Session 7: Traceability

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Session 7Traceability Follow-up Checks

• John Elphinstone (UK)

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Issues for ring rot/brown rot outbreak

• Immediate actions
• Trace-back activities
• Further investigations of source and possible
  spread
• Cleansing and disinfection
• Disposal measures
• Follow-up activities

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Immediate actions

• Suspicion of infection ( 2 x screening tests
  positive)
• Notice served
• movement of potato on and off farm/unit
  prohibited
• Additional investigations initiated
• Trace-back activities
• Further testing
• Additional measures to prevent spread e.g.
• Restrictions on the use of potentially
  contaminated machinery
• Prohibition of the movement of sister stocks
  suspected of being contaminated.

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Immediate actions

• Confirmation of infection ( pathogen
  identified host test positive)
• Trace-back completed
• Contaminated and probably contaminated potatoes
  and other items identified on premises and
  associated premises
• Official Notice served
• Premises demarcated as a zone contaminated with
  Clavibacter michiganensis ssp. sepedonicus
  (Potato Ring Rot)
• Planting of contaminated and probably
  contaminated potatoes prohibited
• Approved disposal of contaminated and probably
  contaminated potatoes required
• EC notified

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Further testing

• Higher rate to increase likelihood of detecting
  low incidence of infection
• In UK 4000 tubers tested per stock (20 x 200)

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Trace-back activities

• Always trace
• up (seed),
• down (progeny)
• sideways (sister stocks)
• Investigate origin of infected plants and tubers
  to trace the source of infection e.g.
• For certified seed the crop number allows full
  traceability
• Certificate number of seed planted
• Supplier details
• Intermediary wholesalers

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Case study Ring Rot in Wales 2003

• The UK's first finding of ring rot confirmed in
  seed potato crop November 2003 in Wales
• Infected tubers found in out-grade material
• One stock of Provento and one stock of a
  Provento/Almera admixture were found to be
  infected
• Source of infection unknown, most data point
  towards infected seed

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Verification of potato variety

• Contaminated stock was admixture of two varieties
  
• All contaminated tubers from only one variety
• Trace-back narrowed down to identify source of
  infection

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Case study Ring Rot in England, 2004

• Linked outbreaks in ware potato on farms in
  Lincolnshire Herefordshire
• Both farms supplied with a Dutch stocks of Sante
  in 2003
• The stocks supplied were derived from a Sante
  stock with a clonal link (2000) to a stock also
  implicated in a 2004 ring rot finding in the
  Netherlands.

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Ring rot Trace-back 2004 outbreak
1998
1999
2000
2001
2002
2003
Herefordshire Ware
Herefordshire Ware
2004
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Further investigation of extent and possible
source of outbreak and risk of spread

• Investigations will include
• All potatoes grown at or nearby the contaminated
  premises.
• Premises linked to the outbreak, e.g. by shared
  equipment or contractors.
• Potato from these premises or present at the same
  time as designated potato.
• Central stores handling designated potatoes.
• Machinery, containers, stores, packaging etc.
  linked to the outbreak.
• Potatoes clonally related to known infected
  stocks or stocks grown on contaminated premises.

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• Additional case studies (DE) to be added here