Prevention and treatment of shallower disease of green onion

(agricultural Wealth net) the pathogen of scallions atrophy disease belongs to virus, which is one of the main diseases in onion and garlic crops in recent years. Green onion atrophy disease, also known as yellow dwarf disease, is the symptoms of green onions infected by the virus. In recent years, onion fields are common in our city, especially in old vegetable areas and green onion production bases. The disease is becoming more and more serious. After the onset of the disease, the output of the mild ones will be reduced by 20%, and the serious ones can be reduced by about 75%.

It shows yellow dwarf virus on onion, yellow stripe virus on leek and garlic, latent virus on green onion and so on. The newly planted onion seedlings grew well. If high temperature and drought occurred in July, a few typical atrophic disease plants appeared in August, and the incidence peak was from mid-September to mid-October. In the initial stage of the disease, the new leaves are tender and thin, the color of the leaves become lighter, the heart leaves appear light yellow spots, the leaves are uneven and twisted in a spiral shape, some leaves are twisted to one side, the plants shrink, and the longer the onions are, the smaller they are. According to field observation: continuous cropping of seedlings in old vegetable fields; early seedling raising before "the Autumn Equinox" and more bolting in the following spring; semi-dry planting of onion seedlings; thrips and aphids in onion seedling stage; soil drought after resurrection; the disease was more serious in years with high temperature in July and less Rain Water.

According to the occurrence characteristics of Welsh onion atrophy disease, comprehensive cultivation measures can greatly reduce the occurrence of this disease. (1) selecting disease-resistant varieties such as Zhangqiu sycamore, Wuyeqi and their first-generation hybrids, Luoyang holly, Tangshan monologue and so on; (2) raising seedlings early before crossing "the Autumn Equinox" and raising seedlings at night after "the Autumn Equinox", vigorously popularizing "the Spring Equinox" plastic film mulching to raise spring seedlings (3) 1000 times of the mixture of 40% dimethoate and 80% dichlorvos at seedling stage, adding a small amount of washing powder or waste soybean milk to increase the adhesion ability (the following drugs are the same), control thrips and aphids; (4) re-apply base fertilizer before planting onions and grade the seedlings. Dip the root with dimethoate 1000 times, and plant strong seedlings. (4) after colonization and resurrection, 250 kg / 667 square meters of wheat bran or potato seedlings were covered in the spring onion ditch, 300 kg / 667 square meters of fresh weeds were moisturized and cooled, and the soil was thinned and fertilized; (6) during the growth period from August to October, 50 kg / 667 square meters of special compound fertilizer for green onions was applied at a time, urea was applied twice, 20 kg / 667 square meters each time, and topdressing was combined with ploughing, soil cultivation and watering to promote the growth of spring onion seedlings. (7) spraying 2 times before planting onions, once every 7-10 days, spraying 3 times naphthalene acetate solution after planting, 1 branch adding 20 kg of water to prevent disease and strong trees; (8) if there are still a small number of diseased plants in the onion field, you can use 0.5% antibiotic No. 1 300-400 times or 25% antiviral No. 1 wettable powder 300 times, or 1.5% Zhanshangling 400 times, thoroughly control and ensure the healthy growth and harvest of green onions.