Red spider mite is a tiny mite of the Tetranychidae family. It attacks leaf and flower plants, indoors and outside.
Red spider mite facts
Name – Oligonychus ilicis, Panonychus ulmi, Tetranychus cinnabarinus & others
Family – Tetranychidae
Lifespan – 4-7 weeks (if not hibernating)
Size – 1/64th inch (0.5 mm)
Danger to plant – fatal if too many
Side effects – none. Rarely transmits viral diseases
Beneficial – no beneficial species
Appears in – spring & fall (year-round indoors)
Contagious – very (wind-carried on web strands)
Treatment – moisture & biocontrol
The term “spider” is a bit misleading, because in reality this is a mite. However, it does have 8 legs, spins webs, and is related to the same zoological class as spiders, Arachnida.
A few red spider mites will only cause little damage. If they are numerous, though, they might lead the plant to perish.
Here is how to eliminate red spider mites with organic treatments.
Conditions for red spider mite to appear
Red spider mites tend to multiply and attack plants when the weather is hot and dry.
That’s why they are found indoors all year round and in the garden in summer, when it doesn’t rain and that temperatures stay above 70°F (20°C).
Additionally, these spiders aren’t insects, and abusive use of pesticides actually contributes to their spread.
- Since many other insects are their predators, killing insects blindly helps spider mites prosper.
- Red spider mites quickly adapt to chemical threats. They build up immunity to many pesticides.
Red spider mite development cycle
Red spider mites feed on sap of plants, sucking it out of leaves to absorb leaf cells.
- Since they reproduce very quickly, an invasion can be devastating if not caught early.
Moreover, they are perfectly capable of migrating from one plant to the next, which leads them to spread to multiple plants if one is infected.
- If you locate an invasion on one plant, move other plants out of reach, especially if they’re touching.
- For plants in pots, moving them is easy, but you might need to stake a few branches away from each other for shrubs planted in the ground.
Red spider mite symptoms
Their tiny size makes them very difficult to see with the naked eye, but a small magnifying glass helps lift any doubt.
- The first symptom is the appearance of small white or yellow dots and then leaves turn completely yellow.
- Unlike thrips that produce larger white patches, red spider mite feeding is randomly spread around the area.
Also, the fact that they weave small webs around the leaves also helps one notice them more easily.
- For that, spray or mist water on the plant and check whether small webs appear.
- Shown just above, a red spider mite that specifically attacks gorse: Tetranychus lintearius
Treatment against red spider mite
As mentioned earlier, red spider mites love it when the air is very dry, it helps them spread.
Red spider mite on indoor plants
On houseplants, getting rid of them is straightforward:
- Spray mineral-free water on the leaves to create a moist environment that will make them disappear. A simple hand-spray is enough for this. Rainwater is a good example, but demineralized water also works.
- Hosing down & showering also dislodges red spider mite. Move the plant to the shower or bathtub first. Wrap the pot in a plastic bag tied with a knot around the trunk to avoid washing soil out.
- For minor infestations, wipe a soft moist cloth on leaves (topside and underside). Repeat daily until no more red spider mites appear.
- If that isn’t enough, purchase mite-killer that can be found in any garden shop.
Although red spider mites often only cause limited damage, keep an eye on your plants, especially in case of high temperatures and dry weather, because that is when they reproduce the fastest.
- Build up moisture around houseplants to deter mites. A simple trick is to use hydroton clay beads.
Red spider mite in greenhouses or in the open
Again, spraying soft water regularly for a few days is usually enough to dislodge small colonies.
There are other forms of biological control that don’t require daily work:
- Fungus against red spider mite – Beauveria bassiana is a type of fungus that greatly reduces red spider mite fertility and and egg hatching.
- Red spider mite natural predators – Phytoseiulus is also a type of red spider mite, but a beneficial one. It eats plant parasites, especially the damaging red spider mites much like a ladybug eats aphids. Ladybugs also eat red spider mites, too, not only aphids!
- Bordeaux mixture is a valid organic mite killer.
- Predatory thrips will also devour eggs, nymphs and adult red spider mites.
- Spiders (real arachnids this time) will also devour red mites.
Different trials have shown that a range of natural pesticides can help get rid of the pest. Pyrethrum-based insecticides are a good example of this.
Red spider mite repellents
Certain plants will repel red spider mite near where they’re planted. Such protection usually extends about a yard (one meter) all around the healthy, mature plant. Sometimes a decoction, an extract or essential oils work better than simply growing the plant itself.
Spraying essential oils or extracts can both kill red spider mite and sterilize their eggs so they won’t hatch.
Herbs that fend off red spider mite
Many herbs naturally repel spider mites, among which you may find:
Garlic, rosemary, cinnamon, peppermint, lemongrass, chamomile, marjoram, horseheal (Inula helenium), thyme, caraway, certain curcuma varieties
- Marjoram and thyme often stay small enough to be planted together with other plants in an indoor pot.
- For rosemary, peppermint, chamomile and lemongrass, it’s the opposite. Give each a pot of its own and place it near houseplants you want to protect.
Vegetables that repel red spider mite
- chili pepper
- wild tomato
Trees and shrubs that repel red spider mite
- malabar nut
- vitex (not a repellent per se, but a decoy plant)
Ornamental plants & flowers that repel red spider mite
- some varieties of croton
Mites similar to red spider mites
Not all small red bugs are red spider mites. Some are of a different species and family. For example, the two mites pictured here are velvet mites. They’re actually beneficial because they’re insectivores and will eat other pests.
