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Dickeya species are bacteria that cause diseases on numerous crops and ornamental plants world-wide. Within the Enterobacteriaceae family, eight genera, including Dickeya, are pathogenic to plants.  Several changes to the taxonomic classification of the group have occurred recently.  There are now six species described within this genus, D. dadantii, D. chrysanthemi, D. paradisiaca, D. zeae, D. dianthicola, and more recently D. solani.  For D. dianthicola, the name has evolved from Erwinia chrysanthemi pv. dianthicola to Pectobacterium chrysanthemi pv. dianthicola to Dickeya dianthicola.

Dickeya spp. are soft rot pathogens that degrades succulent fleshy plant organs including roots, tubers, stem cuttings, and leaves including potato.  Members of the Dickeya genus, generally feed on the tissues of living plants, are able to survive long times only in association with plant material, and multiply only in association with a suitable host plant.  The symptoms associated with Dickeya species infection of potato are often indistinguishable from those caused by Pectobacterium spp. Under wet conditions, typical blackleg symptoms are slimy, black rot lesions spreading from the rotting tuber up the stem.  When conditions are dry, the symptoms are typically stunting, yellowing, wilting, and stem desiccation.  Tuber soft rot symptoms include macerated tissue with creamy exudate which turns black; with secondary bacterial infection, tubers often have a foul smell.



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Lynn Evans-Goldner
National Policy Manager
Telephone: 301-851-2286

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