Effect of sublethal exposure of pyriproxyfen released in a fumigant formulation on Aedes aegypti fertility and fecundity

LAURA HARBURGUER; EDUARDO ZERBA; HÉCTOR MASUH; SUSANA LICASTRO

California

Simposio; 21st Latin American Symposium, 77th AMCA Annual Meeting; 2011

Insect growth regulators (IGRs) are considered a new generation of insecticides having great prospects for insect control. The activity of IGRs generally results in the reduction of adult emergence of the target insect. However, they seem to have side effects, particularly on female reproduction following larval IGR treatments, for example, effects on fecundity (increase or diminution of the number of eggs laid) and on fertility (reduction of hatchability or viability of eggs). This study evaluated the effect of treatment with a sublethal dose of pyriproxyfen, released in a fumigant formulation, on fecundity and fertility of Ae. aegypti. Early 4th instar larvae were treated with a dose that caused between 40 and 50% of adult emergence inhibition. Three to 4 days after emergence, surviving females were fed and mean number of eggs laid was noted. Ten to fifteen days later, eggs were placed in water to evaluate their viability. Also ovaries of surviving females were dissected and mean ovariole number was registered. Results shows a decrease in the mean number of eggs laid by treated females and also a reduction of viability of those eggs, however no difference was observed in the mean ovariole number between treated and control females. This would indicate that the use of this new formulation combined with an adulticide as has been proposed in previous work of our laboratory, not only produce larvae and adult mortality of those individuals present at time of application but also produce a reduction in fertility and fecundity of surviving females.