Soft rot bacteria are the main cause of early seed decay and stand losses in field grown potatoes. These bacteria are present in most surface water and colonize lenticels of early generation seed potatoes and cause disease when conditions are favorable for bacterial growth. Soft rot bacteria, formerly in the genus Erwinia, have been reclassified into the genera Dickeya and Pectobacterium. Because of their ubiquitous association with potato tubers, it is assumed that the soft rot bacteria is spread during handling and planting of seed potatoes and can potentially cause seed decay and blackleg. A soft rot bacterium new to the United States, Dickeya dianthicola was first recognized in 2015 (Secor, unpublished) as the cause of serious stand losses of potatoes in production sites in the eastern US. Replicated and commercial field trials using seed laboratory inoculated and naturally infected with D. dianthicola were conducted in multiple locations to determine spread from infected seed potatoes to healthy seed potatoes during handling and cutting. There is no evidence of increased stand losses or blackleg after simultaneous handling and cutting of Dickeya infected seed potatoes with seed potatoes free of Dickeya. Laboratory trials with labeled soft rot bacteria demonstrated spread of bacteria by cutting knives. There may be other factors that prevent establishment and infection by soft rot bacteria that may spread during seed potato cutting that need to be investigated. We conclude that spread of Dickeya bacteria during handling and cutting of seed potatoes is not a major cause of subsequent seed decay and blackleg resulting in increased stand losses in the field.

软腐细菌是田间种土豆早期种子腐烂和林分流失的主要原因。这些细菌存在于大多数地表水中，并在早期繁殖土豆的皮孔中定居，并在有利于细菌生长的条件下引起疾病。以前属于欧文氏菌属的软腐细菌已被重新分类为迪卡亚菌属和油杆菌属。由于它们普遍存在于马铃薯块茎中，因此认为软腐细菌在种薯的处理和播种过程中会传播，并可能导致种子腐烂和黑腿病。美国新近发现的一种软腐细菌，Dickeya dianthicola于2015年首次被发现（Secor，未出版），原因是美国东部生产基地马铃薯的严重林分损失。使用种子实验室接种并自然感染了石竹的重复和商业田间试验在多个地点进行了测定，以确定在处理和切割期间从受感染的种薯到健康的种薯的传播。没有证据表明，在同时处理和切割感染了迪卡（Dickeya）的种土豆和不含迪基的种土豆之后，林分损失或黑腿现象会增加。带有标签的软腐细菌的实验室试验表明，细菌是通过切刀扩散的。可能还有其他因素需要研究，这些因素可能阻止在马铃薯种薯切割期间传播的软腐细菌的建立和感染。我们得出的结论是，在处理和切割种薯的过程中，迪卡氏菌的传播不是导致随后的种子腐烂和黑腿病的主要原因，后者导致田间林分损失增加。