THERE you are proudly admiring your potatoes, when you see the black blotches which were not there the previous day.

You turn the leaf over you will see a light white layer of mould, these are the spores of potato blight and these will be spread by the wind.

Very quickly the disease moves to the stems, which begin to collapse – and into the potato. And so you have a blighted tattie.

Potato blight is caused by a fungus called phytophthora infestans. It is transmitted by air, wind and soil.

Prevention better than the cure

There are some simple measures which can help but may not completely eradicate blight

1. Crop rotation, move where you grow your tatties from year to year [in a three or four yearly cycle, so pests and diseases, like blight, don’t get a chance to build up, or if growing in containers use fresh compost.

2. A tidy plot, dig up your potato patch at the end of the season, a missed tattie can easily harbour disease over winter. Keep your growing area tidy, clear up the debris straight away to prevent disease.

3. If you need to water your potato plants keep the water to the base of the stems and try not to soak the leaves as this creates in warm weather a perfect microclimate for blight.

4. Always buy seed potatoes from certified suppliers and try to use a blight resistant variety, such as Sarpo Mira, Cara, Carolus, Athlete, Orla, Valor and Charlotte, though this is no guarantee of a blight free year as blight is changing and mutating and varieties that claimed to be resistant 10 years ago are now susceptible.

One thing you can’t alter, though all gardeners wish they could, is the weather and a couple of humid days can mean that blight will appear, so the best weapon you have is the gardeners shadow – this means you are keeping your eye on the plot and acting quickly to cure problems.

Dealing with Blight

As soon as you see any diseased leaves, remove the leaves immediately – cut all vegetation away and do NOT put on compost heap.

Leave a small amount of stalk and leave the tubers in. You might be able to catch the disease before it infects the tatties.

Now you’ve finished this article, go and check those potatoes and stay blight free.