Abstract

Pulse beetle, Callosobruchus chinensis L. responsible for destroying qualitative and quantitative losses to most stored grains. Once the damage done by the beetle, the grains lose their nutritional and germination capacity and become unfit for either consumption. Seed treatment still mainly relies on heavy synthetic chemicals which cause residual effect and threaten public health. However, the natural plant products containing insecticidal activity have recently displayed a great scope as they tend to come up with low mammalian toxicity, less effect on environmental and broad public adoption. Therefore, an experiment was conducted with variable doses of Eruca sativa L. seed oil (0.5 ml, 1 ml, and 1.5 ml) against C. chinensis. The data were recorded for corrected mortality, repellent effects, and seed protectant at different intervals (24, 48, 72 hrs and 1 week). We found the higher corrected mortality (32.65%) at 1.5ml after 24 hrs. Later, the mortality percentage decreased at different intervals but remained higher at maximum dose of E. sativa. However, the overall highest mortality of C. chinensis was 50.00% at 1.5 ml and the lowest 41.00% at 0.5 ml. Meanwhile, the index showed repellent effect with R.I value <1 in all treatments at different intervals. The seed protectant data showed that the minimum number of 1.66+-0.33 eggs laid on treated seeds at 1.5 ml and 8.00+-1.15 eggs on untreated seeds in choice experiment. In total, maximum number of 17.33+-4.93 eggs laid at 0.5 ml in choice experiment and minimum 4.83+-1.51 eggs at 1.5ml. However, in no choice experiment, the maximum number of 51.00+-4.58 eggs on control treatment and minimum 0.33+-0.33 eggs on 1.5 ml were laid by pulse beetle. The most effective dose of 1.5ml caused maximum mortality, repellent and seed protectant.

Keywords: Callosobruchus chinensis, Chickpea, Eruca sativa, Repellent, Mortality.