A further finding of potato ring rot has been confirmed, at a farm in Lincolnshire included in the investigation to identify the source and extent of infection associated with the recent ring rot outbreak in Herefordshire. The finding was diagnosed by the Central Science Laboratory, using two different laboratory methods - immunofluorescence (IF) and polymerase chain reaction (PCR).

The Lincolnshire farm received Sante seed potatoes for planting in 2003 from one of the same Dutch stocks supplied to the farm in Herefordshire. Farm saved seed was retained from the 2003 harvested crop and replanted in 2004; ring rot has been detected in the 2004 crop.

The seed potatoes supplied to the farms in Herefordshire and Lincolnshire derived from a Sante stock with a clonal link (in the year 2000) to a stock implicated in a 2004 ring rot finding in the Netherlands.

The results of sampling and testing from other farms involved with the second phase of the investigation into the Herefordshire outbreak, involving the 2004 crop, have been negative to date. Some stocks remain to be harvested and tested. As well as the Lincolnshire farm, the programme is focusing on the outbreak farm in Herefordshire and farms in Norfolk, Newcastle and Suffolk.

While investigations in both the UK and the Netherlands are still in progress, this finding increases the likelihood that the Sante seed potatoes received from the Netherlands in 2003 were a factor in the Herefordshire outbreak, as well as the Lincolnshire outbreak.

BACKGROUND

1. Full details about ring rot can be found on Defra's website at http://www.defra.gov.uk/planth/ring.htm including Defra's contingency plan for dealing with outbreaks http://www.defra.gov.uk/planth/ring.pdf

2. The UK's first ring rot outbreak was in 2003. Details are available at http://www.defra.gov.uk/planth/ring/repfinal.htm