Cyclodiene-BHC resistance in Cosmopolites sordidus (Germ.) (Coleoptera, Curculionidae) in New South Wales, Australia

Abstract

AbstractDieldrin, aldrin and γBHC in kerosene were applied topically to adults of Cosmopolites sordidus (Germ.) collected from banana plantations with no history of insecticide application and from plantations that had been treated regularly with dieldrin for many years. Adults from the latter source were highly resistant to dieldrin and aldrin, while resistance to γBHC was lower; those from the former source were susceptible and the results could be used as base line data. Females collected in spring from two untreated plantations showed LD50 values for dieldrin varying by a factor of 1·5, while females collected in the spring were 1·7 times more susceptible than those collected in the autumn from the same plantation. A discriminating dose of 1 μl of 1·0% dieldrin per weevil is considered suitable for detecting resistant individuals.