Potato wart disease is caused by the fungus Synchytrium endobioticum, which is an EU quarantine organism.
Wart disease has not occurred in the field in Scotland since 1977 but the disease still occasionally occurs in other European countries. Vigilance in Scotland is therefore paramount and any suspected findings should immediately be notified to your local SG-RPID Area Office.
The effect of infection on potato crops can be severe. The pathogen causes cauliflower-like growths on tubers which, on decomposition, release millions of thick-walled resting spores; these may remain viable in the soil for at least 30 years. Scottish fields where wart has been found are officially scheduled for this disease which means that no seed potatoes are allowed to be grown there.
Legal aspects of the control of wart disease in Scotland are covered by The Plant Health (Scotland) Order 2005 which implements EU Directive 69/464/EEC on the control of Potato Wart Disease.
Certain countries outside the EU importing Scottish potatoes may stipulate that these must have been grown a certain distance away from fields scheduled for wart disease. More information on this can be found in the Potato Exports section.