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Potato blight


Find it on: potatoes, tomatoes
Time to act: summer, autumn, winter


Caused by the same fungus responsible for tomato blight, potato blight causes the leaves to develop dark patches, starting at the edges. In humid conditions a white fungus appears around the marks. The infection then travels down the plant to the tubers, which turn a reddish-brown and, if a secondary infection strikes, the crop turns slimy and rots.

Here are organic and chemical ways of dealing with the problem.


Grow cultivars that have some blight resistance, such as 'Cara', 'Kondor', 'Valor' and 'Remarka'. Immediately destroy any leaves or stems showing the symptoms (never compost them), and any infected tubers.


As a preventative measure, spray the crop with copper fungicide every 10 days or so. They don't provide 100 per cent protection, but an attack will be slowed down and you should get a ripe crop.

Discuss this problem

Talkback: Potato blight
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nannyhazel 24/11/2011 at 15:27

This is my first year growing potatoes but last year my tomatoes suffered from blight so this informaton is useful

alan_nelson 24/11/2011 at 15:27

i have just started with a veg garden, i have chosen potatoes as we can use them
as a novice i need lots of help,which your site seems to have, long my it continue.
thank you

wilder 24/11/2011 at 15:27

really useful info for a newbie to veg gardening like me!
I see on one of the Blogs somone said he didn't get blight last year as he planted them near the neighbours Leylandii !! no idea why that would be the case but interesting all the same!

patty1945 24/11/2011 at 15:30

i would like to be imformed if there may be a time when blight could be likely to be a probem as i have an allotment in perrybarr birmingham and the potatos look so healthy at the moment

Ronnie G 02/01/2012 at 11:34

Year one growing potatos in containers was successful. Year two i planted early variety in November 2011 which have failed with first frost.
I think its blight, as the leaves collapsed and died away.
Do i now have to dig up the tubers and destroy ? Do i have to discard all of the soil in the containers ( Top Soil from garden Centre )? Do i have to deep clean the containers? How ?
many thanks

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