Occurrence and Pathogen Dominant Species of Celery Root Rot in Dingxi City, Gansu Province

PurposeTo define the occurrence and identify the pathogens of celery root rot in Dingxi City, Gansu Province, providing theoretical basis for field control.

MethodsA survey and collection of samples were conducted in eight villages in Dingxi City. Pathogens of celery root rot were isolated by tissue separation and purified by single spore, and identified by morphological characteristic and molecular methods including sequence alignment of rDNA-ITS and the translation elongation factor 1α gene (TEF-1α). The pathogenicity of isolates was tested according to Koch’s postulates.

ResultsThe rate of diseased fields and occurrence of celery root rot in Dingxi were 63.54% and 24.45%, respectively. Two symptoms of celery root rot disease were observed including basal stem rot with constriction and lower taproot rot or vascular discoloration. A total of 78 strains of genus Fusarium spp. were obtained, including 62 strains of F. oxysporum, 11 strains of F. acuminatum and five strains of F. solani, and the isolation frequencies of them were 79.49%, 14.10% and 6.41%, respectively. As measured by pathogenicity, the disease indexes of F. oxysporum, F. solani and F. acuminatum were 78.33, 24.44 and 11.11, respectively.

ConclusionF. oxysporum is the dominant pathogen with highest virulence of celery root rot in Dingxi City. F. solani and F. acuminatum are weaker and this is the first report that F. acuminatum can infect celery root rot in China.