Evaluation of semiochemical toxicity to Aedes aegypti, Ae. albopictus and Anopheles quadrimaculatus (Diptera: Culicidae)

Abstract

Background: Mosquitoes are the most important vectors of human pathogens. Wide-scale use of pesticides has led to the development of resistance to most common insecticide groups. The need to develop novel products that have a low impact on human health and the environment is well established. The toxicity of selected semiochemicals with molecular structures indicative of insecticidal activity was determined against adult Aedes aegypti (L.) and Anopheles quadrimaculatus (Say). The two most active insecticides against Ae. aegypti were also evaluated against Ae. albopictus (Skuse).

Results: Fifteen semiochemicals classified as terpenoid alcohols, ketones or carboxylic esters showed toxicity to both mosquito species. Geranyl acetone (LC(50) = 38.51 microg cm(-2)) followed by citronellol (LC(50) = 48.55 microg cm(-2)) were the most toxic compounds to Ae. aegypti, while geraniol and lavonax, with LC(50) values of 31.88 and 43.40 microg cm(-2), showed the highest toxicity to An. quadrimaculatus. Both geranyl acetone and citronellol were highly toxic to Ae. albopioctus. No semiochemical showed fumigation activity against either species. All semiochemicals persisted for less than 24 h when tested on filter paper.

Conclusion: Quantification of LC(50) values of several semiochemicals against Ae. Aegypti, An. quadrimaculatus and Ae. albopioctus showed that semiochemicals not only modify insect behaviors but also hold potential as potent insecticides for mosquito control programs.