Feed Additives for Control of Face Fly Larvae in Cattle Dung1

Abstract

Dairy cattle were fed measured doses of insecticides mixed with grain. Dung collections were infested in the laboratory with newly hatched larvae of the face fly (Musca autumnalis De Geer) and survival was observed. The lowest effective daily doses were approximately as defined follows: Co-ral® (O,O-diethyl 0-3-chloro-4-methyl-2-oxo-2H-1-benzopymn-7-yl phosphorothioate) and Bayer 22408 (O,O-diethyl O-naphthalimido phosphorothioate)-0.125 to 0.25 mg./kg., Bayer 29493 (O,O-dimethyl 0-[4-(methylthio)-m-tolyl] phosphorothioate)-1 to 2 mg./kg., SD-4204 (dimethyl 2-(alpha-methylbenzyloxyearbonyl(-1-methylvinyl phosphate)-2 to .5 mg./kg., ronnel and Zytron (0-(2,4-diehlorphenyl O-methyl isopropyl phosphoramidothioate)-2 mg./kg. Effective control did not persist beyond 24 hours after termination of treatment. DDVP, Ruelene® (O-4-tert-butyl-2-chlorophenyl O-methyl methylphosphoramidate), and dimethrin (2,4-dimethylbenzyl chrysanthemumate), when fed at 5 mg./kg., were not effective. Mineral blocks containing 5.5% ronnel were fed ad libitum to Hereford cattle for 1 month. Survival of face fly larvae in dung samples was extremely variable, although average consumption of ronnel was 3.5 mg./kg. daily. There was some reduction in face fly populations on the animals.