Black scurf of potato: Insights into biology, diagnosis, detection, host-pathogen interaction, and management strategies

Black scurf/stem canker disease, caused by the basidiomycetous fungus Rhizoctonia solani Kuhn, became one of the major constraints to potato production worldwide. R. solani isolates of AG-3 are considered the main causal organism of black scurf, characterized by the presence of sclerotial bodies on the surface of potato tubers. R. solani limits the potato plants growth by developing cankers on sprouts, stems and tubers which make tubers ugly due to the appearance of corky spots and elephant hide symptoms on the tubers. To stop the establishment of disease, early detection and precise identification of pathogens are important components of an integrated disease management system. The present review summarizes the current knowledge about symptomology and epidemiology of black scurf, methods for early and accurate detection of black scurf pathogen/s, and molecular basis of potato-R. solani interaction. Elaborative and up-to-date information on various management options including cultural, chemical, biological, genetic manipulation and nanotechnological approaches and their effectiveness for managing black scurf are discussed. Genetic approaches that show promise for the control of black scurf include the development of transgenic lines by overexpressing or silencing pathogenesis-related (PR) genes and genome editing to develop lines with lower susceptibility to the disease is discussed.