多项选择题
A.霉状物B.粉状物C.锈状物D.粒状物(小黑点)
A.叶斑B.溃疡斑C.坏死D.腐烂
A.玉米矮花叶病毒(Maize dwarf mosaic virus,MDMV)B.甘蔗花叶病毒(Sugarcane mosaic virus,SMV)C.南芥菜花叶病毒(Arabis mosaic virus,ArMV)D.小麦线条花叶病毒(Wheat streak mosaic virus,WSMV)