Plant disease control is one of the essential aspects of food production Use of pesticide causes severe damage to our environment and have terrible effects on human health. It has been observed that the abundance use of pesticides also disturbs natural populations of various beneficial insects. Now environmental pollution has become a global problem, and due to the negative effect of chemical control, we must focus on new methods to control plant diseases, and the best of them is to use biological control method; this method includes the use of various beneficial microorganism having the potential to control plant diseases. Viruses that infect fungi are called as mycoviruses, and some of them could confer hypovirulence and thus have the capacity to control fungal diseases. Sclerotinia sclerotiorum, a widespread ascomycete fungus, can attack more than 450 plant species and subspecies. It causes stem rot on rapeseed and leads to substantial economic loss each year. Previously, several hypovirulence-associated mycoviruses have been identified from S. sclerotiorum, suggesting that this fungus could host various mycoviruses. Keywords: Biological control, Hypovirulence, Mycovirus, Sclerotinia sclerotiorum, RNA-seq, virus transmission