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Best management practices for buying seed potatoes for 2017


February 7, 2017
By Steven B. Johnson University of Maine Cooperative Extension

Topics
Dickeya dianthicola symptoms on a potato plant. Cornell University

February 7, 2017, Presque Ilse, ME – Potato seed tubers harboring Dickeya dianthicola and Pectobacterium wasabiae are the only confirmed source of these pathogens.

At this point, there is no evidence that either of the two pathogens overwinter in the soil. The generally accepted length of survival time in the soil for these pathogens is one week to six months, climate dependent. Longer survival is possible on plant matter in the soil. With that, the source of the inoculum, and hence the source of the disease, is seed. Therefore, any best management practices efforts on Dickeya dianthicola or Pectobacterium wasabiae must start with the seed.

Select seed from farms where Dickeya dianthicola or Pectobacterium wasabiae have not been detected and seed marketed in previous years has not been associated with Dickeya dianthicola or Pectobacterium wasabiae.

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Check North American Certified Seed Potato Health Certificates before purchasing seed and select seed that had not been increased on a farm associated with Dickeya dianthicola or Pectobacterium wasabiae.

Select seed with zero blackleg levels reported on the North American Certified Seed Potato Health Certificate.
 
Select seed that has been PCR tested by an independent laboratory and confirmed to be free of Dickeya dianthicola and Pectobacterium wasabiae.

Select seed from farms where a zero tolerance approach to Dickeya dianthicola and Pectobacterium wasabiae is being implemented.

Seed lots with field readings of blackleg present should have reports that suspect plant samples were taken for testing and found to be Dickeya dianthicola and Pectobacterium wasabiae free.

Avoid seed from fields where symptoms of Dickeya dianthicola or Pectobacterium wasabiae were observed, even if affected plants were rogued out.

Where possible, avoid irrigated seed crops.

Where possible, avoid planting whole-seed lots that were stripped from multiple lots.