Pantnagar Journal of Research

Abstract

The long-term efficacy of some essential oils was studied against Lesser grain borer, Rhyzopertha dominica) and Rice weevil, Sitophilus oryzae) at 0.40%(v/w) under laboratory condition. After 6 months storage, essential oils of Mentha arvensis), M. piperita), M. spicata), Pinus roxburghii), Cymbopogon winterianus), Eucalyptus globulus), Curcuma longa), M. citrata) and P. graveolens) were found to be highly effective by inhibiting 91.9 to 100.0 per cent progeny of R. dominica). On the other hand, the oils of E. citriodora) and C. flexuosus) became least effective due to 7.5 and 59.1 per cent suppression of progeny after 6 months. Treatment of grain with essential oils of M. arvensis), M. piperita), M. spicata), P. roxburghii), C. winterianus), E. globulus), C. longa), M. citrata) and P. graveolens) suppressed 97.3, 99.2, 99.1, 98.2, 96.8, 99.5, 98.9, 94.3 and 89.7 per cent infestation of this insect, respectively, after 6 months storage. The oils of M. arvensis), M. piperita), M. spicata), P. roxburghii), C. winterianus), E. globulus), C. longa), M. citrata) and P. graveolens) also suppressed 97.2, 99.2, 99.1, 98.3, 98.7, 98.6, 95.6 and 89.8 per cent weight loss after 6 months storage. The oils of M. arvensis), M. piperita), M. spicata), P. roxburghii), C. winterianus, E. citriodora) and E. globulus) were also highly effective against S. oryzae) after 2, 4 and 6 months storage due to 90.1 to 100.0 per cent inhibition of progeny. Except C. winterianus), all these oils were also highly effective in reducing the infestation and weight loss of grain due to S. oryzae) after 4 and 6 months storage. The result indicated that essential oils were highly effective against R. dominica) and S. oryzae) for 6 months and they can be used for protection of grain in short to medium term storage.