Research Product

Dimilin (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. Perhaps more significant was the decreased production of young per female mysid at an estimated concentration of 0.075 µg/litre in 28 days. Data from the chronic tests suggest that test concentrations decreased reproduction not only in the parents but also affected the reproduction of the progeny. The loss in reproduction success occured even though exposed parents or progeny were moved to water that contained no Dimilin. Should Dimilin reach estuarine waters, the larval, or juvenile, stages of other nontarget estuarine crustaceans may by threatened in a manner similar to that observed with M. bahia.