1
Tiny pale dots on the leaves.
Like the leaf was sanded, often worst along the veins.
Spider mites
Tiny pale dots on your leaves?
Know for sure. Then send in the mite that eats mites.
Check that it's spider mitesIs it spider mites?
Dots and webbing give them away.
2
Fine webbing.
The later sign. Mostly under the leaves and between stems.
The easiest check? Turn a speckled leaf over and look underneath.
Karen's noteKaren Horn, owner
Webbing isn't the first sign. It's the last. By then, they've unpacked.
Not quite matching?
Specks that aren't spider mites.
Powdery mildew
White powdery patches that wipe off. Nothing moves, and there's no speckling.
Meet the spider mites
A spider's tiny cousin.
A colony that builds its own fort.
Eight legs, an oval body, two dark spots, and under 1/20 inch long. Yours is most likely the two-spotted spider mite, Tetranychus urticae.
What it eats
Each pale dot is one emptied cell.
A spider mite pierces a leaf cell and sucks it out. Enough dots, and the leaf turns dull, bronze or yellow.
Where it lives
Under the leaf, every stage at once.
Scroll down the plant to see where.
Under the leavesEggs, young and adults.
They feed and lay there, side by side. Up top you see the dots.
Joints and tipsWebbing.
The silk is a shelter. It keeps many predators out, and newcomers move right in.
Karen's noteKaren Horn, owner
Hot, dry and thirsty: their happy place. Keep yours watered.
The life cycle
Egg to adult in about ten days.
At 77°F. Every stage lives on the underside of the leaf.
Days 0–3Egg
Round and clear.
Days 3–5Larva
Pale, six legs, and feeding at once.
Days 5–9Nymph
Two stages, now with eight legs. The dark spots appear.
Day 9 onAdult
Lays within a day or two, and spins as the colony grows.
Swipe for the next stage →
How fast they multiply
200
eggs from one female.
One female, up to about 200 eggs.
Over a life of two to four weeks. In the heat, a whole generation can take less than a week.
Why sprays miss
Some sprays make it worse.
Many insecticides barely touch spider mites but kill the predators that eat them, and a jump in mites often follows. The eggs often ride out a spray too.
A winter coat
In fall, some of them turn orange.
Where winters get cold, mated females turn red or orange and wait out the winter under bark and leaf litter. Same mite, winter coat.
Now, who eats them.
What to get
Webbing and humidity decide it.
Question 1 of 2
What's on the leaves?
Question 2 of 2
How many plants?
Count them all, not just the ones with damage.Our pick for you
Neoseiulus californicus
Neoseiulus californicus eats spider mites and handles warm, dry rooms. It lives on pollen when spider mites are scarce, so it stays on the plant after the first wave.
See Neoseiulus californicusOur pick for you
Spider Mite Rapid Response
Persimilis and californicus together. Persimilis walks into the webbing and eats every stage; californicus copes with drier air and cleans up the stragglers.
See Spider Mite Rapid ResponseOur pick for you
Phytoseiulus persimilis
Phytoseiulus persimilis is the spider mite specialist. It goes straight into webbing that stops other predators and eats eggs, nymphs and adults. Take heavy webbing off with a jet of water first.
See Phytoseiulus persimilisOur pick for you
Special Blend
Four predatory mites in one bottle (andersoni, californicus, swirskii and cucumeris) for mixed or unclear pests. If you know it's only spider mites, persimilis or Rapid Response is the better match.
See Special BlendSee all picks
| If you see | Our pick | Why |
|---|---|---|
| Speckling, no webbing yetPale dots on the leaves and tiny moving specks underneath |  Neoseiulus californicus |
Neoseiulus californicus eats spider mites and handles warm, dry rooms. |
| Webbing on the plantsAn established colony, in an ordinary or dry room |  Spider Mite Rapid Response |
Persimilis and californicus together. |
| Webbing in a humid roomAbout 60% humidity or more, or you can keep it there |  Phytoseiulus persimilis |
Phytoseiulus persimilis is the spider mite specialist. |
| Something else is there tooThrips, broad mites, or you can't tell which mite |  Special Blend |
Four predatory mites in one bottle (andersoni, californicus, swirskii and cucumeris) for mixed or unclear pests. |
Our suggested plan
Repeat until new leaves come in clean.
- 1
Release day
Spider Mite Rapid Response.
