On 2 Aug 2017 23:09, Janet G wrote:
For the last few years I've grown Sarpo Mira potatoes as blight very badly afflicts other maincrop potato varieties. They have always been successfully blight resistant.
This year, I've had a significant number of Sarpo potato plants (perhaps 10% - 15%) yellowing and showing signs of blight and, even this early, the potatoes from those plants have mushy, smelly cores to them. This seems to affect the big potatoes especially. I'm assuming this is blight and quite bad blight. I wonder whether Sarpo Mira is losing its blight resi
stance and whether anyone else is growing it and has similar or different experience.
Janet G

Re-reading your post I think the problem you have isn't blight, if the
larger potatoes are affected with brown cores yet look OK on the
outside it may be Spraing.

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Regards
Bob Hobden