乐都县是全省蔬菜的主要种植基地 ,其中韭菜的种植面积最大。近年来 ,危害韭菜的害虫日益严重 ,其中韭蛆和根蛆十分猖獗 ,造成很大的经济损失 ,当地农民普遍采用甲拌磷 (也称 3911)进行防治。该药是一种高效、剧毒、残效期长的内吸性杀虫剂 ,对人畜有剧毒。为了使农户掌握正确 Ledu County is the main planting base of vegetables in the province, of which the largest planting of leeks. In recent years, pests that endanger leeks have become increasingly serious. Among them, leek maggots and root maggots are very rampant, causing great economic losses. Phytophosphorus (also called 3911) is widely used by local farmers for prevention and treatment. The drug is a highly efficient, highly toxic, long-term residual systemic insecticide, highly toxic to humans and animals. In order to make farmers grasp the right