If a pesticide is applied the moment a spider mite is suspected, predator populations are reduced, and spider mite populations are free to increase without restraint. Excessive use of pesticide therefore increases the likelihood of spider mite population explosions. A strong jet of water into junipers, cedars and the branches of spruce trees once a week will wash large numbers of mites off the trees without killing predators. Predatory mites are fast-moving carnivorous mites that feeds on spider mites. They can be purchased and released onto infested plants.
Insecticidal soap can be effective.
However, since mites are tiny and soap works by contact, thorough coverage is essential. Many domestically registered insecticides are only weak miticides. Insecticides with some effect on mites include dimethoate, chlorpyrifos, diazinon and malathion. The only miticide registered for domestic use is kelthane. It is effective but often difficult to find.