Author: Cyndi

By: Becky Garrison

This year marks the 40th anniversary of Oregon’s Willamette Valley AVA, which runs from Portland in the North to Eugene in the South. According to the Willamette Valley Wineries Association’s website this AVA consists of 931 vineyards and 736 wineries that represent a total 3,438,000 acres. Currently this AVA has 11 nested AVAs that contain two-thirds of the 1,110+ wineries in Oregon.

  While wine has been made in the Willamette Valley since the 1880s, initially this land was considered too cold and wet to grow great grapes even though it is close to the same latitude as Burgundy, France. In 1965, David and Diana Lett picked up on this distinction and planted 3,000 Pinot noir vines in 1965 at The Eyrie Vineyard near Dundee. Other early wine pioneers included Dick Erath, the Knudsens, and the Sokol Blossers.

  A key factor in the early development of the Willamette Valley was the passage in Oregon of the Land Conservation and Development Act (Senate Bill 100). Signed into law on May 29, 1973, this bill set aside land for future agricultural use.

  This AVA’s last recorded harvest resulted in 84,328 tons, which represents 73.5% of the state’s total crop. The majority of grapes planted are Pinot noir (70%) followed by Pinot gris (16%) and Chardonnay (7.5%). In recent years, some growers have been experimenting with other varietals like Pinot blanc, Riesling, Melon, Gewürztraminer, sparkling wine, Sauvignon blanc, Syrah, and Gamay..

  The region’s general attributes that make this valley ideal for growing cool climate grapes include the protection provided by the Coast Range mountains to the west, the Cascade Mountains to the East, and a series of lower hills at the extreme north of the valley. Drew Voit, Owner/Winemaker, Harper Voit Winery (McMinnville, OR) has been making wine for over twenty-five years, as well as consulting with other wineries situated throughout the Willamette Valley. In his estimation, the Willamette Valley represents the Goldilocks zone in terms of climate and latitude. “We have a particularly long growing season with a cool climate, mild winters, warm and dry summers.”

  Furthermore, the unique characteristics of each of the 11 nested AVAs allow for a surprising wide range of wine expressions. As Voit observes, “There’s diversity even within neighboring vineyards. You really have to listen to each vineyard and embrace the terroir of that particular site.”

  From 2005 to 2006, six sub-AVAs were formed: Dundee Hills, Yamhill-Carlton, McMinnville, Ribbon Ridge, Chehalem Mountains and Eola-Amity Hills.

Dundee Hills AVA: The Dundee Hills AVA has the distinction of being where the first grapes in the Willamette Valley were planted, and it remains the most densely planted locale in Oregon. The region’s Jory soils are formed in colluvium derived from basic igneous rock resulting in well-drained very deep soils. This soil was named after Jory Hill, a town in Marion Country named after the Jory family who settled this area in 1852. Voit states how this AVA’s soil produces powerful red fruit with strong floral notes and a classic balance.

Ribbon Ridge AVA: With only 500 planted acres, this AVA nestled within the Chehalem Mountains AVA represents the smallest AVA in Oregon, as well as one of the most prestigious wine growing regions in the world. Most vineyards in this AVA are protected climatically by the larger landmasses surrounding it, and are dry farmed due to the lack of aquifers. The area is comprised primarily of the Willakenzie series of well-drained and moderately deep sedimentary soils that are ideal for growing complex Pinot noirs with earth notes of dark cherry and rose petal.

Yamhill-Carlton AVA: Situated at the foothills of the Coastal range, the Yamhill-Carlton AVA, contains around 60,000 acres centered around the hamlets of Carlton and Yamhill. This region was known for logging, nurseries, fruit tree orchards, wheat fields, and logging until 1974 when Pat and Joe Campbell and Roy and Betty Wahle planted Elk Cove Vineyard and Wahle Vineyard respectively. In Voit’s estimation, this region produces intense, dark and rich grapes similar to Ribbon Ridge, though he adds that the wines from Yamhill and Carlton may have similar marine sediments, but they possess different and distinctive aromatic tones.

McMinnville AVA: This AVA begins a few miles to the west of McMinnville and then extends approximately 20 miles south-southwest toward the mouth of the Van Duzer Corridor. This AVA’s most prominent geological feature is the Nestuca Formation, a 2,000-foot bedrock formation consisting of weathered volcanic and sedimentary soil that sits on top of marine bedrock. Pinot noir grapes harvested from this AVA tend to exhibit darker fruit flavors and a strong backbone of tannin rounded out by earth, spice, and mineral notes due to the AVA’s drier and cooler temperatures.

