Compatibility of Cheyletus eruditus (Schrank) (Acari: Cheyletidae) and Ce­phalonomia tarsalis (Ashmead) (Hymenoptera: Bethylidae) in biological control of stored grain pests

Abstract

A laboratory experiment was carried out on stored wheat infested by the stored product mite Acarus siro and beetle Oryzaephilus surinamensis. The initial infestation was 150 mites of A. siro and 15 beetles of O. surinamensis per 1 kg of wheat. The predatory mite Cheyletus eruditus and parasitoid Cephalonomia tarsalis were added in the ratio 1:20 and 1:12, repectively. Three combinations were tested: (1) mites and (2) beetles separately, and (3) mites and beetles together. The experiment ran for three months at 22°C and 75% RH. The pests were suppressed by their antagonists in all combinations. Synchronous application of both natural enemies resulted in better control of O. surinamensis through an enhanced effect of both antagonists.