Pantnagar Journal of Research

Abstract

The bio-efficacy of essential oils extracted from 16 plants was studied against Lesser grain borer, Rhyzopertha dominica (Fabricius) (Coleoptera: Bostrichidae) under laboratory condition. The overall efficacy of oil on survival, feeding and breeding of insect was measured by observing the inhibition of F1 progeny of insects released in the treated grain. The essential oils exhibiting > 90-100, > 80-89.99, > 70-79.99 and < 70 were classified as highly, moderately, less and least effective, respectively. Significant difference in the efficacy of essential oils was recorded against the test insect. Essential oils of Curcuma longa, Eucalyptus globulus, Mentha arvensis, Mentha. piperita, Pinus roxburghii were found highly effective at 0.1 to 0.4 per cent concentration(v/w) while such efficacy was exhibited by Cymbopogon winterianus, Eucalyptus citriodora and Mentha spicata at 0.2 to 0.4 per cent. On the other hand, essential oils of Mentha citrata and Pelargonium graveolens were highly effective at 0.3 to 0.4 per cent while Cymbopogon flexuosus exhibited such efficacy at a very high concentration of 0.6 to 1.0 per cent. Essential oils of C. flexuosus, M. citrata and M. spicata were moderately effective at 0.2 to 0.4, 0.2 and 0.1 per cent, respectively. The essential oils of C. martini, E. citriodora and P. graveolens were classified as less effective at 0.2 to 0.4, 0.1 and 0.2 per cent, respectively. The essential oils of Cedardeodara, Cinnamomum camphora, Myristica fragrans and Pogostemon patchouli were classified as least effective against R. dominica. The efficacy of some essential oils such as C. flexuosus, C. martini, C. winteri anus and M. citrate also decreased at 0.1 per cent due to which they were classified as least effective at lowest concentration.