Efficacy of Grain Protectants and Phosphine Against Liposcelis bostrychophila, L. entomophila, and L. paeta (Psocoptera: Liposcelidae)

Abstract

The effectiveness of 8 grain protectants and the fumigant phosphine was tested against Liposcelis bostrychophila Badonnel, L. entomophila (Enderlein), and L. paeta Pearman. These species are common pests in Asia and have become important pests in the Australian grain-handling system. L. entomophila and L. paeta were tolerant to all protectants tested, whereas only organophosphates were effective against L. bostrychophila. Phosphine was highly effective against all 3 species. A survey of field populations of L. entomophila and L. bostrychophila suggested that the tolerance to protectant insecticides was a natural phenomenon and not due to resistance. We conclude that of these chemical tactics only phosphine has a place in the management of psocids in general. Organophosphorous grain protectants could be used where L. bostrychophila is prevalent.