Thanatephorus cucumeris

In 1858, Julius Kuhn observed and described a fungus on diseased potato tubers and named it "Rhizoctonia solani". "Rhizooctonia" is from Ancient Greek, ῥίζα ("rhiza", "root") + κτόνος ("ktonos", "murder"). "Solanum", Latin for nightshade, is the genus of the potato. The disease caused was well-known before the discovery and description of the fungus.