Exobasidium dubium and E. miyabei sp. nov. causing Exobasidium leaf blisters on Rhododendron spp. in Japan

Abstract

Two Exobasidium species causing Exobasidium leaf blister on Rhododendron spp. are described. An Exobasidium leaf blister on Rhododendron yedoense var. yedoense f. yedoense has been recognized in Hokkaido Prefecture, Japan, since the first report was issued in 1950. The causal fungus is identified with Exobasidium dubium from the morphology of its hymenial structure and mode of germination of the basidiospores. Another Exobasidium leaf blister on Rhododendron dauricum has been observed in Hokkaido Prefecture, Japan. In comparison with morphology based on hymenial structure and mode of germination of the basidiospores of the 100 validly described taxa, this fungus differs from those known taxa in the size of basidia and basidiospores, the numbers of sterigmata and septa of basidiospores, and the mode of germination of basidiospores. Thus, a new species, Exobasidium miyabei, is established and illustrated.

Three species of Exobasidium causing Exobasidium leaf blight on subgenus Hymenanthes, Rhododendron spp., in Japan

“…Specimens examined are listed in the description of the species (Table 1). Materials for morphological observations were prepared and conducted by light (LM) and scanning electron microscopy (SEM) as described previously (Nagao et al 2003). Samples for SEM were prepared and observed as mentioned previously (Nagao et al 2001).…”

“…Colonies from a single basidiospore were obtained as described previously (Nagao et al 2003). Cultures were kept in the Laboratory of Plant Parasitic Mycology, Institute of Agriculture and Forestry, University of Tsukuba, and some of the isolates of Exobasidium spp.…”

Exobasidium symploci-japonicae var. carpogenum var. nov. causing Exobasidium fruit deformation on Symplocos lucida in Japan

“…Colonies from a single basidiospore were obtained from the fresh materials as described previously (Nagao et al 2003 Isotypus in Herbario Instituti Nationalis Scientiae AgroEnvironmentalis, Tsukuba, Japonia conservatus (NIAES 20530).…”

“…For light microscopy, materials were prepared as described previously (Nagao et al 2003). Observations and measurements of conidia were conducted from the pure culture isolates on Difco potato dextrose agar (PDA).…”

Taxonomy of Exobasidium otanianum causing Exobasidium leaf blight on Rhododendron species in Japan

“…Fresh specimens on R. hyugaense and R. reticulatum f. glabrescens collected in the field were used for morphological observations. Materials for morphological observations were prepared and conducted by light (LM) and scanning electron microscopy (SEM) as described previously (Nagao et al 2003). Samples for SEM were prepared and observed as mentioned previously (Nagao et al 2001 …”