INSECTICIDAL, REPELLENT, ANTIFEEDANT AND GROWTH REGULATORY INFLUENCES OF ESSENTIAL OIL OF INDIGENOUS MEDICINAL PLANTS AGAINST STORED GRAIN INSECT PESTS

Abstract

The present research work was conducted to find a noval, biodegradable, safe and environment friendly replacement of conventional synthetic insecticide to control the insect pests in stored commodities. The repellent, contact, fumigant, antifeedant and growth regulatory activities of essential oils of Azadirachta indica, Melia azedarach, Colocynthis citrullus, Nicotiana tabacum and Eucalyptus camaldulensis were checked against Tribolium castaneum, Rhyzopertha dominica and Trogoderma granarium. Three concentrations of each essential oil (2, 4 and 6%) were tested in each experiment. Findings of this research work revealed that for repellant bioactivities A. indica was found most potent against T. castaneum and R. dominica while M. azidiractha was most active against T. granarium. Overall effect of the concentration was highly significant and the maximum repellency was obtained at 6% concentration followed by 4% and 2%. Results also showed that as the duration of exposure increased repellency decreased. For contact and fumigant toxicities results revealed that A. indica was found most toxic against T. castaneum and R. dominica while N. tabacum was most effective against T. granarium. Results also showed that fumigant and contact mortalities were maximum at highest level of concentration and exposure period. In case of antifeedant and insect growth regulatory activities the most potent essential oil was found A. indica followed by M. azedarach,C. citrullus N. tabacum and E. camaldulensis against T. castaneum, T. granarium and R. dominica respectively. Antifeedant and growth inhibition effect was maximum at 6% followed by 4% and 2% concentration.