Investigations of the Face Fly in Missouri1

Abstract

The face fly, Musca autumnalis De Geer, was first reported from northeastern Missouri in, June, 1960. Studies of large hibernating populations in 1960-61 showed that the hibernating females Were unfertilized, with no ovarian development. Hibernation in some cases occurred with large numbers of Pollenia rudis (F), the cluster fly, and small numbers of other Calliphorid flies. Observations of spring dispersal from hibernation sites indicated that the females are fertilized and disperse to the field leaving the males behind. Winds above 10 m.p.h. were found to reduce face fly activity on cattle. Low relative humidity was found to increase activity. Grazing cattle were found to have fewer face flies than cattle at rest. A phaerta pallipes (Say), a hymenopterous parasite of Orthellia caesarion (Meigen) and Sarcophaga derelicta Walker, was found to parasitize as high as 84% of face fly puparia in central Missouri during September of 1961. Baits, sprays, and backrubber applications of insecticides were used throughout the season under variable conditions of infestation. Best control by baits was that of 1% dimethoate in honey applied twice in a 3-day period. Tests with 50% methoxychlor wettable powder and Sevin® (1-naphthyl N-methycarbamate) dusted on the face gave erratic and unsatisfactory results. Backrubbers using toxaphene, DDT, methoxychlor and Delnav®(a mixture of 2,8-p-dioxane-dithiol S, S-bis(O, O-diethyl phosphorodithioate) (70%) and related compounds) as toxicants failed to give satisfactory control. A mixture of DDT and lindane as a conventional spray application gave more than 50% reduction of face fly on beef cattle for 12 days.