What are the diseases and insect pests of green onions?

What are the diseases and insect pests of green onions? If you want to introduce how to prevent and control the diseases and insect pests of green onions, please introduce that the prevention and control of diseases and insect pests should be based on the prevention and control of green onions for 2-3 years; clean the countryside to eliminate the sources of diseases and insect pests; select disease-resistant varieties; carry out seed disinfection, that is, soak the seeds in 50 ℃ warm water for 25 minutes before sowing, then soak them in cold water, fish out and dry, sow seeds, apply sufficient basic fertilizer, strengthen field management, and cultivate healthy scallions to enhance disease resistance. First, downy mildew. It mainly harms leaves and pedicels. Primary yellow-white or milky yellow, spindle-shaped or oval infection spots on the pedicel, which produce white mold, and then become yellowish or dark purple. The middle and lower leaves were infected, and the leaves above the diseased parts gradually withered and sagged. The pseudostem is often broken and bent when infected with disease. Bulb infection can cause dwarf leaf deformity or distortion of diseased plants. When the humidity is high, a large amount of white mold grows on the surface. Prevention and treatment methods: at the initial stage of the disease, spray 75% chlorothalonil wettable powder 600x liquid, or 50% nail cream copper wettable powder liquid 1000 times, or 64% poisonous alum wettable powder 500x liquid, spray once every 7-10 days for 2-3 times. Second, rust. It mainly harms leaves, pedicels and green stems. At the initial stage of the disease, oval slightly raised orange blister spots were produced on the epidermis, and then the epidermis ruptured and turned outward, spreading orange powder. Prevention and treatment methods: at the initial stage of the disease, spray 15% triadimefon wettable powder 2000-2500 times, or 50% verapamil EC 700800 times, or 70% mancozeb 1000 times plus 15% triadimefon 2000 times, once every 10 days, continuous prevention and treatment for 2-3 times. Sclerotinia sclerotiorum. Damage to leaves, pedicels, most of the disease near the surface. The hyphae expanded from the outer to the inner leaf sheath, and in severe cases, the whole plant was inverted, and the base rotted and died. The diseased part produces white flocculent hyphae and black short rod-shaped or granular nuclei. Prevention and treatment: at the initial stage of the disease, 50% carbendazim wettable powder, or 50% methyl topiramate, or 40% sclerotiorum 1000-1500 times were sprayed at the base of the plant, once every 7-10 days, for 2-3 times. Fourth, Liriomyza sinensis. The larvae zigzag through the leaves all their lives, latent feeding on the mesophyll, and the leaves can see tortuous tunnels. The mesophyll was killed, leaving only the upper and lower layers of white transparent epidermis, and the leaves withered in severe cases. Control methods: during the peak period of adult occurrence, spray Wanling, or 1000-1500 times of methomyl EC plus 1000 times of cypermethrin. Spray once every 5-7 days, a total of 2-3 times. It can also treat pests such as spring onion and thrips. Click to get more green onion planting techniques click to get more vegetable planting techniques