Barley yellow mosaic disease mainly occurs in Hubei, Zhejiang, Jiangsu, Shanghai, Hebei and other provinces and cities in the lower reaches of the Yangtze River, among which Jiangsu, Zhejiang, Shanghai and other places are more severe. The early death of the diseased plant resulted in a reduction in the percentage of spikes in barley, a significant decrease in seed setting rate, a decrease in the weight of one thousand grains, a decrease in the rate of powder extraction, and a decrease in quality. Yellow leaf mosaic disease occurs in barley, with dwarfing plants, loose plant types, reduced tillering, poor root development, and increased brown roots. In the early stage of tillering, a short strip-shaped chlorotic spot parallel to the veins appeared on the undeveloped heart leaves. The chlorotic spots gradually developed and connected, resulting in leaf-shaped leaves. After heading, the symptoms of the upper leaves retire. Some of the severe diseased plants can't be eared. Some of them can produce heading, but they have small spikelets, many empty pods, and flag leaf and leaf sheaths and even chlorotic leaves on the glume. When conditions are appropriate, barley can show obvious symptoms within 1 to 2 months after sowing. The pathogen is the barley yellow mosaic virus. The virus can be transmitted through the soil and the mucilaginous bacteria and sap. It has not been found that the seeds and insects can transmit the virus. The occurrence of barley yellow mosaic disease varies greatly among different varieties. Generally, six-row barley is more resistant to disease, and barley is highly susceptible. Year after year, large-scale planting of susceptible varieties, the number of transmission media and sources of poisons accumulates year after year, which is an important reason for the continuous increase in the area of ​​the disease and its degree of increase year by year. Because of the release of zoospores from M. polymyxa, zoospores need high soil moisture and temperatures of about 15°C. Warm and rainy weather in autumn and winter is conducive to disease occurrence. On the contrary, the sowing season is dry and drizzle, the temperature is low, the incidence is light or the disease is late. The autumn sowing in Jiangsu, Zhejiang and Shanghai is mostly in October-November. The soil temperature at this time coincides with the suitable soil temperature of zoospore invading the poisonous bacteria in the cereals. The earlier the sowing, the earlier and the severer the onset, the more appropriate the late planting. It is possible to avoid the peak period of infestation and transmission of M. polymyxa. Therefore, delayed sowing can reduce the occurrence of diseases. When the incidence of barley is heavy, rotation should be implemented to promote the rotation of dry crops. Strictly controlling the spread of the diseased soil, deepening the diseased soil or pressing a disease-free soil in a severe disease field can control the disease occurrence to some extent. Addition of fertilizing materials to the field can delay the development of the disease and promote the recovery of physiological function of the diseased plant. Folding Half Face Mask,Disposable Face Cover for Self Use,Medical Kn95 Face Mask,Anti-fog Haze Dust Proof Face Dongguan Keyutai Mask Co., Ltd. , https://www.maskkytai.com