As a result of conversations with community gardeners this week, today’s post looks at the alternative to spraying for potato blight every year, by planting blight resistant varieties instead.
I’ve written an extensive post on choosing, understanding the terminology and growing potatoes in the past. I’ve also written one listing eight ways of managing potato blight, but as minds turn towards garden centre shelves and catalogues full of seed potatoes, blight resistant varieties can offer a real alternative to spraying.
Why Choose Blight Resistant Potatoes?
If you choose blight resistant varieties it will eliminate the need to spray with fungicides. I remember Irish weather forecaster Evelyn Cussack telling us that Ireland sees blight conditions nine years out of ten.
For several years we’ve grown Sarpo Mira potatoes in our garden. They’re a maincrop variety so are actively growing during the usual humid months that the blight fungus (Phytophthora infestans) thrives. So far the Sarpos have never been infected with blight, even when the tomatoes succumbed (same vegetable families will pick up the same diseases).
Feeling complacent from our blight free years, last year I planted Red Duke of Yorks (not blight resistant but I’d heard they were delicious). I didn’t spray with the organic blight alternative Bordeaux Mixture, as we generally steer clear of all sprays here, organic or otherwise. It really didn’t come as a surprise when the day before we headed off to the US for the summer, I saw the first signs of blight appearing on leaves.
Chopping the plants off at soil level as soon as I spotted the initial signs (see picture above for symptoms) may well have saved my two potato beds from serious infection, but leaving the tubers in the soil for two months over a very wet summer while we were away didn’t. Despite the problems, we managed to save two small sackfuls and can rest assured that we now have vegetable beds full of very plump worms! I’ve learnt my lesson. From now on in I’ll be choosing one of the blight resistant varieties listed below. (If I’d planted Sarpos, because of their blight resistance they would have been growing throughout August, the foliage would have protected them from the worst of the wet weather and we wouldn’t have come home to mushy spuds.)
From a commercial point of view, farmers face great difficulties growing potatoes in Ireland with our unpredictable weather, as well as suffer huge expenses. Popular potatoes that we’re familiar with in greengrocers and supermarkets are likely to be sprayed 20+ times during their growing season (chemicals such as Dithane can be sprayed every 10-14 days). That’s a lot of unnecessary chemicals entering your bloodstream, however ‘safe’ they claim to be, when a home-grown chemical free alternative can be planted as an option.
In an attempt to address the problems faced by farmers, under a mass of controversy, Teagasc have been growing and researching genetically modified crops in a field in Carlow. Organic farmers and growers (myself included) have been up in arms about this development, concerned that humans are being used as guinea pigs for this untested science.
However, convincing commercial farmers to swap their tried, tested and popular potato varieties for blight free replacements will not be easy.
In 2012 SPUDS (Sustainable Potatoes United Development Project) run by the Lifeline Project in partnership with the Savari Research Trust asked Irish growers to grow naturally blight resistant potatoes (such as Sarpo Mira) as part of their research project (I missed the press release hence the Duke of Yorks). Their website www.spuds.ie is still under reconstruction so I can only assume they’re busy collating responses. I’m anticipating hearing good results given the feedback I’ve heard from other growers, as well as my own experiences of planting Sarpos.
For a full list of potato varieties and their resistance to various disease including early and late blight, see the The British Potato Variety Database which is regularly updated. The following includes the popular blight resistant varieties you should be able to find in your garden centres or online garden shops along with their waxy/floury qualities – one of the first question I’m asked by people looking for advice on what varieties to sow.
Have you grown blight resistant potatoes in the past? Did they resist the parasitic fungal disease and importantly if more people are to be encouraged to grow them, did you enjoy eating them? I’d love to hear your own experiences.