In September 2012, alyssum ( Lobularia maritima ) plants cultivated in a greenhouse in Nagano Prefecture, Japan were observed with yellowing of the adaxial surface of leaves and a white downy growth on the abaxial surface. We identified the causal pathogen as Hyaloperonospora lobulariae based on the morphology and rDNA-ITS sequences. Seedlings of alyssum were inoculated with the pathogen, and the original symptoms were reproduced. This is the first report of downy mildew of alyssum in Japan.

In April 2007, coleus ( Solenostemon scutellarioides ) plants cultivated in a greenhouse in Chiba Prefecture, Japan were observed to have poor growth, with yellowing of the adaxial leaf surface and a gray to black downy growth on the abaxial leaf surface. The causal pathogen was identified as Peronospora belbahrii based on its morphology and rDNA-ITS sequences. Uninfected coleus was inoculated with the pathogen, the original symptoms were reproduced, and the isolate was reisolated. This is the first report of downy mildew of coleus in Japan.

Brown root rot of Russell prairie gentian was observed in the Aomori Prefecture, Japan in April 2011. The fungal isolate from the diseased root was identified as Subplenodomus drobnjacensis on the basis of its morphological characteristics and nucleotide sequences. The isolate induced similar root rot symptoms when inoculated in healthy Russell prairie gentian plants. We proposed the name “brown root rot” for this disease.

Cutting rot in Chrysanthemum is caused by the fungus Plectosporium tabacinum and was found on cuttings of ‘Jimba-No.2’ in 2008. The results of inoculation tests indicated that P. tabacinum infects major Chrysanthemum cultivars in Japan and that cuttings can serve as carriers and propagules of the pathogen already in the soil can serve as inoculum. Other P. tabacinum isolates may also infect Chrysanthemum, and P. tabacinum can be present as an endosymbiont in the plant. In tests of various fungicides, captan, 2,4,5,6-tetrachloroisophthalonitrile, and thiophanate-methyl effectively controlled cutting rot in Chrysanthemum.

An unknown disease of China doll (Radermacheria sinica) was found in Ise city, Mie Prefecture, Japan in July 2007. The causal agents were identified as Fusarium solani, Phytophthora nicotianae and binucleate Rhizoctonia sp. We propose the new disease as Fusarium rot, Phytophthora rot and Rhizoctonia rot of China doll, respectively.

A new species of Phytophthora was isolated from stem and root rot of chrysanthemum in the Gifu and Toyama prefectures of Japan. The species differs from other Phytophthora species morphologically, and is characterized by nonpapillate, noncaducous sporangia with internal proliferation, formation of both hyphal swellings and chlamydospores, homothallic nature, distinctive intercalary antheridia, and funnel-shaped oogonia. The new species can grow even at 35°C, with an optimum growth temperature of 30°C in V8 juice agar medium. In phylogenetic analyses based on five nuclear regions (LSU rDNA; genes for translation elongation factor 1α, β-tubulin, 60 S ribosomal protein L10, and heat shock protein 90), the isolates formed a monophyletic clade. Although the rDNA ITS region shows a high resolution and has proven particularly useful for the separation of Phytophthora species, it was difficult to align the sequences for phylogenetic analysis. Therefore, ITS region analysis using related species as defined by the multigene phylogeny was performed, and the topology of the resulting tree also revealed a monophyletic clade formed by the isolates of the species. The morphological characteristics and phylogenetic relationships indicate that the isolates represent a new species, Phytophthora chrysanthemi sp. nov. In pathogenicity tests, chrysanthemum plants inoculated with the isolates developed lesions on stems and roots within 3 days, and the symptoms resembled the ones originally observed. Finally, the pathogen’s identity was confirmed by re-isolation from lesions of infected plants.

In Hyogo, Japan, an unknown disease was observed on Himalaya-bergenie in 2007. The causal agent was identified to be Colletotrichum acutatum. We propose to name this disease “anthracnose of Himalaya-bergenie.”

The success of the Journal of General Plant Pathology largely depends on the quality of manuscripts submitted by authors, on the careful review by associate editors, and on the painstaking proofreading by editorial managers. We express special and sincere appreciation to Dr. Beth E. Hazen (USA) for her great efforts in correcting the English in the manuscripts. In addition to the associate editors and the editorial managers, the reviewers listed below provided constructive critical reviews of at least one manuscript during the year 2008. Their names are published here in grateful appreciation for their significant contribution to the journal as well as to the development of plant pathology.

Root and stem rot with wilt of above ground parts of cultivated chrysanthemums was first found in Ibaraki, Toyama and Kagawa prefectures, Japan in 2002 and 2003. Pythium species were isolated from the diseased tissues and identified as P. dissotocum , P. oedochilum , P. sylvaticum , P. ultimum var. ultimum and asexual strains of P. helicoides based on their morphologies and sequences of rDNA-ITS region. All the Pythium species were strongly pathogenic to chrysanthemums in pot conditions and were reisolated from the inoculated plants. Because Pythium root and stem rot of chrysanthemum has never been reported in Japan, we propose that this is a new disease that can be caused by the five Pythium species.

We assayed for Chrysanthemum stunt viroid (CSVd) in cultivated chrysanthemum (Chrysanthemum morifolium) collected from 10 prefectures in Japan and 8 wild species (Chrysanthemum spp.) cultivated at the National Institute of Floricultural Science (NIFS), Japan and determined complete nucleotide sequences of CSVd isolates infecting plants. CSVd was detected in 80 of 89 samples of cultivated chrysanthemum, and samples from all prefectures were infected. Since all 8 wild species had CSVd in RT-PCR results, they were recognized as hosts of CSVd, even though no stunt symptoms were observed. Five sequence variants of CSVd were distinguished among the 21 isolates based on the difference of the nucleotide sequences. Mutations were common in the P (pathogenicity) domain. Variant 5 from C. morifolium, and variant 4 from C. yoshinaganthum had different nucleotide sequences from those reported previously. Variant 1 was most frequently detected from samples in 6 prefectures and is assumed to be the predominant CSVd variant distributed in Japan.

Ikuo KADOTA Koji KAGEYAMA Masanori KAIDO Yuuji KAJITANI Takeshi KANO Kimihiko KATO Kazunori KATSUBE Masato KAWABE Akira KAWAGUCHI Akira KAWAKAMI Kazuto KAWAKITA Hitoshi KAWAMATA Tsutomu KAWASAKI Akinori KIBA Junichi KIHARA Nobuhiro KITA Issei KOBAYASHI Takao KOBAYASHI Motoichiro KODAMA Hironori KOGA Masanori KOIKE Motoo KOITABASHI Shinzo KOIZUMI Norio KONDO Yoshiki KONO Yoshitaka KOSAKA Yasuyuki KUBO Shiro KUNINAGA Motoaki KUSABA Shin-ichi KUSAKARI Satoko KUSUMOTO Manabu KUSUNOKI Hirotaka KUWATA Shigeru KUWATA Jan E. LEACH Yong-Hwan LEE