- Thanks Neil for the pointer in the comments!
If you see these soft-looking tiny spiders without any telling long hairs on their body, you don’t need to eliminate them. They’re among the many helpers you can have in the garden to help control pests!
- Also interesting: attract helper insects to the garden
CC BY-NC 2.0: Lori Erickson
CC BY-SA 4.0: Uwe Schneehagen
CC BY-SA 2.0: Franco Bianco
CC BY 4.0: Lek Khauv
CC BY-NC-ND 2.0: Angelo Milioto
CC BY 2.0: Thomas Shahan
Excellent article! I was wondering where the little spider webs came from on the top flowers and seed pods of my hibiscus plant. Some of these leaves have turned yellow and fell off. It is never outside and there have never been any new potted plants introduced into the house in years. Also, after another wonderful bloom on my 2 poinsettias this year (6 and 7 years old plants), most of the leaves on both are now falling off. I’m wondering if they might also have mites. I’ll certainly check that option tomorrow in better light. I’ll spray all of them down with that 70% alcohol which should be available at the local pharmacy. Thanks, Doug.
Your photo of 2 red mites are not spider mites, but velvet mites, completely different creatures. These are often beneficial, as their nymphs eat pest insects.
You’re correct Niel and I thank you for taking the time to correct me. I added a few new pictures and rewrote part of the article to also explain the difference between spider mite and velvet mite (the hairs on their body). As you say, velvet mites are very beneficial – they even help control spider mites! Thanks again for having taken the time to share your insight, I appreciate that!
Hello, I am new to your site, and I like your advise. I know it sounds crazy, but I do look for damaged, and uncared for plant, as as a challenge, I try to save them. I do receive a discount for taking the plants, and most of time, I am lucky/blessed when they live. Today bought a Dipladenia Pink trumpet-shaped flowers, in bad shape from a nursery here in town. Poor thing has several broken stems, yellowing, and a total mess. Any Idea where I start? I live in Zone 6B. I have not had a Dipladenia of any kind before, so I rather uneducated with this flower. Is it a flower or a flowering evergreen?
Also, if you know about Roses, and the Rose Rosseta Disease/Virus (RRD/RRV) I could use help there also.
Hi Debi, it’s a great idea to salvage plants that are often deemed unsellable. Congratulations! There is a wealth of information on dipladenia specifically here. It’ll help you get started on light, exposure, watering, soil, etc. As for the broken stems, either start off a few cuttings or discard them to the compost. Since you’re in zone 6b, it freezes so you’ll have to bring it indoors for winter. It’s not frost hardy at all.
Regarding roses, we’ve got quite a few pages for rose lovers here.
I have a long beech hedge (about 80 yards) that has been severely impacted this summer by red spider mite infestation. I badly need advice on how to get rid of them and keep them away!
Hello Philip, a long hedge with a severe infestation is going to be a lot of work… but it isn’t hopeless!
First of all, get a few batches of fermented fertilizer started from weeds. Comfrey weed tea excels at fertilizing, and nettle weed tea will act on the bugs themselves.
In the meantime, get that hedge wet! Spray it down to raise moisture – the red spider mites hate that. Each hosing down will also get rid of a portion of the buggers. Of course, ideal is to do it daily, but every run will do the hedge good even if it’s only once or twice a week. Hopefully you don’t have water restrictions in your area, 80 yards is a long way to go.
In parallel, you might want to take a look at products for sale that contain Phytoseiulus persimilis. This is a spider-mite predator which is itself a type of mite. Release or spray the product onto the hedge wherever you notice the highest concentration. It’s a natural solution, too.
Lastly, plant some of the spider-mite repellent plants listed above, just at the foot of your hedge. The more, the merrier.
The goal is to apply all the techniques within the same season, hopefully driving the invasion out! And if the damage is already too significant, consider pulling a few shrubs out and replacing them with another species. This is called mixed hedging, and it’s a great way to avoid spread of diseases from one shrub to the next!
Thanks for every help. Is it really true that I can use eucalyptus fresh fresh branches to control high red spider mites infestation instead of using chemicals in my passion fruits farm?
Hi Ngabo, yes it would certainly work, but you would have to see which method works best.
Since it’s your livelihood, it’s important not to change everything at once. I would recommend only trying eucalyptus on 5 or 10% of the farm. Take note of what happens and adjust the next year.
Fresh branches will repel red spider mite, meaning they will prefer to go elsewhere. You could try to attach one leafy branch to each passion fruit plant, for example.
Another way to use eucalyptus is to spray eucalyptus leaf extract or essential oil on the leaves and stems of your passion fruit plants. This essential oil has two effects: it kills adult and larvae, and it also destroys eggs. It isn’t perfect, though, as about 1 in 5 mites still survive and nearly half the eggs still hatch. In one study, Chamomile essential oil was more effective, killing nearly all adults and destroying 90% of eggs within 24 hours.
Just plant garlic cloves next to, or very near, the plants being attacked. The grown garlic plants repel the red spider mites.
That’s very true! And I also discovered that other plants do the same too. Added those I found research for in the article – thanks for having sparked my interest in that!