Researchers start project to study Dickeya bacteria

Managing Editor

(Sept. 20, 2016) Delaware Cooperative Extension researchers are beginning a soil and water sampling project to help growers manage for Dickeya dianthacola, a relatively new disease affecting potatoes in the Mid-Atlantic region.
The sampling is directed at fields that had or were suspected of having Dickeya issues recently and fields that growers are considering planting potatoes in next year, said Dr. Nathan Kleczewski, Extension field crop plant pathologist in Delaware.
He said the project is meant to give potato growers more information as they make planting and management decisions for next year.
In potatoes, the bacteria exhibits symptoms similar to blackleg, a disease caused by several bacteria, so detection of Dickeya in particular is difficult.
While research from Europe indicates Dickeya doesn’t overwinter in soil without a host, the recent onset of the disease means there little data to work with.
“To help address this issue, we are collaborating with plant pathologists familiar with Dickeya to ascertain if Dickeya can be detected in Delaware fields and water,” Kleczerwski wrote in a posting on Delaware Cooperative Extension’s Sept. 9 Weekly Crop Update announcing the project. “This information will not only provide you the grower with valuable piece of mind, but will also help provide useful information with that will ultimately help improve potato producer productivity.”
Kleczewski said sampling will be at no cost to participating growers and results will remain confidential.
Last year, an outbreak of Dickeya, a bacterial pathogen that causes plants to wilt and potatoes to rot, caused significant crop losses for some growers.
The pathogen was confirmed in Maine, Delaware, Pennsylvania, Maryland, Virginia, North Carolina, West Virginia, and Florida this summer. Kleczewski said in Delaware, growers experienced similar losses this year as in 2015 but “since we knew better what we’re looking for, detections were up.”
Growers were urged to be more diligent about scouting for symptoms of the disease and reporting any suspicions of its incidence.
Plant pathologists say the bacteria has probably been in the region for a few years but on a smaller scale and weather conditions and other factors led to an increased presence in recent years. The bacteria is often spread from the potato seed piece and infected seed was traced back to seed lots in Maine in 2015 and to New Brunswick, Canada this year.
Growers who are interested in participating in the sampling project are being urged to contact Phillip Sylvester at This e-mail address is being protected from spambots. You need JavaScript enabled to view it or 302-730-4000.