The Effectiveness of Insecticides Administered Orally to the Fowl as a Deterrent to the Breeding of Flies in Droppings 12

Filth-inhabiting flies are capable of transmitting at least 30 human diseases. Poultry droppings are of special significance as one of the major sources of fly breeding, particularly when birds are maintained in wire cages. At least 24 species of Ries belonging to 14 families breed in chicken manure in Hawaii (Tanada, et al, 1950). Musca domestica (L.) is the predominant species, yet there are nine other economically important species breeding in large numbers. The treatment of poultry manure to control fly larvae is generally effective for a comparatively short time (Hoffman and Monroe, 1956, 1957; Wilson and Gahan, 1957). The major factors involved in the failure of such larvicidal sprays were discussed by Sampson (1956) and are mainly associated with the lack of penetration of the insecticide deep into the manure mass. The use of animals as vehicles for the distribution of insecticides in the manures would offset some of the difficulties inherent in the conventional methods of application, especially that of penetration. Over seven years of in tensive investigation in our laboratory showed that ingestion by poultry of certain organophosphorous insecticides will prevent fly breeding in the drop pings. However, the inclusion of toxic substances in the diet of poultry is particularly hazardous from the public health standpoint. Relatively little in formation is available on this subject. In recent years the publication of Rachel Carson's Silent Spring has stimulated discussion and concern regarding the effect of the use of pesticides on wild life as well as on humans. It is essential, therefore, to clarify the actual extent of the hazard. With this in mind, the specific aims of this research program in our laboratory are: