First Report of Rhizoctonia solani AG 3‐PT causing black scurf on potato tubers in Namibia

Rhizoctonia solani develops sclerotia on the tubers (black scurf), brown sunken lesions (cankers) on the stolons, stems and roots of the plant (Banville, 1989) as well as tuber deformation, cracking, “elephant hide” and pitting (Woodhall et al., 2007; Muzhinji et al., 2015). The cultures were observed microscopically and two isolates (RT01 and RT02) with Rhizoctonia-like structures (Figures 1 and 2), i.e., aerial mycelium, right angled branches having a constriction at the point of origin (Ogoshi et al., 1983), were sub-cultured on PDA and incubated at 25°C for 48 hrs. OL353907-OL353908) showed 99.7% identity with other AG 3-PT sequences in GenBank (KJ777666 and AB905388). [...]based on morphological and molecular sequencing, the isolates were identified as R. solani AG 3-PT.