PEI Day 2017  is the name of a group of .

 Various Dickeya species cause different plant diseases.

 Two species of Dickeya cause blackleg in potato.  Dickeya blackleg is a more aggressive disease than blackleg caused by atrosepticum.

 One of the blackleg-causing Dickeya species now occurs in Maine, and has been spread to other states.

Blackleg is a potato disease with characteristic symptoms  seed-piece decay

 black-pigmented soft rot of stems

 soft rot of tubers Blackleg is caused by several bacteria:

. Pectobacterium atrosepticum . Pectobacterium brasiliense . Pectobacterium parmentieri (formerly wasabiae) . Dickeya dianthicola . Dickeya solani

ATROSEPTICUM BLACKLEG DICKEYA BLACKLEG

 Usual cause of blackleg in  Recently introduced into the Canada – in the past and United States, probably from currently Europe

 Favours lower temperatures  Favours higher temperatures

 Symptoms: almost always  Symptoms: sometimes clearly evident and visible on restricted to internal pith tissue stems of the stem

 Causes limited yield loss  May cause serious disease loss ATROSEPTICUM DICKEYA  Blackleg develops from bacteria that move from the seed tuber into the vascular tissue of the stem.

 These bacteria grow and multiple and produce soft-rotting Drawing from Potato Health Management. R.C. Rowe, ed. enzymes. APS Press Blackleg Disease Cycle  The Seed Potato

. They may look healthy and well BUT blackleg bacteria may be present in lenticels or stolon end vascular tissue

 During the growing season — from bacteria that spread from decaying seed pieces

AND

 During harvesting, bin piling, sorting, etc. — whenever tubers come in contact with contaminated surfaces  Clean seed ▪ High generation seed (fewer field generations)

▪ Know your seed source

▪ Good grower practices (your own and seed supplier)

▪ Laboratory tests (if unsure)  Sanitation ▪ Bacteria are readily spread on equipment

▪ Blackleg bacteria are sensitive to common disinfectants

▪ Keep equipment clean

▪ Disinfect equipment between lots

▪ Clean up culls

 Roguing – yes, BUT be careful not to spread blackleg bacteria from infected plant.

 Survival in soil and water – yes, but for a limited time only (Dickeya probably a little more than P. atrosepticum).

 Spread by insects – theoretically yes, but not shown to be important. 1. Remain vigilant

2. Maintain good practices: clean seed & sanitation

3. If blackleg increases – get it lab tested (so you know what you are dealing with)