http://www.potato.org.uk/department/knowledge_transfer/fight_against_blight/index.html
http://www.potato.org.uk/media_files/FAB_GAs/05blightonthebpcwebsite2006.pdf
According to an article in 'Organic Way', a particularly virulent mutated variety called 'Blue 13' was found in 2005; 90% of the blight in the UK is now of this strain. Even varieties which had partial resistance to earlier strains are susceptible. That explains the dreadful outbreaks we've been getting the last few years.
thanks, sawfish, just signed up :)
Robert,
Thanks for the info.
Seems we can't win somehow?
It was the usual story; some idiot imported tubers affected with another strain, which means they now reproduce sexually and this sort of situation has become far more likely. For that matter, we had potatoes here for 200 years before anyone introduced blight at all.
Robert, you have to remember that for most of that 200 years we used our own seed tubers, grown on this island. I had been growing potatoes for nearly 30 years before I even saw blight. Now growers import seed potatoes from everywhere under the sun with obvious risks - remember the Ring Rot panic a few years ago after a grower imported dutch seed?
I`ve long suspected that most of the blight epidemics originate from dodgy seed from less salubrious sources.