Incidence regularity and control points of broccoli virus disease

Virus disease is the main disease of broccoli, which is common and serious. The incidence regularity and control methods of the disease are introduced as follows: first, in the areas where cruciferous vegetables are not planted in winter, the virus overwinters on stored cabbage, cabbage, radish or overwintering spinach, and cruciferous vegetables are planted in winter. the virus overwinters in the host. The virus source was transmitted to all kinds of cruciferous vegetables by peach aphid, cabbage aphid, cabbage aphid and so on. With high temperature and drought and high ground temperature, the growth and development of host root system was affected, the disease resistance decreased significantly, and aphids propagated rapidly and moved frequently, which led to the widespread occurrence of diseases. If the management is extensive, the soil is dry, lack of water and fertilizer, the disease will be serious. There were differences in disease resistance among different varieties. Second, the symptom of this disease occurs more seriously in the seedling stage. At the initial stage, near-round small chlorotic spots were produced on the leaves, and then the color of the whole leaves became lighter, or appeared green mottled alternately. With the development of the disease, the leaves shrank and twisted, and finally the whole plant necrotic. In the adult stage, in addition to the uneven mottling of the young leaves, the back of the old leaves sometimes produce dark brown necrotic spots, or accompanied by vein necrosis. finally, the diseased plants are short and deformed, the petiole is crooked, the bouquet becomes smaller, and the heavy ones do not bear balls at all. Third, prevention and control methods 1. Select more disease-resistant varieties according to local conditions, such as Green Ridge, Jasda and so on. two。 Reasonable intercropping, intercropping, rotation, stay away from other cruciferous vegetables, find seriously diseased plants and remove them in time. 3. Adopt the cultivation technique of insect prevention net cover, increase the application of organic base fertilizer, pay attention to watering small water and control aphids, and control the occurrence and spread of diseases. 4. At the initial stage of the disease, 20% virus A wettable powder can be sprayed 1000 times, or compound foliar fertilizer can be sprayed to inhibit the disease and enhance the disease resistance of broccoli.