The predatory mite Neoseiulus californicus is an effective natural enemy of various species of spider mite.

Predatory Mite (Neoseiulus californicus)

Neoseiulus (= Amblyseius) californicus is an oblong, tiny predatory mite that feeds on a variety of prey and is useful in prevention, control and management of infestations of various Spider Mite species. Since they are slower feeders than other mite predators, N. californicus should be used in conjunction with other suitable beneficial insects in the presence of large pest populations.

Californicus is tolerant of various temperatures and low humidity, but works best under warm to hot conditions. It tolerates higher temperatures and lower humidity than Persimilis. When pests are low, Californicus will feed on pollen which keeps predatory populations around your crop.

Californicus is a generalist mite should be used on its own. When no food is available it may feed on other beneficial mites eggs, so is not recommended to use in conjunction with others. As a generalist, it has had an impact on eriophyid mites that we have seen, but control is a question mark at this point.

Field observations - Releasing Neoseiulus californicus within a population of spider mites on a cannabis plant. N. californicus was able to attack and consume the spider mite eggs and the juveniles, but not the spider mite adults.

Target Pest:
Spider Mites, Possibly Broad and Cyclamen Mites

Optimal Environment:

50-110°F, 40-60% RH

Release Rates:

General release:

Apply 5-10 mites per square foot. Or general reccomendation is one predatory mite for every 5 pests.


Females will lay about 60 eggs over a lifetime, at the rate of about 2-3 per day. The eggs are oval and pearly white in color, and laid on the underside of leaves where spider mite populations are high. The eggs hatch after 1-2 days, where they will pass through a 6 legged larval and two different 8 legged nymphal stages before adulthood. Depending on temperature, the cycle from egg to adult is roughly 4-10 days, and then another 20 days as an adult.

Strategic Considerations:

The predators should be distributed evenly throughout the crop on the foliage, with higher concentrations at the end of row and in warmer areas that are prone to spider mites.  Neoseiulus californicus tolerates a range of chemical pesticides. Release these mites at sundown the day they arrive. Mist the foliage of the plants to be treated just prior to release. Concentrate the bulk of them at release points on or near the most heavily infested areas. Leave the bottle or vial in the treatment area for 24 hours after release to ensure all mites have exited.

Selected References

University of Florida Department of Entomolgy and Nematology

University of Vermont

UC Pest Management Guidelines