Larvicidal and oviposition-altering activity of monoterpenoids, trans-anithole and rosemary oil to the yellow fever mosquito Aedes aegypti (Diptera: Culicidae).

BACKGROUND Aedes aegypti L. is the major vector of dengue fever and dengue hemorrhagic fever. In an effort to find effective tools for control programs to reduce mosquito populations, the authors assessed the acute toxicities of 14 monoterpenoids, trans-anithole and the essential oil of rosemary against different larval stages of Ae. aegypti. The potential for piperonyl butoxide (PBO) to act as a synergist for these compounds to increase larvicidal activity was also examined, and the oviposition response of gravid Ae. aegypti females to substrates containing these compounds was evaluated in behavioral bioassays. RESULTS Pulegone, thymol, eugenol, trans-anithole, rosemary oil and citronellal showed high larvicidal activity against all larval stages of Ae. aegypti (LC(50) values 10.3-40.8 mg L(-1)). The addition of PBO significantly increased the larvicidal activity of all test compounds (3-250-fold). Eugenol, citronellal, thymol, pulegone, rosemary oil and cymene showed oviposition deterrent and/or repellent activities, while the presence of borneol, camphor and beta-pinene increased the number of eggs laid in test containers. CONCLUSIONS This study quantified the lethal and sublethal effects of several phytochemical compounds against all larval stages of Aedes aegypti, providing information that ultimately may have potential in mosquito control programs through acute toxicity and/or the ability to alter reproductive behaviors.