FUMIGANT AND CONTACT TOXIC POTENTIAL OF ESSENTIAL OILS FROM PLANT EXTRACTS AGAINST STORED PRODUCT PESTS

Abstract

ABSTRACT Essential oils isolated from pine (Pinus longifolia L.), Eucalyptus (Eucalyptus obliqua L’Her) and coriander (Coriandrum sativum L.) were screened for contact and fumigant activities against rice weevil, Sitophilus oryzae L. (Coleoptera: Curculionidae), adzuki bean weevil, Callosobruchus chinensis L. (Coleoptera: Bruchidae) and rice moth Corcyra cephalonica (Stainton) (Lepidoptera: Pyralidae) in laboratory assays. Responses varied with test material, insect species, and exposure time. In fumigation assay, coriander and eucalyptus oils at 130µg/cm2 , caused 100% toxicity to all the species within 24 hrs of treatment, whereas pine oil revealed, 90% mortality at same concentration after 72 hrs of treatment. In contact assay, the test oils were effective against adults of S. oryzae, C. chinensis and C. cephalonica producing about 90% toxicity only after 72 hrs of treatment. Against C. chinensis adults, all test materials revealed potent insecticidal activities than other two insects in both fumigation and contact assays even at lower concentrations. These studies showed the strong insecticidal activity of coriander, eucalyptus and pine oils and its potential role as a fumigant for S. oryzae, C. chinensis and C. cephalonica. From this study we conclude that these essential oils have potential for applications in IPM programs for stored-grain pests because of its high volatility and fumigant activity.