BIOPOTENTIALS OFAZADIRACHTA INDICAANDCEDRUS DEODARA OILS ONCALLOSOBRUCHUS CHINENSIS

Abstract

Oils obtained from neem (Azadirachta indica) seed kernel, the Himalayan cedar wood (Cedrus deodara) and their combination (1:1) each at 3, 2 and 1% concentrations were tested against adults of pulse beetle (Callosobruchus chinensis L.). Cedar wood oil exhibited highest fumigant potential at 3, 2 and 1% concentrations showing corrected inhibition (knock-down) of 100, 100 and 96%, respectively. While neem oil + cedar wood oil (1:1) at 3, 2 and 1% concentrations inhibited 96, 84 and 51.66%. The least corrected % knock-down of 62, 45 and 32 were observed by application of neem oil at 3, 2 and 1%, respectively, by Potters spray tower in 24 h of treatment. However, corrected percent mortality of the same study reveals highest mortality in the cedar wood oil rather than neem and their combinations. Topical application by Arnold hand microapplicator at the rate of 0.5 μl per insect at 3, 2 and 1% concentrations of both the oils and their combinations showed negligible mortality after 24 and 48 h of treatment. In general observations on the behavioural effects due to treatment under Potter's spray tower method showed that cedar wood oil and its combination with neem oil treated insects quickly recovered from the anesthetic effect when compared to insects in neem oil treatment and control. In ovipositional behavioural experiment, cedar wood oil treated chickpea, Cicer aeritinum, grains had 134.3, 114.0 and 112.3 mean number of eggs/5 females while neem oil had 98.3, 118.7 and 57 at 3, 2 and 1% concentrations, respectively. Methanol+acetone (1:1) treated control had only 89.67 eggs/5 females. However, negligible difference was noticed among 3, 2 and 1% concentrations of cedar wood oil + neem oil and control. Joint action potential of Himalayan cedar wood oil with neem oil and its possible use in the formulation of botanical insecticides are discussed.

Keywords: :

• Aradirachta indica
• biopesticide
• Callosobruchus chinensis
• Cedrus deodara
• fumigant
• oviposition behaviour
• toxicity