Spider mites are a common garden and houseplant pest. These tiny arachnids spin silk webs on infested plants and feed on sap, causing leaves to yellow and plant growth to stunt While insecticides may seem an easy solution, spider mites quickly build resistance, requiring repeated applications. The good news? Many beneficial predatory insects will happily feast on spider mites, providing natural biological control. This article will comprehensively cover the best spider mite predators available to help you win the battle against this parasitic pest
Why Spider Mites Are a Problem
Spider mites particularly the two-spotted spider mite (Tetranychus urticae), reproduce rapidly in warm conditions. A single female can lay up to 20 eggs per day and mature in as little as 5 days. This allows populations to explode exponentially in a short period.
Spider mites damage plants by feeding on sap and chlorophyll via piercing mouthparts. This causes yellow stippling, discolored leaves and stunted growth. Webbing becomes apparent on heavily infested plants. Spider mites also spread quickly to nearby plants through silken threads and by hitching rides on people.
Left uncontrolled, large spider mite populations can seriously damage or kill plants. Natural predators provide an eco-friendly solution without the need for harmful broad-spectrum pesticides.
3 Top Natural Spider Mite Predators
Many beneficial insects will prey on all stages of the spider mite life cycle. Here are the top 3 natural predators for biological spider mite control:
1. Phytoseiulus persimilis
Phytoseiulus persimilis is the most voracious spider mite predator. These fast-breeding mites can each consume up to 5 adult spider mites or 20 eggs per day.
P. persimilis is best suited to high pest populations and hot spots. They can survive dense webbing and will immediately target spider mite colonies. Weekly applications are needed until predators overwhelm the infestation. Ideal for greenhouses as they require temperatures above 15°C.
2. Amblyseius californicus
Amblyseius californicus is another predatory mite that can survive without spider mite prey. It feeds on pollen and mold and tolerates temperatures as low as 10°C, allowing preventative release.
A. californicus excels at low pest numbers. It is unable to penetrate dense webbing. Use breeder sachets for prolonged control over 4-6 weeks. Combine with P. persimilis for heavy infestations.
3. Amblyseius andersoni
Amblyseius andersoni is the predator of choice for cool conditions down to 6°C. It consumes eggs and young spider mites but avoids adults and dense webbing.
Best used preventatively and during early stage infestations. For heavy pest pressure, combine with P. persimilis in warmer weather.
Other Notable Spider Mite Predators
While the above are the primary predatory mites in commercial use, many other beneficial insects will feed on spider mites:
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Ladybugs (Stethorus spp.) – Voracious predators, both larvae and adults. Each ladybug can consume up to 75 mites per day.
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Lacewings – Larvae only feed on spider mites. Eggs are laid amongst prey.
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Predatory thrips (Scolothrips sexmaculatus) – Tiny insects, up to 200 mites consumed per day.
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Predatory midge (Feltiella acarisuga) – Larvae inject toxins into spider mite eggs.
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Minute pirate bug (Orius spp.) – Adults and nymphs feed on eggs and young spider mites.
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Six-spotted thrips – Feeds on eggs and all mobile stages.
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Western predatory mite – Generalist feeder, tolerates variable conditions.
In addition, many common garden birds will feed on adult spider mites. Creating a diversity of habitats to attract beneficial predators is key to natural pest control.
How to Use Natural Spider Mite Predators Effectively
Here are some tips for getting optimal results from natural enemies:
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Release preventative predators like A. californicus before infestations start. Sachets provide sustained control.
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Introduce P. persimilis at first signs of spider mites. Apply directly to infested areas for immediate impact.
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Make repeat applications 7-10 days until predators overwhelm pests. Predator numbers should build with each release.
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Combine predatory mites with ladybugs, lacewings, and minute pirate bugs for maximal impact across pest stages.
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Spray plants with water to dislodge webbing and allow predators access to protected spider mites. Avoid pesticide use.
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Monitor plants closely and act fast – early intervention prevents population explosions.
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Be patient for predators to establish and do their work. It takes time to sway the balance.
Employing a diversity of predators is the best biological control strategy for long-term spider mite management. With some planning and prompt action, these natural enemies can keep spider mite populations in check safely and sustainably.
Spider mites can be a persistent headache for gardeners and houseplant owners. Their rapid reproduction allows populations to quickly get out of control, resulting in damaged, unsightly plants.
The good news is there are many predatory insects and mites eager to feast on these pests. Introducing predators like Phytoseiulus persimilis, Amblyseius californicus, and Amblyseius andersoni provides an effective, eco-friendly solution without the need for harmful pesticides.
Combined preventatively with ladybugs, lacewings and other beneficials, natural predators can stop spider mites in their tracks. A little vigilance to monitor for early signs, paired with prompt predator release, is the recipe for successfully protecting your plants from spider mite damage. Employ nature’s cleanup crew and reclaim your garden from these parasitic pests.
The Best Predator For Preventative Applications: Amblyseius californicus
Amblyseius californicus is also an effective predator of Spider Mites and can be introduced at lower temperatures than the Phytoseiulus. The californicus can also survive without Spider Mites for a prolonged period of time and can feed on pollen. This enables them to be introduced earlier and before Spider Mite appear. Their activity starts from temperatures over 10°C up to about 33°C.
They are available in bottles, or breeder sachets, that can be hung on plants, releasing predators over a period of weeks. They can be combined with Phytoseiulus for an effective bio control programme.
The Number One Predator: Phytoseiulus persimilis
Phytoseiulus persimilis is the most effective Spider Mite predator if applied in the optimum conditions. The predators are supplied in shaker bottles, and should be sprinkled over your infested plants, ideally on areas rife with Spider Mite activity.
Phytoseiulus breed quickly on plants, with faster egg laying than the Spider Mites, and they will begin feeding immediately on application. The predators consume the Spider Mite faster than all other available predators and will happily move into dense webbing to feed, which some of the other predators will not.
The Phytoseiulus mites do not, however, survive long without food and cannot be introduced before Spider Mites are present. They also require temperatures to be above 15°C to be active and are most active from 20-30°C, temperatures above this will reduce and stop their activity.
Introduce the predators after Spider Mite have been observed, and apply them close, or onto, the infected areas of the plant. In high infestations, repeated applications may be required to build up their numbers to a level where they will outcompete and completely control the Spider Mite.
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FAQ
What bug eats spider mites?
Common insect predators of pest mites include bigeyed bugs, brown lacewings, dustywings, green lacewings, minute pirate bugs, mite midges, the spider mite destroyer lady beetle (ladybug), spider mite rove beetle, and sixspotted thrips.
What is the best predator for red spider mites?
Phytoseiulus is the number one method for controlling glasshouse red spider mite, and is widely used by both amateur gardeners and commercial growers.
What do spider mites hate the most?
Rain, wind, humidity and cold temperatures are enemies of the spider mite, which is why houseplants tend to be more susceptible to large spider mite infestations than outdoor plants.