Category: Vineyard Info

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

A Decade of Challenge, Change and Resilience

By: Mike McNulty, Managing Principal at EPIC Insurance Brokers & Consultants

Over the past decade, California’s wineries have witnessed changes in the property insurance marketplace that would have seemed impossible ten years ago. As an insurance broker focused on the winery industry, I have seen firsthand how movements in the insurance marketplace have reshaped how our wineries do business. As we look for a way forward, it helps to look back at the road that brought us to where we are today.

  Think back to harvest time in 2013; vintners prepared to reap the rewards of a long and sunny year, enjoying a high-yield, high-quality crop of fruit. We were all a little nervous about another dry year (California’s rainfall was less than 34% of what forecasters had hoped to receive). And while the state was in the grip of what we eventually realized was its worst drought in recorded history, there was no question that the California wine industry was ascending.

  There was so much confidence in the future of California’s wineries that insurers were fighting for the right to provide property and liability coverage. In 2013, the average winery owner/operator could expect four to five insurers to compete for their business, each offering broad coverage, low deductibles, and attractive pricing.

  As the wine industry grew and expanded, it sprawled, literally. New wineries were established further and further from urban centers, nestling closer to and even within California’s forests. Proprietors created tasting “experiences” as their properties became tourist destinations. They used the backdrop of California’s incredible geography to blend their wineries into the picturesque terrain with breathtaking results.

The Rise of Climate Change

  We would soon discover the unmanaged fuel in those woodland areas were ticking time bombs.

  The drought of 2013 would last for another 4 years in most of California – killing plant life, felling trees by the millions and creating acres of tinder ready for a spark. California is no stranger to wildfires, but most of the state’s coordinated efforts went into suppression, not prevention.

  According to the California Department of Forestry and Fire Protection, 601,635 acres of California burned in 2013 wildfires – worryingly ahead of 2013’s rolling five-year average of 449,178 acres of yearly wildfires.

  Our current five-year average for California wildfires has grown to 1,158,028 acres. To give a sense of scale, that is on par with the entire Grand Canyon National Park set ablaze every year. There is every indication that this is the “new normal.”

2023: The Dynamic Shifts

  The insurance industry was not ready for the increasing magnitude and severity of wildfires in California. Blazes like the Glass Fire of 2020, which spread from Napa into Sonoma Valley, threatened the stability of carriers who had once competed for the privilege of serving California wineries.

  Their retreat was not subtle. Coverage policies became more restrictive, narrowing the safety net wineries had come to rely on. For many, the cost of insuring their wineries became prohibitively expensive. And it was not just about the cost – the very availability of comprehensive insurance became a luxury item.

  Proprietors bolt sprinklers onto rooftops, create fuel breaks, remove trees, bushes, and anything else a blaze could use to sustain itself. In many cases, these owners are frustrated to learn their efforts are not enough to get insurers’ attention and support.

Embracing Technology and Collaboration

  We have discovered there is no turnkey answer to the threat of climate change. But wineries have two advantages that might have been unthinkable 10 years ago: emerging technologies and a willingness to collaborate with competitors for mutual survival.

  Early detection can make all the difference in responding to a wildfire event. Communities can install camera monitoring systems throughout the community in hopes of catching fires before they get out of control. Once a novelty, flying drones are now table stakes for many wineries. They conduct routine flyovers and capture aerial imagery that can persuade insurers of the comprehensive scale of their mitigation practices.

  These images and high-fidelity satellite imagery can now be used in tandem with data analytics to optimize fire mitigation planning and prevention. Companies like FortressFire use aerial assessments augmented with site inspections and other indices to identify and correct fire vulnerabilities that might otherwise have been overlooked.

  Wildfires do not respect property lines or municipal jurisdictions, so homeowners and businesses in wine country have banned together to coordinate their mitigation strategies collaboratively.

The New Normal

  Over the past few years, California wineries have undergone a profound transformation, confronting challenges that have reshaped their operational landscapes. As the threats of climate change and shifting insurance dynamics loomed, the industry’s response was pragmatic: leveraging technology, refining practices, and fostering collaboration.

  The road ahead for California’s wineries remains uncertain, with climate unpredictability and financial challenges. However, the past decade has shown the wine industry’s proactive strategy, built on innovation, collaboration, and strategic adaptation, has equipped their communities to overcome the challenges it faced. It’s a strategy of resilience we should all hope to emulate, including the insurance industry.

