Spider mites are a common garden pest that can quickly get out of control if left untreated. These tiny arachnids feed on plant sap and can stunt growth, spread disease, and even kill plants.
While chemical pesticides may seem like an easy solution, they can harm beneficial insects, contaminate crops, and Spider mites often develop resistance to traditional pesticides. A safer, more sustainable approach is to use beneficial predatory insects that naturally prey on spider mites.
In this comprehensive guide, we’ll cover everything you need to know about using biological control for spider mite management, including:
What Are Spider Mites?
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Spider mites are not insects but members of the arachnid family along with spiders.
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There are many species, but the most common garden pest is the two-spotted spider mite (Tetranychus urticae).
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They have eight legs and measure only 1/50 of an inch long when fully grown
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Spider mites can reproduce rapidly in warm conditions, completing their life cycle in as little as a week
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They feed by piercing plant cells with their mouthparts and sucking out the contents, causing yellow speckling, discolored leaves, and wilting
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Heavy infestations can cover plants with webs and cause defoliation.
Why Use Biological Control for Spider Mites?
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Natural predatory mites and insects provide an effective, non-toxic way to suppress spider mite populations.
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Unlike pesticides, pests cannot develop resistance to predation.
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Beneficial predators are safe for humans, plants, and the environment.
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Biological control helps maintain ecological balance in the garden.
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Releasing predators is simple and sustainable. Natural enemies will reproduce and provide ongoing control if habitat and food sources are available.
Top Predatory Insects That Feast on Spider Mites
Several beneficial insects prey on spider mites at different stages of development. Using a combination of predators provides the best control. Common natural enemies include:
Lacewings
Both the larvae and adults of lacewings are voracious predators. Each lacewing larvae can consume up to 200 spider mites per week. They also feed on moth eggs, mealybugs, leafhoppers, and other soft-bodied insects. Attract them to your garden by growing nectar-rich plants like dill, fennel, and angelica.
Ladybugs
The familiar ladybug beetle is a well-known beneficial insect. Both the larvae and adults feed on spider mites, as well as aphids and other small pests. A single ladybug can eat over 50 spider mites per day. Plant pollen and nectar-producing flowers to draw in hungry ladybugs.
Minute Pirate Bugs
These tiny black and white insects have a voracious appetite for mites. Both adults and nymphs inject paralyzing venom and enzymes into their prey, liquefying the internal contents which they then suck out. Minute pirate bugs will also feed on thrips, whiteflies, and other small insects.
Predatory Mites
Several species of predatory mites feed exclusively on spider mites. Phytoseiulus persimilis mites are specialized to hunt spider mites and can consume up to 20 per day. Amblyseius californicus and Amblyseius andersoni also prey on spider mites and can survive when pest populations are low. Releasing predatory mites or mite sachets is an easy and effective biological control solution.
Green Lacewings
Green lacewings are common beneficial insects found in gardens worldwide. The ferocious larvae, sometimes called aphid lions, prey on spider mites as well as aphids, thrips, mealybugs, leafhoppers, and other soft-bodied insects. Support green lacewings by avoiding broad-spectrum insecticides and providing nectar plants.
Tips for Using Predatory Insects to Control Spider Mites
Follow these tips to get the most out of using beneficial predators for spider mite control:
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Time releases carefully – predators require pest prey to survive. Introduce them after spider mites are observed.
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Mix predators – Choose 2-3 species for the most effective control at all spider mite life stages.
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Follow release rates – Introduce recommended numbers of predators per square footage. Higher pest populations require more predators.
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Consider environmental factors – Heat and drought stress spider mites and predators. Provide shade and water if needed.
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Avoid broad-spectrum insecticides – These will kill beneficials along with pests. Stick to selective products like horticultural oils and soaps.
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Provide habitat – Predators need shelter, water, and alternate food sources like pollen. Plant diverse vegetation to support them.
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Be patient – It takes time for predator populations to establish and bring the pest under control. Avoid disrupting them once released.
Using beneficial insects to biologically control spider mites is an environmentally-friendly, non-toxic solution. By releasing predaceous mites and insects, gardeners can safely knock back spider mite infestations and restore ecological balance.
A strategy for managing spider mites in susceptible crops
Californicus and Persimilis predatory mites can both do a good job to help manage spider mite problems in a wide range of crop environments. They are quite different species and do offer pros and cons depending on the crop, the nature of the infestation and environmental conditions. As a general rule we suggest regular releases of Californicus predatory mites in susceptible crops for use in a preventative way. If monitoring indicates that the problem persists (or is getting worse) then release of Persimilis mites may be warranted. Do not wait until your spider mite problem is severe before initiating releases of beneficial mites.
Biological control of spider mites
Spider mites have several biological control agents including lacewings, tiny mite feeding ladybirds (Stethorus spp.), predatory gall-midges (Feltiella spp.) and a variety of predatory mites (including Phytoseiulus persimilis and Neoseiulus californicus).
It is possible to achieve excellent results using predators to control spider mites. Sustainable control is best achieved using a combination of biological and cultural controls. Cultural practices such as increasing humidity in the crop microclimate during extremely hot or dry periods can favour predators and disadvantage the pest.
Natural solution against Spider Mites for healthy plants #gardening #garden #pestcontrol
FAQ
What bugs get rid of spider mites?
Natural enemies include small lady beetles, predatory mites, minute pirate bugs, big-eyed bugs and predatory thrips.
What do spider mites hate the most?
If you catch them early enough, you can quickly solve the problem by simply removing them from the plant. Rinse & Wipe All the Leaves Down: Spider mites hate water.
What is mites’ natural enemy?
Predatory mites are commonly the most important natural enemies of plant-feeding mites. Predatory species include Anystis, Amblyseius, Euseius, Neoseiulus, and Phytoseiulus species and the western predatory mite.
Do ladybugs eat spider mites?
Yes, ladybugs are known to eat spider mites. Both adult ladybugs and their larvae prey on spider mites, making them a beneficial insect for controlling these pests. Ladybugs are attracted to the scent of spider mites and the damage they cause to plants.