Month: January 2026

Why some high calcium soils produced excellent grapes

By Neal Kinsey, Kinsey Agricultural Services

One quandary that continually presents itself for vineyards as well as other crops is why some high calcium soils produced excellent grapes while others in the same vicinity (and sometimes the same variety in the same vineyard) looked and tested exactly the same, but were of less quality and at times even a definite problem in terms of the wines produced.

  When that happens, could it be the soil test being taken incorrectly?  It could be, especially if there are wide variations in the soil test numbers, and particularly the expression of cation exchange capacity, from year to year.  But what if the soil tests are basically consistent from year to year and look the same in the good and bad areas?

  First, consider that when results seem inconsistent from the use of the same methods that can ordinarily identify why soils have good or average or poor fertility, something more must be considered.  There is usually a good, common-sense answer, we just must search to find what it is and use it to solve the problem.

  We have worked with soils producing from excellent to extremely poor wines that measured exceedingly high in calcium since the 1970’s.  From that experience it has become evident that the problem is more than just too much calcium, as some soils with higher calcium levels produce better wines than others that have lower concentrations in the soil where poorer results have been experienced.

  Considering all the soils that were analyzed from year to year, the problem seemed relatively rare, but still the problem was always present in enough soils to be of concern and continue looking for a sensible solution.  These different areas are not normally submitted for a comparison. Most of the time such soils were either doing well or doing poorly, not enough of both in the same vineyard for growers to be sufficiently concerned to pay the cost and have both analyzed separately.  And the few times it was done, the good and bad soil all looked to be bad.

  Around 2005, while reviewing some of the original work of Dr. William Albrecht there was a clue that just “jumped out” from a page on his explanation of measuring cation exchange.  He explained that the sum of the cations was generally the best approach to determine the soils cation exchange capacity due to the costs involved, but there was a more accurate way it could be used to establish that number.  But he did not say what it was.  Still his comment was sufficient enough to point out that, though generally too costly to use for the general soil test, there is a more effective way to determine how many positively charged cations can be attracted and held on the surface of soil particles until enough acidity from plant roots or soil microbes could release them for use by the plants growing there.

  For years some concerned educators and consultants had asked the question, “But when you measure calcium, what about the influence of free calcium?”  This was referring to the amount of calcium in an available form in the soil which was so plentiful there could not be enough negatively charged clay particle for all of them to be attracted and held – adsorbed – by a more limited number of clay colloids present? 

  Here was a possible way to differentiate between how much calcium was present in a soil, but also how much was able to be attracted and held and how much more was present that had no negatively charged clay particles to attract and hold them – thus the “free calcium” still there that influenced the sum of the cations, but the assumed negatively charged clay particles were not actually abundant enough to be holding them along with the other normally needed cations, namely magnesium, potassium and sodium.

  Since the “sum of the cations” was used to calculate the amount of negative charge provided by a matching amount from the clay colloids in a soil, the Cation Exchange Capacity was thus overstated.  This also eventually showed that the amounts needed of the other cations (especially Mg, K and Na.) when extremely excessive in a vineyard soil can also be overstated, making it appear such soils needed more than they could tolerate.

  This was the beginning of the process that ultimately helped determine and define not only soils that had too much calcium, but also magnesium, potassium, or sodium, or some combination of those.  This was then causing the “sum of the cations” to over-inflate the amount of negative charge (expressed as the cation exchange capacity)?

  This took time to work out and discover, it did not all come to be understood at once, because there was no protocol developed to determine all of this at the time.  The initial efforts began with the crop of 2006, but it took years of actual field work to solve the myriads of problems this has created.  And that field work was based on results that when achieved more than paid for what needed to be done and increased profits by increasing either yield or quality and oftentimes both at once.

  Initially it was thought that only a few dozen such tests would be needed based on the volume of soil we saw before beginning this project.  But as the results became evident and the word spread to others with similar problems in their grapes, that numbers has grown to be hundreds per month, especially from the extremely high calcium soils of the Western United States, Austria, France, and Germany.

  In fact, reputable long-established wineries from Europe have sent samples for analysis with no mention of such a problem, but by doing the tests properly, it was possible to point out what was happening.  One example was a winery that had a history of many prize-winning wines, but the soils they submitted did not reflect that.  And when we pointed out that these were problematic vineyard soils, the owners admitted that on these vineyards the quality of the grapes had been slowly declining over the last 20 years, but the soil tests still appeared to be the same as when the vines were doing their best.