Mike McNulty is managing principal at EPIC Insurance Brokers & Consultants. Mike holds over 30 years of experience in the insurance industry, specializing in cost and risk management. He oversees the delivery of extensive insurance and risk management solutions to clients in the consumer beverage business.

Image 1: Vineyard with hail damage

By: Kirk Williams, Lecturer-Texas Tech University

For many grape growers that are East of the Rocky Mountains, hailstorms can occur throughout the growing season from late Spring through the Fall.  Hailstorms can reduce shoot growth, reduce yield and occasionally damage the woody parts of the grapevine.   The severity of these hail events can be mild to severe.  Multiple hailstorms are possible in some years at hail prone vineyard sites.  An example of an extremely severe early season hail event is seen in Image 1.  Late season hail events can cause fruit damage, increase disease issues and cause leaf area loss which can impact fruit ripening.    Leaf area loss can decrease carbohydrate production and storage which can reduce bud hardiness in the dormant season as well as reduce growth and yield the following growing season.   An example of a late season hail event can be seen in Image 2:

 Image 2: Late Season Hail Event

  A strategy that is being adopted for reducing the impact of hailstorms on grapevines is the use of hail netting.   Hail Netting is a high-density polyethylene woven fabric that is installed on both sides of the grapevine canopy.  The hail netting is flexible and can absorb energy from falling hailstones to prevent damage to the canopy and fruit.  The mesh spacing on hail netting is much tighter than on bird netting and is around 4mm by 6 mm (0.16 inches X 0.24 inches).   A common width of the hail netting is around 40 inches although other widths are available.  Most hail netting has reinforced edges on the top and bottom of the netting. 

  The hail netting is usually attached to the top catch wire using clips and then the netting is attached below the canopy, sometimes to the drip line or sometimes to an additional wire that is added for that purpose.   Hail netting use is limited to vertically shoot positioned trellis systems with catch wires high enough to spread the hail netting vertically.  Varieties that have a mostly upright growth habit are preferred but a wide range of varieties are being grown under hail netting.  Hail netting does promote upright shoot growth as the shoots are held in place vertically and compressed by the hail nets.   See Image 3 for an example of hail netting and its installation.  Hail netting is installed as a permanent part of the trellis system and is usually lowered soon after final pruning is completed to prevent damage from early season hailstorms.   Hail netting is usually installed after a vineyard has started producing fruit but when installed soon after planting, hail netting can prevent hail damage to the developing woody portions of the grapevine which can prolong the productive life of the grapevine.  

Image 3: Hail Netting Installed 

While hail netting does prevent damage from hailstorms it does require extra steps to complete work in the vineyard.  To do work in the canopy, the hail netting must be raised up prior to the work and then lowered after the task is complete.   Having dedicated lower wires that the hail netting is attached to and are loose enough to move up to the cross arms can speed up raising and lowering of the nets.  Hailstorms can quickly develop especially in the late Spring and early Summer when canopy management practices are taking place so care should be exercised to raise the hail netting on just a few rows at a time.   At harvest time, the hail netting must be raised and rolled up to be out of the way of harvesting activities whether harvesting is done mechanically or by hand.  The hail netting will usually stay raised and rolled up until final pruning is completed.  

  Installing hail netting requires a substantial investment in vineyard infrastructure.  The hail netting and clips will cost around $1,600 to $2,000 per acre depending on the density of the vineyard.    Installation of the hail netting is estimated to take eight to ten hours of labor per acre.  While the cost of the hail netting and installation is expensive, the saving of a crop from a severe hailstorm or reducing crop loss from several small hailstorms will recover the cost of the hail netting.  The hail netting has an estimated life of eight to ten years when properly cared for. 

  In addition to prevention of damage from hail, hail netting can reduce bird damage.  If bird pressure is high, birds can still get into the hail netted grapevine canopy from either the bottom or top where there are narrow openings.  Tying the bottoms of the two panels of hail netting together can prevent most of the birds from getting into the grapevine canopy.   Under heavy bird pressure, the tops of the panels of hail netting may also need to be tied together. 

  Hail netting reduces hail damage but can the closely woven fabric impact the grapevine canopy?  In a study that took place on the Texas High Plains, two varieties of grapevines were studied with and without hail netting and it was found that there were differences.  Grapevines grown using hail netting had a change in the vine canopy’s microclimate. The hail netting was found to make the canopy cooler, reduced air and leaf temperatures and altered the moisture level in the canopy.  This change was likely due to reduced canopy airflow in the netted vines.  These canopy microclimate changes could cause increased disease pressure for grapevines grown under hail netting. 

