大葱比较容易发生褐斑病、锈病、紫斑病,黑斑病及霜霉病。危害大葱的主要虫害有葱蝇、葱斑潜蝇和蓟马。一、防治虫害(一)蓟马蓟马属于缨翅目蓟马科。危害大葱和葱蒜类其他蔬菜。虫体很小,成虫善跳跃若虫和成虫均刺吸葱叶汁液,严重时伤面形成密布灰白色小斑点,使葱叶寿命缩短、光合能力降低。蓟马5～9 Onion is more prone to brown spot, rust, purple spot, black spot and downy mildew. The main pests harmful to green onions are onion fly, green onion leaf miner and thrips. First, pest control (A) thrips thrips Thysanoptera Thrips family. Harms onion and garlic and other vegetables. Insects are very small, adult good jumping nymphs and adults are punctuated onion juice, severe injuries to the formation of small gray spots on the white spots, so that the onion leaves shortened life expectancy, reduced photosynthetic capacity. Thrips 5 to 9