It has been hailed as a wonder drug that can fix a headache, treat fever and even help prevent a heart attack or cancer. Now, it seems, aspirin has added yet another life-saving string to its bow – at least for tomatoes and potatoes.
Gardeners are being advised to spray their plants with a solution containing the drug to help prevent devastating blight infections that can turn them to mush.
James Wong, an ethnobotanist and BBC science presenter, told The Independent on Sunday that aspirin could induce a state called "systemically acquired resistance" – a kind of general readiness state.
Mr Wong, a regular on Gardeners' Question Time, advised dosing the plants with a water-based aspirin solution, particularly with heavy rain forecast for the rest of the week for much of the country. Wet weather produces the ideal conditions for blight and other pests.
One recent study found that the use of the spray, which can be made at home, resulted in a "47 per cent reduction" in blight.
Scientists at the US Department of Agriculture (USDA) found that salicylic acid – the active ingredient in aspirin – primes plants in the nightshade family, including potatoes and tomatoes, against microbial or insect attack, according to a study published in the Annals of Applied Biology. The US research was directed towards commercial use, but aspirin will equally protect garden tomatoes, say gardening experts.
Late blight, Fusarium and Verticillium are particularly common after wet summer rain, and can strike swiftly – with spores spreading on the wind – and result in total crop loss.
Rebecca Brown, a professor of plant sciences at the University of Rhode Island, who has conducted trials on tomatoes, recommended adding 250 to 500mg of aspirin to around 4.5 litres of water and spraying this on plants two or three times a month.
However, Professor Brown told Fine Gardening magazine that this solution was only effective "before the first sign of disease".
For organic gardeners, she suggested using willow water made from fresh-cut trees. "Willows are naturally high in salicylic acid," she said.
The Royal Horticultural Society Advisory Service advised gardeners to look out for brown, rapidly spreading patches on leaves and stems and to destroy infected plants, without letting them touch other plants or adding them to compost heaps.
The bark of willows has been used for thousands of years to treat fever and pain, but the latest use for the drug perhaps puts a whole new spin on the old doctor's refrain: "Take two aspirin and call me in the morning."