Grape & Wine Magazine - April/May 2024

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April / May 2024


Volume 2: Issue 3
30 Years
the Unified Wine & Grape Symposium Winery Feature: Tres Sabores Winemaking in Today’s Climate Conditions
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January 2023 3 CONTRIBUTING WRITERS & INDUSTRY SUPPORT Surendra Dara Director, North Willamette Research and Extension Center Kevin Day UCCE Pomology Farm Advisor, Tulare and Kings Counties Elizabeth Fichtner UCCE Farm Advisor, Kings and Tulare Counties Katherine Jarvis-Shean UCCE Orchard Systems Advisor, Sacramento, Solano and Yolo Counties The articles, research, industry updates, company profiles, and advertisements in this publication are the professional opinions of writers and advertisers. Progressive Crop Consultant does not assume any responsibility for the opinions given in the publication. Steven Koike Tri-Cal Diagnostics Jhalendra Rijal UCCE Integrated Pest Management Advisor, Stanislaus County Mohammad Yaghmour UCCE Area Orchard Systems Advisor, Kern County UC COOPERATIVE EXTENSION ADVISORY BOARD PUBLISHER: Jason Scott Email: EDITOR: Taylor Chalstrom Email: PRODUCTION: Phone: 559.352.4456 Fax: 559.472.3113 Web: Muriel Bañares Brown-Miller Communications, Inc. Vicky Boyd Contributing Writer
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2024 marked the 30th anniversary of the Unified Wine & Grape Symposium (all photos

Attendees had the opportunity to taste wines from 18 regions throughout the U.S.

30 Years of the Unified Wine & Grape Symposium

Industry’s Largest Informational Gathering

Took Place in Sacramento in January

Marking its 30th year as one of the American wine industry’s premier events, the Unified Wine and Grape Symposium was back in full force after years of COVID-19 and a temporary change of venue. As the nation’s largest show of its kind, Unified has again proven to be more than a convention; it’s a destination, a cultural hub of connection, innovation, education and energy. Unified is the place to be for all things wine and winegrape.

From January 23-25, Unified opened to over 10,000 industry professionals eager to explore 900 exhibit booths spanning

two floors of the SAFE Credit Union Convention Center. Attendees engaged in three days of program sessions with nearly 100 speakers from around the world. They also had the opportunity to taste wines from 18 regions throughout the U.S. and join their colleagues in a collective effort to understand the trends of the industry today and find solutions for tomorrow.

“As our industry navigates through challenging times, the Unified Symposium is a rare opportunity for industry leaders and experts to gather, examine the latest data and discuss potential strategies

to right the ship,” said Natalie Collins, president of the California Association of Winegrape Growers (CAWG) and co-host of the Unified Symposium. “For 30 years, Unified has served as a space to unite the industry, discuss emerging trends and find the technology, supplies, services and partners essential for charting the year ahead.”

State of the Industry

For many, a key reason for attending Unified is to gather the latest data, trends and products that will help with their business decisions for the upcoming year. The popular State of the

4 Grape & Wine Magazine April / May 2024
courtesy Unified Symposium.)


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Industry session continues to provide the most comprehensive outlook of the industry, offering an in-depth analysis of market dynamics, trends for consumers and competitors, the winegrape market’s supply and demand, and this year, a special global perspective from Spain’s wine market.

Drawing on industry experts, the State of the Industry session offered a holistic and unvarnished look at the industry from a supply and demand perspective. Speakers addressed the challenges and opportunities ahead, offering the latest data across all segments of the industry.

Education and Inspiration

In addition to the State of the Industry, Unified is the place to learn and find inspiration with 23 sessions spanning various topics in winemaking, grapegrowing, business and operations, and marketing and public relations during the three days of the conference. California’s Secretary of Agriculture Karen Ross was the keynote speaker at this year’s annual luncheon.

Another inspirational session titled “Wine Industry Game Changers: A Deep Dive Conversation on the Future of Wine and How We Got Here” offered a unique and informal opportunity to interact with the session’s speakers. Attendees had the chance to meet with industry pioneers, including Cathy Corison of Corison Winery; Carole Meredith, professor emerita at UC Davis; and Theodora Lee of Theopolis Vineyards over a light breakfast. On the business side, attendees learned about California’s bottle bill labeling requirements and compliance regulations. The PR/ marketing side offered several tactics and strategies, including messaging for wine and health, leveraging artificial intelligence (AI) and how and why short videos are essential for today’s audience.

The winemaking sessions offered a second look at Merlot that included a tasting, understanding the nutrient and ingredient labeling requirements and the latest trend of no- and low-alcohol winemaking. The grapegrowing sessions included the Viticulture X Games, which was a highly interactive presenta-

tion on winegrowing in extreme weather. Additionally, growers had a list of other sessions that covered disease-resistant vines, regenerative agriculture and tools for digital viticulture.

Unified further set itself apart by offering an exclusive full-day workshop in Spanish. This session addressed AI and how it can support grape growers and wineries, and the importance of implementing climate change strategies. The workshop included a Q&A and a guided wine tasting of emerging products and new styles featuring hybrids, noncommercial Vitis vinifera and cider/wine blends.

Attendees had the opportunity to sample and taste wines from several wine regions throughout the U.S. Participating associations pouring various wines from their region included Atlantic Seaboard Wine Association, Calaveras Winegrape Alliance, Idaho Wine Commission, Illinois Grape Growers and Vintners Alliance, Lake County Winegrowers, Livermore Valley Wine Community, Lodi Winegrape Commission, Mendocino Winegrowers Inc., Monterey County Vintners & Growers Association, New Mexico Wine, New York State Wine Grape Growers, Ohio Wine Producers Association, Paso Robles Wine Country Alliance, San Diego County Vintners Association, Sonoma County Winegrowers, Temecula Valley Winegrowers Association, Virginia

Wine Board and Wineries of Santa Clara Valley.

Largest Tradeshow of Its Kind

Unified hosted 900 exhibit booths, the largest collection of products, services and machinery in the show’s 30-year history. The massive trade show floor, which is larger than three football fields, showcased the supplies, equipment and services that drive the American wine industry. It was the place to meet vendors, shop for leading-edge technology and discover the latest research on water, soil, disease-resistant applications in the vineyard and so much more.

“This was the largest trade show Unified Symposium has ever had, and we’re continuing to see growing interest from

6 Grape & Wine Magazine April / May 2024
The 2025 Unified Wine & Grape Symposium will take place January 28-30 at the SAFE Credit Union Convention Center in Sacramento, Calif. Scan this QR code to watch the Unified Symposium 30th-anniversary tribute video.


the wine and grape community,” said Dan Howard, executive director of the American Society for Enology and Viticulture (ASEV) and the show’s other cohost. “We are already seeing increased enthusiasm for next year’s show. It’s a great reminder of how important a show such as Unified is to the success and progress of the American wine industry.”

Organized by ASEV and CAWG, the 2025 Unified Wine & Grape Symposium will take place January 28-30 at the SAFE Credit Union Convention Center in Sacramento, Calif. Built with the joint input of growers, vintners and allied industry members, Unified serves as a clearinghouse of information important to wine and grape industry

professionals as well as hosting the industry’s largest trade show of its kind. For more information, visit

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April / May 2024 7
State of the Industry session offered a holistic and unvarnished look at the industry from a supply and demand perspective.
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Driving down the dirt road that leads to Tres Sabores on the west side of Napa Valley on prime Rutherford benchland, you might not expect to find a vineyard tucked up against the steep Mayacamas. Oak-forested slopes rise steeply ahead.

Just to the east on the main highway is Grgich Hills’ Rutherford estate. South are the fabled vines of historic Inglenook. This is high-class wine country.

Then there’s homey Tres Sabores, which offers a distinct contrast to the glamor and gussy-uppedness that so much of Napa thrives on. Owner and vintner Julie Johnson would rather talk to you about her pomegranate trees, the latest bird study she’s working on with university researchers (this time it’s four kestrels who’ve nested on her land) or how her goats are eating enough poison oak and undergrowth to keep a fire-safe periphery around the place. It’s a soilfirst, nature-friendly place.

But her dry-farmed estate wines keep pace with those illustrious neighbors, winning high praise for both her estate-grown Cabernet Sauvignon ($125 a bottle) and her award-winning, headtrained, historic Zinfandel ($51) from vines planted in 1971.

Total production is 3,000 cases.

