Susceptibility to diazinon in populations of the horn fly, Haematobia irritans (Diptera: Muscidae), in Central Brazil

• DOI: 10.1590/s0074-02762002000600029
• Publication Date: 2005-04-26T08:10:30Z
• Authors: Antonio Thadeu M ...; Alberto Gomes; Ana Paula K Ismael; Wilson W Koller
• Keywords: Haematobia irritans; Nuisance

From October 2000 to April 2001, insecticide bioassays were conducted in 18 ranches from 10 counties the states of Mato Grosso and do Sul, Central Brazil. Horn flies wild populations exposed diazinon-impregnated filter papers immediately after collection on cattle, mortality was recorded 2 h. A high susceptibility diazinon observed all tested populations. The LC50s ranged 0.15 0.64 µg/cm², resistance ratios always lower than one (ranging 0.1-0.6). Pyrethroid products, most applied by backpack sprayers, have been used since horn fly entered region, about years ago. indicates that this (as probably other organophosphate insecticides) represents an useful tool for control management, particularly pyrethroid-resistant