So great is the risk of blight in the UK from June onwards, he tells me, that as a preventative measure, growers commonly spray their potato plants with pesticides once or even twice a week, until the crop is lifted in September. So a typical crop can receive 25 or more pesticide treatments in just one growing season. Yummy!
That's just the sort of information that sends you searching out an organic alternative but the dominant wisdom has been that organic potatoes can't be grown on a commercial scale because they will be hit by blight. Which makes all the more exciting the new potato varieties that have been developed by the Sarvari Trust in Wales.
Two of these, Sárpo Mira and Axona, show unprecedented blight resistance and virus resistance, which has persisted over 10 years of organic trials, despite very high blight pressure in the past three years. Other supposedly blight-resistant varieties, such as the ubiquitous Sante and Cara, have been wiped out within weeks.
What is instructive here is that these varieties have been developed using conventional plant breeding techniques, not genetic modification.
Biotech evangelists love to make out that only their industry has the solutions to intractable farming problems, but here's a glowing example of breeding a crop with a desirable characteristic without using controversial and unpredictable GM techniques such as the introduction of antibiotic resistance marker genes that open the door to environmental and health risks.
With such promising results for Sarpo Mira, the Welsh Assembly is encouraging farmers to grow more Sarvari seed potatoes but potato growing is a notoriously conservative industry. Supermarkets must put their weight behind these new varieties by stocking them, encouraging more enlightened growers to step off the chemical treadmill.
Now these highly blight-resistant varieties that lend themselves to organic cultivation are a practical proposition, retailers must bin their ridiculous specifications for cosmetically perfect spuds that require heavy pesticide inputs. Their argument, as always, is that consumers expect a lovely bloom and will freak out at any slight visual imperfection. But if consumers knew it came at the cost of 25 pesticide treatments, they might take a different view.
Joanna Blythman is a food journalist and author of Bad Food Britain.