Chehalem Mountains AVA: This AVA’s history dates back to 1968 when Dick Erath purchased 49 acres on Dopp Road in Yamhill County that he named Chehalem Mountain Vineyard. He was joined by other pioneers in the 1970s, including the Adelsheim and Ponzi families. The Chehalem Mountains AVA was formally approved in 2006. The Chehalem Mountains are made up of several spurs, ridges, and hilltops with the tallest point Bald Peak, at 1,633-feet above sea level. These features shelter the vineyards from the high winds that blow south through the Columbia Gorge. The soils found throughout this AVA consist of marine sedimentary soils, volcanic soils, and a series of loess called Laurelwood, which is a a geologically younger windblown silty soil of glacial origin.

Eola-Amity Hills AVA: While this agricultural history of this area near Salem dates back to the mid-1850s, winemakers like Don Byard of Hidden Springs didn’t discover this region as an ideal place for growing high-quality wine grapes until the 1970s. The soils of the Eola-Amity Hills consist predominantly of volcanic basalt from ancient lava flows. This feature when combined with alluvial deposits and marine sedimentary rocks results in a rockier and shallower well-drained soils that result in small grapes that are highly concentrated. As Voit observes, this AVA, is impacted by the Pacific Ocean influence where the winds rapidly cool the valley at night, thus helping the grapes retain their acidity as they ripen. “This produces wines with lots of spicy, savory and other non-fruit characteristics that are very compelling and distinctive.”

  From 2019 to 2022, five additional nested AVAs were formed: Van Duzer Corridor, Tualatin Hills, Laurelwood District, Lower Tom AVA and Mount Pisgah, Polk County, Oregon.

The Van Duzer Corridor AVA: This AVA, which went into effect in 2019, consists primarily of marine sediments is a natural break in the Coast Range results in afternoon winds that are 40 to 50 percent stronger when compared to other Willamette Valley AVAs. Voit works extensively with this AVA that he describes as the most Pacific Ocean influenced place in the Valley. “If a vineyard is in the windward blast zone of those strong breezes, there’s rapid cooling in the evening and howling winds. The winds are a little more delicate on leeward side of the hills.” This wind variability leads diverse wines that are both compelling and distinctive with an overall a cooling afternoon effect that dries out the vine canopy and degrees the presence of fungus, along with thickening the grape skins, which produces and abundance of tannin and anthocyanins (color).

The Tualatin Hills AVA: 2020 marked the approval of the Tualatin Hills AVA, a 15-mile stretch of land situated in the far Northwestern corner of the Willamette Valley that is is defined by the watershed of the Tualatin River with an elevation range between 200 and 1,000 feet. This AVA has a lower rainfall, cooler springtime temperatures and more temperate and drier weather during fall harvest as it’s sheltered by the Coast Range and Chehalem mountains. In addition, this AVA features the largest concentration in Oregon of Laurelwood soil, which is a windblown volcanic soil mixed with basalt (loess) deposited by the Missoula Floods at the end of the last ice age.

Laurelwood District AVA: In this same year the Laurelwood District AVA, which comprises more than 25 wineries and 70 vineyards, got approved as a result of petitioning by Ponzi Vineyards and Dion Vineyards. This AVA nested within the Chehalem Mountains AVA comprises more than 25 wineries and 70 vineyards with Laurelwood soil as the predominant soil found on the north- and east-facing slope of the Chehalem Mountains. The Laurelwood District AVA encompasses over 33,000 acres and includes the highest elevation in the Willamette Valley, at 1,633 feet. Laurelwood soil is composed of a 15-million-year-old basalt base with a loess (windblown freshwater silt) top layer accumulated over the past 200,000 years and at depths of 4’ to 0” depending on the elevation.

Lower Long Tom AVA: The next AVA to be approved was the Lower Long Tom AVA, which was established in November 2021 and is situated at the southern Willamette Valley. The AVA’s 24 vineyards are located on stream-cut ridge lines running east to west This AVA is situated within the west side of the Lower Long Tom Watershed and dominated by Bellpine soil. This term is used to describe moderately deep, well drained soils that are formed in the colluvium and residuum derived from sedimentary rocks. This region tends to have hotter days and cooler nights with more planting at higher evaluations. Voit observes how this combination tends to produce intense exotic wines that are unlike anything in the valley.

Mount Pisgah, Polk County, Oregon:  The latest AVA is Mount Pisgah, Polk County, Oregon AVA established in June 2022. Located 15 miles west of Salem, Oregon, this AVA is defined by the rain shadow of Laurel Mountain to the west, a mild influence from the Van Duzer winds, and the warmth of the Willamette River. While this is the Valley’s second smallest AVA at 5,530 acres, it’s also one of the most densely planted AVAs was 584 acres planted with Willakenzie, Bellpine, and Jory, along with some Nekia soils.

The Future of Willamette Valley Wine

  Even though the number of wineries in the Willamette Valley has doubled since 2005, most wineries fall into the boutique category producing under 5,00 cases a year with many of the vineyards and wineries remaining family owned and operated. Prior to 1990 only two major Pinot noir clones represented the vast majority of Pinot noir grapes produced in the Willamette Valley Since then, these vineyards now plant over a dozen varieties of Pinot nor clones.

