AN ATTEMPT TO CONTROL PHLEBOTOMINE SAND FLIES (DIPTERA, PSYCHODIDAE) BY RESIDUAL SPRAYING WITH DELTAMETHRIN IN A COLOMBIAN VILLAGE

An attempt was made to control phlebotomine sand flies biting indoors in a rural community near Cali, Colombia, using the residual insectici de ''K-Othrine'' (deltamethrin) sprayed on the inside walls of houses. Twelve houses were divided into matched pairs based on physical chara cteristics, one house in each pair being left untreated while the insi de walls of the other were sprayed with 1% deltamethrin at a concentra tion of 500 mg a.i./m(2). Sand flies were sampled each week using prot ected human bait and sticky trap collections for four months after spr aying. The number of sand flies (Lutzomyia youngi) collected on sticky traps was significantly lower (P = 0.004) in the untreated houses tha n in the treated ones with which they were matched. This difference wa s not significant for L. columbiana; the other anthropophilic species were not present in large numbers. The numbers collected on human bait in treated and untreated houses were not significantly different for either species. Activity of the insecticide as determined by contact b ioassays remained high throughout the study and failure to control the insects was attributed to two factors: the tendency of sand flies to bite before making contact with the insecticide and the fact that the number of sand flies that entered houses represented a relatively smal l proportion of the population in the wooded areas surrounding the set tlement in the study.