Origin, current distribution and general description The predatory mite Phytoseiulus persimilis, of South American origin, is a well-known biological control agent against spider mites. Its use is very popular both in the Americas, Europe and Asia. The adult female is an orange-red pear-shaped mite rather longer than its prey. It has longer front legs and a characteristic rapid movement when disturbed or exposed to bright light. The nymphs are oval and pale-pink in color.
Basic biology Females lay eggs singly on the underside of leaves among colonies of spider mites. After about 3 days (at 20oC) a six-legged larva hatches and a day later it moults into an eight-legged nymph which can consume 4-5 eggs of its prey before turning into another nymphal stage. The latter is able to eat about 6 eggs or young spider mite stages within two days. Adults consume about 7 mites/day. Oviposition may continue for about three weeks at a rate of 2-3 eggs/day (total around 50). Under favorable temperatures (21-27oC) the predatory mite completes its life cycle within a week, almost twice as quickly as its prey. It is, therefore, not surprising that this predator is considered to be highly effective and is capable of eradicating spider mite populations.
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