Identification and Pathogenicity of Species Isolated from Stored Potato Tubers Showing Symptoms of Dry Rot Disease

Abstract

Disease arises during the storage of potatoes as a result of pathogens introduced during growing and harvest of the tubers. In this study, the causative fungi of domestic potato dry rot disease were identified, and their pathogenicity was confirmed. A total of 76 species were isolated from 93 potato necropods collected from samples inoculated with dry rot disease. These 76 isolates were identified as Fusarium boothii, F. circinatum, F. citricola, F. foetens, F. iranicum, F. longifundum, F. oxysporum, F. pseudoanthophilum, F. solani, Botryotinia ranunculi, Clonostachys rosea, and Humicola nigrescens. The average size of the inoculation site was ≥ 4.6 mm in F. oxysporum and F. solani, which were pathogenic to dry rot in potatoes but were not pathogenic compared to other strains up to 5 weeks in a 15 to 20 °C and 99% RH environment. The pathogenicity of F. foetens and F. pseudoanthophilum was related to a strong relationship by forming a single system with F. oxysporum. However, except for F. oxysporum and F. solani, these strains have not yet been reported to be associated with dry rot disease. Additionally, the length of the cross-section and longitudinal section of the potato damage symptom inoculated with C. rosea increased the most among all strains. This suggests that C. rosea is the dominant species involved in domestic potato dry rot disease. By contrast, there are no reports of the involvement of B. ranunculi and H. nigrescens in dry rot disease. Therefore, these strains can be seen as parasitic using potato sclerosis as nutrients in in vivo experiments through wounds and are not directly related to dry rot disease.