Fly production in relation to refuse disposal in recreational areas.

Fly production in garbage pits constructed by the U. S. Army Corps of Engineers on the Clark Hill Reservoir, Clark Hills, S. C., was found to be extremely variable from June 1 to Sept. 22, 1967. During the 15 weeks the traps were operated 26,434 flies were trapped, of which 9856 were Psychodidae, 10,954 were Phaenicia spp., and 3468 were the secondary screw-worm, Cochliomyia macellaria (F.). Dichlorvos dispensers (1/2 or 1 unit per pit) gave 95% or more reduction of all flies for 8 weeks and 73% to 88% reduction during weeks 9 through 12. Dimethoate or diazinon failed to significantly reduce the number of flies trapped at dosages of 1 or 2% spray. Dichlorvos dispensers, I unit per privy, gave greater than 70% reduction of Fannia spp. And Ophyra leucostoma (Wiedemann) for 4 weeks but were ineffective against Psychodidae and Hermetia illucens (L.).