  As a testament to this region’s commitment to sustainability and regenerative agriculture, Oregon produces 1% of wine made in US but is home to 52% of Demtmer Certified Biodynamic wineries. Other similar initiatives include Salmon Safe, which promotes products made without pesticides or causing runoff that would harm salmon and LIVE (LoW Impact Viticulture and Enology) certification of sustainable practices.

  In Voit’s estimation, the quality of vineyard farming and winemaking has exponentially grown and expanded resulting in wines with fewer technical flaws. “This is partly because the industry is older. But also, climate change put us into a position where we need to understand how to deal with very difficult seasons,” Voit says.

  In celebration of this region’s bounty, the International Pinot Noir Celebration was launched in 1987 as an annual summer celebration held in July that brings together international Pinot Noir producers, Northwest chefs, and wine aficionados for a celebratory educational weekend. Also in 2000, a group of Oregon wineries launched Oregon Pinot Camp, a weekend of presentations, seminars, and tastings dedicated to Pinot Noir. While this event was designed as a one-time event but has since become an annual summer event.

  As a sign of the region’s push towards diversity, the Willamette Valley is host to the Asian American Pacific Islanders Food and Wine Fest in May, the Queer Wine Fest in June, and the Women in Wine: Fermenting Change in Oregon Conference in July. Other Willamette Valley wine events reported in earlier issues of The Grapevine Magazine include Women in Wine (May/June 2023) and Alt Wine Festival (March/April 2023) with upcoming events posted at the Willamette Valley Wine’s website at https://www.willamettewines.com/things-to-do/events

By: Cheryl Gray

No vineyard wants to watch its profits disappear. Yet, left undetected, pests can feed and multiply on the fruit, vine, leaf, root and even the soil of vineyard plants. While many of these threats are undetectable to the naked eye, the end result is all too visible. Pests multiply, spread disease and ultimately cost vineyards money through lost crops and vineyard plants.  

  Scientists have long considered what methods work best for grape growers who want to protect their crops without harming the environment. Multiple studies have been published, including those from the National Center for Biotechnical Information, which is under the umbrella of the National Institutes of Health. Those studies point to multiple defense strategies, specifically, ways to increase the populations of natural predators as well as the controlled use of biochemicals. These methods aim to destroy microorganisms and pests by targeting their ability to reproduce. The first and most important rule of engagement is knowing the enemy. 

  Among the most destructive pests for vineyards are mealybugs. Experts say these culprits can travel from vineyard to vineyard, sometimes on equipment, vineyard workers or by whatever means they can hitch a ride. The first stop for these pests is usually the vine trunk wood, where they set up during the winter. As early as spring, the mealybugs make their way onto the canopy. Before long, they wind up on the grapes, where they infect the fruit with egg sacs and larvae. Left uncontrolled, mealybug infestations can not only reduce crop yield but can also lead to plant stress and, ultimately, plant death.

  Scientists say that natural enemies of these vineyard wreckers include a predator beetle known as the “mealybug destroyer.” Its scientific moniker is Cryptolaemus Montrouzieri. Another natural predator is a parasite known as the Anagyrus wasp. Both are produced by the millions each year by a California cooperative, Associates Insectary, which specializes in integrated pest management systems.

  Associates Insectary, founded in 1928, brands itself as the only producer of the mealybug destroyer beetle in the United States. The co-op, headquartered in Santa Paula, California, says it has the capability to ship these and other beneficial insects not only to its regional customers but also to global markets throughout North America, Central America and Asia.

  How does IPM work in the vineyard using natural predators? For mealybug control, the battle is all about appetite. The mealybug destroyer beetle basically eats through an infestation of mealybugs, feasting on every stage, from egg sacs to larvae to fully grown pests. The female beetles lay more than 400 eggs, making for a ready army to combat mealybugs.

  Unlike the Anagyrus wasp, in which only the female wasps attack mealybugs (by laying eggs inside them), an entire “family” of mealybug destroyer beetles – male, female, juvenile and adult beetles—literally feed on these pests. Many IPM programs use a combination of the destroyer mealybug beetle and the parasitic wasp to fight mealybugs.

  Another benefit to deploying mealybug destroyer beetles in the vineyard is that they go undetected by ants, which have a symbiotic relationship with the mealybug. Again, it is about one insect feeding off another. Ants consume the honeydew that the mealybug secretes, the same honeydew that can destroy grapevines. In exchange for an unending food source, the ants defend mealybugs from other predators – all except the mealybug destroyer beetles. 

  Controlling the ant population that defends its mealybug “meal ticket” is a separate challenge for vineyards. Among the most destructive ant species to vineyards is the Argentine ant, which became more prevalent in California vineyards during the late 1980s. Containing an ant population in the vineyard usually requires a controlled chemical application, including bait systems and spray options.

