Bacterial blight of cotton (Gossypium hirsutum L.), caused by Xanthomonas citri pv. malvacearum, induces serious economic damage throughout all major cotton producing areas in the world. In 2020, the disease was confirmed in five commercial fields in the Regional Unit of Drama in Greece with yield losses reaching 30%. The symptoms on leaves included angular necrotic spots, narrow necrotic stripe along the veins of the leaf and dark lesions on petioles. On bolls circular water-soaked spots, brown necrotic spots and large irregular necrotic areas developed, eventually resulting in boll rot. Xanthomonas citri pv. malvacearum was isolated and subsequently identified morphologically, biochemically and molecularly, based on PCR with the specific primers MSCT1-P2F/ MSCT1-P2R and partial 16S rRNA gene sequencing. The pathogenicity of the isolates was confirmed using artificial inoculations on cotton seedlings with subsequent re-isolation and re-identification. This is the first time that the causal agent of bacterial blight of cotton, Xanthomonas citri pv. malvacearum, although earlier observed and isolated, is fully identified by biochemical, molecular and pathogenicity tests in Greece.

由柑橘黄单胞菌引起的棉花细菌性枯萎病（Gossypium hirsutum L.）。锦葵属对世界上所有主要棉花产区造成严重的经济损失。2020 年，该病在希腊戏剧区域单位的五个商业领域得到确认，产量损失达到 30%。叶片上的症状包括角状坏死斑点、沿叶脉的狭窄坏死条纹和叶柄上的深色病斑。棉铃上出现圆形水渍斑、褐色坏死斑和大片不规则坏死区，最终导致棉铃腐烂。柑橘黄单胞菌光伏发电。锦葵属基于使用特异性引物 MSCT1-P2F/MSCT1-P2R 和部分 16S rRNA 基因测序的 PCR，分离并随后在形态学、生化和分子上进行鉴定。分离株的致病性通过对棉花幼苗进行人工接种并随后重新分离和重新鉴定来确认。这是棉花白叶枯病病原菌Xanthomonas citri pv.的首次发现。尽管较早地观察到并分离出锦葵属植物，但在希腊通过生化、分子和致病性测试已完全确定。