While two thirds of her land is up steep slopes, she grows grapes on the mostly clay loam bench lands. Most of the vines are 50+ years old, and that includes 10 acres of her major love, dry-farmed old vine Zinfandel, which she’s kept going

She buys another 50% of grapes in both traditional and non-traditional varieties; Picpoul Blanc and Saint Laurent, for example, making favorites like a red blend and a rosé. Slow Wine Guide 2024 awarded her 2020 Zinfandel its top award as Slow Wine, giving it its highest rating.

ever since she acquired the property with her then husband John Williams back in 1987. She also grows Cabernet on 2.5 acres.

Anyone else would have ripped out the Zin (we’re talking the world famous Rutherford bench here) and planted Cabernet, but Johnson remains devoted to the vines, their history and complex, satisfying flavors. She’s a dedicated grower, picking Zin at three different moments in time to capture optimal ripeness.

8 Grape & Wine Magazine April / May 2024
Julie Johnson (left) and husband/winemaker Jon Engelskirger. Johnson is owner and vintner at Tres Sabores, a soil-first, nature-friendly winery on the west side of Napa Valley (photo by P. Strayer.)

A Long-Term Relationship with the Land

“We moved to the property in 1987,” said Johnson, a former public health nurse who graduated from Bowdown College in Maine. She raised her family here.

“I’ve had the opportunity to steward this land and to grow into it, and a lot of empathy, really, for this merging of farming with nature we’re surrounded by,” she said.

She and Williams certified the vineyard organic in 1991. Partnered in the wine business with their close friend Larry Turley as Frog’s Leap winery, they were the first in Napa to become certified organic.

Their professional companion on the journey was organic royalty, the legendary Amigo Bob Cantisano, who also married them there under a tree now signed “The Wedding Tree,” a massive oak that is thought to date back to 1660. Cantisano (founder of CCOF, the

USDA NOP certifier in California as well as Ecofarm, the organic farmers conference) inspired organic farmers to cultivate biodiversity.

The pioneering Johnson started Women for WineSense, one of the first organizations for women vintners, and created her own label, Tres Sabores, Spanish for “three tastes.” Initially, she intended to work with three winemakers making wine from the same grapes, but found that too challenging to sell commercially. Today, she is the winemaker and is married to another winemaker, Jon Engelskirger.

She thinks of the three tastes now as the land, the vines and the company around the table.

Biodiversity by Design in a Closed Loop Farm System

Part of what attracts tourists, Johnson said, is the feeling of being surrounded by gardens and biodiversity. Guests sit next to the vines and can wander

Tres Sabores Owner Julie Johnson integrates farm animals into the winery for increased biodiversity. Pictured are resident Shetland sheep (photo courtesy Tres Sabores.)

around into the informal, exuberant, agrarian paradise with its vegetable gardens, farm animals, hedgerows and her friendly Golden retrievers. But it’s not about cosmetics; it’s an intimate, high-touch setting with both nature and agriculture, scaled for humans, that pulses with life and authenticity. Small is beautiful.

“People feel like they could do this,” she said. “It’s not so pristine. I think

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Part of what attracts tourists to Tres Sabores is the feeling of being surrounded by gardens and biodiversity (photo courtesy Tres Sabores.)

we’ve had the opportunity to create an atmosphere where people can engage. They can put themselves in the position of growing things… that gets people thinking.

“It really is a place where we can welcome people. We have a limited number of seats, but we’re very dog-friendly, we’re very family-friendly… I raised my kids here,” she said.

The property has 10 varieties of pomegranate trees (200 in all), a companion planting Cantisano encouraged, as well as 40+ olive trees, many of which predate her arrival.

“I make all sorts of things from them, and we have a big party to celebrate them. Wherever you find pomegranates, you tend to find grapes. I inherited a growth that was planted sometime in the late 19th century. It’s really quite special.

She’s also planted a lot of lemon trees.

“All the peripheral part of the growing area and the vineyard and all the olive orchards is full of hedgerows that have herbs that are very productive in their own right. They’re feeding these beneficial insects and providing food for birds. So, it comes together as it comes together.”

She also integrates farm animals into the scene.

“We have our own little mini herd of Shetland sheep, and goats, and a lot of

chickens, and guinea fowl. And that’s in itself great because those guys in their pens produce a lot of manure, the manure we use with all of the green waste from the production process to make compost. So that’s another kind of thing that kind of makes the world go round.

“And then the guinea hens are there to clean up the fly larva, and to be part of the whole system, as well as are the chickens. And then the chickens use scraps from the winery and... help fill our compost bin.

“The animals on the property can eat the grass and the cover crop and so on.

“I’ve re engaged with goats. Right now, we have the second litter of goats. And they eat brush up in the hills, reducing the fire danger.”

A Living Lab

Johnson never stops thinking about what’s next for her farm ecosystem.

“I look at my property as kind of a laboratory,” she said. “It’s really so small, 35 acres with 12 planted. But I try to see what we can do to build more soil health and feed the soil microbiome. It’s really about the understanding that we’re feeding the soil and living with the soil, and it’s the soil that feeds the vines.”

The same spirit of creativity and adventure applies to her wine business and guest engagement: hosting weddings, mixing in dance group performances and art, and building more word of mouth.

She sells estate-grown pomegranate vinegar and olive oil. Wine club members can give their friends and families free visits. Picnicking is allowed. She also hosts events (with a super long table) and partners with the renowned “Outstanding in the Field” group, which hosts large-scale public gourmet meals with celebrated chefs ($395 a head). She’s also big on food photos on her Instagram feed.

All of which has led to acclaim. The San Francisco Chronicle named Tres Sabores “A Top Winery in Napa Valley.”

Similarly, Lonely Planet calls it “a top choice in Napa Valley.”

Being family-friendly, dog-friendly and nature-friendly turns out to be a winning strategy in even the most competitive and concentrated wine tourism region. Excellent wine is a must, too. Tres Sabores’ sense of people and place, wine and values clearly appeals.


Today, Johnson’s winery is a word-ofmouth hit with tourists as exemplified by a recent prestigious wine tourism award.

In 2023, Great Wine Capitals honored her as the regional winner of the Best of Wine Tourism Award in the Sustainable Wine Tourism Practices category, a high bar to meet in Napa, to be sure.

“I don’t know who even nominated us,” she said. But read the rave reviews on Yelp and TripAdvisor and it’s easy to understand why this honor came her way.

“What a gem of a place, so different from other large wineries. It is a farm and it feels like it; the whole experience is very authentic,” said one reviewer.

“They offer pet-/dog-friendly tastings outdoors right next to the vineyard so you can sip your wine overlooking the vast grounds,” said another.

And another: “Unlike some of the other places we’ve visited, Tres Sabores is very relaxed and off the beaten path; the ambiance is peaceful and you aren’t rushed through the tasting.”

And these: “It was picture-perfect in every corner and definitely felt like heaven on earth. I can totally sit there all day!”

“Sheep and dogs and wonderful wine and service make this a must stop!! Ambiance is peace, calm and beauty.”

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Winemaking in Today’s Climate Conditions

We are talking about quality challenges from climate-related events and ways to plan ahead to achieve better wines,” said moderator Alisa Jacobson to explain the focus of “Winemaking in Today’s Climate Conditions,” a panel discussion at the 2024 Unified Wine & Grape Symposium in Sacramento. “After all, if we’re able to raise the quality of our wines, it will help our entire industry.”

Jacobson, owner and winemaker at Turning Tide Wines in Santa Ynez, Calif., noted recent extreme weather events in Oregon, such as last year’s heavy rains, heatwaves and fires, “caused quality and economic impacts.”

She added California winemakers “had their own heatwave extremes in 2022 during the critical berry ripening season... and Washington seems to be ground zero for heat and cold events.”

“We have to think of extremes when we talk about the economics of wine,” said Elisabeth Forrestel, assistant professor at UC Davis, whose current study focuses on the impacts of varying irrigation on vines, berries and wines.

“What we found is every single year, and through every single heatwave... we had a decrease in tannins and flavonoids,”

she said. “If you do not irrigate at all before and during heat waves, you have a reduction in anthocyanins.”

Forrestel advises winemakers to start irrigating their vineyards two days before a heatwave starts and continue until it is over. This strategy “ has really positive impact on yield and positive impact on quality.

