摘要
According to incomplete records, there are about 50 fungus diseases of rice in China.Rice blast and sheath blight are the most destructive and cause severe damage. Other fungus diseases, such as rot, narrow brown leaf spot, leaf scald and brown spot are not serious. Four bacterial diseases of rice occur in China. Bacterial blight is the most common and destructive one, followed by bacterial leaf streak, rice brown spot and brown stripe.The latter two appear sporadically and are less important. The virus and virus-like diseases of rice that have been recorded in China are rice yellow dwarf, rice dwarf, rice yellow stunt, rice black-streaked dwarf, rice stripe, dwarf-like diseases, rice orange leaf disease, rice transitory yellowing, and grassy stunt etc. They are distributed mainly in the southern part of China beyond the Yangtze River. Rice yellow stunt virus has recently become important and widespread in China. It causes 20-30% of yield losses in areas where it prevails.
