Late blight threat at bay, for now

ADDISON COUNTY — As late summer draws on, farmers and home gardeners alike are checking their tomatoes and potatoes for signs of late blight.
So far, though, they’ve mostly been able to breathe a collective sigh of relief, since the fungus that was widespread by the middle of last summer has only reared its head in a handful of isolated cases this year.
“I’m hyper vigilant about noticing anything,” said Karen LeRoy, whose tomatoes at Popoma Farm in Whiting were hard hit by the late blight last summer. “I think I’m finding more (this year) because I’m looking for it.”
But so far, this year has been much better for LeRoy.
“It’s one of the best tomato years we’ve had,” she said. “I have an incredible crop — they’re flavorful and red and abundant. It’s an enormous relief.”
Ann Hazelrigg, director of the Plant Diagnostic Clinic at the University of Vermont, has kept her eye out this summer for signs of the fungus that last year crippled tomato and potato crops across the Northeast.
“(Late blight) has been found in the state, but I’ve only seen it in Lamoille County,” said Hazelrigg.
The two cases she has found are isolated, likely originating from volunteer potatoes — plants infected with the fungus last year that overwintered in the ground and sprang up this spring.
This growing season, the weather has been warm and dry enough to stave off the spread of the blight. Late blight has a tendency to spring up late in the growing season, generally in the end of September as the weather cools off, but Hazelrigg emphasized that it does not always occur late in the season, and that if it takes hold it can spread at any time.
“Last year was a perfect storm of events,” said Hazelrigg.
She said that the disease showed up early, carried on plants from out of state, and spread all through July and August, helped by the cool, wet, rainy weather.
This year, she said, the weather has been warm and dry enough to prevent the spread of the fungus.
Wendy Sue Harper, who runs the fruit and vegetable technical assistance program at the Northeast Organic Farming Association of Vermont, said this year farmers and home gardeners are also more vigilant.
“There’s been a real effort to educate people about late blight,” she said. “Last year a lot of people didn’t know how to recognize it.”
This year, Hazelrigg said, her clinic has analyzed mostly common tomato diseases, including early blight and septoria leaf spot. Still, the search for late blight is not over. She invites anyone who suspects late blight to send a plant sample to her lab for analysis.
“It really can run through your crop in a manner of days,” Hazelrigg said.
For more information on late blight, including pictures of late blight and information on detecting look-alike diseases, visit
Reporter Andrea Suozzo is at [email protected].

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