“I think it’s real important to note water is our biggest tool, whether you’re going to use it for new irrigation or you’re going to use it for misting, or even just misting the ground. It’s really critical to use it with restraint because we know there’s going to be limitations on it.”

Forrestel explained the recent climate on the West Coast has “way more extremes” than in prior years, and this affects her research.

“It’s important to note we’re not looking at just some variations with a baseline change,” she said. “We’re looking at really, really large extremes that are going to have a strong impact on wine considerations, so we really need to think about what those extreme conditions are.”

Ben-Min Chang, a research scientist at the Summerland Research Development

An infrared sensor being installed in the canopy will measure heat in the vineyard (photo courtesy Washington State University.)

Centre of Agriculture and Agri-Food Canada, focused his presentation on damage from heat and cold extremes. He explained his terms.

“Cold damage is basically when the temperature decreases to actually freeze the cell,” he said. “Once the cell is frozen, it expands and explodes the whole cell.”

Cold hardiness means the coldest minimum temperatures that a fully dormant plant can tolerate.

“There’s actually a different level of the whole hardiness around the organs like the trunk,” said Chang. “They can tolerate really cold temperatures.”

However, the same temperatures will hurt the tertiary buds as well as the secondary buds, he said.

“The first thing, of course, if the primary buds are killed, you’re losing a yield, and later on you have to do other jobs like pruning procedures,” said Chang. “What we usually do as some kind of compensation is leave more buds, but that actually means in the coming season you will get more shoots.”

Another factor is the duration of the low temperature. A vine may be able to survive for six hours, but the most recent

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low temperatures lasted for 54 hours, according to Chang.

That record-breaking weather event in British Columbia happened in January. The temperature went down to minus 25 degrees C at the Summerland Centre. Chang reported more than 50% of the vineyard had major damage, including the trunks.

“Eventually, the trunk damage will influence the decision whether to replant,” he said.

The response is much different when a heatwave threatens a vineyard.

“We actually use the strategy of evaporative cooling,” said Chang. “We want to remove the excessive heat from a canopy, so the concept is a fairly simple: We spray water over the canopy.”

Dr. Tom Collins, assistant professor of grape and wine chemistry in the

April / May 2024 13
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Wildfires are a threat to wine production in in California, Oregon and Washington (photo courtesy Washington State University.)

Viticulture and Enology Program at Washington State University (WSU), manages a research program in wine and spirits aroma and flavor chemistry. His current research focuses on the impacts of wildfire smoke exposure on grape and wine quality.

“If we’re making wines from vineyards that have been exposed to smoke, the wines can sometimes develop these characteristic aromas and flavors: the smoky ashy cigar butt or cigar smoke, cigarette smoke kind of characters,” he said. “Sometimes it’s in the aroma, sometimes it’s in the flavor, sometimes the wines smell fine; they don’t smell smoky, they taste smoky.”

Collins showed a screenshot of WSU’s Department of Ecology air quality monitoring network, a collection of equipment that measures the air quality index of area vineyards, which is especially important when there is a lot of smoke in Eastern Washington. He said similar programs exist in California and Oregon.

“These systems really developed with an eye toward human health, so they’re looking at air quality in cities and towns where the populations are,” Collins said. “It gives us a pretty good indication of where the smoke is, particularly in an event where there was smoke everywhere.”

During the 2020 fires in Washington, monitors were placed in eight differ-

ent commercial vineyards in Eastern Washington. These monitors collected information to determine what the air quality would be for the rest of the growing season.

“It turned out it was a really great year from the perspective of collecting data about smoke events; not a great year for vineyards, but a good year for our research efforts,” Collins said, adding that much of the smoke in Eastern Washington came from fires in Oregon and California.

Data was collected from a 2020 Labor Day fire that produced smoke in area vineyards.

“Depending on which vineyard you were at, we had densities between about 5 mg per cubic meter up to about 2, which is actually consistent with the kinds of smoke that we apply when we’re doing our smoke exposure trials,” Collins said.

The final speaker was P.J. Alviso from the Duckhorn Wine Company located just outside St. Helena, Calif. When he finally had his opportunity to address the audience in the limited time that was left, he explained that luckily he talks fast.

“I’m going to sum my entire life’s work up in the next seven minutes for you guys,” he said. Actually, he gave some advice instead.

1 in 10 vintages has something go wrong,

Misters such as the one pictured at left can help protect a vineyard during high temperatures (photo courtesy Washington State University.)

according to Alviso.

“The reality is these things are happening more often and they’re happening at the worst times for wine quality,” he said, before advising those in the wine business to not put all their eggs in one basket.

Alviso applied that old maxim to the wine business that faces more and more climate extremes, telling those in attendance to consider diversifying, especially if a quarter to half of their business depends on a single vintage.

“Each fermentation is a basket,” he explained. “If something goes wrong, if that fermentation represents some significant part of your business from a qualitative or quantitative perspective, that’s a huge risk, so maybe step back and say, ‘Okay, how do we diversify?’”

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Regenerative Viticulture

‘Rockstar’ Researchers Share Latest Findings on Improving Soil Health

How can nature help? That was the basic message underlying three “rockstar” viticulture experts who presented at a packed panel session titled “Regenerative Agriculture - Next Step in Sustainability” at the Unified Wine & Grape Symposium.

Washington State University; and Luca Brillante, assistant professor of viticulture at Fresno State.

The background context could be considered gloomy as wine sales are declining, winegrape growers in marginal areas are pulling out vines and new state policies aim to reduce synthetic chemical inputs. But leading academic researchers studying how growers can best harness nature’s regenerative processes say better days are to come, using more natural processes to grow better grapes and increase resilience in the face of climate change.

The trio of researchers presenting their latest findings on effective practices included Amelie Gaudin, associate professor of agroecology at UC Davis; Devin Rippner, USDA research soil scientist and adjunct faculty member at

Moderator Clint Nelson, then senior director for vineyard operations and grower relations at Bonterra Organic Vineyards, stressed regenerative agriculture can be commercially successful at scale as Bonterra has shown. The company adopted no- or low-till practices on its Mendocino estate vineyards in 2021. Though Bonterra’s estate vines are currently certified by the Regenerative Organic Alliance, he said organic farming is not for everyone in the state, but regenerative can be part of broader sustainability programs.

The state of California is currently working on a definition of regenerative agriculture.

“One of the main points of being a sustainable farmer is continuous improvement,” he said, giving shoutouts to sustainability groups in Lodi, the Central

Coast, CSWA and Napa Green on their role in grower education and insights.

Evolve in Stages

Gaudin painted a portrait of three stages of sustainability in regenerative agriculture.

“Boosting beneficial ecological interaction... is a pillar of regenerative agriculture,” she said.

The first stage is increasing farm efficiencies in the use of inputs, the second is input substitution and the third is vineyard redesign based on agroecological principles, she said.

As an example of the second stage, she said, “We can think about replacing till with no till, and fertilizer with compost, for instance,” she said.

Further fleshing out the stages, she said, “The first level of a regenerative system is going to be a system designed primarily to build up soil health, cycles

16 Grape & Wine Magazine April / May 2024
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and sequestering carbon. A deeper system will also optimize for biodiversity and conservation overall,“ she said, adding the new systems should reverse decades of extraction.

“I’m an ecologist,” she said. “So I think about it based on ecological principles. What would be a rich system? First, it’s a system that maximizes biodiversity and implements soil health principles, such as maintaining living roots in the system, keeping the soil covered with living plants, or mulch, and frequent and diverse input of organic matter. So having a diverse set of type of organic inputs, whether it’s compost, cover crops, etc., into the system.

“Doing agriculture is about disturbing a system, right? So when we say ‘no disturbance,’ I think we’re not being very accurate,” she added. “It’s about being strategic in how we want to apply disturbance in the system.

“Eventually, what it comes down to is that you rely on biodiversity... in time, in space, above ground, but also below ground. And it also relies on the living soil ecosystem.”

Animal Integration

“We’ve seen a lot of grazing innovation happening now in California. I’ve been working on it for 15 years, and what’s happening right now is kind of cool,” Gaudin said. “Vineyards are a good entry point to think about sheep grazing.”

On average, in the New Zealand grape growers she

surveyed, vineyard managers saved 2.2 mows and 1.8 herbicide applications from seasonal sheep grazing.

Sheep grazing impacts “on nutrient cycling, nitrogen availability in particular, and then just providing an additional value to the cover crop through forage and as well as providing tremendous benefit to soil biodiversity.