  The normal soil test does not detect such problems, even if you can identify and test the areas good and bad.  An extra test that adds another 50% to the cost of each test must be performed and there is no protocol that has been written up and described to do so.  The reason it can be done is due to actual  hands on “field” or vineyard soil work. 

  The key is in soil chemistry that applies to the verified saturation of all the nutrients most involved in affecting the soil pH.  This type of experience is not written up and published to this point, because the results are from on-site experience, not officially randomized, replicated experiments.  The only way to learn it works is by doing this type of testing and following through with what is necessary on each specific vineyard soil.  Because the circumstances can vary greatly from one soil to another, perhaps the best way to learn if there is merit to the process is to send two soils – one from the good and one from the bad, or to increase the odds of a lucky guess, several bad areas to see if they can be correctly identified and why.

  Until Cation exchange capacity and base saturation of nutrients are accepted as a valid way to conduct that research it is not likely to be considered for research, because it is the only testing method at present to identify the differences that exist and need to be corrected to achieve the proper results.

  True science begins with observation.  Using the proper tests both the good and the bad and the reasons why can be determined.

“We can always prove a definite theory wrong. Notice, however, that we never prove it right.”

Richard Feynman (1918-1988), American theoretical physicist & Novel Laureate

For the love of wine and Mother Earth

By Hanifa Sekandi

As sentiment that many Millennial and Gen Z consumers hold dear in a modern world where consumerist practices often lead to cutting corners to yield profits. It’s true, these wine enthusiasts value sustainable cultivation practices as much as they value the quality of the wine. They are also willing to pay premium prices for brands that go the extra mile. Just like fast fashion has seen its demise, drinking for sport is also at its tipping point. It’s not just a matter of what looks good or about feeling that buzz. One could call it a renaissance that is calling consumers back to the formalities of the past, where wine is sipped slowly over a slow-cooked meal. Each bottle is selected with care. The quality of the wine is just as important as the quality of the food served.

  Every bottle of wine has a story that is more than meets the eye. As you stroll through the vineyards you will feel the rich soils that feed the vines that intertwine and gently kiss one another; a story of how a wine is brought to life with love. At Bonterra Organic Estates, each bottle tells a story that calls to a future where planet, society, and industry harmoniously co-exist. Where nature and wine are not in opposition.

  We had the pleasure of gaining insights from Joseph Brinkley, Bonterra’s Senior Director of Regenerative Organic Development. Bonterra is heralded as America’s #1 Organic Winery due to its commitment to regenerative organic agriculture.

  Bonterra is the largest producer of Regenerative Organic Certified® wines in the U.S. Are there specific biological products that have delivered the biggest measurable improvements in soil health and vine resilience?

  As a part of our ongoing commitment to holistic farming and operational excellence, we trial and use a variety of organic-approved products and methods.  To date, the most effective biological tool has been the use of predatory mites in some years when we have had mite flare-ups.  We have also used soil-applied biologicals to maximize root growth and increase nutrient availability.  As far as the aerial plant parts go, we have used an organic-approved biofungicide tank mixed with our more commonly used organic fungicides to activate the vines’ physical and biochemical defenses, thus reducing the amount of sulfur or oils needed to keep the fruit free of powdery mildew.

  You use sheep, chickens, and insectaries extensively. Can you describe one “closed-loop” biological system you’re proud of?

  We have used sheep in our vineyards for about 15 years. The benefits they bring to our soil health, including weed management and soil fertility, are noteworthy and something we are proud of.  The integration of ruminants in a perennial cropping system using cover crops is a great example of a “closed-loop” system.  We sow a cover crop in the fall. We bring the sheep in late winter once we have a good stand of forage for them. They eat the cover crop down as well as any other plants growing in the middles and under vine.  We typically get about 2 to 3 rotations, allowing for re-growth and multiple grazing passes.