  The Entomological Society of America (ESA) has published studies about the Argentine ant and its impact on vineyards, particularly in California. As the largest organization of its kind in the world, the ESA is focused on serving the professional and scientific needs of entomologists and individuals in related disciplines. This, of course, includes grape growers who need to know how to rid their vineyards of pests without harming the environment.

  In the case of Argentine ants, experts say it is important to recognize that ant colonies operate with a hierarchy all their own. While chemical sprays can kill or repel forager ants, the ones that go out for food, those ants are easily replaced with other foragers. Moreover, entomologists note that foraging ants comprise only a small number of ant colonies. This means that spray applications may be somewhat limited in that they are not likely to affect either the queen ants or larvae protected within the ant colonies. The other downside of sprays is that some chemicals can break down within 30 days and harm beneficial insects and the environment.

  Experts say that baits offer an alternative to sprays. Many contain a slow-acting insecticide with the idea that once an ant comes in contact with the bait, it will bring that bait back to the nest, expose it to other ants and, as a result, more ants die. The added plus is that the small amount of insecticide in baits is unlikely to impact either the environment or the natural predators that attack mealybugs and other pests. 

  Suterra is an Oregon-based company that specializes in providing a comprehensive IPM program that includes controlling ants in the vineyard with bait deployment. The type of bait and overall treatment is contingent upon the species of ant being treated and the location of the vineyard.

  Suterra produces hundreds of products that are used by its agricultural clients worldwide, including more than 400,000 acres just in the state of California. Part of its lineup includes products manufactured to disrupt the mating pattern of mealybugs by imitating chemicals known as pheromones. Pheromones are naturally occurring chemicals emitted by organisms that allow them to connect within the same species. The chemicals serve multiple functions, including searching for food sources, identifying potential dangers and finding a potential mate.

  Suterra’s Celada™ VMB vapor dispenser works by deploying a continuous synthetic pheromone release that is designed to disrupt the mating pattern among mealybugs. The idea is to confuse the males by keeping them away from the females of the species. The Celada™ VMB vapor dispenser lasts for a full year and is designed to blend into the vineyard with its unique color and shape. Suterra has other products designed to disrupt the mating patterns of mealybugs, such as CheckMate® VMB-F, a sprayable microencapsulated formula and CheckMate® VMB-XL, a membrane dispenser. The active ingredient in both products is a synthetic replica of the sexual reproduction pheromone of the mealybug.

  When vineyards consider what equipment to use to combat pests, multiple factors come into play, such as vineyard size, specific needs and, of course, how much of its budget is devoted to pest control. Spray Innovations has answers. The company,

headquartered in Grand Island, Nebraska, not only services the cattle industry but also other agricultural sectors, including grape growers. It has been

operating for some 40 years. Chris Whiting is the sales manager for the company and shares details about some of its popular products and how they save time and money for clients.

  “Our most popular sprayers for vineyards are our 10-nozzle dual volutes,” Whiting said. “This volute allows the grower to drive down the row and spray both sides with one pass, reducing time in the field. We have several models available in our Little Hercules engine-driven line (rope or electric start versions available) and our PTO-driven line.”

  He went on to share, “Our sprayers are all built in-house at our Grand Island, Nebraska location. We fabricate 90 percent of the parts that go into our sprayers, which cuts down on costs. We sell most of our sprayers directly, so there is no middleman, and we can keep the cost down. Our frames are powder-coated and include a 10-year warranty. Our volutes are all made with galvanized sheet metal, which is more rigid and can take more abuse than volutes made out of plastic.”

  Customers of Spray Innovations include Krista Hartman, co-owner of Red River Wines and Provisions at the Hartman Vineyard in Sadler, Texas. She gives the Spray Innovations P-D15-611 Mist Sprayer a “thumbs up” for performance. 

  “The fine mist and powerful fan system deliver uniform and thorough coverage with all my spray program products,” Hartman said. “I love how I can turn off either volute individually for end rows or a specific target area if needed. This was a big investment for my small vineyard operation, and well worth it. I save time, use less product, feel safer while spraying and keep my canopy as healthy as the elements allow, thanks to this terrific machine.”

  Whether using chemical applications or natural predators, grape growers can deploy an arsenal of weapons to fight vineyard pests from fruit to root. Understanding timing, weather, equipment use and appropriate application of either biochemicals or the release of natural enemies all affect results.

By: Becky Garrison

In What Your Food Ate: How to Heal Our Land and Reclaim Our Health (W.W. Norton & Company), authors David R. Montgomery and Anne Biklé expound on their research into regenerative farming practices that can put carbon back into the ground and improve soil health. This research builds on Montgomery’s introduction to carbon farming that he presented at the 2020 Oregon Wine Symposium. (See the June/July 2020 issue of The Grapevine Magazine).

