病虫害是影响大葱产量与品质的主要因素之一。从大葱移栽到收获期间，病害、虫害发生的种类较多，危害较重。现介绍几种常见的病虫害及防治方法。 一、病害 1、紫斑病 此病主要发生在高温高湿的夏秋季节，沙质土、旱地、早苗或老苗、肥料不足、管理不善、葱蓟马为害严惩的地块 Pests and diseases are one of the main factors affecting the yield and quality of green onions. During the transplanting from green onions to harvesting, there are more kinds of diseases and insect pests that are more harmful. Now introduce several common pests and diseases and prevention methods. First, the disease 1, purple spot disease occurs mainly in the summer and autumn of high temperature and humidity, sandy soil, dry land, early seedling or seedlings, inadequate fertilizers, poor management, Thrips tabaci severely punished land