  Each one of these growth cycles adds organic matter, root exudates, and other necessary soil health components. The sheep not only save us multiple tractor passes, saving both diesel usage and the associated emissions, but additionally, the sheep provide living fertility to the vineyards – something that tractors can’t provide. In this way, we are utilizing the wisdom of the natural world and life processes to create healthy and resilient farm systems with great yields, high-quality fruit, and minimizing the potential negative impacts of what could otherwise be an extractive, high-input farming approach.

  How do you track and measure carbon sequestration or biodiversity gains from your biological practices?

  In addition to biennial soil sampling with more traditional organic matter testing, in 2024, we installed several Agrology meters in our vineyards. These are devices that measure soil and environmental parameters to assess soil health, moisture levels, and other factors critical for regenerative agricultural practices.  More specifically, the meters measure soil respiration, transpiration, and CO2 flux in the canopy, all of which can be used as indicators of healthy soil functioning.

  Climate change is generating hotter summers. How are biological inputs helping you manage water stress and canopy health?

  Biological inputs are just one tool, but it’s really our holistic, regenerative farming system that makes the biggest impact. By creating healthier soils through cover crops, compost, integrating sheep, reduced tillage, and well-timed farming practices, we improve water retention and root strength, which helps vines stay resilient during extreme heat events. That translates to more balanced canopies, better protection for the fruit, and less stress during hotter, drier summers, all yielding higher quality fruit.

  What’s the biggest myth conventional growers still believe about scaling biological and organic farming?

  I’d like to start by saying that growers, like in any other business, respond to market signals and consumer demand. The best way to increase the uptake of regenerative farming in any sector is for our customers to support, via their dollar, those growers and businesses committed to these practices.  As more distributors, retailers, restaurants, and individual consumers demand products grown and produced regeneratively, the more uptake we will see on the grower side of regenerative farming.

  There is also the myth that organic and regenerative farming cannot scale because it is inherently too expensive or too complex. What is often labelled as “higher cost” is a short-term view that ignores the true cost of conventional farming, including impacts to clean air, water, soil health, and community well-being. When those externalities are accounted for, organic systems are far more economically rational in the long run.

  Consumer buying decisions indeed fuel the market. Concerning the organic wine category, it is an integral element to building a community where regenerative farming is not shied away from due to cost or the myth that scaling is impossible. What makes this possible is a growing community of vineyards practicing regenerative farming, highlighting the benefit of sustainable wine cultivation beyond a singular point of view. Bottomline, what happens on farms is not isolated. It is important to see where and how your food grows and understand that it is part of an ecosystem that must coexist.

  Is organic wine a niche? Older demographics may believe so and lean towards non-organic wines due to cost. A buying decision that may also be rooted in the idea that all wines are the same. Or that don’t be fooled by the sticker adage, a common viewpoint held by older wine consumers. Many people do not think about agriculture’s reliance on pesticides and synthetic fertilizers when purchasing a bottle of wine. What is needed to change this? More education and entry to the industry. The more the merrier will help this niche category become an industry standard, encouraging those who may be price-conscious to see the personal benefits of consuming organic wines. The benefits will outweigh the cost when they are pushed to the forefront of marketing initiatives.

  Grgich Hills Estate began farming organically without synthetic inputs in 2000. Their holistic approach to organic farming and winemaking, while building a community by fostering education, is promising for the future of organic winemaking. Ivo Jeramaz, Head Winemaker and VP of Vineyards and Production at Grgich Hills Estate, believes it is possible to farm without pesticides and fertilizers, a belief rooted in his formative years in Croatia. He provides great insights into the benefits of regenerative agriculture.

  Grgich Hills earned Regenerative Organic Certification in December 2022. Which biological amendments do you rely on most for your famous Rutherford Dust Cabernet?

  Vermicompost tea, fish emulsion/hydrolysate, and liquid kelp are the amendments we find are most useful across all our vineyards, including in Rutherford.

  How does reducing soil compaction tie into your overall biological soil-health strategy?

  Reducing soil compaction is vital to our soil health strategy. Because compacted soil is lacking in porosity, oxygen and water are unable to be easily stored – a substantial hindrance to the development of microbial life. Maintenance of our soil microbiome is a pillar of our soil health strategy, so compaction is something we prevent and attempt to undo wherever possible. The most effective strategy to limit soil compaction is through the root growth of plants.

  Can you describe your cover-crop and compost program and how soil organic matter has increased over the decades?

