Sweet crab apple (Malus coronaria) is a popular ornamental tree planted in gardens and urban forests in South Korea. In 2018, severe symptoms were observed on street plantings of sweet crab apple in Jinju, South Korea including shoot blight: shoot tips, twigs and foliage of infected trees turned brown, and dried completely. The causal agent isolated from the disease lesions was identified as Pseudomonas viridiflava based on biochemical tests, pathogenicity, and 16S rRNA and rpoD gene sequencing. On artificial inoculation, this pathogen not only caused shoot blight on sweet crab apple, but also bulb rot and leaf blight on onion. Here, we report the occurrence of bacterial shoot blight caused by P. viridiflava in sweet crab apple for the first time in the world.

中文翻译：

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绿黄假单胞菌引起的甜海棠芽枯病

甜海棠（Malus coronaria）是一种流行的观赏树，种植在韩国的花园和城市森林中。2018年，韩国晋州甜海棠的街头种植出现了严重的症状，包括茎枯病：受感染树木的茎尖、枝条和叶子变成褐色，并完全干燥。根据生化测试、致病性以及 16S rRNA 和 rpoD 基因测序，从病灶中分离出的病原体被确定为绿色假单胞菌。人工接种时，该病原菌不仅引起甜海棠茎枯病，还引起洋葱鳞茎腐烂和叶枯病。在这里，我们在世界上首次报道了甜海棠中绿黄假单胞菌引起的细菌性茎枯病的发生。