Dickeya dianthcola Update

Kate Everts, Vegetable Pathologist, University of Delaware and University of Maryland; keverts@umd.edu

Several plants with suspected Dickeya dianthicola symptoms have been reported in the mid-Atlantic region in spring 2017 and sent for diagnosis. The results of the tests are still pending. Growers should be vigilant in scouting their fields. If you see any suspect symptoms of blackleg, or your potatoes had poor emergence, or you believe that you have Dickeya in your field, it is important to submit the plants for diagnosis. Suspect samples should be sent for testing to your county extension educator or to Dr. K. Everts (keverts@umd.edu), or Dr. N. Kleczewski (nkleczew@udel.edu) for submission to a diagnostic lab. Remember that this disease results from infected seed pieces. We have no evidence that the bacterium can overwinter in soils here in the region, which means it is introduced to field through infected seed pieces.

Figure 1. Potato plant exhibiting symptoms of Dickeya dianthicola infection. Note darkened aerial stem lesions

Figure 2. Potato plant exhibiting symptoms of Dickeya dianthicola infection. Note lesions emanating from the soil line

In addition to testing, it is important that you have your seed health certificate. This certificate will indicate the source of your potatoes and the lot of origin. Information on best management practices for buying seed can be found here:
(http://vegetablemdonline.ppath.cornell.edu/NewsArticles/Potato%20Dickeya%20recommendations-Northeast-2017.pdf )