  The primary purpose of our composting regimen is to enhance the growth of our cover crop. The composition of seeds we sow varies from year to year, as we take note of which plants do best in each of our different vineyards. The combination of compost and cover crops enriches microbial life, which directly contributes to increases in SOM, as their remains become a part of that metric.

  It was my goal when I began managing our vineyards to increase SOM across our vineyards, but I found that organic and even biodynamic methods were unable to affect growth meaningfully, and we remained at around 2.5% SOM across our vineyards. After the implementation of regenerative farming, we saw a 2% increase in SOM as of 2025 across our 360 acres of vineyard.

  With Napa getting hotter and drier, which biological practices are now essential to achieve physiological ripeness without excess sugar?

  Companion planting is the most salient way to see the benefits of regenerative agriculture when it comes to the changes in climate that have been on the rise in recent years. Not only do the root systems of these plants structure soil, improving water holding capacity, but they also act as soil armor. We allow the dead plant matter to remain in our rows throughout the summer, as it creates a barrier against the sun that keeps our soil cool. This is crucial during late summer heat waves, as bare soil cooked in the sun allows heat to rise and cook the ripening grapes on the vine. This protection means we don’t have to worry about overripening even in the most excessively hot years. 

  Mike Grgich proved California could beat France in 1976. What would he say today about farming regeneratively and biologically on the same Rutherford Bench?

  When Mike Grgich was growing up in former Yugoslavia prior to the Second World War, all farming was performed naturally, without chemical additions. I was brought up much the same way in the Croatian town where I grew up, so we had that advantage when coming to the United States; we knew that farming without artificial pesticides and fertilizers was feasible. Mike was a big supporter of our natural farming initiatives, and I know he would be proud to see how far we’ve come.

  Both wineries exemplify hope in a bottle. A return to the past and a leap forward into a future. Regenerative farming is a great possibility. Those who question this surely have never experienced the delight of opening a Grgich Hills Estate 2014 Miljenko’s Selection Cabernet Sauvignon or felt the wonders of a Biodynamic®, Single Vineyard 2020 ‘The McNab’ Cabernet Sauvignon by Bonterra Organic Estates dance on their palate. But when they do, there is no denying that the hands that nurture the soil and harvest each grape with the utmost respect in Mother’s garden, free from pesticides and fertilizers, made this. No, not all wines are the same; some are simply unique and of value, wines worth more than their weight in gold. Wines that give more than they take.

Q&A with Winemaker Eric Martella

By: Allie Nelson

As both an educator and winemaker, Erik Martella has spent decades thinking about how people encounter wine, not just as a beverage, but as an experience shaped by history, hospitality, and human connection. A Lecturer and Wine Specialist in Appalachian State University’s Department of Chemistry and Fermentation Sciences and proprietor of Erik Martella Wines, Martella brings together industry experience and a deep belief in experiential learning.

  That philosophy is at the heart of the Wine and Fine Dining for Emerging Professionals Program, a two-day immersive initiative Martella created at the university. The program introduces participants to the fundamentals of wine, fine dining, and professional etiquette through behind-the-scenes restaurant experiences, tastings, and a culminating fine-dining meal shared with local business and community leaders.

  Martella reflects on the motivations behind the program, what students are seeking from wine experiences, and how innovation in education and American viticulture can shape a more engaged wine culture for the next generation.

  How did the idea for the Wine and Fine Dining for Emerging Professionals program come about?            The idea was actually born of frustration with all the hand-wringing within the industry about decreasing wine sales. While those conversations are important, it seems that the only solutions being offered are either technology (social media, AI, novel packaging) or the old “make wine accessible” trope. I wanted to do something concrete to get more people excited about the history, traditions, stories, and experiences associated with fine wine.

  What gap did you see in students’ preparation for professional life that this program is designed to fill?

  The disruptions from the COVID shutdown meant that many families were simply unable to include fine dining experiences in their lives while these students were growing up. And, as young adults, they haven’t been of drinking age long enough to have had much of an opportunity to explore the world of wine. This program walks students through the fundamentals of wine and fine dining, including table manners and etiquette, from the perspective of the Business Meal, an experience they are likely to encounter very soon after graduating.

  What did you want students to feel and understand at each stage of the course?

