Pathogenicity of fungal species in aroid ( Colocasia and Xanthosoma ) rhizomes

Abstract

Among the diseases affecting aroids is rhizome rot caused by various pathogen fungi. These rots usually appear in poorly drained heavy soils with high organic matter content. These diseases appear more during the rainy season because it is a fungus complex living in the soil and is favored by high humidity. In order to know the virulence of different pathogens involved in this syndrome, cross-species inoculations were performed. Species of Rhizoctonia solani Kühn and Sclerotiun rolfsii Sacc were used in croos inoculations as they showed a higher percentage of appearance in the analyzed samples. The pathogenicity of the major fungal species was confirmed in Xanthosoma: S. rolfsii, F. sulphureum and F. chlamydosporum and in Colocasia: Phoma sp, Diplodia sp.and S. rolfsii. In the combined inoculations, Rhizoctonia solani showed synergism in the fungus Phoma sp in Xanthosoma and F. chlamydosporum in Colocasia and an antagonistic effect with the rest of the species. S. rolfsii showed synergism with all fungi in Colocasia except with Diplodia sp. and Phoma sp. while in Xanthosoma it showed antagonism with all species.

Keywords

• Infection
• dry rot
• rhisomes
• symptoms