title: Evaluation of a yearly insecticidal ear tag rotation for control of pyrethroid-resistant horn flies (Diptera: Muscidae).
abstract: From 1991 to 1997, the yearly alternated use of synergized pyrethroid (lambda-cyhalothrin + piperonyl butoxide) and organophosphate (pirimiphos-methyl) ear tags was evaluated for the control of two pyrethroid-resistant horn fly populations in Louisiana. At each site, weekly fly counts were used to assess product efficacy. Control achieved by synergized pyrethroid ear tag treatments was reduced from 7 to 2 weeks and from 4 to 0 weeks at St. Joseph and Winnsboro, respectively. Control by organophosphate ear tags decreased from 15 to 3 weeks and from 10 to 7 weeks at St. Joseph and Winnsboro, respectively. The rotation of synergized lambda-cyhalothrin and pirimiphos-methyl ear tags did not improve pyrethroid ear tag efficacy or prevent further development of resistance to the pyrethroid or OP compound.
authors.affiliation: Embrapa Pantanal, Corumbá MS, Brazil.
authors.forename: A T
authors.initials: AT
authors.lastname: Barros
authors.forename: M W
authors.initials: MW
authors.lastname: Alison
authors.forename: L D
authors.initials: LD
authors.lastname: Foil
mesh_terms: D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000517:prevention & control*; D007305:Insecticide Resistance; D007306:Insecticides / Q000592:standards / Q000627:therapeutic use*; D008145:Louisiana; D009117:Muscidae / Q000254:growth & development*; D009943:Organophosphorus Compounds; D011722:Pyrethrins
chemical_list: D007306:Insecticides; D009943:Organophosphorus Compounds; D011722:Pyrethrins