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

Red spider mite

Red spider mite is a tiny mite of the Tetranychidae family. This sap-sucker infects indoor and outdoor plants.

Red spider mite facts

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

Tiny red spider mite on green leaf.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

Symptoms of spider miteTheir 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.

Red spider mite symptomsAlso, 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

A single red spider mite on a leafAgain, 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 predatorsPhytoseiulus and Galendromus are beneficial spider mites that eats pest mites, just like mite-eating ladybug, lacewing larvae and predatory thrips.
  • Fungus against red spider miteBeauveria bassiana is a type of fungus that greatly reduces red spider mite fertility and egg hatching.
  • Bordeaux mixture is an organic pest killer.
  • Spider eating red spider miteSpiders (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.

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.

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.

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:

Mites similar to red spider mites

Two red spider mites nibbling the same morcel.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!

Images: adobestock: imatk, Weronika, CC BY 2.0: Thomas Shahan, CC BY 4.0: Lek Khauv, CC BY-NC 2.0: Lori Erickson, CC BY-NC-ND 2.0: Angelo Milioto, CC BY-SA 2.0: Franco Bianco, CC BY-SA 4.0: Uwe Schneehagen

Written by Gaspard Lorthiois | Loves helping out, especially when it comes to growing things. Worked in herbal medicine, runs a farm, and dabbles in tech. Master's degree and engineer.