Insecticidal Activity and Chemical Composition of theMorinda lucidaEssential Oil against Pulse BeetleCallosobruchus maculatus

Abstract

Insecticidal activity of essential oil extracted fromMorinda lucidawas tested on pulse beetleCallosobruchus maculatus, which is a pest that causes serious damage to several pulses. The insecticidal activity was compared with two pesticides, Phostoxin and Primo-ban-20. 120 mixed sex adultC. maculatuswere introduced, along with 30 g of cowpeas. Four concentrations (0.40, 0.20, 0.10, and 0.05 μg/mL) of theM. lucidaessential oil, Phostoxin, and Primo-ban-20 were tested. Essential oil chemical composition was analyzed by GC-MS.M. lucidaessential oil showed a high toxicological effect, producing 100% mortality after 72 hours at a dose of 0.20 μg/mL.M. lucidaessential oil had a potent insecticidal activity (LC90= 0.629 μg/mL) compared to both pesticides, Phostoxin (LC90= 0.652 μg/mL) and Primo-ban-20 (LC90= 0.726 μg/mL), at 24 h. The main compounds of the essential oil were the oxygenated monoterpenoids, 1,8-cineole (43.4%), andα-terpinyl acetate (14.5%), and the monoterpene hydrocarbons, mostly sabinene (8.2%) andβ-pinene (4.0%). Results clearly indicate thatM. lucidaessential oil can be used as an effective alternative for pulse beetleC. maculatuscontrol, and it could be tested against other pulse beetles affecting Asia and Africa and throughout the world, thereby reducing use of synthetic pesticides.