Toxicity of Litsea petiolata Hook.f. essential oil against Aedes aegypti (Linn.), Aedes albopictus (Skuse), Anopheles minimus (Theobald) and Culex quinquefasciatus (Say)

Abstract

This study evaluated the oviposition deterrent, ovicidal, larvicidal, pupicidal, and adulticidal activities of essential oil (EO) from Litsea petiolata leaves against Aedes aegypti, Aedes albopictus, Anopheles minimus and Culex quinquefasciatus with double choice, dipping, and contact assays. Litsea petiolata EO was tested at 1, 5, and 10% concentrations in ethanol and their efficiencies were compared with those of 1% w/w temephos and 10 % w/v cypermethrin. Oviposition deterrent was evaluated on gravid females. Larvicidal and pupicidal activities were tested on the fourth larvae and 2-day-old pupae. The adulticidal activity was tested against two-day-old adult females. Ten percent of L. petiolata EO exhibited the highest oviposition deterrent activity against gravid females and 100% repellency against Ae. albopictus and An. minimus, 97.0% against Ae. aegypti and 94.6% against Cx. quinquefasciatus. The oviposition activity index (OAI) against females of those four mosquito species ranged from -0.9 to -1.0. Ten percent of L. petiolata EO also exhibited the highest ovicidal activity against the eggs of the four mosquito species, with an inhibition rate ranging from 87.2 to 100%. Moreover, it also showed the highest larvicidal and puicidal activities against the larvae and pupae of the four mosquito species, with a 100% mortality rate at 10 and 60 min, respectively. The adulticidal activity was recorded at 1 and 24h. Ten percent of L. petiolata EO exhibited the highest toxicity to female adults of the four mosquito species, with 100% knockdown (1h) and mortality (24h) rates. On the other hand, 1%w/w temephos did not deter gravid females, and it was only slightly toxic to the eggs and larvae and non-toxic to the pupae. In the same manner, 10%w/v cypermethrin was less effective against the female adults of the four mosquito species than 10% L.petiolata EO. L.petiolata EO is a highly effective and eco-friendly alternative to synthetic insecticides.