“I’ve been looking at soils for quite some time and I’ve never seen so much life in soils, and when you start putting an animal in there, and that makes sense because plants and

18 Grape & Wine Magazine April / May 2024
UC Davis Agroecologist Amelie Gaudin is seeing grazing innovation taking place at a high rate in California. The state of California is currently working on a definition of regenerative agriculture.

animals have co-evolved. They’re supposed to be with each other,” she said.

Her latest work on grazing’s impacts on soil health has been published in Geoderma, entitled Long-term integrated crop-livestock grazing stimulates soil ecosystem carbon flux, increasing subsoil carbon storage in California perennial agroecosystems.

Earthworm Surprises

Rippner’s talk focused more on minimizing soil disturbance. But along the way, he and his team found earthworms played a bigger role than previously thought when it comes to water infiltration.

“It turns out in our cover crop system, infiltration was governed by the presence of earthworms rather than the plants in place,” he said. “We’ve increased biodiversity in our system. Now we have earthworms that are doing all this work for us. They’re actually disturbing our soil but in a thoughtful way, and increasing our infiltration. So this was a really cool and fun finding,” he said.

Pivot to the New Path

A native of northern Italy, Brillante brought regenerative down to a real-world level when he started his talk, and said, “If you’d asked my grandfather what agriculture meant for him, he was a small farmer, it looked a lot like he was mining with sweat and tears… he was extracting something from the land.

“Now three generations after, we’ve become much lazier, instead just saying, ‘You know what, I’m tired of fighting nature; can you just give me a hand?’ And so trying to have nature work on our side… basically that’s what regenerative farming is in my opinion.”

Echoing what his colleagues said, it’s about soil health, increasing carbon accumulation in the soil, promoting biodiversity, reducing toxicity in pest control, increasing nitrogen fixation (through the use of cover crops) and so on.

He said the new sustainable pest management (SPM) policies in California will reduce the use of fumigants, herbicides and insecticides, but he also painted a picture of cost-effective alternatives, relying on nematode-resistant rootstock, pheromones (rather than specific insecticides) and biodiversity.

“My role here is just trying to give you a little optimism and to take a look at different strategies that we can still farm our grapes by changing some of our practices,” he said.

“So in conclusion, the sustainable and holistic approach to vineyard management is possible at least with a change of mind.”

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April / May 2024 19
Sheep grazing impacts nitrogen availability, benefits cover crops through forage and promotes soil biodiversity.

Could Sauvignon Blanc’s Rising Popularity Lead to Overplanting? Industry insiders worry about production outpacing the market.

Sauvignon Blanc was already being touted as “the coolest wine on the planet” and “the toast of the wine world” when the Lake County Winegrape Commission held its international 2018 Sauvignon Blanc Experience in Kelseyville, Calif.

Now, six years later, Sauvignon Blanc’s star is still ascending. The white wine has grown increasingly popular among consumers, bucking the current trend of stagnating U.S. sales in both red and rosé wines, according to Debra Sommerfield, LCWC president.

As a result, “wineries statewide have been really leaning in to meet consumer

demand, so California’s growers have responded by planting more,” she said.

That vineyard response, however, has some California industry insiders worried.

“If the industry starts to slow down overall, do we really have room for that extra production?” asked Jeff Bitter, president of Allied Grape Growers, a marketing cooperative of 500 winegrape growers. The long-time industry executive has been pushing for more vineyard acreage to be removed from the Golden State to help bring supply and demand back into better balance.

By the Numbers

A few numbers highlight Sauvignon Blanc’s upturn. From 2019 to 2022, the white varietal’s acreage in California increased by 1,192 acres, Sommerfield said, based on the California Grape Acreage Report for 2022, released last April. Overall, statewide vineyard acres planted to Sauvignon Blanc equaled 16,889 as of 2022.

Further, the grape’s total tonnage in California has swelled by nearly 30% since 2020, according to recent data from Ciatti Company, a global wine and grape brokerage firm.

In addition, the 2023 Grape Crush

20 Grape & Wine Magazine April / May 2024
Bottles of Sauvignon Blanc await consumers at a Trader Joe’s store in Bakersfield (photo by C. Merlo.) These Sauvignon Blanc grapes grow in Lake County, California’s third largest producer of the varietal behind Sonoma and Napa (photo by Jeff Tangen for Lake County Winegrape Commission.)

Preliminary Report, released earlier this year by CDFA, showed the state crushed 162,765 tons of Sauvignon Blanc in 2023, almost 32,000 tons more than the year before.

Higher yields likely accounted for some of that increased tonnage as was the case for most California winegrapes last year. But more plantings are a big part of Sauvignon Blanc’s larger production, Bitter said. He worries if overall wine-consuming habits don’t pick up, there could be an oversupply of Sauvignon Blanc in the next few years.

Already, Bitter foresees a 29% increase in California’s Sauvignon Blanc bearing acreage by 2026 in vineyards producing the varietal for the $11- to $25-per-bottle category. That price segment is where the lion’s share of Sauvignon Blanc heads. If all bottled price points are calculated, Bitter estimates California will see a 14% increase in bearing-acreage growth for the varietal over the next three years.

“We need to be careful not to plant too much Sauvignon Blanc,” Bitter said.

Another voice of caution comes from Joy Merrilees, vice president of production for Shannon Family of Wines. The company farms 1,200 acres of winegrapes in Northern California’s Lake County and produces 14 brands of wine including its flagship Clay Shannon label. The vintner has expanded its volume of Sauvignon Blanc by 10% over the last two or three years, with the varietal now making up 30% of its overall acreage. Even so, Merrilees advised growers not to “get ahead of the market.”

“When growers see small upticks, they jump on it, and a lot of people plant,” she said. “Then oversupply comes into play. Be cautious about planting Sauvignon Blanc. The trend is alternative whites. Look for other alternative whites that may also become popular in the future.”

The Market’s “Hottest” Grape

Amid overplanting concerns, many still view Sauvignon Blanc as one of the

April / May 2024 21
Joy Merrilees of Shannon Family of Wines prepares to sample a glass of Sauvignon Blanc at the company’s Lake County winery (photo courtesy Shannon Family of Wines.) Leading grape varieties crushed in California per USDA’s 2023 Grape Crush Report. Sauvignon Blanc makes up 4.4% of all varieties. The growth in demand for Sauvignon Blanc wines “isn’t a fad,” says Debra Sommerfield of the Lake County Winegrape Commission (photo by LCWC.)

It’s projected that Sauvignon Blanc’s bearing acreage will increase by 14% in California by 2026 (photo by C. Merlo.)

Winegrape producer Craig Ledbetter likes growing Sauvignon Blanc because it’s easy to farm (photo by Vino Farms.)

Sauvignon Blanc is coming into its own as a major varietal among white wines, says Glenn Proctor of Ciatti Co., a global wine and grape brokerage firm (photo by Ciatti Co.)

bright spots in the troubled wine industry. Although it’s long been overshadowed by Chardonnay in both supply and demand, Sauvignon Blanc is giving a relatively robust market performance.

Lake County’s Sommerfield pointed to a November 2023 article in Wine Spectator, which reported Sauvignon Blanc sales rose 1.2% to 16.6 million cases in 2022. Both imported and domestic Sauvignon Blanc sales grew.

“No grape is hotter in today’s market,” writer Mitch Frank noted.

That growth isn’t a fad, Sommerfield added. “Consumers aren’t buying Sauvignon Blanc because it’s trendy or some sort of status symbol or because everyone else is,” she said. “Rather, they’re buying Sauvignon Blanc because they actually enjoy it. It’s delicious with or without food. It fits into all social settings and is also perfect for a night in. And, because there are so many styles of Sauvignon Blanc and a bottle isn’t crazy-expensive, it’s really fun to try different ones, to discover. It’s sort of low-risk, high-reward.”

Sommerfield gave two reasons for Sauvignon Blanc’s new demand. First, there’s the “pandemic effect,” when people stuck at home discovered Sauvignon Blanc as an “affordable, approachable wine for daily drinking,” she said. Second, younger drinkers who were exploring new wine varieties, “the “nottheir-parents wine effect,” and looking for crisp, aromatic wines found Sauvignon Blanc.

“We need to be careful not to plant too much Sauvignon Blanc,” says Jeff Bitter of Allied Grape Growers (photo by Allied Grape Growers.)

