Pathogen Identification and Pathogenicity of Fig (Ficus carica L.) Branch Canker Disease in Kashi, Xinjiang

Little is known about the fungal pathogens responsible for fig (Ficus carica L.) branch canker in the Kashi region of Xinjiang, China. Using a combination of morphological characterization and multilocus sequence analyses of ITS, TEF1-α, and RPB2, we identified fungal isolates obtained from cankered fig branches collected in commercial orchards in this region. The pathogenicity of representative isolates was evaluated by artificial inoculation of fig branches under natural field conditions. Two dominant fungal species, Fusarium proliferatum and Alternaria alternata, were consistently isolated from diseased tissues. In inoculation assays, both species induced typical branch canker lesions similar to those observed in the field. Lesions caused by F. proliferatum were generally larger than those induced by A. alternata. The original pathogens were successfully re-isolated from the inoculated branches, thereby fulfilling Koch's postulates. This study represents the first report of F. proliferatum and A. alternata as causal agents of fig branch canker in Xinjiang and expands the known spectrum of pathogens associated with fig branch diseases. These findings provide a scientific basis for improved disease monitoring and the development of sustainable management strategies in local fig orchards.