Category: Archived Articles

PR For Release: 6/1/20

In helping to lead the defense against PD, Carter Creek Winery Resort & Spa, located in Johnson City in the heart of the Texas Hill Country, has just planted more than seven acres of Pierce’s Disease (PD) resistant vines from Wonderful Nurseries. After several years of preparing and working with UC Davis to obtain licensing to sell the vines, Wonderful Nurseries delivered the first batch this spring and will continue to grow these PD resistant vines and supply them to growers throughout the United States.

Caused by the bacterium Xylella Fastidiosa, PD has become a common scourge for grapevines and the grape growing industry at large. Carter Creek winemaker Jon McPherson noted that, as one of the country’s first vineyards to plant the PD resistant vines, a new day may be dawning for growers everywhere in large part due to this transformational breeding project spearheaded by Andy Walker, Ph.D., Genetics, University of California at Davis. “With these new vines, our Texas estate vineyards will now be 100 percent Pierce Disease-resistant,” said McPherson.

Wonderful Nurseries, growing one success after another, is proud to play a part in this game-changing industry innovation. These newly planted vines; the Walker Clones of Paseante Noir and Errante Noir are both red grape varieties with ample balance. Offered too are Camminare Noir (red) and two white varieties, Ambulo Blanc and Caminante Blanc.

Carter Creek Winery Resort & Spa is a new winery resort in the rolling hills of the Texas Wine Country with tasting rooms, an onsite microbrewery, outdoor event center and 78 guest villas, owned by Carter Hospitality Group, LLC. This is the same team that owns and manages award-winning South Coast Winery Resort & Spa, in Temecula, as well as many other wine and hospitality establishments.

It’s always “Growers First” at Wonderful Nurseries, whether it’s PD-resistant grapevines or any number of industry innovations. For more information call Wonderful Nurseries at (661) 758-4777 or visit their website at WonderfulNurseries.com.

By: Judit Monis, Ph.D.

You probably know that I worked and developed several grapevine disease detection labs in the past.  Now I am on the other side and am able to choose the lab that is able to fir with the needs of the specific project I am working on and evaluate their practices.

  Presently there are many laboratories that provide testing services dedicated to the detection and diagnosis of plant pathogens.  It can be confusing to the grower, vineyard manager or nursery staff to decide which laboratory to choose.  My recommendation is to work with a plant pathologist who can provide guidelines towards the best option.  At the time, there is no accreditation for grapevine diagnostic laboratories in USA.  Therefore, each laboratory is free to develop their own testing and sampling methodologies.  

  This article will describe the different methods used for grapevine pathogen diagnostics and discuss the advantages and pitfalls of each of them.  Ultimately, I will attempt to convince the reader that the standardization of the diagnostic methods used for the detection as well accreditation of testing laboratories should be adopted by the grapevine industry

Different Testing Scenarios

  In an ideal world, the nursery or grower is interested in learning that their propagation and planting material is free of important pathogens.  But unfortunately, many times, the grower may suspect disease in the vineyard due to specific symptoms.  A knowledgeable plant pathologist will be able to help on statistical sampling as well as what type of laboratory is best suited for each case.  Regardless of the purpose for testing, below I will describe the most common methods available for the detection of important bacterial, fungal, and viral infecting pathogens.

Microbiological Culture

  Fungal and bacterial pathogens can be cultured and isolated in specialized media.  However, microorganisms may compete among each other.  Generally, the microbe(s) with the most competitive growth capacity will overshadow slow microbes that grow slower, making the diagnosis difficult or even sometimes impossible.  In some cases, the diagnosis will be biased and a laboratory may not be able to report the disease causal agent unless sophisticated molecular methods are used (see NGS/HTS section).  However, in the case of the diagnosis of a declining vine in the vineyard or nursery, the identification of the fungal family (i.e., Diatripaceae species are associated with cankers) or bacterial genus (Agrobacterium species causes crown gall) may be sufficient to decipher the cause of the problem.  Phytoplasmas (a special type of bacteria that lack cell walls) and viruses cannot be cultured and their identification must be carried out using molecular and serological methods.

ELISA, PCR, and RT-PCR

  ELISA is the abbreviation for “enzyme-linked immuno-sorbent assay, and consists of sticking the virus coat protein on a plastic test plate that was coated with specific antibodies.  The detection can be seen when there is a change of color in the wells of the test plate (colorimetric enzymatic reaction). ELISA detection is limited to the amount of virus present in the sample. PCR, is the abbreviation for polymerase chain reaction.  The technique allows the multiplication of viral nucleic acid from the initial titer (concentration) of pathogen present in the vine. The process is specific, and utilizes copies of small portions of the pathogen’s genome to start the copying process. The amplification is repeated many times, with each copy making more copies, so after the completion of an appropriate number of PCR cycles, more than a billion copies of the nucleic acid is produced. For RNA viruses the detection is done using RT-PCR (RT = a copy of the viral RNA via reverse transcription) before PCR can start.  PCR and RT-PCR are sensitive techniques used for the detection of grapevine pathogens.

