Insecticide resistance of house fly, Musca domestica (L.) from Argentina.

The status of resistance to cyromazine, 2,2-dichlorovinyl dimethyl phosphate (DDVP), and permethrin relative to field populations of the house fly, Musca domestica L. from Argentinean poultry farms was studied. All the three studied populations (SV, Q, and C) showed resistant ratios (RRs) to cyromazine of 3.9, 10.98, and 62.5, respectively. We observed high levels of resistance toward the organophosphate DDVP and permethrin. The RRs to DDVP ranged from 45.4 to 62.5. No significant differences were found among the studied populations. All the house fly populations were permethrin-resistant, in comparison with the susceptible strain. Two of the analyzed populations (SV and Q) differed significantly in toxicity to the population C. This is the first evidence that house flies from Argentina showed a multi-resistance pattern. The implementation of an insecticide monitoring program on poultry farms of Argentina is needed to prevent field control failures. Furthermore, integrated control strategies are needed to delay detrimental development of insecticide resistance.