Comparative efficacy of eighteen essential Oil againstRhyzopertha dominica(F.)

Abstract

Plants are known to be a potential source of chemicals affecting feeding, breeding and survival of insects. Present study was conducted to study the fumigant toxicity of essential oils against major insect pest of stored grain Rhizopertha dominica. The bio-efficacy of essential oils extracted from eighteen plants, namely, Aegle marmelos, Cinnamomum camphora, Citrus sp., Eucalyptus globules, Psidium guajava, Thuja orientalis, Cymbopogon flexuosus, Bidens pilosa, Ageratum conyzoides, Saraca asoca, Cannabis sativa, Murraya koenigii, Tagetes erecta, Citrus limetta, Artemisia annua, Callistemon citrinus, Ocimum gratissimum and Citrus limon was studied against R. domanica at 0.2, 0.1, 0.05, 0.025, and 0.012% concentration (v/w). The study revealed that most of the essential oils inhibited the development of the test insect. However, the level of inhibition was highly correlated with the dose at which oils were used for treatment. Among eighteen essential oils, A. marmelos, C. camphora E. globulus and T. orientalis were most effective against R. dominica because no insect developed from the grain treated with it even at lower concentration of 0.05%. All the essential oils were found highly effective at 0.2 and 0.1% concentration except A. conyzoides, S. asoca, C. sativa, O. gratissimum and Citrus sp, which permitted adult emergence during test. None of the oil was found highly effective against R. domanica at 0.025 and 0.012% concentration. The essential oil of E. globulus and T. orientalis were found moderately effective at 0.025% concentrations at which they caused 83.92 and 87.17% inhibition, respectively. Rests of the treatments were found less effective against R. dominica due to less than 70% inhibition of progeny production