/ Food & Drink

Blighted by blight – are we to blame for failing potato crops?

Potatoes on ground

If you’ve ever tried to grow your own potatoes, you’ll probably be all too familiar with potato blight. But are we gardeners to blame for poor potato crops due to the spread of blight from our gardens?

Late blight (Phytophthera infestans) is a devastating fungal disease of potatoes. It was one of the main causes of the Irish potato famine in the 1840s and can still ruin crops for gardeners and growers today.

The potato industry has been hit by a ‘perfect storm’ of misery this year after the wettest summer in 100 years and the dullest since 1987; both of which have badly hit yields and quality. The worst crop in 35 years means the wholesale price of potatoes is almost 80% higher than last year with further increases expected.

Amateurs to blame for spread of potato blight?

Alan Stephenson, chairman of the Potato Council, has pointed to amateur gardeners for a ‘disproportionate amount of overall blight pressure’, suggesting that inexperienced gardeners could make the problem worse by composting infected potatoes, and allowing wind-borne spores to spread. He told The Grocer that:

‘People should be encouraged to grow their own vegetables to learn about the origins of their food. But the blight risk is real and it would be preferable if people bought healthy, well produced potatoes from their retailer rather than grow their own.’

But is it fair for farmers to blame gardeners for their poor crops? There have been double the number of Smith periods (when conditions are ideal for the spread of blight) this growing season, so it follows that blight will be more prevalent, whatever gardeners are doing.

And I’m sure most gardeners are wise enough to know that they should take measures to stop the spread of blight in their garden or plot by removing and destroying infected plants as soon as they’re spotted.

Blight resistant potatoes

Some potatoes have been bred to be blight-resistant, and a trial by Which? Gardening in 2009 showed that two varieties, Sárpo Axona and Sárpo Mira, first bred in Hungary by the Sárvári family, showed good resistance to blight.

Dr David Shaw of the Sárvári Research Institute in Wales (which breeds blight resistant varieties) was quick to respond to the comments asking:

‘Why do gardeners bother to grow their own? Exactly because they do not want to buy “well-produced potatoes” sprayed every week with chemical fungicides’.

Sadly, the Institute is faced with closure – ironic given that coming up with new, blight-resistant varieties has never been more important.

I have to admit that after suffering from infection myself over the past few years, I have now made the switch to resistant varieties.

Have you been hit by blight this year? Do you think gardeners are to blame for farmers’ poor crops – or is it just a case of a poor year?

Comments
Profile photo of wavechange
Member

We can blame people for dumping unwanted aquarium plants, fish and animals in our rivers and canals and helping spread invasive species but perhaps the blight problem has more to do with the weather and the need for more effort to produce blight-resistant varieties of potatoes.

Thank goodness we are less dependent on potatoes than the Irish were in the 19th century.

There is a small typo in the article: Late blight is Phytophthora infestans. Even those doing research on the problem have been known to spell this wrong.

Member
jack cox says:
21 October 2012

No blight is a fungus in the air thats why farmers spray for blight and you get blight warnings on the tv

Member
Dr Shumi says:
21 October 2012

I have just noticed desire potatoes are really poor this year! Have bright potatoes had any influence on our health?

Member
Peter Killick says:
22 October 2012

I grow potatoes regularly on an allotment and this year has been awful thanks to the weather. Yields down by 50% and lots of slug damage plus blight, scab and a noticeable lack of taste. The ‘Rooster’ variety has been the best of a bad bunch. I would still rather eat fewer potatoes that I have grown myself than buy commercial sprayed ones.

Profile photo of Victoria Pearson
Member

The slugs got to my potatoes before the blight even got a look in! So I don’t think you can blame me for it this year.

Member
Sandy Astin says:
13 November 2012

This has been my worst year for potatoes after 6 years on an alllotment – slugs and awful weather probably to blame. However I’m now worrying whether potato cyst nematode may have a bearing. I’m going to have to plant potatoes next season that are resistant to everything – is there such a variety though, apart from the Sarpos?.I am very fed up with discovering great slug tunnels in seemingly good spuds.

Profile photo of Patrick Steen
Member

James has written a great Convo about slugs as well if you’re interested: https://conversation.which.co.uk/energy-home/slug-snails-get-rid-organic-slug-pellets-garden/

Member
GRichard says:
13 December 2012

Potatoes in our allotments in Stockport also suffered more than usual this year with exceptionally poor yields, partly due to the ultra-wet conditions (many drowned, instead of growing) and partly due to a very early onset of blight. I cut the haulms off of mine as soon as it struck, so the main-crop ones were a bit on the small side. However, whilst Charlotte were not too bad with only a little slug (etc.) damage, the red varieties did as usual fare much better than white ones. Red Duke of York first earlies and Romano early main-crop did very well for me with almost no loss to pests despite leaving some of them in the ground for several months after de-haulming. I suspect that the red skins are less attractive to slugs, wire-worms, and so on. More research is still needed!

Member
B C Thomas says:
26 December 2012

I am not sure that I am doing the right thing; if so, my apologies.
December issue, p60 regarding Mr P Killick’s note. I am not clear as to the “sprayed” potato problem worrying him. As far as i can discover there are two possible sprayings. One, to kill/reduce blight, ( process recommended by Which? Gardening) and one to kill the tops to ease the harvesting. That used to be done with materials now removed, and in their stead, sulphuric acid is used. In any case neither of these operations affect the quality of the crop according to my information. V011033268

Profile photo of James Robbins
Member

Thanks for all your comments.
Our potato trial in 2009 showed that by growing one of our recommend blight resistant varieties, you can get a good yield of potatoes without the need to spray.
However, if you are growing a variety that does not show resistance, it is a good idea to use a suitable fungicide when plants are at risk to prevent infection.
Commercial growers of potatoes will sometimes spray the crop with a desiccant before harvesting to dry the top growth so it doesn’t get stuck in their machinery, but this process is not necessary for home gardeners.

Member
B C Thomas says:
17 January 2013

Additional comment on Blight.
Spread can be due to what the farmer calls ‘ground keepers’, diseased tubers
that are left in the ground, or thrown aside, and which produce the spores on the
new growth. The same goes for tomato residues, which are also in the family solanium.