Assessing the use of croton tiglium l.oil as a seed-protectant against callosobruchus maculatus (f.) (coleoptera:chrysomelidae)

A study was carried out to protect Vigna radiata L. seeds from the common storage product pest, the pulse beetle, Callosobruchus maculatus (F.) by using oil prepared from the seeds of a wild plant, Croton tiglium (L.). This oil was found to be toxic to C. maculatus adults. The 24 and 96 h LC50 values (in ml/100g grain) were 0.93 and 0.74 respectively. C. tiglium oil was found to have an effective ovicidal action. At oil concentrations of 0.6 and 0.8 ml/100g grain, adult emergence was as low as 26 and 9 percent respectively, compared to 98 percent emergence in the control group. The grains drenched in C. tiglium oil germinated normally, indicating the non-toxic nature of the oil on the grain endosperm, and hence, the oil is very effective in protecting the grains without affecting seed germination. At the highest drenching concentration of 1.0 ml/100g grain, the mean germination percentage of V. radiata seeds was 96, whereas 100 percent germination was recorded in the control group. The oil concentration at which high ovicidal activity was recorded, failed to affect the germination potential of the grains.