title: Laboratory evaluation of four organophosphate compounds as larvicides against field collected salt marsh Culicoides spp. (Diptera: Ceratopogonidae).
abstract: The relative effectiveness of 4 organophosphate compounds was tested in the laboratory against Culicoides spp. larvae obtained from salt marsh areas on the Gulf coast of Florida. Larvae were exposed to the insecticide either in estuarine water or in a combination of estuarine water and dried substrate from the salt marsh habitat. The relative potency of the 4 chemicals varied greatly, with chlorpyrifos being the most toxic. Nine times as much temephos, 22 times as much fenthion, and 176 times as much malathion were required to achieve the 50% mortality level compared to chloryprifos (LC50, 0.5 ppb) in water. Addition of habitat soil did not change the order of effectiveness, but 9 times as much chlorpyrifos, 2.3 times as much temephos, and 1.3 times as much fenthion or malathion were required to cause the same mortality as in estuarine water alone.
authors: Insects Affecting Man and Animals Research Laboratory, USDA, Gainesville, FL 32604.
authors: D L
authors: DL
authors: Kline
authors: J R
authors: JR
authors: Wood
authors: R H
authors: RH
authors: Roberts
authors: K F
authors: KF
authors: Baldwin
mesh_terms: D000818:Animals; D002519:Ceratopogonidae; D004390:Chlorpyrifos; D005069:Evaluation Studies as Topic; D005284:Fenthion; D007306:Insecticides; D007814:Larva; D008294:Malathion; D012044:Regression Analysis; D000002:Temefos
chemical_list: D007306:Insecticides; D005284:Fenthion; D004390:Chlorpyrifos; D000002:Temefos; D008294:Malathion