  The change in temperature and light due to the netting affects the vine’s leaf gas exchange, a key process for the plant’s health and growth. Differences were also noticed between grape varieties in the study (Malbec and Pinot Gris). For instance, the rate at which the fruit matured was influenced both by the netting and the type of grape. 

  The study showed vines without netting had more clusters. The ‘Malbec’ variety, in particular, showed lower yields under netting. Additionally, netted vines, especially ‘Pinot Gris’, showed less vegetative growth. 

  Installing hail netting can prevent crop loss, preserve grape quality and improve grapevine longevity in areas that receive hailstorms during the growing season.  While hail-netting is beneficial for protection against hail, it is essential to understand its broader effects on grape growth, disease pressure and yield and adjust your vineyard practices accordingly. 

  References: Ruland KT, Montague T, Helwi P (2023) Impact of hail-netting on Vitis vinifera L. canopy microclimate, leaf gas exchange, fruit quality, and yield in a semi-arid environment. Viticulture Data Journal 555: e108805.

  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

The Old Vine Conference

Old Vine From Angelica Vineyard – Photo Credit Catena Zapata

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

Recently, I did some research on “old vine” heritage  grapevines after seeing a post on LinkedIn that showed a vineyard with characteristic “red leaf” symptoms likely due to viral infection. There are “old vine” projects throughout important winegrowing regions in the word.  The definition of an old vine ranges from 35-50 years, but if you ever heard me give presentations at meetings, my motto is: “vineyards should live to be over 100 years”.  My search brought me to the Old Vine conference held last October. 

  A non-profit company registered in the United Kingdom with a mission to safeguard and preserve old grapevines through research and education.  The non-profit organizes yearly conferences.  In 2023, the old vine hero award was given to Dr. Laura Catena, the managing director of Catena Zapata winery.  Many of you know that I am originally from Argentina.  Hearing about an award given to a compatriot in my field inspired me to write about her presentation.  

Malbec, Argentina’s Signature Variety

 Dr. Catena’s presentation: “How an agricultural philosophy is using science to preserve the past” focused on the history of Argentine viticulture as it relates to old germplasm.  Especially, how her family’s winery put Argentine’s malbec wine into the world’s map.   The malbec variety is originally from France and was brough to Argentina in the mid-19th century by a French viticulturist named Miguel Pouget. Dr. Catena referred to her father, Nicolas, as responsible for starting to use malbec in a single variety wine in the mid-1990s. 

  After the vineyards  grown in France were affected by phylloxera in the 1800’s,  many malbec plantings (among other varieties of grapes)  were decimated by the pest.  However, in the absence of phylloxera, the plants brought to Argentina survived and became an important reservoir of malbec’s genetic material. The family business celebrated last year the 100th birthday of their Angelica vineyard planted in 1922. Presently, collaborative work with INTA (the equivalent to our USDA) is helping Catena and other vineyards characterize the present germplasm.

Dormant Old Vines in a California Vineyard

Sélection Massale, the Renewed use of an Old Practice

  In the past, and due to  economic restrictions, importations were not allowed into Argentina.  Therefore, it was unusual for grape growers to plant clones of specific varieties.  Instead,  cuttings of the original plants introduced from France in the mid-1800’s were propagated to make new plants.  These were generally planted on their own roots (i.e., not grafted).  The vineyards are most often planted with cuttings that have been selected in the vineyard based on visual observation or the quality of wine produced from its grapes. Generally, a number of “good looking” or well performing vines are marked in a vineyard and used to collect budwood that will be propagated or grafted to produce new vines. This process of field selection is known as sélection massale. Since the selection is done based on visual aspects and vines are generally not grafted, viral symptoms are generally masked, therefore vines infected with virus are often selected.

  The advantage of using field selections versus a clone of a given variety is the genetic diversity that can be found in the vineyard.  Of course, not always this is an advantage, as a vineyard with genetic diversity might be more difficult to manage because some vines may be taller or more vigorous than others, may need more or less water, nutrients, etc. As it relates to wine production, some of the fruit from some vines may mature earlier than others creating difficulty during the harvest of the fruit.  However, an interesting study from the Catena Wine Institute showed that the variation among the vines was so wide that some vines could produce only one bottle of wine, while others could produce up to seven bottles.  On the other hand, the genetic variation in the vineyard allowed more resilience as the vineyard overall was more resistant to inclement weather such as freeze, hail, or wind.