  I wanted students to feel like they had a back-stage pass to the world of wine and fine dining. The first session is a behind-the-scenes tour focusing on how restaurants operate, how service works, how intention shapes experience. Students see that what can seem fancy for its own sake is actually based on core ideals of quality and creating amazing experiences. But all this requires the efforts of real people, so I thought it was important to also inspire empathy among the students for hospitality professionals.

  The wine session provides basic vocabulary and orientation to wine without overwhelming them. We emphasize that tasting is subjective, but language matters. By the time they reach the final dinner at Artisanal, the goal is for students to feel curiosity and excitement about tasting unfamiliar wines, not anxiety or self-consciousness.

  In the etiquette session, I wanted the information to be very tactical. While a lot of this information seems like common sense, people don’t know it unless they’ve been taught it. Having the students pre-read the materials puts everyone on a level playing field and prepares them for the group exercises that make up the session. Here, I wanted students to come away feeling like they had real strategies for presenting themselves well and putting others at ease during fine dining experiences.

  For the culminating dinner, I wanted students to understand first-hand how amazing good wine, good food, and good company can be, and I wanted them to come away with one thought: “I want more of this!”

  What conversations did you see unfolding at the culminating dinner between students and community leaders, and why are those intergenerational interactions so important?

  What stood out most was how quickly the conversations moved beyond career advice. Yes, there were questions about graduate school and career paths, but real connections were made. In a post-event survey, the Table Hosts overwhelmingly supported keeping the ratio of three students to one Host rather than increasing the number of students at each Host’s table. They valued the opportunity to make deeper connections as much as the students did.

  Those intergenerational interactions matter because they humanize success. Students see accomplished professionals as people who once felt unsure themselves. At the same time, the professionals are reminded what it feels like to be new to the world of wine and fine dining.

  How would you describe the mindset of this new generation when it comes to wine? What are they curious about? What turns them off?

  Most students see wine as just another option in the world of beverage alcohol, and they see it primarily in terms of its intoxicating effect. Most students have no idea what the world of wine has to offer in terms of aroma, flavor, and food pairing experiences, let alone its variety, history, and geographical and cultural significance, until someone opens that door for them. Opening that door also helps them understand why some wines are so expensive and others quite affordable.  High prices are a major turn off, especially when students don’t understand how they might be justified. Interestingly, for some, knowing that high-priced wines exist makes them suspicious of lower-priced wines. So they avoid wine all together: “I can never afford the good stuff and the cheap stuff must be bad!” Fortunately, students are curious about everything and they’re surprisingly adept at taking individual wines on their own terms.

  What role does education play in shaping how this generation will engage with wine long-term?

  Unfortunately, the attention economy seems to reward three main voices related to wine: wineries with big advertising budgets, the ‘no safe level of alcohol’ crowd, and those who use the wine snob trope for humor or derision. Educational programs such as this one are ways to provide this generation with a broader perspective on wine and to bring context to what those voices are saying. I think efforts like this, driven by the industry and by enthusiasts rather than by individual brands, is the key to reaching this generation. We need to be telling the story of Wine, with a capital W, and we need to do it in-person with glasses and open bottles in front of us. That’s what gets students excited and engaged, and it just so happens that’s also the foundation that gives every winery’s brand story its power, including my own.

  You’ve spent more than two decades in wine, and now focus on muscadine-based fine wines. How do you define “innovation” in American viticulture today?

  I think a lot of innovation in American viticulture falls into the category of increasing precision. Take irrigation as an example. It’s only been about 75 years since flood irrigation and movable sprinklers were replaced by PVC-piped permanent overhead sprinklers, which were themselves replaced by drip and root-zone irrigation. Now, some vineyards are focusing on irrigation strategies that encourage vines to develop the deep root systems compatible with dry farming. It’s always been about giving vines water, but leveraging science and technology to do it ever more thoughtfully and precisely.

  There’s also a lot of exciting work happening around developing new varieties and rediscovering old ones to meet changing or challenging growing environments. I’m a big fan of this kind of innovation: matching the grape variety to the ecosystem instead of asking the ecosystem to bend to the grape you want to grow. We just need some marketing innovation to go along with it to help sell esoteric varieties!

