Pathogenicity of Sclerotium rolfsii on cocoyam varieties in Ghana

2011

English

The pathogenicity of five strains of Sclerotium rolfsii on four varieties of Xanthosoma mafaffa, identified as 'Amankani fitaa', 'Arnankani fufuo', 'Amankani kyirepe' and 'Amankani pa', and Cofocasia escufenta (Synonym: Cofocasiq antiquorum) in Ghana was investigated using the prescribed pathogenicity! infection tests. All the cocoyam varieties were susceptible to the five strains at difTerent rates. After 20 days of inoculation, all cocoyam plants were infected; leaves were dead and the cormels were heavily rotted. The rot progressed from top downwards. However, cormel rot was greater at the basal region than at the apical region. Strains SrXAI and SrXA2 caused the greatest rot in wound-inoculated cormels, while infection of 3-month-old plants proceeded fastest in soils inoculated with strains SrELI and SrEU. The pathogenicity was greatest on X mafaffa vat. 'Arnankani fitaa' and least on X mafaffa Vat. •Amankani kyirepc,' especially by the rotting activity of strains SrXA I, SrELI and SrEL2. Considering the pathogenicity of all five strains on the cocoyam varieties tested, C. esculenta was most vulnerable to the tested S. rolfsii strains in Ghana.

Tortoe, C.; Clerk, G. C.