Date of this Version
Plant Health Progress 17:3 (2016), pp. 155-157.
Over the last five years, the production of dry yellow peas (Pisum sativum L.) has been increasing in Nebraska and other areas of the Central High Plains, according to a USDA report (Jasa 2013). Dry pea is a short-season crop with a low water requirement, making it a good rotational crop for the high plains. We have noted bacterial pathogens, potentially a disease complex, that may negatively impact the production of pea in this region, and one of the emerging pathogens is Erwinia rhapontici. This pathogen is a gram-negative bacterium that has been reported from soil, seed, and different plant tissues, causing pink seed, crown rot, shoot and stem rot, blossom rot, or soft rot on more than 20 plant hosts, including pea (Huang et al. 2003). The disease was first reported on pea in the United States from Montana in 2002 and was later found in North Dakota in 2006 (Wise et al. 2008). Erwinia rhapontici belongs to the carotovora subgroup of Erwinia. Unlike many members of the soft rot carotovora subgroup that produces pectolytic enzyme, E. rhapontici does not degrade pectate. The organism is capable of fermenting glucose, fructose, maltose, and sucrose. Also, it produces a diffusible pink pigment on sucrose-peptone agar but not on potato dextrose agar nor nutrient agar. However, it has been shown that some strains may not produce pink pigments regardless of the type of media used (Huang et al. 2003). Proferrosamine A has been identified in the pink pigment produced, it is associated with iron deficiency in plants, and was suspected by Huang et al. (2003) as partly a pathogenicity determinant and virulence factor of E. rhapontici.