Beef Cattle Fly Control

Geographic Distribution

The face fly Musca autumnalis (De Geer) was first reported in the U.S. in 1952 and has spread all the way across the northern half of the U.S. and southern Canada since and has now extended its range south into Alabama in the southeast U.S. It is generally a pest along waterways or areas of higher rainfall. However, irrigated pastures in the more arid regions and pastures with tree cover will also support large populations of face flies. Apparently the manure in which the flies breed dries out too rapidly for the fly to complete its larval development in the arid open ranges.

Livestock Losses

Losses to the livestock industry as a result of the face fly is estimated by the USDA to be $68 million annually (1979). The losses from this pest are more difficult to document than for the horn fly. However, the fly has been implicated in the transmission of pinkeye which thus makes it a serious pest.

The face fly is not a blood sucker since its mouthparts are the sponging type like those of the house fly. The face fly feeds on various animal secretions. Tears, saliva, nasal mucus, blood and serum exuding from wounds, perspiration and filth adhering to the animal hair are all attractive to the face fly for feeding purposes. The persistence and habit of the fly in congregating about the eyes and nose of an animal cause the cattle to bunch and seek shade or water. These evasive actions by the cattle undoubtedly interfere with normal grazing patterns and thus cause reduced milk and weight gain production.

Identification and Life History

Adult face flies closely resemble house flies except they are slightly larger and darker. The persistence and habit of congregating About the eyes and nose of animals helps in distinguishing the face fly from the house fly. The larger size (double) helps distinguish the face fly from the horn fly. Most of the face flies on cattle are females and the fly spends considerable time away from cattle which makes control of this pest more difficult than for control of horn flies which spend most of their time on cattle. The face fly, like the horn fly, deposits its eggs in fresh cow manure. The eggs hatch in 1-2 days; the larval stage lasts from 3-6 days and the pupal stage (transitional larvae-adult) lasts 7-10 days. Unlike the horn fly, which overwinters in the pupal form in the pasture, the face fly overwinters as an adult in barns, houses, other farm buildings and probably in trees, cracks and crevices and wild animal shelters in pasture areas. It thus can be a pest of humans around dwellings when it is migrating into the overwintering site in the fall and out again in the spring.

Face Fly Control

Adequate face fly control is very difficult to obtain under Great Plains cattle management systems. The face fly spends most of its time on the face of cattle which means that the animal's face must be treated with insecticide. It also spends a great deal of time away from the animal which means its chance of contact with an insecticide is less than with horn flies which are on cattle continuously. Unlike horn flies, face flies are at least equally attracted to calves as to cows which means the calves also have to be treated to insure adequate control. Because of these factors it is necessary to get insecticide on the faces of cows and calves by some method 2 or 3 times weekly. The methods available would include: ~

Self-treatment devices: Dust bags and oilers. Normally these are used as a free choice use system for horn fly control. This is not generally adequate for face fly control. Forced use of these systems is almost mandatory to obtain face fly control. Water, feed or salt should be fenced and dust bags or oilers hung in gates to force cattle to use them on a daily basis. The bags or oilers have to be lowered to the point that cows contact them with their faces while entering and so that calves also use them. It may be necessary to lower them gradually after the cattle get used to them. It is generally easier to get cattle accustomed to oilers or dust bags if they can see under them at the start.

Ciodrin (crotoxyphos), Co-Ral (coumaphos), malathion, methyoxychlor and Prolate (Imidan) are registered as dusts for dust bag use. Ciodrin, Co-Ral, Delnav (dioxathion) ronnel (Korlan), lindane, malathion, methoxychlor, ruelene and toxaphene are registered for use in oilers. Oilers and dust bags should not face the prevailing winds or the oiler will dry out too fast and the dust bag will whip, thus wasting dust. Dust bags should be checked after rains for caking of dust. The cakes need to be broken up for adequate dusting. Read, understand and follow label directions for use, mixtures, use restrictions and treatment-slaughter intervals for all insecticides.

Power sprayers or dusters: Pick-up mounted sprayers and dusters that are operated by hand crank, battery or small motors are now available for livestock insect control. It is necessary to drive among cattle and treat at 2 or 3 day intervals for face fly control. Treatment should be done when wind velocity is low and equipment is close to the animals to avoid waste of insecticides. Wet sprays can still be applied but the necessity of corralling cattle and repeating the application rather often probably renders this method economically unfeasible.

Feed additives: Insecticides are incorporated into salt, mineral or supplements and fed to livestock. The insecticide passes through the digestive system of the animal and is available in the manure to destroy fly larvae. The success of this system depends on animal intake. Animals grazing on salty vegetation, calves in the cow-calf herd and variability of intake among mature animals means that some manure is left untreated and thus good fly control isn't achieved. This method does seem to work very well on steer or heifer herds grazing on non-salty vegetation.

Aircraft: Aircraft ULV insecticide applications for control of face flies has been discouraging. Not enough of the flies are on the cattle at any one time and the usual habitat of the flies provides too much canopy for adequate control by this method.