Red spider mite, best organic treatments to get rid of it

Barely half a millimetre across, red spider mites stipple leaves with tiny white and yellow dots and drape fine webs over the undersides. These sap-suckers of the Tetranychidae family thrive indoors all year and outdoors in hot, dry spells; bring the moisture back early and a plant that would be overrun within six weeks pulls through.

Red spider mite at a glance

Name	spider mite, red spider
Family	Tetranychidae
Danger to plant	fatal if too many
Side effects	may cause viral diseases
Appears in	spring & fall (year-round indoors)
Spread	fast (crawls, wind-carried)
Treatment	moisture & biocontrol

The term “spider” is misleading: this is a mite. However, it does have 8 legs, spins webs, and is related to the same animal family as spiders, Arachnida.

A few red spider mites will only cause little damage. Too many, though, can kill a plant in a couple months.

Here’s how to eliminate red spider mites with organic treatments.

→ These treatments also work against scale insects

Red spider mite symptoms

Their tiny size (half a millimeter or 1/64″) makes spider mites very difficult to see with the naked eye, but a small magnifying glass lifts any doubt. Red spider mites feed on sap, sucking it out of leaf cells.

• First symptoms are appearance of small white or yellow dots and then leaves turn completely yellow (example on this spotted bean plant leaf).
• Unlike thrips that cause large white patches, red spider mite feeding is randomly spread around the area.

Also, they weave small webs around the leaves, another telltale sign.

• For that, spray or mist water to check if small webs appear.
• Shown just above, a red spider mite that specifically attacks gorse: Tetranychus lintearius

Webs protect spider mites from predators and keeps humidity out.

→ Other webby pests: processionary & boxwood moth

Treat against spider mite

As mentioned earlier, red spider mites love it when the air is very dry. And the antidote to dryness is 💦 moisture 💦 !

→ Water treatments should be repeated daily, and other forms are best repeated every 2-3 weeks to get rid of new hatchlings.

→ Although red spider mites rarely cause severe damage, check on your plants often, especially in hot, dry weather. That is when they reproduce fastest.

Get rid of spider mite on houseplants

On houseplants, getting rid of them is straightforward:

• Spray rainwater every day on leaves to create a moist environment (another trick is to use leca beads under the pot). They’ll disappear within a week. A simple hand-spray does the job.
• Rainwater is best, demineralized water also works fine.

Hosing down & showering flushes red spider mite away.

• Move the plant to a sink or tub first. Wrap the pot in a plastic bag with a knot tied around the trunk to keep soil from washing out.
• For smaller colonies, wipe a soft moist cloth on leaves (top- and underside). Clean them daily until you don’t see any more red spiders.
• If that isn’t enough, organic mite-killer products below are an option, too.

Control spider mite in greenhouses or outside

Again, spraying soft water regularly for a few days is usually enough to dislodge small colonies.

Biological control is effective and doesn’t require daily work. You can find these online or in stores, but in the long run it’s best to make your garden attractive for all sorts of animals and insects.

• Red spider mite natural predators – Phytoseiulus and Galendromus are beneficial spider mites that eats pest mites, just like mite-eating ladybug, lacewing larvae and predatory thrips.
• Fungus against red spider mite – Beauveria bassiana is a type of fungus that greatly reduces red spider mite fertility and egg hatching.
• Bordeaux mixture is an organic pest killer.
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  Spiders (real ones this time) also devour red mites.

• Herb decoctions, extracts and essential oils work well, too.

Essential oils/extracts kill both red spider mites and their eggs.

Trials show that many natural pesticides help get rid of the pest. Pyrethrum-based insecticides are a good example of this. Also, below, you’ll discover a list of spider-mite repelling plants and herbs.

Organic treatments compared

All of the methods below are organic, but they do not suit the same situation or the same size of colony. Use this table to pick the one that matches where your plants are and how far the infestation has gone.

Water treatments are repeated daily, while the other forms are best repeated every 2-3 weeks to catch new hatchlings.

What makes red spider mites appear?

Red spider mites 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 temperatures stay above 70°F (20°C).