“We want to be excited about Sauvignon Blanc but not overshoot the mark in production. You’ve just got to be sure the market wants it.”
- Glenn Proctor, Ciatti Company

Consumers aren’t the only fans of Sauvignon Blanc. Vintners also like the varietal not just for its fresh, clean taste but because “it’s probably the first wine that’s done, bottled and out the door every vintage,” Merrilees said. “So you get to see the fruits of your labor so quickly, which is satisfying to a lot of winemakers.”

“Sauvignon Blanc’s got a nice cash flow to it because you’re bottling it and selling it a little earlier,” agreed Ciatti Company’s Glenn Proctor, who works closely with California’s wine industry.

22 Grape & Wine Magazine April / May 2024

A Vineyard Favorite Sauvignon Blanc also has admirers among growers like Craig Ledbetter. He is vice president of sales and a partner with Vino Farms, which farms about 17,000 acres of winegrapes throughout California. The enterprise has increased its production of Sauvignon Blanc over the last four years, including about 100 acres of new plantings in the Lodi area and another 60 acres near Paso Robles.

“I love growing Sauvignon Blanc because it’s easy to farm,” said Ledbetter, who himself prefers drinking Sauvignon Blanc to Chardonnay. “It’s not a difficult varietal. Where you’re going to make your money in Sauvignon Blanc as a grower is in the production because it’s a good producer. You’re not having to spend excess money on protecting the grapes from the different things the environment can create like mildew or pests. Sauvignon Blanc grapes seem to be able to withstand those.”

As demand has increased, so too have Sauvignon Blanc per-ton prices. Ciatti Company numbers show California’s overall average prices for bulk Sauvignon Blanc grapes rose from $942/ ton in 2020 to $1,132 in 2023. That compares with Chardonnay’s per-ton price, which averaged $842 in 2020 and climbed to $1,071 in 2023.

“You’ll see some Napa Sauvignon Blanc deals get close to $4,000,” Proctor said.

Of course, where Sauvignon Blanc, or any winegrape, is grown matters, as does quality. In general, the lower the yield, the higher the fruit quality. Wineries are willing to pay growers more for higher quality. For example, the interior Central Valley grows most of the Sauvignon Blanc grapes destined for the lower price point of $6 to $11 per bottle. The average yield for the varietal in the valley’s San Joaquin County is 12 to 18 tons per acre; the average per-ton price paid was $601, according to the 2023 Grape Crush Report.

In contrast, most Sauvignon Blanc grapes grown for higher per-bottle price points are produced in the coastal growing regions like the North Coast, in-

cluding Lake County. Sauvignon Blanc’s average yield in Lake County was just 6 to 10 tons/acre, but the average price paid to growers was significantly higher at $1,319/ton.

Despite Sauvignon Blanc’s growing popularity, Proctor echoes other voices recommending growers be careful about planting more in hopes buyers will come.

“Sauvignon Blanc is establishing itself as a major white varietal, but be cautious about putting the cart before the horse,” Proctor said. “We want to be excited about Sauvignon Blanc but not overshoot the mark in production. You’ve just got to be sure the market wants it.”

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April / May 2024 23
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Life After Freedom Research

looks at nematode-resistant replacements for rootstock susceptible to sudden vine collapse.

Known for its high vigor and related strong yields, Freedom rootstock gained popularity and accounts for about 25% of recent wine grape vineyard plantings within the state. Nevertheless, the rootstock has lost favor in some areas as it is sensitive to viruses and may succumb to sudden vine collapse (svc) when leafroll virus and vitiviruses are present.

In a quest to find replacements for Freedom, Karl Lund, a UCCE viticulture advisor in Madera, Mariposa and Merced counties, conducted replicated trials in two Central Valley vineyards with seven rootstocks.

RS3 and RS9 are interspecific hybrids from the USDA breeding program with broad resistance to many of the common nematodes, including virulent rootknot nematodes. The GRN series of hybrids (GRN1, GRN2, GRN3, GRN4 and GRN5) have broad resistance to many of the commonly found nematodes, including ring nematode, as well as to phylloxera. They were developed by the UC Davis grape breeding program.

These newer rootstocks have varying levels of vigor and not all may be suited to the Central Valley, Lund said.

“We have to figure out how they’re going

Now that I’ve seen [sudden vine collapse], this is a big deal. We probably shouldn’t be using Freedom in the future if we can’t control leaf roll.
-Karl Lund, UCCE

to affect the rest of the quality beyond nematode resistance,” he told attendees of the 72nd Annual Lodi Grape Day.

Lund’s counterpart in Fresno County, George Zhuang, completed a trial evaluating seven rootstocks including two UC nematode-resistant ones under saline soil and water conditions in western Fresno County in 2022. Among the readings he took were pruning weights and yield.

Following that trial, Zhuang planted a new one in 2021 with seven rootstocks and two different scions including two of the new UC nematode-resistant rootstocks.

Virus Complex Complicates Rootstock Choices

The cause for concern is Freedom when it’s infected with both grape leafroll-associated virus 3 (GLRaV-3) and vitiviruses. Freedom is one of the most virus-sensitive rootstocks currently on the market.

Although the exact mechanisms aren’t fully understood, researchers hypothesize vines grafted onto virus-sensitive rootstocks that become co-infected with the two viruses as well as possibly other viruses are predisposed to root stress. Combinations of the viruses appear to be synergistic and can lead to vine decline.

24 Grape & Wine Magazine April / May 2024
“ ”

Although not fully understood, vines grafted onto virus-sensitive rootstock, like Freedom, that become co-infected with grape leafroll associated virus 3 and vitiviruses and possibly other viruses may succumb to Sudden Vine Collapse (photo by Akif Eskalen, UC Davis.)

Additional infections by fungal pathogens associated with grapevine trunk diseases, such as esca, dieback, canker and black foot, may cause rapid vine collapse.

“Until I saw it, I thought this wasn’t a big deal,” Lund said about sudden vine collapse. “Now that I’ve seen it, this is a big deal. We probably shouldn’t be using Freedom in the future if we can’t control leaf roll. The vines were perfectly healthy at the end of June and had raisined in July, a one-month period. By the end of August, the vines had died.”

If he were a grower, Lund said he’d be wary of planting Freedom when GLRaV-3 was nearby. That’s because the viruses can be spread by scale insects and vine mealybug, which can hitchhike on equipment and infested plant material.

Freedom gained popularity because it is vigorous and produces a large canopy that helps support the yields needed in the Central Valley, he said. Harmony, another high-vigor rootstock, lost popularity because it is susceptible to virulent root-knot nematode populations.

New Rootstocks Put to the Test

Both of Lund’s trials were in vineyards planted on single high-wire trellis

systems designed for full mechanization. The Madera vineyard, planted in 2009, was grafted with the scion petite verdot. It had both RS rootstocks as well as the five GRN series. Freedom and 1103P were the industry standards that acted as controls.

The Merced vineyard, planted in fall 2016, had GRN2, GRN3, GRN4, RS3 and RS9 rootstocks as well as 1103P as the standard control. It was grafted with the scion malbec.

The two trials also differed in their layout, with the Madera one having a larger variety of rootstocks per replicate and the Merced site having a larger number of vines on each rootstock.

One of the main traits Lund focused on was canopy size. To determine that, he placed a solar panel beneath the canopy between noon and 2 p.m. to measure the amps produced. By comparing it to readings taken in full sun, he was able to determine crop shading and ultimately canopy size.

In the Madera trial in 2023, Freedom, GRN2, GRN3, GRN4 and GRN5 were in the larger canopy group while the remainders were in a smaller canopy group. Throughout the seasons, Free-

George Zhuang, UCCE viticulture advisor for Fresno County, completed a trial evaluating seven rootstocks including two UC nematode-resistant ones under saline soil and water conditions in western Fresno County in 2022.

Karl Lund, UCCE viticulture advisor for Madera, Merced and Mariposa counties, conducted replicated trials in two Central Valley vineyards with seven rootstocks in a quest to find replacements for Freedom.

April / May 2024 25

dom and GRN2 always had the largest canopies, with GRN1, RS9 and 1103P bringing up the rear.

Yields roughly followed canopy vigor, with Freedom topping the Madera trial with 19 tons per acre. GRN2 and GRN3 yielded about 16 tons per acre, followed by GRN1, GRN4 and GRN5 producing between 14 and 15 tons per acre. RS9 and 1103P were at the bottom with less than 12 tons/acre.