Persimilis onto the worst spots, californicus wider.
- 2
Every 2–4 weeks
Another round.
While new leaves still pick up speckling. Two or three rounds is the normal course.
- ✓
Stop
Two clean weeks in a row.
New growth stays clean. Then switch to a sachet.
Why doesn't persimilis just stay?
Spider mites are its only food. When they're gone, it starves or leaves. That's the job finishing, not failing.
For a typical infestation. Every other week or monthly is usually fine. A light one may need less. A heavy one may need a closer repeat, every 2 weeks at the closest: a second persimilis release 2 weeks after the first. Adjust to what you see, or ask us.
How to release
Rinse the webbing. Then the mites.
Before you order
Confirm it's spider mites. Dots, specks that walk, or webbing. One is enough.
While it ships
Mark the hot spots. The plants with webbing or the most dots get the first predators.
Wait out any spray.
Once dryNeem or oil
1 dayInsecticidal soap
7 daysBifenazate
14 daysSpinosad
21 daysSulfur or abamectin
Different spray? Send us the active ingredient. A longer label wait always wins. Never release with a sulfur burner running.
Release day
Release them the day they arrive.
A strong stream takes thick webbing off. A light mist helps the mites stick.
Small piles near the webbing, worst plants first.
Onto the infested plants and the plants touching them.
Group plants or run a humidifier if you can.
Karen's noteKaren Horn, owner
Waiting on your order? Hose the leaf undersides. Not a cure. Just rude.
What to expect
The dots you have stay. Watch the new leaves.
- Right after release
The speckling you have stays. Those leaves were fed on before the predators arrived.
- As it takes hold
Webbing stops spreading, and new speckling slows.
- When it's working
New leaves come in without speckling. A few stragglers aren't a new infestation.
New speckling on new leaves? Go again.
Karen's noteKaren Horn, owner
Two or three releases is normal for a settled colony. Nobody missed.
Why treatment fails
Three usual reasons, and how to avoid them.
1
Sprayed just before release.
Residue harms predatory mites as easily as pests. Check the waits above.
2
Persimilis in a dry room.
The room picks the mite. Dry air? Californicus or Rapid Response.
3
A bottle spread too thin.
Split across too many plants, the predators can't outnumber the pest. Size it to the plants you're treating.
Prevention
Two clean weeks? Hang a sachet.
A sachet lets predatory mites out over four to six weeks, so they're already there when the first spider mites land. One every 3 to 5 feet of shelf, or one on a large plant.
Humid roomPersimilis
Hot or dryCalifornicus
Temperatures that swingAndersoni
It won't catch up with webbing you can see. That needs a bottle.
Karen's noteKaren Horn, owner
They usually come home on a new plant. Or the air turns hot and dry and they invite themselves.
Often shows up with
Dry rooms bring more than mites.
Broad and cyclamen mites
Twisted new growth beside the dots. Andersoni takes both.
Field Notes
Mites, magnified.
Spider Mites Are on the Menu
Californicus or Persimilis?
You Did Not Lose to a Spider Mite. You Lost to Ninety-Six of Them.
Spider Mites Brought Their Own Security
Spider Mites Have Winter Plans
Spider Mites Have a Type
My Plant Has Webbing. Help.
How Predatory Mites Use Chemical Signals
Follow the Pests After Release
Seven Ways To Waste Your First Mite Release
Questions
Yes, every plant that touches them.
Do I need to treat every plant?
Every plant with dots or webbing, plus the plants touching them. Spider mites travel on hands, sleeves, tools and air currents, so neighbors often have them before they show it.
Does raising the humidity help?
It helps persimilis more than it hurts the mites, so a humidifier or grouped plants make it work better. On its own, humidity won't clear a colony that's settled in.
Are predatory mites safe around kids and pets?
Yes. Persimilis, californicus and andersoni are safe around people, pets, plants and food crops. They don't bite, can't feed on plants and leave no residue, so there's no wait before anyone can be near the plants.
Further reading
- Spider Mites (Pest Notes 7405), UC IPM, University of California
- Yano 2012, Cooperative web sharing against predators promotes group living in spider mites
- Shimoda, Kishimoto and Takabayashi 2008, Thread-cutting behavior in three specialist predatory mites
- Shimoda, Kishimoto and Takabayashi 2010, Penetrating the complex webs of Tetranychus spider mites