Viral Disease Introduction to Argentina Occurred with Imported Vines

  At some point in history Argentina’s nurseries and vineyards started their own clonal selection.  In addition, the Argentine market eventually opened its business to import plant material from nurseries in Europe and recently from California’s Foundation Plant Services (FPS).  According to Dr. Catena, this is when the majority of viral and fungal diseases were introduced into Argentine vineyards. Vineyards planted with older field selections at Catena Zapata appear to be healthier than the newer introductions planted.  This information matches research by Jimena Balic performed by Santa Carolina Winery  in Chile.  Dr. Balic reported at the 19th International Congress of ICVG the detection of more virus infected vines in nursery propagated clones compared to Santa Carolina’s own heritage field selections.  Interestingly, a study in California by  Kari Arnold determined that the older vines were infected with more viruses than the newer plantings

  We know that important viral diseases (fanleaf, leafroll, rugose wood, and red blotch) are present in Argentina.  Further, .  Many of the original field selections have now become infected with fanleaf (transmitted in the soil by nematodes) or leafroll (transmitted from vine to vine by mealybugs).    As a trained medical doctor, Dr. Catena mentions that the winery is serious about keeping viruses out of the vineyard.  However, the imported plants that brough the viral diseases have spread along different vineyards not only affecting a broad area since introduced.  Since virus testing is expensive and ranges between $150-$250/sample compared to the cost of $4 per plant, not every plant can be tested.  Catena Zapata’s strategy is to test their grafted clones but the field selections that are not grafted are rarely tested

Argentina Grapevine Certification Program is Different from California’s

  In Argentina each nursery is responsible for maintaining and testing their own mother and increase blocks.  In other words, there is not a central foundation block such as what is maintained by FPS. 

  Besides a few commercial nurseries, many wineries have nurseries that provide the cuttings or grafted plants grown in their own vineyards.  Just like in California, there is a list of viruses that the certified vines must be free of.  Similarly, the certification of grapevine plants in Argentina is optional.  In reality, very few vineyards are planted with certified vines and most vineyards are planted with non-grafted vines as phylloxera in not yet ubiquitous. 

Disease Testing and Elimination

  During my long career as a plant pathologist working in diagnostics and pathogen elimination, I was fortunate to have been able to apply tissue culture techniques to preserve heritage clones in California.  I am also fortunate to have visited vineyards planted with these clones. Feedback from clients has always been that the vines perform similar to the original selection or clones but have the advantage of being healthy and more productive, even 30 years after being planted.  I have covered diagnostic testing and tissue culture disease elimination in other articles. 

  I will mention here briefly, the meristem tissue culture technique.  The method relies in growing the apical meristematic dome of a vine cutting to create a new plant.  The smaller the meristem size is, the higher probability of eliminating viruses, especially those that are phloem limited.  In her presentation, Dr. Catena mentioned that she expects that the meristem culture method may improve over time.  In my opinion the method works very well.  It requires manual labor and experience but it is the best method available for disease eradication.   Perhaps one day, we could replace technicians with sophisticated robots with the capacity of dissecting minute portions of the meristem under the microscope! However, in my experience technicians I have worked with have been able to perform the repetitive tasks over and over with fine and quick precision (almost like robots!).   The meristem tissue culture is a true and tried method that promises to improve the health of new grapevine plantings.

Conclusions

  I have learned through Dr. Catena’s presentation and the Old Vine Conference  that there is a huge amount of generic diversity that needs to be preserved in grapevines.  The health status of different vineyards varies and depends a lot on their care and isolation.  The use of meristem culture for disease eradication offers an advantage in heritage selection preservation. One usually thinks that the method is used solely for virus elimination but an added bonus is the elimination of bacterial and fungal pathogens.  Tissue culture methods of grapevine heritage selections and  clones are performed in a laboratory in vitro under sterile conditions. Another tissue culture application is the preservation of plant material in small vessels creating a germplasm repository bank.  The preserved plant material would be readily available for propagation and planting to replace affected vines in the case of viral infection (or other issue) in a vineyard.

  Judit Monis, Ph.D. provides specialized services to help growers, vineyard managers, and nursery personnel avoid the propagation and transmission of disease 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 word.  Please visit juditmonis.com for information or contact juditmonis@yahoo.com to request a consulting session at your vineyard or virtually.