  What excites you most about the potential of native American varieties, like muscadine, that haven’t historically been seen as “classical” fine-wine grapes?

  Cabernet Sauvignon, Chardonnay, etc. are global. There’s good reason for that – they turn into amazing wine! Working with native varieties is an opportunity to create wines with totally unique characteristics that can’t be found anywhere else in the world. I secretly enjoy it when people are somewhat befuddled by their first glass of dry muscadine wine. By the second glass people usually have a pretty good idea what the wine is all about and how its parts actually do fit together. But you only get one opportunity to taste it for the first time!

  If you could offer one piece of advice to young professionals feeling intimidated by wine, what would you tell them?

  If you’re intimidated by wine, you’re probably worried about getting the show aspects of the experience wrong.  There’s really only one component of the show that you need to worry about: smelling and tasting wine with focus and intent. You can know nothing about a wine and even mispronounce its name, but if you take your time to authentically experience the wine, to savor it, your audience will be happy…even if the audience is yourself and you’re second-guessing the bottle you picked up at the grocery store for no other reason than it was on sale.

About the Author:  Allie Nelson is a communications professional specializing in food and beverage, with more than nine years of industry experience working with small wineries and hospitality-driven businesses. She holds the WSET Level 3 Award in Wines and is a French Wine Scholar and American Cider Professional. She currently serves as PR Manager and Digital Marketing Specialist at Tabletop Media Group in North Carolina, where she works with food and beverage clients including the North Carolina Wine & Grape Council.

Prevention & management practices to avoid the propagation and spread of fungal pathogens.

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

Grapevine trunk diseases occur worldwide and are caused by bacterial, fungal pathogens, or a combination of both. Trunk disease fungal pathogens can be airborne and/or soilborne.  These pathogens not only affect grapevines but other fruit and tree species and can be found colonizing the orchard or vineyard soil.   Grapevine planting stock material can be infected with important pathogens.  It is important to test and inspect nursery material for their presence prior to planting to avoid long lasting problems in the vineyard.

Disease Prevention and Diagnosis

  The best  way to manage and control diseases is to prevent the introduction of pathogens in the vineyard.  Because of the complexity of infection, number of fungal pathogens and diseases they cause, none of the US-certification programs exclude trunk disease pathogens.  Therefore, propagation material is expected to be infected with various fungal pathogens.  As a first step, it is important to inspect the quality of the planting material (graft union integrity, lack of galling, absence of streaking or pitting).  A laboratory and a knowledgeable plant pathologist are best suited to provide specifics of the fungal pathogens and diseases.  Fungal pathogens can be cultured and isolated in specialized media.  However, even when using selective media, microorganisms are known to compete among each other.  A fungal species that grows faster will expand over others that grow slower, making the identification of certain fungal pathogens difficult to ascertain.  In these instances, the diagnosis will be biased or the laboratory may not be able to report the disease causal agent unless sophisticated molecular methods are used. In some cases, the identification of the fungal taxonomic family (i.e., species of the Diatripaceae or Botryosphaeriaceae) isolated from a canker may be sufficient to decipher the cause of the problem and determine the best management practice.  In the past, in my lab we developed methods to isolate DNA from these cultures to allow to determine a precise identity of the fungal species by sequencing its DNA.  Recently, some commercial laboratories had started offering plant and soil testing using the next generations sequencing (NGS) technology also known as high throughput sequencing (HTS).  This is a powerful method that allows a laboratory to detect any organism present in a sample. When NGS is applied, the complete sequence of the plant genetic material and its microbiome can be obtained.  During preparation of the sample, it is possible to “enrich” the sequences of pathogens of specific interest.   For example, the lab may amplify only fungal sequences prior to NGS, increasing the sensitivity of the assay.  The data obtained is processed with software that analyzes the microorganism’s (beneficial or pathogenic) sequences present in the sample.  The method can provide relative quantitative data, generally expressed in percentages, of each microorganism found.

