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Rick Peters, a research scientist and prominent potato expert with Agriculture and Agri-food Canada in P.E.I., is helping combat late blight by promoting the benefits of blight-resistant tomatoes. Photo: AAFC.

Late Blight Offensive: Targeting Tomatoes

A campaign to promote blight-resistant tomatoes in Prince Edward Island is not only benefitting home gardeners but is also a boon to the Island’s commercial potato industry.

Last year, for the first time in more than a decade, there were no lab-confirmed cases of late blight in Prince Edward Island’s commercial potato crop. And the province’s home gardeners can take much of the credit.

A program launched by Agriculture and Agri-Food Canada and the P.E.I Department of Agriculture and Fisheries in early 2015 urged gardeners to help protect the province’s $1 billion potato industry by planting tomato varieties with a proven resistance to a new strain of late blight, US-23.

Gardeners were also urged to properly dispose of infected tomato plants if late blight was found in their gardens. In addition, nurseries were encouraged to stock blight-resistant tomato plants, and AAFC added seed money to the project by purchasing and supplying just over 5,000 packages of blight-resistant tomato seeds to Island gardening clubs and gardeners.

All of that disease in home gardens is creating inoculum for spreading to adjoining potato acreages. That, of course, is a very serious problem.

– Rick Peters

Heidi Riley is an avid gardener who heard a pitch from Rick Peters, the AAFC research scientist involved in the campaign, when he spoke to the P.E.I. Garden Club in Charlottetown in January of 2015. She picked up the blight-resistant seeds and was delighted to have a bumper crop after two successive crop failures due to late blight.

“It was fantastic, and it was made better by the idea that I was helping to protect the potato crop,” says Riley. “Potatoes are incredibly important in P.E.I. A lot of people depend on the income that comes from potato production, and we want to do everything we can to help those farmers.”

Riley says her success with tomatoes last year followed two years of total crop loss due to late blight. “Every couple of years I have a complete crop failure, so it’s been an ongoing problem,” she notes.

Riley points out the summer of 2015 was particularly dry, which is weather less conducive to late blight. “We will need to test the blight-resistant tomato varieties in a wet, rainy, humid summer to really see how they perform,” she says.

Heidi Riley shows off her bumper tomato crop, produced with help of late blight-resistant seed. Photo: AAFC.

Heidi Riley shows off her bumper tomato crop, produced with help of late blight-resistant seed. Photo: AAFC.

Outbreaks Traced to Gardens

Since US-23 first turned up in P.E.I. in 2012, there have been multiple outbreaks of this late blight strain in commercial potato crops that were traced to gardens where spores from infected tomato plants were carried by the wind, says Peters.

In 2014, there were 22 lab-confirmed cases of late blight in commercial potato fields. Peters acknowledges that drier weather during the 2015 growing season played a role in the drop last year, but “we did have conditions in some parts of the summer that were conducive for blight. However, we didn’t see any of the disease and that’s because the inoculum wasn’t there.”

Peters notes that prior to 2015, 2001 was the last year there were no lab-confirmed cases of late blight in commercial potato crops on the Island.

“It’s very common here. We really have a typical climate here in the Maritimes that is conducive to blight — a little bit cooler, fairly moist, especially at certain times in the spring and the fall. When conditions ramp up like that, blight can be devastating,” he says.

“Certainly growers have had to plough down acreages because of blight, and they’ve had to implement very rigourous fungicide programs to mitigate the impacts of blight. So not only have crop losses happened, but there’s also an increased cost of inputs because of trying to manage this disease,” Peters adds.

“In the last couple of years, US-23 has taken over across the country and it’s now our main strain in Canada,” he says. “It can move on tomato transplants, it can move on potato seed, it can move of course in the wind quite long distances on storm systems, so it doesn’t really know borders.”

According to Peters, the newer late blight strains like US-23 are unlike previous strains in that they’re quite aggressive on tomatoes.

When the home gardeners are growing the blight-resistant tomatoes, it’s a win for everybody.

– Angus Mellish

“We’re really into a kind of a new dynamic with this disease,” he notes, adding these new strains are not just aggressive on tomatoes, they can also easily infect potatoes, especially tubers. “They’re very aggressive on potato tubers,” Peters says.

“A few years ago, I got hundreds of calls from growers around the Maritimes and other parts of the country saying they really couldn’t grow tomatoes in their back yards anymore because of blight,” he adds.

“All of that disease in home gardens is creating inoculum for spreading to adjoining potato acreages. That, of course, is a very serious problem that jeopardizes a very important commercial crop.”

Sales Up in P.E.I.

Peters says that in addition to Island gardeners who have supported the campaign, there’s been significant buy-in from tomato seed suppliers, nurseries and other stores that sell garden supplies.

For example, Veseys Seeds, one of the country’s largest mail order garden supply companies that’s based in York, P.E.I., packaged and provided the blight-resistant tomato seed packages that were distributed at meetings, and also assisted with promotional activities for the campaign.

Angus Mellish, seed manager at Veseys Seeds, says their sales of blight-resistant tomato seeds more than doubled in P.E.I. in 2015 and sales are up again this year.

“Home gardeners are realizing how much better it is to be growing these varieties of tomato because they just stay healthy so much longer. …They have tomatoes late into the fall and they just don’t have to worry about disease issues,” Mellish says.

“It reduces blight pressure for the potato growers as well. When the home gardeners are growing the blight-resistant tomatoes, it’s a win for everybody.”

Brian Beaton, potato industry co-ordinator with P.E.I’s. agriculture department, is helping lead the campaign to promote sales of blight-resistant tomatoes. He says owner-operators of local nurseries and garden centres have been particularly supportive of the initiative.

“We got very good buy-in from that group of people,” he says. “A couple of them really bought in wholeheartedly and … completely switched over to blight-resistant varieties.”

Beaton and Peters say the campaign is being expanded in P.E.I. this year to get the message out to more people.

Potatoes are incredibly important in P.E.I. A lot of people depend on the income that comes from potato production, and we want to do everything we can to help those farmers.

– Heidi Riley

Beaton acknowledged that the national chains “are a tougher nut to crack, so we have more work to do there to get to the right people who make the decisions and making them aware.”

Peters agrees “the work’s not over. It’s really critical to get more people to understand what the options are and what’s happening [with blight-resistant tomatoes].”

In that vein, the positive impact on commercial potato production is being spread across the country, led by prominent potato experts in New Brunswick, Manitoba and Alberta, says Peters.

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