【摘要】 开发利用天然杀虫剂是当今科学界热点的课题之一。本试验采用苦楝、黄花蒿、银杏等三种植物浸出液对菜青虫进行田间防治。试验表明 ,三种植物浸出液对菜青虫的田间防治效果随着自身浓度的升高而升高 ,其中 ,苦楝 4倍液对菜青虫的防治效果最好 ,药后 1、2、3天的防效分别达 88.7%、87.9%和 88.7%。其他 2种植物浸出液也表现出较好的防效更多还原

【Abstract】 The experiment was to measure the controlling effect with the extracts from Meliaazedrach Linn,Artemisia annua Linn and Ginkgo biloba on Pieris rapae in the field. Four kinds of density were set on every plant. Results indicated that with the concentration of extract increasing,the control effect improved. Expecially the 4 times solution of Meliaazedrach Linn had the best controlling effect,and 1d,2d,3d after spraying,the effect rose to 88.7%,87.9%and 88.7%, respectively.The effect of other extracts were significant as well.更多还原