DEVELOPMENT OF SYSTEMIC INSECTICIDES FOR PESTS OF ANIMALS IN THE UNITED STATES1

The first encouraging results in the search for systemic insecticides were obtained in 1944 by Lindquist and his co-workers (53), who found that bed bugs, Cimex lectularius Linnaeus and C. hemipterus (Fabricius), died after feeding on rabbits treated orally with DDT or pyrethrins. In 1946, Knipling and associates (48) treated rabbits with oral and intravenous dosages of insecticides,and reported that rabbits tolerated treatments of lindane and 2 -pivalyl-I,3-indandione at rates that were lethal to mosquitoes, Aedes aegypti (Linnaeus), and human body lice, Pediculus humanus humanus Linnaeus when feeding on the rabbits. These findings, made at the Orlando, Florida, laboratory of the United States Department of Agriculture in conjunction with wartime research on the development of military insecticides, justified the initiation of a project on animal systemic insecticides at the Kerrville, Texas, Livestock Insects Laboratory. Since that date, en­tomologists at Kerrville have worked intensively, screening candidate ma­terials in the laboratory and conducting small-scale field tests with promising compounds. Concurrent toxicological observations have been made by co­ operating veterinarians of the Animal Disease and Parasite Research Divi­sion, and analyses of residues of insecticides in meat and milk have been made by cooperating chemists of the Pesticide Chemicals Research Branch of the Entomology Research Division. A description of steps in the development of the first practical systemic insecticide by the cooperative effort of entomologists, veterinarians, and chemists, both in the U. S. Department of Agriculture and from other or­ganizations and industry, is presented below