Control of Face Flies Attacking Commercial Dairy Herds

Abstract

Six dairy herds were treated for control of the face fly (Musca. autumnalis) with DDVP (O, O-dimethyl 2,2-dichlorovinyl phosphate), 0.5% syrup bait using 1/9 oz. per cow per day on the forehead. Although treated herds were located an adjoining farms, there was no area-wide reduction of face flies. Regular daily application of the syrup bait resulted in fly counts of 0-10 per face on treated cattle as opposed to 25-45 flies per face on untreated heifers on the same farms and on an untreated herd several miles away. The treatment made a difference in behavior, as treated cattle grazed, or rested at will, but untreated cattle were harrassed and often bunched together for relief. Irregular use of the syrup bait did not give satisfactory results.