Repellent Properties of Plant Oil Vapours on Pulse Beetle (Callasobruchus maculatus L.) (Coleoptera: Bruchidae) in Stored Green Gram (Vigna radiata Walp.)

The repellent effects of ten oils, Domba (Calophyllum inophyllum L), Batu (Solanam indicum L), leaf oil and bark oil of Cinnamon (Cinnamomum verum Presl.), Mustard oil (Brassica juncea Cross.), Neem oil (Azadiracta indica A.Juss), Mee oil (Maduka longifolia Koenig.), Castor oil (Ricinus communis L.), Citronella oil (Cymbopogon nardus L.) and Sesame oil (Sesamum indicum L.) were tested for pulse beetle (Callosobruchus maculatus L.) in the laboratory conditions. Data were recorded on distribution, oviposition and adult emergence. Ventilated containers each with five pairs of newly emerged adults with 20 green gram seeds were exposed to different oil vapours at the rate of 200μml. Each container was fixed to a device that provided a tunnel for pulse beetle to escape from or enter into any container. Citronella oil, Neem oil, Cinnamon leaf oil and Cinnamon bark oil vapours recorded significantly lowest number of pulse beetles after infestation and their oviposition and adult emergence indicating the highest repellent action and toxic effects. Mustard oil, Domba oil, Mee oil, Castor oil and Batu oil show indications of higher repellent effect at 4DAT on the distribution of the C. maculatus. Mustard oil and Domba oil showed a lower rate oviposition than that of Mee oil, Castor oil and Batu oil. All the treatments except Sesame oil had significantly reduced adult emergence at 18DAT. Sesame oil showed positive effect on distribution, oviposition and adult emergence and no repellent activity against the C. maculatus.

Key words: C. maculatus; Green gram; Oil vapours; Repellent effects

DOI: 10.4038/tare.v12i1.1978

Tropical Agricultural Research & Extension 12(1):2009 13-16