  Biklé and Montgomery set out to examine the regenerative practices on farms that grow food crops by assessing 10 farms from California to Connecticut that engaged in these practices. When they analyzed how the topsoil from these farms compared to their neighboring farms, they found three broad principles that are central to supporting soil life. The first was the need to minimize the disturbance of the soil. This can translate into no-till or minimal tillage. The second principle is to avoid having bare soil by keeping the ground covered with living plants. Third, grow a diversity of living plant matter.

  Also, they suggested a fourth optional principle: reintegrating animal husbandry. While animals are not necessary for building healthy soils, their presence can serve as an accelerant in speeding up the process.

  In Biklé’s estimation, all of these principles are tailorable. He said, “They’re customizable to a given grower’s setting because what’s going to work in in the Pacific Northwest is going to be different than what’s going on in, say, California or upstate New York.” Hence, it’s key to find a mix of species for a particular cover crop that works on a regional basis. For example, a farm in California that’s subject to ongoing heat and drought would benefit from cover crop species that are particularly resistant to heat waves and do not require much water. Also, a cover crop mix can attract beneficial insects specific to a region that are pest predators or provide other benefits.

  Biklé adds, “If you think of the soil as having a diet it will be different depending on each vineyard’s unique conditions. In other words, the basic principles and practices of maintaining soil health need to be tailored to the soil. Growers can leverage soil health into vine health and a generally more resilient crop, along with minimizing pests and pathogens.”

How to Assess Soil Health

  They recommended assessing the health of one’s soil using the Haney soil test, which was named for USDA scientist Rick Haney. This test includes more than a dozen different soil test values, including standard macro- and micro-nutrients for plant consumption. Compared to other soil tests, the Haney test also estimates nutrients for microbial consumption with a focus on how much nitrogen and carbon are present in the soil.

  This analysis enables growers to ascertain not just the nutrients contained within this soil sample but also how the microbes are making these nutrients available to the soil. If these numbers are low, that’s a strong indication of the need to increase the organic levels through practices like cover crops, leaving residue on the ground or planting high exudate producers (a term that refers to carbon-rich materials).

Results of Applying Regenerative Farming Practices

  They found that, on average, in less than a decade, the topsoil on the regenerative farms in their study had about twice the soil organic matter and a three times higher soil health score than their neighboring farms. Also, when they compared the minerals, vitamins and phytochemical density in the crops they grew, they found that regenerative farms have roughly a 20 percent higher level of phytochemicals, such as carotenoids, phytosterols and polyphenols. Furthermore, they could not find an instance where the regenerative farm performed worse than the conventional farms in the same region. 

  In particular, they noted how regenerative farmers constantly observe what’s transpiring in the field.

Putting These Principles Into Practice

  At this point, they don’t have data demonstrating specifically how these practices work in vineyards. However, their research into how these practices impact food crops points to some positive practices that Biklé and Montgomery hypothesize can be applied to the vineyard. For example, it’s highly suggestive that cover crops planted between the vines will influence both the microbial communities that the plants interact with and the levels of phytochemicals and potential minerals the vines can pull out of the soil and incorporate into their fruit. The end goal is to create an environment where the vine can succeed by relying on its inherent biology.

  Here, Biklé stresses the need to find that sweet spot where there’s just enough stress from physical factors like drought and freeze and biological factors, such as nibbling pests. These stresses cause the plant to churn out phytochemicals. “We know these phytochemicals relate to the flavor and quality of wines, as well as nutritional and health benefits found in wine and other kinds of crops.”

  Too often, Biklé and Montgomery find farmers consider no or minimal till an adequate response to carbon farming practices and do not pursue the other principles for maintaining quality soil. As grapevines aren’t plowed over every year, there’s already some minimal disturbance at play. But growers also need to manage the rows between their vines by planting diverse cover crops. While some growers feel cover crops will compete with their vines, As Montgomery reflects, “If you raise cover crops and then knock them down so they become mulch, these cover crops help keep moisture in the soil more than they respire themselves.” 

  When planting new vines, Biklé recommends doing so with an eye to things like cover crops and animals if a grower is considering those practices. For example, she says to think about the height at which to train the lowest branches to allow enough clearance for cover crops and room for animals like sheep to graze.

  On the topic of inputs, Biklé says, “Occasional use of synthetic chemicals like fertilizers or pesticides probably isn’t a big deal in most cases. But their routine use can affect soil health through interfering with the communication and signaling between a vine host and its root microbiome. As a consequence, root microbiota significantly curtail their normal activities, like stimulating vine phytochemical production and delivering water and must-have nutrients to vines.” 

Challenges in Adopting Regenerative Farming Practices

  In their experience, the biggest difficulty with growers making this switch is their mindset. “If something is working well enough, there’s a reluctance to change,” Biklé opines. Once one can get over this reluctance and adopt an experiential mindset, one can begin to move into the world of carbon farming.

  Other concerns include the need to purchase new equipment. In addition, a given practice might be more labor intensive, which can be a challenge, especially if a region is facing a labor shortage. Also, some may not wish to have sheep in their vineyard based on the assumption these animals would disturb their guests or workers.