⚠️ These spiders aren’t insects! ⚠️

Using pesticides contributes to their spread:

• Insects are their predators. Killing mite eaters results in more mites.
• Red spider mites quickly adapt to chemical attacks. They build up immunity within a few generations.

• Quarantine new plants in a separate room for at least three to four weeks, inspecting them closely and regularly, which greatly reduces—though it cannot entirely eliminate—the risk of introducing spider mites.
• Drought-stressed plants are more susceptible to opportunistic attackers such as spider mites, wood-boring beetles and canker fungi, so mulch and water steadily through dry spells outdoors to keep roots from drying out.

How fast do red mites spread?

A spider mite’s lifespan is 4-7 weeks. They reproduce very quickly, like scale and aphids, so an invasion is devastating if not caught early. A healthy plant can be overrun in about 6 week’s time, if not treated.

• Moreover, they crawl and fly from one plant to the next, spreading fast.

Handle infested plants last, since mites travel on hands, sleeves and secateurs to the next pot.

Red spider mite repellents

Certain plants repel red spider mite near where they’re planted. Such protection usually extends about 3 feet (one meter) around the healthy, mature plant.

Herbs that fend off red spider mite:

Many herbs repel spider mites: Garlic, rosemary, cinnamon, peppermint, lemongrass, chamomile, marjoram, horseheal (Inula helenium), thyme, caraway, certain Curcuma varieties

• Marjoram and thyme stay small: great for planting together with taller houseplants.
• For rosemary, peppermint, chamomile and lemongrass, it’s the opposite. Give each a pot of its own and place it near vulnerable plants.

Vegetables that repel red spider mite:

• lettuce, chili pepper, wild tomato

Trees and shrubs that repel red spider mite:

• eucalyptus, neem, pongam, malabar nut
• vitex (not a repellent per se, but a decoy plant)

Flowers that repel red spider mite:

• santolina
• some varieties of croton

Mites similar to red spider mites

Not all tiny red bugs are bad. For example, the two pictured here are velvet mites. They’re beneficial insectivores that eat other pests.

• Thanks Neil for the pointer in the comments!

These soft-looking velvet spiders don’t have any typical Tetranychus long hairs on their body, so don’t eliminate them. They’re great  helpers to have in the garden to control pests!

• Size settles most doubts: a velvet mite is easily seen without a lens, while a spider mite is a barely visible speck.
• Look at where the creature is: velvet mites roam soil, mulch and paving, whereas spider mites cling to leaf undersides.
• Clover mites (Bryobia praetiosa) are reddish too, spin no webs, and carry a very long first pair of legs often mistaken for antennae.

Frequently Asked Questions

How quickly do red spider mites spread and damage plants?

Red spider mites reproduce very quickly with a lifespan of 4-7 weeks, and a healthy plant can be completely overrun in about 6 weeks if not treated. They spread by crawling and being wind-carried from one plant to the next, and too many mites can kill a plant in a couple of months.

What are the most common signs of red spider mite infestation?

The first symptoms are small white or yellow dots on leaves that eventually turn completely yellow, and red spider mites weave small webs around the leaves. Their tiny size (half a millimeter) makes them difficult to see with the naked eye, but a magnifying glass confirms their presence.

How often should I water or spray plants to treat red spider mites?

For houseplants, spray rainwater on leaves every day to create a moist environment—mites will disappear within a week. For other organic treatments like biocontrols or fungus, repeat applications every 2-3 weeks to eliminate new hatchlings.

What are natural predators and biological controls for red spider mites?

Beneficial spider mites like Phytoseiulus and Galendromus eat pest mites, and natural predators include mite-eating ladybugs, lacewing larvae, predatory thrips, and real spiders. The fungus Beauveria bassiana greatly reduces red spider mite fertility and egg hatching.

Can plants be used to repel red spider mites?

Certain herbs like garlic, rosemary, thyme, peppermint, chamomile, and lemongrass repel red spider mites when planted nearby, providing protection within about 3 feet around a healthy mature plant. Vegetables like lettuce and chili pepper, and trees like eucalyptus and neem, also offer this repellent effect.

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