CHAPTER 33: Detection of Pectobacterium spp. and Dickeya spp. in Potato Tubers

Bacterial soft rot in potato foliage and tubers is caused by various species in the genera Pectobacterium and Dickeya. Most potato stem rots have been characterized as blackleg, a distinctive black-colored decay, or aerial stem rot, a soft rot of aboveground stems. The causal agents of these diseases are mainly Pectobacterium atrosepticum (=Erwinia carotovora subsp. atroseptica) and Pectobacterium carotovorum subsp. carotovorum (=Erwinia carotovora subsp. carotovora), respectively. Bacterial soft rot in potato stems usually starts underground from an infected seed tuber. Black discoloration of infected tissue, including the outside of the stem, is particularly associated with P. atrosepticum stem rots, but the other soft rotters, such as Dickeya spp., also cause tissue discoloration, particularly of the vascular tissue. Disease symptoms, management methods, and protocols for pathogen detection are included in this chapter.