Local potato and tomato gardeners are keeping a close eye on their crops this week for signs of late blight — the disease behind the Irish Potato Famine.
The St. Albert & District Garden Club sent out an advisory last week that the disease late blight had been spotted in the city's botanic and community gardens. The virulent disease destroys potato and tomato plants and can spread rapidly.
The blight, known for the fast-spreading brown or black spots it creates on leaves, was first identified in the St. Albert Botanic Garden Aug. 29 by local horticulturalists, said Derrick Harrison of the St. Albert & District Garden Club. "We saw their diseased state and that it was fairly widespread."
Members immediately began a cleanup, coordinating with public works to transport the infested plants to the landfill.
The blight has since been spotted in the city's community garden and several private plots, Harrison said, and has effectively wiped out their tomato and potato harvest. "This is a situation that can affect any gardeners within mainly St. Albert and possibly the Edmonton area," he said.
Harrison urged gardeners to scout for the disease and, upon finding it, to keep infested plants out of their compost piles. "Tag it up and dispose of it properly."
Blight watch
Late blight, or phytophthora infestans, is a plant disease that affects potatoes, tomatoes, and occasionally eggplants and peppers.
It's a fungus-like disease that spreads by spores, said Jim Hole of Hole's Greenhouses & Gardens, and is best known for causing the Irish Potato Famine. "It's a pretty devastating disease," he said, one he'd received many calls about this summer. "Once you get it, you pretty much have to pull the plants out."
It's been many years since Alberta's last bout of late blight, said Sturgeon County potato farmer Wayne Groot. He suspected this latest outbreak was caused when someone planted infested seed in the region. This summer's weather likely helped spread the blight, as it prefers cool, moist conditions.
Late blight causes brown or black blotches on leaves that spread rapidly, Hole said. "The plant looks good, and then boom, it's done." Infested fruit appears rotten with brown or black blotches, while infested leaves often have a white, mould-like substance on their underside. Both can spread the disease through spores.
The St. Albert Food Bank gets several hundred pounds of vegetables from the community garden each year, said director Susan Krecsy, including potatoes and tomatoes. "That's a shame," she said of the blight outbreak, but she did not believe it would have a noticeable effect on the bank's operations.
Potato farmers manage blight through careful patrols and preventative spraying, Groot said. Most of the chemicals they use aren't available for smaller gardens, however.
Anyone who spots the disease in their garden should pull and bag the affected fruits, roots, tubers, and plants, said Bob Stephen, operations manager with the City of St. Albert. "There's only three ways to dispose of it: burn it, bury it, or put it in a landfill." Since you need a permit to burn and burying is a hassle, he recommends landfilling.
Residents should not keep any tomato seeds or seed potatoes from an infested garden, Harrison added — infested seed could cause the disease to return next year. Infested material should be kept out of compost piles for similar reasons.
Provided you clean the area properly, Harrison said, your garden should be safe for potatoes and tomatoes next year. Still, he advised gardeners to stick to certified seed and to practice crop rotation to reduce the risk of disease.
For information on the blight, visit www.stalbertgardenclub.info.
