Insecticidal activity of propoxur- and carbaryl-impregnated flea collars against Ctenocephalides felis.

Ten dogs were fitted with 10% propoxur-(0-isopropoxyphenyl methylcarbamate) and 10 dogs were fitted with 16% carbaryl-(1-naphthyl-N-methylcarbamate) impregnated flea collars. Ten cats were fitted with carbaryl-impregnated flea collars. There were 5 control animal for each trial. Insecticidal activity against experimental infestations with the cat flea (Ctenocephalides felis) was evaluated. The propoxur collars on dogs reduced the flea populations by 90% within 2 days of infestation for at least 13 weeks. By the 16th week, the flea population was reduced 65% in 2 days and 87% in 7 days. In subsequent infestations, efficiency was less than 80% after 7 days. Carbaryl collars on dogs reduced the flea population by as much as 80% in 2 days for a period of 16 weeks. An efficiency of at least 80% at 7 days was maintaned for 17 weeks. Carbaryl collars on cats reduced the flea population within 2 days by 80% or more for a period of at least 19 weeks--the last experimental infestation.