  According to Montgomery, a key concern is the need to develop a regional understanding of what would work for vineyards in a given region. He recommends establishing a consortium of local growers who could collectively experiment with what would make for good cover crops between the vines. These growers could set aside a block where they can tinker in their quest to assess the best practices that work in their particular vineyard. In particular, look for any connection between the polyphenol levels of the wine and what’s present in the soil.

  Historically, terroir has been viewed from a winemaking perspective as reflective of the climate, soil and environment. Montgomery and Biklé hope their ongoing research into regenerative farming practices will expand this definition to include an understanding of the soil’s microbial components and how these microbes’ impact both soil health and the quality of the fruit harvested from the vine.

By:  Judit Monis, Ph.D. – Vineyard and Plant Health Consultant

The National Clean Plant Network (NCPN) is a USDA funded program focused on specialty crops such as berries, citrus, grapevines, fruit trees, hops, roses, and sweet potatoes.  The clean planting material is to be distributed to nurseries for further propagation and distribution to growers. The NCPN operates under high standards for the production of true-to-type and pathogen-tested (mainly viruses) plant material.  The branch of the NCPN that focuses on grapevines (wine, table, and raisin) met on January 26 in Davis, CA and virtually.  Grape Clean Plant Centers are located in California, Florida, Missouri, New York, North Carolina, and Washington States.  Representatives of the clean centers, as well as members of the grape industry, extension, State and US regulators participated in the meeting.  Each of the Clean Plant Center directors presented an update highlighting last year’s activities.  In addition, a few presentations focused on NCPN business, strategic plan, economic research on the return of investment of clean centers, and extension activities.  Here I summarize the highlights of the discussions.

The NCPN Strategic Plan (2023-2028)

  Before I describe the strategic plan, I will define and clarify what are G1 clean plants propagated at any of the clean plant centers.  The first generation of plants propagated in a clean plant center is known as a G1 plant.  Plants propagated from G1 are known as a G2 plants, plants propagated from G2 plants are G3 plants, and so on.  Under NCPN, a clean plant is defined as one that has been tested at the G1 level for viruses and certain pathogens of economic importance (the pathogens were not detected).  Note that so far more than 101 viruses have been reported in the grapevine crop, and only a few of these viruses are of economic importance.  NCPN also tests for the bacterial pathogen Xylella fastidiosa and certain phytoplasmas.

There are five goals in the NCPN strategic plan: security, redundancy, capacity, availability of tested plant material, and sustainability.  Security refers to NCPN ensuring that G1 stock propagated in clean centers are free of economically important viruses by utilizing standard operating procedures for testing and to prevent reinfections.  Redundancy applies to the need of having at least two different plants of commonly planted cultivars and rootstocks in at least two different locations. Capacity pertains to the development of an inventory of the plants propagated in each clean plant center and determine the priorities of selections needed to be protected nationwide.  Availability refers to the need of having plant material tested for economically important viruses available.  Finally, sustainability relates to the assurance that the program meets financial and fiscal stability and the support from NCPN is not higher than 30% of the total center’s budget.  In other words, each center is expected to procure financial support to carry out the clean plant activities (user service fees, other grants, etc.).

Highlights of Clean Plant Center Director Updates

California:  Maher Al Rwahnih, Foundation Plant Services in Davis, reported that the Classic Foundation Block (an older block planted in the field at UC Davis) continues to test free of Grapevine red blotch (GRBV) and Grapevine leafroll -3 (GLRV-3) viruses. The completion of a greenhouse in Davis has allowed to move plant material to be protected from insect vectors and potential virus transmission. Funding is being procured from the industry to build a second greenhouse as NCPN does not fund construction of buildings or any infrastructure.

Washington: Scott Harper, Clean Plant Center North West reported on the removal of the outdoor foundation block due to the infestation of dagger nematodes and Tobacco (TRSV) and Tomato ringspot virus (ToRSV) infection is some of the accessions.  At the moment, the only available foundation block is planted in a screenhouse with regular testing for the presence of GRBV, GLRV-3, and Xylella fastidiosa.  In addition, the foundation was subjected to the testing of TRSV and ToRSV due to the outdoor infestation findings stated above.

Missouri: Sylvia Peterson and Wenpin  Qiu, Midwest Center, reported that all of their G1 plants are hosted indoors in a greenhouse were subjected to RNA-seq HTS.  The results of the two positive findings (GLRaV-2 and GLRV-3) were verified by RT-PCR.

North Carolina: Christie Almeyda, Muscadine Grapes Clean Program, reported that all plants are hosted in triplicate in a screenhouse and tested for 13 different pathogens.  Plants were distributed in Arkansas and North Carolina.  The program NCPN funding has fluctuated throughout the years and stresses the importance of locating supplementary funding to run clean plant programs.