“Freedom still is the yield king, with GRN2 and GRN3 a step behind,” Lund said. “GRN1, GRN4 and 1103P were further behind.”

The results from the Merced trial differed slightly with 1103P performing more as expected as far as canopy size. GRN2 produced one of the largest canopies, followed close behind with GRN3. GRN4, RS3 and 1103P had more moderate canopies, while RS9 had the smallest canopy. Yields didn’t necessarily correlate to canopy size due to wide variability within the site.

Overall, GRN3 had the highest yield, followed by RS3, RS9, GRN4 and 1103P. Bringing up the rear was GRN2. Lund said the poor performance could be due to the rootstock taking longer than others to become established, a trait also seen by Zhuang and UCCE Viticulture Advisor Tian Tian in Kern County.

Fresno Trials

Zhuang’s original replicated trial involved the scion pinot gris and seven rootstocks including GRN2 and GRN3 planted on a single high-wire trellis system.

Although the trial focused on boron and salinity tolerance, he also took pruning weight samples as well as yields. Pruning weight typically reflects plant vigor. And both GRN2 and GRN3 had heavy pruning weights and strong yields.

“One of the interesting things about GRN2 and GRN3 is they were better not just from the pruning weight and yield but they also tended to have boron tolerance,” Zhuang said. Sampling found lower levels of boron in the petioles of vines grafted onto those two rootstocks.

Another trait he noted was the slow start for vines grafted onto GRN2 and GRN3.

“The first two years, you have to be very careful about training those vines because they’re very slow to begin,” Zhuang said. But once they become established, he found they yielded well.

The second replicated trial, planted in 2021, involved scions French colombard and barbera planted on seven rootstocks including RS3 and GRN3. He didn’t include many of the other UC nematode-resistant rootstocks because Lund’s trial showed they didn’t perform as well.

Zhuang and his crew harvested the first crop in 2023, and he said he liked to have at least three years of data before drawing conclusions about rootstock performance.

Looking Beyond Yield

Yields aren’t the only rootstock traits to consider, especially with repeated droughts in the San Joaquin Valley and the Sustainable Groundwater Management Act, Lund said. He also looked at how the rootstocks reacted to droughtlike conditions throughout the growing season as well as regulated deficit

irrigation over a specific period such as post-veraison.

Across three seasons of water stress in the Madera vineyard, Freedom and GRN2 had the lowest level of water stress. On the other end, RS3, RS9 and 1103P exhibited the highest levels of water stress.

The one issue Lund has with GRN3 is it also becomes highly water stressed and throws a “water stress tantrum.” But it returns to low to moderate water stress levels once irrigation is restored.

When the vineyard management team implemented post-veraison stress for grape quality, Freedom and GRN2 still showed the lowest stress levels. On the surface, 1103P also appeared to exhibit lower water stress, but the outer canopy layer burned, leaving the canopy damaged. After the canopy recovered, 1103P went back into the high-water stress category.

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26 Grape & Wine Magazine April / May 2024
UCCE Viticulture Advisor George Zhuang and his crew harvested the first crop last fall from a multi-year rootstock trial west of Fresno (photo by G. Zhuang, UCCE.)


Now is the time to start preparing for early season pests such as powdery mildew, Botrytis and anthracnose. These pests will quickly reduce peak yield potential if they are not carefully monitored and effectively treated.

Rotating modes of action is one of the most powerful approaches in an effective integrated pest management (IPM) program. “In addition, research indicates that combining biologicals with chemistry can improve management of problematic pests,” says Dr. Melissa Jean O’Neal, Ph.D., Senior Product Development Manager, Pro Farm Group, Inc.


Regalia® Biofungicide is one such product that is highly compatible with other crop protection products and can be incorporated into tank mix or rotational programs.

Particularly effective against powdery mildew, Regalia Biofungicide has a broad spectrum of activity against many fungal and bacterial diseases. “It is a good product to apply preventatively before disease gains a foothold,” says O’Neal.

Another product to consider is Stargus® Biofungicide with the active ingredient Bacillus amyloliquefaciens strain F727. It contains a unique strain that is broad spectrum and provides multiple modes of action, for which efficacy data appear in the grape Botrytis dataset below. This Bacillus differs from other species and strains in that it generates living spores to form a protective barrier; therefore, pathogens have a more difficult time establishing within the plant.

These two biofungicides, Regalia and Stargus, show their greatest efficacy when applied early – when conditions become conducive to disease development or at the very onset of disease.

4-16% Less Botrytis Incidence vs. Alternatives

Dr. Eskalen, UCD, Clarksburg, Ca, 2020

• Variety: ‘Riesling’


5/15/2020 6/15/2020 6/28/2020

Pre-Bloom Pre-Close Veraison

Regalia and Stargus Biofungicides support plant health and impart overall stress tolerance for grapes by boosting a plant’s innate ability to defend itself through induced systemic resistance (ISR) and systemic acquired resistance (ISR).

Adding Jet-Ag® 5%, a peroxyacetic acid (PAA), in tank mixes or rotations is another IPM approach to improve disease management by utilizing a contact curative. “This product kills pathogens on contact and has an extremely broad spectrum of activity,” says O’Neal. Jet-Ag also tends to be widely available and is quite economical to purchase.


Combining the power of biology with the performance of chemistry is called a BioUnite ™ approach by Pro Farm Group.

for best results.

• Stargus 1-2 qts./A OR

• Regalia 1-2 qts./A

• Jet-Ag 2-4 qts./100 gal.

• Stargus 1-2 qts./A OR

• Regalia 1-2 qts./A

In summary, benefits of biologicals in an IPM program include utilizing novel modes of action that improve pest management, reducing the development of pesticide resistance, and offering cost-effective tools through new formulations.

For more information, visit the grape page at or scan this QR code to download the Early Season Disease Management IPM Guide.

April / May 2024 27 FORMERLY MARRONE BIO INNOVATIONS ©2023 Pro Farm Group, Inc. All rights reserved. Always read and follow label instructions. Please find labels and more information at *Regalia®, Grandevo®, Jet-Ag® and BioUnite™ are registered trademarks of Marrone Bio Innovations. Luna® is a registered trademark of Bayer. Vanguard® and Miravis® are registered trademarks of Syngenta. Advertorial
Untreated Program with Regalia 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% REGALIA® BIOFUNGICIDE’S PERFORMANCE ON GRAPES Percent Control of Powdery Mildew
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• Pacific Ag Research, UC Davis Percentage Control 2009 2010 2010 2011 2011 2011 2015 2016 2017 2018 2018 2020 2021 PRE-CLOSE VERAISON PRE-BLOOM • Regalia 1-2 qts./A
disease is already present, tank mix with Jet-Ag as a contact fungicide
46% 44% 42% 40% 38% 36% 34% 32% 30% Mean % Incidence Untreated Control Miravis®
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Red table grape appeal lies in uniform berry color and a crunchy, crisp texture.

Managing the crop to achieve color and firmness at harvest and preserve those qualities in cold storage requires recognition of the many factors that can affect berry color and firmness.

At the Southern San Joaquin Valley Grape Symposium, UCCE Kern County Viticulture Advisor Tian Tian said variety difference, harvest timing, environmental conditions, vineyard management and weather are all factors that can influence berry firmness. Trials conducted to date have been inconclusive in finding which products work best for firmness, color and brix.

Tian said in a variety named Krissy, berries begin losing firmness at the onset of veraison and their firmness decreases during ripening. This softening is due to degradation of pectin and cellulose in the cell wall, reduction in intercellular adhesion and loss of turgor pressure with increased concentrations of fructose and glucose in the berry apoplast,

the extracellular space outside of plant cell membranes.

Berry color develops as anthocyanins accumulate in berry skin. High temperatures slow down anthocyanin synthesis and accelerate its degradation.

Role of Nutrition and Other Practices

Tian said foliar-applied nutrition plays a part in berry quality, strengthening cell walls and reducing heat damage. Even a small portion of calcium and magnesium in a foliar spray is allocated to the fruit, and increase in calcium in the fruit may lead to pectin degradation and strengthen the cell-to-cell adhesion, improving fruit firmness. A foliar orthosilicic acid spray may increase cross-link between polysaccharides and reinforce cellulose fibers. It may also reduce cell wall destabilization under high temperature.

