Laboratory Comparison of Some Insecticides as Larvicides against Nonresistant House Flies1

Abstract

Seven chlorinated hydrocarbon insecticides, DDT, methoxychlor, toxaphene, benzene hexachloride (95% gamma), chlordane, dieldrin, and aldrin, were tested as larvicides in spray applications of emulsion formulations on the surface of breeding media at -1, 1, 3, and 5 days from the introduction of newly hatched larvae of nonresistant flies. Effectiveness of dosages ranging from 2.5 to 1250 mg of insecticide per sq. ft. was determined on the numbers of pupae and of defective and normal adults in treated cultures compared with check cultures. On 5-day-old cultures containing mainly pupae and some full-grown larvae only chlordane at dosages of 250 to 1250 mg per sq. ft. gave reductions of at least 70% making it the best insecticide for general effectiveness. Against 1-to-3-day-old cultures, BHC, aldrin, toxaphene and dieldrin were more effective than chlordane at dosages below 250 mg per sq. ft. BHC (95% gamma) appeared to be the most active, giving complete mortalities at 25 mg per sq. ft. and killing almost all the fly larvae before they could pupate.