Photo 2. Close-up of underground stem of potato showing cankers caused by black scurf, Rhizoctonia solani.
Photo 3. Black scurf, the name given to the appearance of potato tubers when sclerotia of Rhizoctonia solani form on the surface.
Black scurf, rhizoctonia canker
Rhizoctonia solani. It is also called Thanatephorus cucumeris, which is the sexual state; it may occur on the lower stems of potato. There are a number of strains, and the common one on potato is referred to as AG3.
AUTHOR Grahame Jackson
Information from Diseases of vegetable crops in Australia (2010). Editors, Denis Persley, Tony Cooke, Susan House. CSIRO Publishing; and from Wharton P, Wood E (Undated) Rhizoctonia stem canker and black scurf of potato. University of Idaho Extension. (https://www.cals.uidaho.edu/edcomm/pdf/CIS/CIS1198.pdf). Photos 1-3 Gerald Holmes, California Polytechnic State University at San Luis Obispo, Bugwood.org. Photo 4 Bouchek-Mechiche K (2016) Black scurf. GNIS/INRA. (https://www.potato-tuber-blemishes.com/Symptoms/Pitted-or-raised-symptoms/Black-scurf).
Produced with support from the Australian Centre for International Agricultural Research under project PC/2010/090: Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production, implemented by the University of Queensland and the Secretariat of the Pacific Community.
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