Taxonomic Reassessment of the Causal Fungus of Peach Fusicoccum Canker in Japan.

The causal fungus of peach Fusicoccum canker in Japan had been identified as a species in the genus Fusicoccum. However, isolates from the canker of peach in Niigata had phialidic conidiogenous cells and produced beta conidia in vitro, which are typical in the genus Phomopsis. Comparative studies of the Niigata isolates and an French isolate of Phomopsis amygdali (synonym: Fusicoccum amygdali) in morphology of colony and conidia, pathogenicity to peach shoots revealed that these isolates are identical and belong to the same species. W- and G-type isolates from peach Phomopsis rot in Japan had alpha conidia similar to the Niigata isolates, but isolates of neither type caused symptoms of peach Fusicoccum canker in inoculation tests. It was concluded that the causal fungus of peach Fusicoccum canker is not a Fusicoccum but Phomopsis amygdali (Delacroix) Tuset et Portilla.