EFFICACY OF GRAIN PROTECTANTS AND PHOSPHINE AGAINST LIPOSCELIS-BOSTRYCHOPHILA, LIPOSCELIS-ENTOMOPHILA, AND LIPOSCELIS-PAETA (PSOCOPTERA, LIPOSCELIDAE)

The effectiveness of 8 grain protectants and the fumigant phosphine wa s tested against Liposcelis bostrychophila Badonnel, L. entomophila (E nderlein), and L. paeta Pearman. These species are common pests in Asi a and have become important pests in the Australian grain-handling sys tem. L. entomophila and L. pacta were tolerant to all protectants test ed, whereas only organophosphates were effective against L. bostrychop hila. Phosphine was highly effective against all 3 species. A survey o f 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. O rganophosphorous grain protectants could be used where L. bostrychophi la is prevalent.