Florida: Violeta Tsolova, Muscadine/Southern Grapes reported hosting and maintaining a G1 outdoor  Muscadine and Pierce’s Disease tolerant interspecific hybrids (3-12 plants) and a single plant of each in a screen or greenhouse. New plants are tested for 19 viruses and Xylella fastidiosa.  The G1 foundation is tested yearly for leafroll, red blotch, and Grapevine virus B.

New York: Marc Fuchs, The North East Clean Plant Center at Cornell University, reported that the center does not host a G1 foundation.  The center has focused their activities in the introduction, therapeutics, and release of a number of accessions.

Economic Studies on the Advantage of the Clean Plant Programs

  Jie Li from the Dyson School of Economics and Management Department at Cornell University lead a discussion on the need for more economic studies related to the use of clean planting material.  A study was completed by Dr. Li and colleagues that analyzed the activities performed at the Foundation Plant Services program at the University of California at Davis.  The study focused on the return of investment of producing and distributing grapevine leafroll disease tested plant material to nurseries planted by growers in different regions in California between 2006 and 2019.  The  results showed that depending on the disease incidence estimated, the hypothetical return of investment was 1:22 (assumes a 5% leafroll disease incidence) or 1:96 (assumes a 20% disease incidence).  In other words, $1 spent to produce plants at FPS yielded $22 or $96 in return, assuming a 5 o 20% disease incidence, respectively.  The research identified the main beneficiaries were the nurseries, but logically the benefits ultimately trickled down to growers and wineries.  The discussion led by Dr. Li was done to determine how to design other studies that would focus on additional clean plant centers and other diseases (i.e., red blotch, Pierce’s disease, etc.).

Production of NCPN Extension Videos

  Cain Hickey, viticulture extension educator at Pennsylvania State University, lead a discussion on the potential of developing informative videos focusing on different aspects of the NCPN program.  The Pennsylvania State University in cooperation with Cornell University already produced four videos describing the NCPN program, grapevine certification and clean planting stock, as well as other regional focused viticulture issues such as delayed pruning, spring freeze vine protection, etc.  The videos can be viewed following the link: https://extension.psu.edu/answers-from-the-vineyard-winery-and-tasting-room.

  The group brainstormed ideas on future video productions that could focus on: virus elimination methods, crown gall and fungal pathogens, grower testimonials on the use of clean planting stock, definition of G1 and G2 plants, disease spread in the vineyard, etc.

Conclusions

  It is important to understand that a clean plant is one  derived from a plant that has been tested for a number of economically important viruses and certain pathogens and the target pathogens were undetected.  It does not mean that the plants are free of all pathogens.  Most of the clean plant centers do not test or exclude fungal trunk disease pathogens or Agrobacterium vitis (the causal agent of grapevine crown gall).   In no way it means that that nursery material derived from plants released from a clean plant center will always be clean (pathogen-free). There are still challenges for maintaining a virus-free grapevine plant collection. It is good to see that NCPN is moving towards having redundancy on the grapevine variety collection. This will ensure that if there is a disease outbreak in one of the centers, another center will have the plant material available for easy replacement.

  There was agreement from both participating NCPN and nurseries that currently it is not possible to certify vines free of Agrobacterium vitis.  This is important to point out particularly in cold climate grapevine growing areas prone to freezes.  But in my experience, I have seen  vines develop galls due to the bacterial infection in California too.

In spite of the limitations of clean plant programs, the use of certified material is less risky than planting field selections of unknown infection status.  It is always prudent to test the planting material for important pathogens to verify lack of infection. Last but not least, when developing a new vineyard block it is important to plan in advance.  The timely planning will allow inspection of the nursery increase blocks early in the fall (before the leaves fall) as well as the evaluation of the quality of the finished planting product.  

  Judit Monis, Ph.D. provides specialized services to help growers, vineyard managers, and nursery personnel avoid the propagation and transmission of diseases caused by bacteria, fungi, and viruses in their vineyard blocks.   Judit (based in California) is fluent in Spanish and is available to consult in all wine grape growing regions of the world.  For more information or to request a consulting session at your vineyard please contact juditmonis@yahoo.com or visit www.juditmonis.com

By: Kirk Williams, Lecturer-Texas Tech University

Pesticide applications in the vineyard whether using an organic product or a synthetic product, are often needed to maintain a weed free vineyard with a healthy canopy, to prevent the loss of fruit and preserve fruit quality. We want to ensure that when we make a pesticide application in the vineyard that we get the most efficacy out of that product that we apply. There are many factors that contribute to a successful and effective vineyard spray application. One factor is good coverage of the target, which, for foliar applications to grapevines, includes the fruit and canopy.  The primary factors affecting coverage are the application rate, pressure, droplet size, and penetration into the grapevine canopy which is usually assisted with air produced by the sprayer.

