New host for raspberry bushy dwarf virus: arctic bramble (Rubus arcticus)

Raspberry bushy dwarf virus (RBDV) was detected in three new host plants inRubus species,i.e., arctic bramble (R. arcticus ssp.arcticus), Alaskan arctic bramble (R. arcticus ssp.stellatus) and their hybrid (R. arcticus L. nothosubsp.stellarcticus G. Larsson). The virus was identified as RBDV by the symptoms elicited in the test plantsChenopodium quinoa andC. amaranticolor, by sedimentation profile in sucrose density gradient, by RNA banding pattern in agarose gel electrophoresis, by protein analysis of the purified viruses in SDS-polyacrylamide gel electrophoresis, and by Western blotting. There was a high incidence of RBDV-infected plants in the experimental plots. The presence of the virus in arctic bramble did not always induce foliar symptoms. However, yellowing of the leaves around central and lateral veins was quite frequently observed, especially in spring and autumn.     

First report of downy mildew of carnation caused by Peronospora dianthicola in Japan

Yellowish lesions with downy, gray growth developed on the leaves of carnations (Dianthus caryophyllus) in a greenhouse in Hokkaido Prefecture, Japan, in March 2011. We identified the fungus on diseased plants as Peronospora dianthicola on the basis of the morphologies of the conidia, conidiophores, and oospores. To confirm pathogenicity of the fungus, we inoculated healthy plants with a conidial suspension of the fungus, and the plants developed the same signs and symptoms as the naturally infected plants. We then reidentified P. dianthicola from the diseased lesions. This is the first report of downy mildew of carnation in Japan.     

First report of anthracnose on tillandsia caused by Colletotrichum sp. in Japan

Journal of General Plant Pathology - In July 2018, tillandsia (Tillandsia sp.) plants with brown to dark brown lesions on the leaves and pseudobulbs were found in Japan. Based on morphological and...     

A new yellowing disease of cucurbits caused by a luteovirus, cucurbit aphid-borne yellows virus

Since 1988, a yellowing disease of melon, cucumber and zucchini squash has been frequently observed in summer and autumn crops in France. Infected plants show yellowing and thickening of the older leaves; symptom intensity differs depending upon cultivar and season, and can be easily overlooked when plants are already infected by mosaic-inducing viruses or other pathogens. The disease is associated with the presence of a virus with spherical particles c. 25 nm in diameter, which is readily transmitted in a persistent manner by the aphids Myzus persicae and Aphis gossypii , but not mechanically. Serological analysis, nucleic-acid-hybridization experiments and host-range studies indicate that the virus is distantly related to, but distinct from, beet western yellows virus (BWYV). We propose to name this virus cucurbit aphid-borne yellows virus (CABYV), and to consider it as a tentative new member of the luteovirus group. CABYV was found to reduce significantly the yields of melon and cucumber by decreasing the number of fruit per plant but not by altering the fruit shape or quality. Preliminary investigations of the epidemiology of CABYV indicate that the virus is common in weeds and in cultivated cucurbits. CABYV was frequently detected in various regions of France, suggesting that it is one of the most prevalent viruses infecting cucurbits in this country.     

水稻新病害南方水稻黑条矮缩病发生特点及危害趋势分析

由斐济病毒属(Fijivirus)暂定新种南方水稻黑条矮缩病毒(Southern rice black-streaked dwarf virus,SRBSDV)引起的水稻矮缩病,自2001年在广东省阳西县被发现以来,已迅速扩散至我国南方广大稻区。2009年,该病害在我国南部及越南晚季稻上暴发成灾,造成严重的产量损失。本文简介了该病害的症状、危害特点、病原病毒及其传毒介体特征,对其发生趋势进行了讨论,提出了以秧苗期治虫为重点的病害防控应急措施。     

First report of horn gall disease of Cinnamomum pseudopedunculatum caused by Laurobasidium hachijoense in the Bonin Islands,Japan

Journal of General Plant Pathology - In June 2017, deer-horn-like galls covered with a whitish, powdery fungal layer were found on the trunks of Cinnamomum pseudopedunculatum (Lauraceae) in...     

First report of bacterial blight of crucifers caused by Pseudomonas cannabina pv. alisalensis in Japan

In October 2010, a bacterial disease produced flecks and spots on leaves of Chinese cabbage, cabbage and Japanese radish in Nagano Prefecture, Japan. The symptoms started on the abaxial surface of leaves as angular, water-soaked flecks of 1–2 mm in diameter with a yellow halo of 3–4 mm width. These flecks then became visible on both leaf surfaces, enlarged and coalesced into large blight lesions. The symptoms were similar to bacterial leaf spot caused by Pseudomonas syringae pv. maculicola. The bacterium isolated from leaf lesions formed a white colony and produced polysaccharides on YP agar. The isolates were identified as P. syringae group by LOPAT tests and the 16S rDNA sequence. Moreover, the results of pathogenicity on cruciferous plants, bacteriological characteristics, rep-PCR and the sequences of rpoD and gyrB showed that the isolates should be identified as P. cannabina pv. alisalensis (recently transferred from P. syringae pv. alisalensis). This is the first report of P. cannabina pv. alisalensis isolated from diseased crucifers in Japan.