Grape Growers Brace for Syrah Decline
Popular clones in British Columbia experience reduced vigor, leading growers to pull them out
More than 546 acres of Syrah grow in B.C., where it forms a cornerstone of Rhone-style wines and Australian-style Shiraz from producers across the province.
Vines at risk
But a large proportion of vines—perhaps as many as 200 acres—are at risk of being pulled out due to a genetic trait in two specific clones that causes the vines to decline and die.
“It’s really a genetic problem,” Dr. Patrick Vuchot, who oversees research and development activities as director of the Institut Rhodanien in Orange, France, told winemakers in response to a question from Howard Soon, the veteran winemaker at Andrew Peller Ltd.’s operations in the Okanagan, during the closing plenary session at the recent B.C. conference (see “British Columbia Winemakers Talk Tannin”).
The problem has been observed on grafted vines in British Columbia as well as own-rooted vines in Argentina, Vuchot explained.
“It prevents the sap to come back to the roots,” Vuchot said, noting that a key effect is to make vines less cold-hardy, more susceptible to winter damage and, ultimately, less productive.
“The vigor of the plant decreases every year. That’s why they don’t die straight away. It’s not a disease. They get less and less vigorous, and then more and more sensitive,” he said.
Worse, because it’s not a disease, there’s no cure. The only strategy for addressing the phenomenon is kind vine management that reduces stress on producing vines.
“Any factor that can increase the capacity of the vine to put reserves back into the roots is good,” Vuchot said. “And every technique that does the opposite will accelerate the death of the plant.”
Syrah clones targeted
The worst news for B.C. growers is that the most susceptible clones of Syrah are the two on which the industry was established in the 1990s: clones 99 and 100.
“Those were the two clones that our industry was set up on here in British Columbia,” said Kevin Usher, the session moderator, and research scientist at the Pacific Agri-Food Research Centre in Summerland, B.C.
John Simes, winemaker for Mission Hill Family Estate in West Kelwona, B.C., agreed, taking the microphone to explain that phytosanitary restrictions largely prevented growers from accessing other clones during the 1990s.
“They were the only clones that Agriculture Canada actually allowed into Canada back in the 1990s,” Simes said. “They thought there were all these viruses, and they were protecting us. Turns out these viruses were already here, but (clones) 99 and 100 were the only two that were approved—unless you went to the United States.”
The significant role of the clones is seen in the growth of acreage, and the Syrah crop.
Veteran industry writer John Schreiner relates in his book, “The Wineries of British Columbia,” that the Nichol family first planted Syrah at its property in Naramata, B.C., just north of Penticton, in 1991. The vines (1,350 of them) came from the Morisson-Couderc in Vogue, France.
By the end of the decade, that initial 1.33 acre planting had increased to 51.25 acres across the valley. In 2004, the Syrah acreage stood at 191 acres yielding 383 tons (or 4.85% of that year’s red grape harvest).
Syrah is now the fifth most-planted red grape in the province, with more than 546 acres planted and a harvest of 1,328 tons in 2012, representing 10.15% of the total red grape.
How bad things may get is another question, however.
“We haven’t seen any Syrah decline at Ruby Blues. Maybe the vines haven’t been stressed enough,” Lyndsay O’Rourke, winemaker at Ruby Blues Winery in Naramata, told the meeting. “The vines are old enough now, about 12 years old.”
Simes was less sanguine.
“From what I’ve seen from our own vineyards...if you’ve got 99 and 100, you’re going to end up pulling it out sooner or later. It’s just a matter of time before it becomes unproductive,” he said.
The good news is that alternative clones are available now, although supplies have been tight for the past two years.
Simes has planted some blocks with clone 877, while Vuchot said three to four other clones may be suitable for conditions in B.C. These include clones 470, 524 and 747, which have “very low” mortality. Clone 471 is also decent, but quality is an issue. Similarly, 747 tends to have low yields, while 470 and 524 are too productive.
Vuchot said that the use of new clones, and a greater understanding of vine decline, should mean newer vineyards won’t see the problem. There are now also tests to identify genetic markers pointing to the potential for vines to enter decline, something that didn’t exist in the 1990s.
“The problem of decline is behind us, because now we know the or igin, and we know that we should not plant these clones and we’ll reuse other clones,” he said. “We have a genetic marker that could predict the sensitivity of a clone of Syrah to decline; it’s not 100% sure, but if you have this marker you are sure you will have problems.”
Of course, no solution is perfect, and Vuchot noted that the absence of a known genetic marker for decline isn’t a guarantee of vine reliability.
“If it’s not present, it doesn’t mean you will be safe,” he said.