[Effect of pyriproxyfen for the Aedes (S) aegypti control (Diptera: Culicidae) in strains with various degrees of temephos resistance].

Abstract

Introduction: the continuous use of the organophosphate temephos for Aedes (Stegomyia) aegypti (Linnaeus, 1762) has prompted the emergence of resistance to this product in several countries. Pyriproxyfen is an analogue of the juvenile hormone recommended by the World Health Organization as one of the alternative regulators of the dengue vector in drinking waters.

Objectives: to evaluate the efficacy of pyriproxyfen in those strains with various degrees of temephos resistance, in order to be used as a possible regulator of Ae. aegypti.

Methods: for this study, two reference Ae. aegypti strains were used, one susceptible and the other resistant to temephos, and three field strains collected in Boyeros, Cotorro and 10 de Octubre municipalities, all of them from the City of Havana province, Cuba. For the temephos and pyriproxyfen evaluation, the WHO recommended bioassays were used.

Results: at high concentrations, pyriproxyfen showed larvicidal properties. At 0,01 and 1 ppb concentrations, inhibition of emergence due to increase of pupal mortality and to lesser extent in adults in the process of breaking the pupal exubia was demonstrated. This growth regulator was effective at the same doses in all the strains, regardless of the degree of temephos resistance, being IE50 values within the range for Aedes genus.

Conclusions: according to the results, the effectiveness of pyriproxyfen was not affected by the degree of temephos resistance in the studied strains, and this is a useful tool in the Ae. aegypti control.