago, on my off time, I started growing to have some more green in my life.I never imagined I would fall in love with botany and discover so much about this plant. Since then I keep learning everyday, meeting new awesome people of our community and which keeps me growing constantlyYou can always get in touch with me on our Instagram!