Crop load adjustment is a management practice that allow vine resources to go to remaining clusters after thinning. Leafing at veraison is another management practice that can promote better

light penetration in the canopy. While light is essential to trigger anthocyanin accumulation in some varieties, it can also lead to sunburn. Tian said a 2022 study of leaf removal did not show any improvement in berry coloration.

Tian’s data presented at the symposium showed findings by the first harvest. She was not able to complete the trial due to the summer storm. She also noted that the experimental block had a lower-than-normal crop load. The trial will continue this year.

Possible solutions for pre-harvest fruit softening in red table grape varieties include early harvest or slowing down the decrease in berry firmness during fruit ripening to minimize the risk of pre-harvest fruit softening.

Ashraf El-Kereamy, UC Riverside and UC Lindcove, said the use of ethylene-releasing compounds to improve red color in grapes needs more attention due to increased global temperatures.

Understanding Growth Cycle

Understanding grape berry growth cy-

28 Grape & Wine Magazine April / May 2024
Berry color develops as anthocyanins accumulate in berry skin. High temperatures slow down anthocyanin synthesis and accelerate its degradation (all photos by T. Tian.)

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cle can help with promoting color. The first stage is the formation cycle where berry formation starts with cell division in pericarp tissue and flower starts to transform into fruit. Water transfers into berries via xylem and phloem to enlarge berries. The berry is green and hard. The second stage is the ripening cycle. Sugar accumulations, phenolics and flavor compounds begin. Color changes from green. Formation of each compound is temperature- and light-dependent, but the ripeness of the berry is determined by sugar level and color.

In research funded by the California Table Grape Commission, published in Frontiers in Plant Science, El-Kereamy notes red color results from anthocyanin pigment. The anthocyanin pathway is regulated by light and antioxidant activity, among other factors. Even with cultural practices, he said it is still challenging to produce table grapes with high coloration.

Five plant hormones play a role in grape berry development: auxin, cytokinin and gibberellins, which are active in early development, and abscisic acid and ethylene, which are active at onset of ripening. These ripening hormones need to be kept in balance, El-Kereamy said, and work together to produce color.

In El-Kereamy’s research, treatments included ethephon (ET) at 600 mg/L, silicon at 175 mg/L and a commercial light-reflective white ground cover (RGC) alone and in various combinations. Treatments were conducted either with or without a combination of cluster-zone leaf removal at veraison (LR) on Flame seedless grapes.

The treatment was carried out at veraison when 30% of berries in the clusters were turned red, and maximum red grape coloration was observed when combining ethephon with the ground white plastic cover and Si due to enhancing both anthocyanin biosynthesis and antioxidant enzyme activity. Using the light-reflective white ground cover did not restrict the water supply as the water was freely reaching the vine rootzone. LR at this stage increased berry temperature that might reduce

the effectiveness of ethephon on berry coloration.

Data collected in 2019 and 2020 in ElKereamy research showed the best treatment to improve berry coloration was using ET in combination with Si and RGC, applied at veraison. Adding LR to this combination did not improve berry color any further but rather caused a reduction in color development. Use of reflective ground cover without LR at veraison significantly increased the quantity of reflected blue and red lights as well as the red to far-red ratio around clusters.

Manipulating the light spectrum and application of Si in combination with the ethephon treatment could be used in table grape vineyards to improve the ethylene-induced anthocyanin accumulation and coloration, he noted in his research.

The control and LR had the least effect on color. LR, El-Kereamy noted,can have harmful effects in high-heat situations and may reduce the effectiveness of ethephon on berry coloration.

Take-away message is excessive stress can impair anthocyanin biosynthesis and accumulation in the berries. Other hormones can positively or negatively affect the vine’s response to ethylene. Using appropriate cultural practices to allow ethylene to properly release will prevent triggering other promoter


El-Kereamy’s study showed the importance of light quantity and quality on ethylene-induced anthocyanin accumulation in red table grapes and its coloration. Manipulating light conditions surrounding the vines using RGC in addition Si enhanced the effect of ethephon.

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30 Grape & Wine Magazine April / May 2024
Red table grape appeal lies in uniform berry color and a crunchy, crisp texture. Possible solutions for pre-harvest fruit softening in red table grape varieties include early harvest or slowing down the decrease in berry firmness during fruit ripening to minimize the risk of pre-harvest fruit softening.
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Although monoculture farming is the right move for winegrapes, limiting biodiversity in an area year after year can take a toll on the natural habitat. Cultivating diverse habitats is important (photo by Michelle Cordova.)

Anyone who travels to California’s Central Coast knows it is a hot spot for agriculture. A visit quickly reveals the sheer diversity of natural ecosystems, from beaches and coastal ranges to rolling hills and rangeland.

Along with the ecological diversity comes a range of development and activity, including dedicated wildlife

preserves and numerous agricultural operations.

Thanks to the Pacific Ocean’s influences, one of the Central Coast’s top commodities is winegrapes. Over the past couple of centuries, its valleys and rolling hills have become home to dozens of world-renowned vineyards and wineries.

Winegrape vineyards ranging from a

few to several hundred acres can be found across the region and are typically grown as monoculture crops.

In monoculture farming, the same crop grows on the same land yearly. Since vines stay in the ground producing grapes for decades, monoculture farming makes sense for the plant and the grower.

32 Grape & Wine Magazine April / May 2024 SUSTAINABLE STORY

Cultivating Diverse Habitats

Although monoculture farming is the right move for winegrapes, limiting biodiversity in an area year after year can take a toll on the natural habitat. Biodiversity suffers when soils are disrupted and plant life is limited.

Soil contains a lot of life, including beneficial bacteria, fungi and much more. These lifeforms offer ecological benefits like nutrient conversion and transportation, and plant growth stimulation and decomposition.

Working hand-in-hand with microbial life below the soil, the native plant life that grows from it plays a major role in the carbon cycle. Native plant species are especially adept at sequestering carbon, as they thrive in the area’s climate and conditions and don’t depend on external interventions to remain resilient.

But by preserving and regenerating natural habitat alongside cultivating their crops, vineyard growers can reap the benefits of biologically rich soils and help regulate the amount of CO2 in the atmosphere.

Agricultural systems become more resilient and functional under changing climate conditions when they include a variety of plant, animal, fungal and bacterial life.

The regenerative nature of the practices sustainable vineyard stewards use comes from the founding principle that farming practices influence a system much larger than just the vineyard, more commonly referred to as the whole farm system, which includes the vines, the rows between the vines, the wildlife

April / May 2024 33
nutrients, biopesticides and specialty inputs designed to optimize crop production. Contact us today to learn more! SOLUTIONS FOR SUSTAINABLE CROP HEALTH AND NUTRITION
Cover crops like the native grasses that flourish in the sloped blocks of Maverick’s properties serve as homes, food and mating and hunting grounds for insect life (photo courtesy Maverick Farming.)

Maverick Farming in Santa Maria, Calif. uses tractors and heavy equipment to perform generalized tasks like discing and leveling soil. When these tasks are mechanized, workers can dedicate their time and expertise to tasks that require more skill and precision (photo by Michelle Cordova.)

habitat, adjacent oak and riparian areas, surrounding wetlands, receiving waters and other non-cropped areas.

Balancing Mechanization and Hands-On Work

Sustainable vineyard stewards like Maverick Farming in Santa Maria, Calif. take a big-picture approach to their management practices. They manage several commercial vineyards on California’s Central Coast, so many of their vineyard sites have rows of vines planted up and along steep hills.

Managing sloped crops poses navigational challenges, which is why many vineyard owners turn to experienced management companies who have the tools and experience necessary to handle these challenges.

Maverick uses tractors and heavy equipment to perform generalized tasks like discing and leveling soil. When these tasks are mechanized, workers can dedicate their time and expertise to tasks

Operations like Maverick that implement SIP Certified® sustainable practices have an easier time managing a property that experiences reduced erosion and greater water holding capacity, improved carbon and nitrogen cycling, and a plethora of biological activity (photo by Michelle Cordova.)

that require more skill and precision.

On top of increasing efficiency, mechanization makes for a safer work environment. People specializing in hands-on vineyard care need to walk up and down each and every row of vines. Gopher mounds pose a safety risk to people as they move through the vineyard rows, which is why Maverick brings in equipment to level them out.

But there are downsides to driving tractors through the rows of vines.

Heavy equipment compacts the soil. When soil becomes too tight for water to soak, roots aren’t optimally hydrated.

