Soybean (Glycine max Willd.) is one of the most economically important crops in the world, and it’s importance continuously increasing. Routine screening of Polish soybean fields has revealed an outburst of a new disease of soybean plants, with symptoms resembling those described for the bacterial blight, caused by Pseudomonas syringae pv. glycinae, and bacterial pustule caused by Xanthomonas axonopodis pv. glycines. The symptoms were observed in the field, on the leaves of investigated plants. The goal of this paper was the identification and characterization of the causal agent of that disease. Our studies have excluded virus and fungi and pointed the bacteria as the disease causal agent. Identification based on biological (Biolog Gen III), and molecular methods (16S rDNA, and gyrB sequencing, PCR species-specific testing) revealed that the soy pathogenic bacteria is Kosakonia cowanii species. We believe that the presence of such pathogens in the environment pose a serious threat for the crops and is also a warning, that in the near future we may be faced a new type of bacterial pathogens: both epi- and endophytic, abundant in the natural environment, with huge metabolic potential, and ability of quick colonization of new ecological niches and hosts, e.g. opportunistic pathogens of plants or humans. What’s important is that the plant-pathogenic and plant-epiphytic “environmental” strains of such species can be distinguished from each other only post factum, in the pathogenicity tests. They are indistinguishable or very hard to distinguish morphologically, biochemically or molecularly.

大豆（Glycine max Willd。）是世界上最重要的经济作物之一，其重要性不断提高。对波兰大豆田的例行检查发现一种大豆新病暴发，其症状类似于由假单胞菌丁香假单胞菌PV引起的细菌性疫病。轴突黄单胞菌（Xanthomonas axonopodis pv）引起的糖尿和细菌性脓疱。甘氨酸。在实地观察到的植物叶片上观察到症状。本文的目的是识别和表征该疾病的病因。我们的研究排除了病毒和真菌，并指出细菌是疾病的病因。基于生物学（Biolog Gen III）和分子方法（16S rDNA和gyrB测序，PCR物种特异性检测）的鉴定表明，大豆致病细菌是考萨尼亚牛种类。我们认为，此类病原体在环境中的存在对农作物构成了严重威胁，也是一个警告，即在不久的将来，我们可能会面临一种新型细菌病原体：表生和内生菌，天然环境，具有巨大的代谢潜力，并且能够快速定居新的生态位和寄主，例如植物或人类的机会病原体。重要的是，在致病性测试中，此类物种的植物致病性和植物表生性“环境”菌株只能在事后才进行区分。它们在形态，生化或分子上难以区分或非常难以区分。