Disease Management and Control

  The implementation of appropriate sanitation measures at the nursery is most needed to produce high quality planting grapevine material.  It is known that one infected vine can produce between 100 -200 vines each year, potentially producing a significant number of infected grafted plants.  The use of hot water treatment (HWT) consists of soaking the plant material in hot water (122F = 50C) for 30 minutes at the nursery.   In spite of the treatment reducing the population of fungal pathogens in the propagated vines, there are mix reports on the effect of the HWT on bud mortality.  Reports in warmer winegrowing regions (e.g., Spain) have shown a lower effect on bud mortality compared to HWT in cool climate regions (e.g., Australia).   The use of ozone is used and can be effective as a disinfectant in nursery settings.  However, controlled studies carried out at the Universidad de La Rioja, Logrono, Spain has shown no effect of ozonated water on beneficial or pathogenic bacterial and fungal population when used in irrigation settings.

  Many of the fungal pathogens that cause disease in grapevines are endophytic, meaning that they can live in the vine without causing disease.  However, the same fungal species can become pathogenic during stress situations (lack of water, heat wave, etc.).  Furthermore, because fungal pathogens cannot be completely eliminated in the vineyard once introduced, it is important to apply the best management practices available once planted at the vineyard.   I recommend inspecting the mother vines and planting material to judge the quality of planting material.  The high-quality planting material must be grown in well prepared and drained soil, at the correct season.  Ultimately (and always!) the best practices in the vineyard must be applied (i.e., enough water, nutrients, etc.). 

  It is known that the effect of grapevine fungal pathogens increases as the vineyard ages because its fungal population continues to multiply yearly.  Therefore, growers must adopt management and control measurements as soon as the vines are planted in order to prevent and minimize the propagation and dispersal of fungal pathogens.

  Management at the vineyard should include trained personnel for pruning activities.  In areas where the rainy season coincides with the pruning season it is recommended to prune as late as possible prior to bud break. Pruning late has the advantage that the produced wounds will heal faster, as the vines become active in the spring.  Additionally, most fungal spores would have been depleted and unavailable to start a new infection, the later the pruning activity starts.   If the vineyard size is extensive and does not allow workers to complete the activities before bud break, the double pruning method is recommended. This consists of  pre-pruning the vines as soon as the dormant season starts, leaving canes of 1-2 feet long.  In the late winter or early spring, pruning would be completed by leaving the desired number of buds per spur. The freshly produced wounds should always be protected using fungicides or a sealant such as Safecoat VitiSeal.  I prefer the latter product because it provides a protective layer that does not allow the fungal spores to enter, does not affect beneficial fungi, and allows wound healing .  During pruning it is important to avoid producing large wounds, cutting near the trunk, or pruning after long periods of rain.  Finally, it is important to remove the vine residues in the vineyard floor as this would be a source of inoculum to start new infections.

  Economic studies performed by Dr. Kendra Baumgartner and colleagues (USDA at the University of California in Davis) has shown that preventative methods (late pruning, double pruning, and pruning wound protectants) are sustainable only if applied before symptoms appear in the vineyard.  Adopting these methods in older vines will not recover the cost of the treatments.

  A more drastic disease management practice includes vine re-training also known as remedial surgery.  The procedure consists of training a new shoot from the base of the trunk to replace the old decayed vine trunk or cordons.  The technique can help gain some years of production but will not cure the vines from the disease as likely the pathogens are already established in the vine.  When replacing vines, the grower must understand that many fungal pathogens can survive in remaining portions of the roots and soil, therefore new vines that are planted (even if free of bacterial or fungal pathogens) can become infected over time even if the vine roots are completely removed from the vineyard.

  Other methods that have been reported for the management of fungal diseases include planting white or yellow mustard plants as cover crops that act as a biofumigant and the use of biological control agents such as Trichoderma species, and mycorrhizal fungi.

Conclusions

  Due to the nature of fungal infections in the vineyard and surrounding areas, following precise management practices in the vineyard is the most important step in preventing disease development. Similar to viral and bacterial infections, fungal diseases are complex, as mixed infections are common and can exacerbate the symptoms in the vineyard. Consulting with a knowledgeable plant pathologist can help assess the potential of disease development based on the presence certain fungal species. The application of early and efficient diagnoses will help reduce the infection levels of propagation and planting material, consequently avoiding disease onset in the vineyards. 

  Judit Monis, Ph.D. is a California-based plant health consultant, 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 is fluent in Spanish and is available to consult in other important grape growing regions of the word.   Please visit juditmonis.com for information or contact juditmonis@yahoo.com to request a consulting session.