Mycoviruses infect and replicate independly in plant pathogenic fungi with wide distribution and the hypovirulence-associated mycoviruses have potential for exploitation as alternative biological control agents.Therefore, Screening and application mycoviruses associated hypovirulence as virocontrol agents have been the subject of considerable research interest in plant pathogenic fungi.Members of the family Partitiviridae have bisegmented dsRNA genomes and are not generally known to cause obvious symptoms in their natural hosts.An unusual partitivirus, Sclerotinia sclerotiorum partitivirus 1 (SsPV1/WF-1), conferred hypovirulence on its natural plant pathogenic fungal host, Sclerotinia sclerotiorum strain WF-1.