Potato blight

Potato blight

Find out more about potato blight and how to tackle it in this short guide.

A table displaying which months are best to sow, plant and harvest.
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Time to act
Time to act

Do Time to act in January

Do Time to act in February

Do not Time to act in March

Do not Time to act in April

Do not Time to act in May

Do Time to act in June

Do Time to act in July

Do Time to act in August

Do Time to act in September

Do Time to act in October

Do Time to act in November

Do Time to act in December

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.

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

Find it on

potatoes, tomatoes

Organic

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.

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Chemical

Since most copper fungicides have gradually been withdrawn from sale, there are currently no chemical treatments available for use on blighted potatoes.