Properties and Potential of Natural Insecticides from Plants against Helopeltis theivora Waterhouse

Toxicity of different solvent extracts of Pogostemon parviflorus and Polygonum hydropiper were carried out in the laboratory against Helopeltis theivora Waterhouse. The chloroform extracts of P. parviflorus and petroleum ether extracts of P. hydropiper showed better antifeedant activity than other extracts. At 4.0% concentration of chloroform extracts of P. parviflorus and petroleum ether extracts of P. hydropiper there were only 12.25 ± 0.58 and 13.00 ± 3.29 numbers of feeding spots respectively produced by H. theivora. In control there was 170.00 ± 8.52 number of feeding spots produced by the insect pest. In the comparison of the plant extracts with one of the synthetic insecticides i.e. Endosulfan 35% EC, it showed more reduction in number of feeding spots in the synthetic insecticide. The plant extracts were in crude form and more affectivity than Endosulfan 35% EC is expected from the pure fractions of the plant extracts.