Effects of DDT Mosquito Larviciding on Wildlife: V. Effects on Fishes of the Routine Manual and Airplane Application of DDT and Other Mosquito Larvicides

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Abstract
Extensive tests covering a 3-year period were conducted in the anopheline mosquito breeding ponds of the Savannah, Georgia, area to determine the effects of various types of larviciding operations upon fishes. Applications of the insecticides were made both by hand and by airplane. In the testing with manual application, a variety of formulations were tested with single applns. The results indicated that stable emulsions are much more toxic than are solns. or dusts and in general are not recommended in areas having valuable wildlife. Single applns. of 0.4 lb. or more of the DDT per acre are toxic to fish when applied as solns. Single applns. of solns. at 0.1 lb. or less per acre and dusts at 0.2 lb. or less per acre did not kill fish. Under normal conditions routine applns. of one gallon of oil solns. at 0.05 lb. DDT per acre or of a dust applied at 0.1 lb. DDT per acre can be safely recommended for routine manual operations. For airplane appln., DDT sprays or thermal aerosols have been routinely applied at a dosage of 0.1 lb. per acre for 3 yrs. without harm to the fish population in deep, large bodies of water. DDD is considerably less toxic to fish than is DDT and chlordan appears to be intermediate between the 2. Toxaphene is as toxic or more toxic to fish than rotenone and may prove useful as a substitute for it in fish management work.