Predatory mite

Neoseiulus californicus

(formerly Amblyseius californicus)

Neoseiulus californicus is a predatory mite that develops best on spider mites (a preferred prey), but which can also sustain itself on several other plant-feeding mites (including broad mite and some rust mites), as well as on pollen and various small insects (including immature stages of some thrips). This ability to feed on alternate food sources allows N- californicus to persist for longer than the more specialized Phytoseiulus persimilis when spider mites are scarce.

Adults of N. californicus are an elongated oval in shape and are approximately 1 mm long. The body is a translucent pale pink to pale orange, with the color varying somewhat according to the prey consumed. As with other mites, the egg hatches to a six-legged larval stage, which is followed by two successive eight-legged nymphal stages before the final molt to the adult.

Neoseiulus californicus develops best at temperatures above 20°C, with the optimal range being 25-30°C, with relative humidities of approximately 65-76%, However, this species is more tolerant of high temperatures and Iower humidities than is P. persimilis, withstanding temperatures somewhat higher than 30°C and relative humidities of approximately 45—50%. At 25°C, the life-cycle (egg to adult) takes approximately 5 days. At this temperature, adult females may live for approximately 30 days and lay a total of 30-40 eggs. Development time and adult lifespan will be lower at higher temperatures.

Neoseiulus californicus will usually develop more slowly than P. persimilis when conditions for the latter are optimal. However, N. californicus has the advantage of being able to tolerate a wider range of temperatures and humidities„ and the ability to persist for longer (on alternative prey) when spider mites are scarce.