  The use of adjuvants in the spray tank can help assist in making a good application perform its best.  Adjuvants are not going to fix poor coverage, poor timing of applications or bad weather conditions at the time of the application. Adjuvants are materials added to a spray tank to aid or modify the action of a pesticide or the physical properties of the mixture.  

  There is a wide selection of adjuvants that perform distinct functions so understanding how each adjuvant type works is important in choosing the right one.  We will be looking at different adjuvants that can help in making an application perform its best.   Most adjuvants are used at low rates and their rates are expressed on a volume per volume basis (e.g. 2 pts per 100 gallons).

  We will only be looking at the main adjuvants that are used in grape production.   There are many different brand names with most large agricultural retailers having their own brands.  Due to this we will be talking in general, not about specific branded products.  Adjuvants selection should be based on several factors including what is specified on the pesticide label, your specific water quality and cost.    

Buffers/Water Conditioners

  In certain water situations such as high pH or the presence of large amounts of hard water cations such as calcium or magnesium you might need to consider adding a buffer or a water conditioning agent to the spray tank.  Buffers or water-conditioning agents are compounds that reduce the damage caused by alkaline hydrolysis and adjust the pH of the spray solution to maintain it within a pH range of 4 to 6. Alkaline hydrolysis is a degradation process in which the alkaline water breaks and reduces the effectiveness of the pesticide’s active ingredient.  Certain insecticides such as the pyrethroids and carbaryl are susceptible to alkaline hydrolysis.  Certain weak acid herbicides such as glyphosate and glufosinate perform better in an acidic spray solution than an alkaline solution. Buffers or water conditioners are normally added to the spray tank prior to adding the pesticide. 

Special Purpose Adjuvants

  There are several adjuvants which may be used in certain situations which may not always be needed for all vineyard applications.  Many of these are also components in blended purpose adjuvants. 

Many vineyards spray applications tank mix several products and sometimes include foliar fertilizers.  Some combinations can be physically or chemically incompatible, which may cause clumps to form or products to separate in the spray tank.  Compatibility agents prevent mixing and settling out problems that can occur in these situations. 

•Antifoam agents suppress surface foam in the spray tank and minimize air entrapment which can cause pump and spray problems.

•Drift control agents modify spray characteristics by minimizing small spray droplet formation.  Small spray droplets are more prone to drift so by reducing the number of small spray droplets off site droplet movement should be reduced. 

•Sticking agents, commonly called stickers, assist the spray deposit to adhere or stick to the target such as clusters or leaves.  The sticking agents usually come combined with other adjuvants such as surfactants to allow for easier mixing.   Sticking agents are helpful when periods of rain are expected after an application.  A good example of the need for a sticking agent is the use of contact fungicides in the spring where rainfall is likely.

Surfactants

  One of the most used adjuvants in vineyard spray applications are surfactants.  The primary purpose of a surfactant, also known as a surface-active agent, is to reduce the surface tension of the spray solution to allow closer contact between the spray droplet and the plant surface.  Water droplets are held at contact angles ranging from 60° to 140° with a significant variation between species.   Water droplets with high contact angles on grape leaves are shown on the left side shown above.  Water droplets with surfactant added are shown on the right side shown above.  The water droplets have completely spread out with the addition of the surfactant.   Complete coverage of the target is important for most pesticides and the addition of the surfactant demonstrates how they can improve coverage. 

  Non-ionic and organosilicone are the most used types of surfactants.  Organosilicone surfactants are noted for their increased spreading ability versus traditional surfactants and the low surface tensions of their spray solutions.  Organosilicone surfactants have lower use rates but may be more expensive than   non-Ionic surfactants.  Non-ionic surfactants have a higher use rate but may be less expensive. 

Blended Purpose Adjuvants

  Blended purpose adjuvants contain various combinations such as a surfactant plus a water conditioner plus a drift inhibitor plus an anti-foaming agent.  Because of the multiple adjuvants included they serve primary and secondary purposes.

   If you don’t need all the components included in the blended purpose adjuvant, then you might be better off from a cost standpoint to just use those adjuvants that you need.   Blended purpose adjuvants are becoming more common because multiple ingredients are included in one product. 

  Choosing the proper adjuvant for a vineyard spray application can be confusing but knowing the major types and functions of adjuvants should make selection easier.   Read pesticide labels to see what adjuvants if any are recommended for use.  Once you know which adjuvant you need, select a product that you can source and read the adjuvant label as well. 

Sources:

Curran, W. S., and D. D. Lingenfelter. (2009).  Adjuvants for Enhancing Herbicide Performance.  Penn State Extension.

Hazen, J. L. (2000). Adjuvants: Terminology, Classification, and Chemistry. Weed Technology, 14(4), 773–784.

  Kirk Williams is a lecturer in Viticulture at Texas Tech University and teaches the Texas Tech Viticulture Certificate program.  He is also a commercial grape grower on the Texas High Plains.  He can be contacted at kirk.w.williams@ttu.edu