Acute and Chronic Effects of Dimilin on Survival and Reproduction of
SourceDimilin (diflubenzuron), a new insecticide that inhibits chitin synthesis in insects, was found to be acutely and chronically toxic to an estuarine mysid shrimp, Mysidopsis bahia. The 96-h LC50 was 2.06 µg/litre, the 21-day LC50 1.24 µg/litre. Significantly, a 28-day exposure to an estimated concentration of 0.075 µg/litre decreased the production of offspring per female mysid. Data from the chronic tests suggest that the test concentrations not only decreased reproduction in the parents but also affected the reproduction of the progeny. The loss in reproductive success occurred even when the exposed parents or progeny had been moved to water that contained no Dimilin. Should Dimilin reach estuarine waters, the larval or the juvenile stages of other nontarget estuarine crustaceans may be threatened in a manner similar to that observed with M. bahia.