The overall goal of my research is to contribute to the understanding of R. solani epidemiology in Arkansas. I am particularly interested in the effects of mycoviruses on fungal pathogenicity, and their potential role in biological control. We have optimized a protocol for the extraction of viral dsRNA from fungi and have identified dsRNA bands in > 50% of isolates collected from five different fields. Using next generation sequencing, we have discovered at least 20 new virus species. We have also identified Rhizoctonia solani RNA virus 1 (RsRV1) in an AG-4 isolate. This virus was previously reported in an AGI-1A isolate from China associated with slow growth and reduced fungal pathogenicity. This discovery provides evidence that R. solanimycoviruses may infect different anastomosis groups, elevating their potential for biological control in field environments. Future work will determine spatial distribution of Rhizoctonia spp., anastomosis groups, and mycoviruses; as well as correlations between these and environmental factors. We will also be working to characterize rates of mycovirus transmission via hyphal anastomosis, and the effects of mycovirus infection on pathogen fitness.