Additionally, when water can’t permeate the soil, it is more prone to running off the property, posing a threat to water quality.

Finally, agitating soil with tilling practices hinders its biological activity. When the habitats of soil microbes and

beneficial insects are disrupted, the biological benefits they offer are weakened.

Caring for The Whole Farm System

Knowing that tilling the hilled rows is both necessary and risky, Maverick changed their tilling practices. By doing so, they have found a balance that preserves worker safety and enhances biodiversity in their vineyards.

The vineyard blocks that are sloped and prone to higher water runoff are now on a five-year discing rotation cycle. This allows the vineyard floor to be made level and safe for workers, and it gives time for native grasses to establish themselves as cover crops.

Chad Foster has been with Maverick since 2015. As operations manager for the company’s Santa Barbara and San Luis Obispo county vineyards, he has seen the progression of these reduced tillage blocks as they progress through the five-year cycle.

34 Grape & Wine Magazine April / May 2024

“The biggest thing we’ve noticed from an everyday standpoint,” Foster said, “is improved water infiltration. Now that the cover crops are nice and established, their deep roots help guide the water further into the soil.”

Plant life offers benefits to both water infiltration and quality. As well as guiding water deep into the soil, roots act as a filter that holds sediment in place. This keeps water on the property rather than allowing it to run off and contribute to water pollution.

Moreover, when leaves and stems above ground catch falling rain, they reduce the impact of water drops, thus reducing erosion potential. Soil erosion compromises soil quality and fertility, potentially reducing the quality of grapes and threatening surrounding areas.

But that is not all. Cover crops like the native grasses that flourish in the sloped blocks of Maverick’s properties also

serve as homes, food and mating and hunting grounds for insect life.

Foster noticed an uptick in lacewing and ladybugs where the native grasses flourish. These beneficial insects are natural predators to the mites, mealybugs and aphids which are common vineyard pests. Encouraging functional predator/ prey relationships enables a vineyard steward to reduce chemical inputs that would otherwise be needed to manage insect pests.

While discing and leveling are still periodically necessary due to vertebrate pests and tractor compaction, Foster said the new rotation cycle that allows the native grasses to thrive has benefited their soils, vines and insect activity.

Operations like Maverick that implement SIP Certified® sustainable practices have an easier time managing a property that experiences reduced erosion and greater water holding


capacity, improved carbon and nitrogen cycling, and a plethora of biological activity.

On top of contributing to healthier production sites, farming in a way that cares for the whole farm system leads to a healthier ecosystem that can support many forms of life through the commodities it produces and the regenerative habitat it provides.

While cultivating biologically diverse habitats is a remarkable component in a sustainable winegrowing operation, sustainability doesn’t stop in the vineyard. In the next Sustainable Story, learn about how an estate vineyard and winery in Paso Robles, Calif. involves their entire team in their sustainable business practices.

Comments about this article? We want to hear from you. Feel free to email us at

April / May 2024 35
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Grape Ground California Winegrape Vineyards: 2023 Sales Update



36 Grape & Wine Magazine April / May 2024
continue add grape ground and buyers continue to acquire grape ground despite formidable challenges (photo by JW Lemons.)

California grows grapes in 49 of its 58 counties. Growers and wineries currently face challenges on multiple fronts: labor shortages and costs, post-COVID-19 materials costs and logistics issues, consolidation at the distributor level and higher interest rates. In California, we can always add to those daunting burdens the ever-present encumbrances of climate extremes and water availability.

And yet, despite these formidable challenges, growers continue to add grape ground, and buyers continue to acquire grape ground. This review of recent sales is certainly not all-inclusive but intended to give a large-picture snapshot of some of the year’s more significant sales. Feel free to reach out if you spot a glaring omission or error.

Kern County

79.3 acres Cab Sauv at $25,000/acre; November 2023

80 acres French Colombard at $25,000/acre; November 2023

167 acres Pinot Grigio, French Colombard, Syrah, Chardonnay at $24,400/acre; November 2023

Madera County

78.5 acres Black Muscat, Orange Muscat, Chardonnay at $37,600/acre; April 2023

Mendocino County

Abel Vineyard to Wentworth Vineyards (~21 acres, $1,400,000;



Notable recent winegrape acreage purchases include about 400 acres for over $900,000,000 in San Luis Obispo County and about 1121 acres for $400,000,000 in Sonoma County.

Napa County

Ahmann Vineyard to Cakebread Cellars (209 acres, price undisclosed; Spring 2023)

Alfred Frediani Ranch to Eisele Vineyard (27.65 acres (21 planted), $18,500,000; February 2023) (Pickett Road Property)

Altimeter Vineyard to Shafer Vineyards (~20 (10 planted) acres, $5,555,000; June 2023)

Azalea Springs Way to Memento Mori (~17 acres, $10,310,000; November 2022)

LMR Wine Estates, Rutherford to St. Supery (48 acres, $14,800,000; August 2023)

Montagna to Brion Wise (128 acres, $50,000,000; August 2023) (Now “BRION Estate”)

*Hess Collection to MVSR (Sequoia Grove) (104 acres (18 planted), $3,667,500; June 2023)

*Hess Collection to Kopf Vineyards (unknown acres, $6,213,000; October 2023)

*Hess Collection to Villa Amorosa (<200 acres, $15,250,000; November 2023)

*Multiple correction deeds and lot line adjustments make precise acreage transferred unclear.

Rombauer Vineyard to E.J. Gallo (~700 acres, price undisclosed; Summer 2023)

(Amador, Monterey, Napa, Sonoma Counties)

Spring Mountain Vineyard to MGG Investment Group (845 acres, $42,000,000; July 2023) (purchased out of bankruptcy)

Stag’s Leap to Marchesi Antinori (~300 acres)

Vine Cliff Winery to SCW Fund Corp (~100 acres, $42,100,000 for land alone, not including other business assets)

Vintage Wine Estates to Wonderful (42 acres, $11,000,000; March 2023) (Tenma Vineyard)

San Benito County

Treasury Wine Estates to The Wine Group (642 acres, $15,000,000; November 2022)

Combined with their 2017 purchase of >1,300 acres, The Wine Group now owns over 2,000 acres in the Paicines AVA

Judd Vineyard to Kylix Vineyards (640 acres, $1,500,000; February 2023)

San Joaquin County

Largest winegrape-growing county in California and 5th-largest winery in the U.S. in Manteca, owned by Delicato

Hidden Oaks Vineyard to Farmtogether (~103 acres, $3,200,000; June 2023)

Santa Barbara County

Bridlewood Estate Winery to Santa Ynez Ranch, LLC (81 acres, $5,530,500; January 2023)

Buttonwood Farm to Buttonwood Ranch, LP (107 acres, $6,750,000; July 2023)

Santa Clara County

San Felipe Vineyard to Pura Revocable Trust (187 acres, $3,380,000; February 2023)

San Ysidro Vineyard to Valuable Land Investment, LLC (~312 acres, $7,800,000; July 2023)

(purchased by local buying group)

Sonoma County

Dr. Galante Estate Vineyard to DuMol (~29 acres, $4,525,000; Summer 2023)

Sonoma-Cutrer to Duckhorn (~1121 acres, $400,000,000; November 2023) (Expected to close 3Q 2024)

Soracco Family Vineyards to C and F Company (~81 acres, $8,100,000; September 2023)

Syar Vineyards to Klein Foods (~500 acres, $37,500,000; June 2023)

Undisclosed to Rombauer Vineyards (54 acres, price undisclosed; January 2023)

San Luis Obispo County

And last but the opposite of least, the mind-bending MOAB of 2023 vineyard sales:

Daou sold to Treasury Wine Estates (~400 acres, >$900,000,000; Agreement to Acquire) (Potential for additional $100,000,000 added to purchase price, depending on achieving specified goalsl; not yet closed).

Upcoming in 2024

The Duckhorn Portfolio, Inc. entered into an agreement to acquire Sonoma-Cutrer Vineyards including 1,121 acres for an estimated $400,000,000. The acreage is in the Russian River Valley and Sonoma Coast appellations. Anticipated closing is in late 2024.

Every effort is made to provide accurate information, including verification with publicly available county documentation; however, accuracy is not warranted by author or publisher.

Comments about this article? We want to hear from you. Feel free to email us at

38 Grape & Wine Magazine April / May 2024
April / May 2024 39



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