Contact and ovicidal toxicity of plant essential oils against pulse beetle, Callosobrucus chinensis Linn. (Coleoptera: Bruchidae)

Abstract

Contact and ovicidal toxicity of the nine plant essential oils, viz., Cinnamonum camphora, Cymbopogon citrates, Cymbopogon flexuosus, Mentha longifolia, Lavender agustifolia, Ocimum basilicum, Polargonium graveolens, Elethia cardmomum and Foeniculum vulgare on C. chinensis adults. Residual film bioassay was employed in Petri dish (5 cm dia.) for contact and ovicidal studies and inner surface of petri dish (9 cm diameter, sur­face 63.6 cm2) were used for testing contact and ovicidal activities. Maximum contact toxicity was recorded in lavender oil at 24, 48, 72 and 96 h after exposure different concentrations, the values being (10.00, 10.00, 12.23 and 17.75%), (13.75, 13.75, 28.61 and 42.87%) and (13.75, 17.26, 17.57 and 48.11%), respectively. The highest percent hatching inhibition rate was recorded in lavender oil at all the three dose of 0.25, 0.5 and 1% after 35 days, the values being 37.17, 58.37 and 89.80%, respectively.