Even small breeding areas support very high numbers of flies. If sanitation is not practiced, chemical control may be unsuccessful. There are several methods of reducing stable fly numbers with insecticides. The method of choice depends to some extent on the type of livestock operation. These surfaces can be treated with residual sprays.
Flies rest on the treated surfaces and absorb the insecticide.
Residual insecticides should be effective for 10 days unless washed off by rain or broken down by high temperatures or bright sunlight. Six applications during the fly season should be adequate. The residual spray method is best adapted to dairies or smaller feedlots where fly resting areas are not extensive. Apply residual sprays to the point of runoff, but do not allow puddles to form and do not contaminate feed or water. See EC 1550, Nebraska Management Guide for Arthropod Pests of Livestock and Horses , for specific insecticide information.