From late fall to early spring is the season of wrath for Vermont’s small but lucrative wine grape industry.
Due to the state’s colder climate, the growing season lasts around 150 days. It begins around the middle of May, and by Oct. 1, most grapes are off the vine being processed.
“You need to get grapes off the vine because the frost is almost like a light switch,” said Terence Bradshaw, assistant professor and tree, fruit and viticulture specialist for the University of Vermont’s Fruit Program.
“Ideally, they are picked and crushed within hours (after harvesting). As soon as you take them off the vine, the quality begins to decline,” Bradshaw said.
While plummeting temperatures can damage healthy wines and ruin juice quality, other environmental challenges can turn things sour — viruses, for example, which can take years to destroy healthy vines.
Bradshaw’s team of researchers recently received a $33,680 state grant to evaluate wine grape vines and cultivar practices, and conduct virus screenings to support the Vermont grape industry.
The block grant is part of $254,117 the Vermont Agency of Agriculture recently awarded to benefit speciality crop producers across the state.
“Vermont’s Specialty Crop grants provide critical industry support for growing viable businesses, and also fund research to help producers overcome persistent challenges, innovate and diversify,” said Agriculture Secretary Anson Tebbetts.
At present, the Vermont wine grape industry is relatively small compared with other high-value crops: Less than 200 acres are used to cultivate grapes by a handful of growers.
“There is somewhere in the range of 100 acres of grapes in Vermont distributed among 13 or so growers. A few of us — three or four — have over 10 acres each,” said Ken Albert at Shelburne Vineyard in Shelburne.
“Yes, we are subject to (viruses) and likely have been affected by them. We at Shelburne Vineyard would be interested in participating in any such program and screenings,” Albert said.
Bradshaw said those few valuable acres of vineyard translate into thousands of dollars in seasonal revenues when the sweet purple juice is turned into wine. The state produces around $5 million worth of finished wine each year, he said.
Still, all it takes is a tiny virus to undermine years of hard work and investment.
“Some grape viruses can be pretty detrimental to the vines,” Bradshaw said. “A lot of these viruses affect older crops. It may not express itself for years.”
The UVM Fruit Program study focuses on Northeastern Vine Supply in Pawlet as part of a longer-term program to certify Vermont grape nurseries as virus-free. The program would provide a huge quality-control boost to the industry, Bradshaw said.
“Right now, (virus testing) is done pretty ad hoc,” he said. “This will give us a peek behind the curtain. We’re not throwing the doors open.”
Northeastern Vine Supply owner Andrew Farmer called the impact of grape viruses “not well understood” and said there are at least 15 viruses that can potentially damage Vermont grape vines.
“It’s a matter of testing for all of those,” said Farmer, who started the nursery 16 years ago with just a few vines.
The lab testing is being done in conjunction with Cornell University in Ithaca, New York.
Marc Fuchs, a virologist at Cornell, said the purpose of virus screening is to “identify clean vine stocks from which clean budwood can be collected for the production of high-quality, clean planting material.
“Tissue from selected vines will be processed and tested for detrimental viruses using laboratory diagnostic techniques. Test results will be used to identify infected vines to be culled and clean vines for further use in the Vermont program,” Fuchs said.
Farmer said every fourth vine will be screened for viruses each year over a span of four years. The cost of each tested vine is $100, so the grant will only go so far.
“It’s a very high-dollar proposition. This is a first step in the right direction for an industry as young as this. We are trying basically to get a certification program in Vermont if possible. That is a very long-term project,” Farmer said.