  The sensitivity and specificity of the detection of pathogens can be influenced by the season as well as the part of the vine from which samples are collected. While ELISA is generally thought to be less sensitive than RT-PCR, the ELISA has a broader spectrum of detection but is available only for grapevine viruses and can detect a range of virus variants. On the other hand, PCR can be too specific, and miss the detection of isolates of the same virus even when slightly different. Using both ELISA and RT-PCR consecutively is recommended to reliably detect grapevine leafroll viruses, as each method is designed to detect different portions of a virus.

Single Use Strips for “in house” Detection

  A molecular single use strip test has been developed for the detection of Grapevine red botch virus (GRBV) that can be used for in-field testing.  Although, this test is marketed for use in the field, for reliable results, the assays should be conducted by experienced technicians in a clean laboratory.  If a lay person were to attempt to run the assay, they the instructions must be carefully followed, as the steps are complicated and require measuring small quantities of material (microliters of components).   In my opinion, it is worthwhile to have an experienced laboratory run these tests.  It is expected that laboratory personnel are trained to keep the sample and other materials free of contamination.  In the past, a kit was available for the “in house” detection of Grapevine leafroll associated -3 (GLRaV-3).  However, many different leafroll viruses can cause leafroll disease and obtaining a negative result for GLRaV-3 would have given the false impression that the vineyard block or sample in question was not infected.

Next Generation or High Throughput Sequencing

  The next generation sequencing (NGS) also known as high throughput sequencing (HTS) is a powerful method that allows the laboratory to detect any organism present in a sample.

  When NGS or HTS is applied, the complete sequence of the genetic material or microbiome present in the tested plant material or soil can be obtained.  Generally, during the sample preparation, the pathogens specific sequences are enriched to increase the sensitivity of the assay (for example the lab may just amplify fungal sequences).  The data obtained is analyzed with sophisticated software that is able to list the bacteria, fungi, virus, or other organisms (beneficial or pathogenic) present in the sample.  The method can provide relative quantitative data, generally expressed in percentages, of each organism found.   The NGS has been widely used in research and has allowed the discovery and characterization of important viruses such as Grapevine red blotch associated virus. Presently, this technique is being applied for the commercial testing of plant and soil samples to detect bacterial and fungal microorganisms.  A plant pathologist with expertise in bacterial, fungal, and viral taxonomy is able to associate the presence of the microorganisms found with disease symptoms (or potential disease development).

Need for Accreditation of Laboratories

  As mentioned earlier, at the moment, there is no accreditation system for laboratories performing grapevine diagnostic testing.  The closer we have gotten to these efforts is a ring test run by the Lodi Wine Grape Commission.  A ring test consists in providing laboratories with “blind” samples of known infection status to determine if the laboratory’s in-house procedures are able to detect the correct infection status in each sample. In the past, while affiliated to various laboratories I was a participant of such ring tests.

  In the fall of 2018, the Lodi Wine Commission ran a ring test to evaluate the different labs that offer testing for the diagnostics of grapevine viruses.   The laboratories received a large number of homogenized samples that were infected with various grapevine viruses.  The results of each laboratory were shared privately with the participant laboratories.  To the best of my knowledge no accreditation was granted.  While it is a great first step to carry out a ring test with the laboratories, future tests could be improved by providing the laboratory with portions of grapevines rather than a homogenized powder.  While it is understanding that homogenized samples may avoid the possibility of uneven distribution of viruses in the grapevine material, the capacity of the laboratory to process whole samples is important.  The integrity of the samples would determine if the laboratory is proficient on processing each sample without cross contamination or degrading the potential viruses present.

Conclusions

  The standardization of the diagnostic methods for the detection of grapevine pathogens should be a goal for the viticulture industry in the near future.  The accreditation of laboratories is of upmost importance for evaluating the reliability of testing labs.  Standardization of sampling and testing is common in other fields of food and plant pathogens.  It is puzzling that the grapevine industry has not adopted a system given the importance of this perennial crop.  My philosophy is that a vineyard must be planted with the healthiest available material as vineyards must live a long healthy life.  If a vineyard is planted with diseased material, the life expectancy is reduced (not to mention the possibility of perpetration and spread of pathogens in the vineyard and neighboring vineyards) 

  It is encouraging to know that new and more sensitive pathogen detection methods are being developed and applied for the diagnostic of grapevine pathogens.   The next generation sequencing or HTS is becoming more affordable and available for the detection at the species level of microorganisms in plants and soil.  It is expected that in the near future, these methods will be applied on new planting material and help develop healthy vineyards.

  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.

By: Tracey L. Kelley

  Spring pruning is one of the most vital applications vineyard managers can control, so it’s always beneficial to cross-check your processes with an expert or two. Depending on the air temperatures in your region, you might be edging into budburst (also referred to as budbreak) right now, and believe most of your pruning is complete.

However, according to Fritz Westover, owner of Westover Vineyard Advising and Virtual Viticulture Academy in Texas, there are always reasons to examine the results of pruning not only at the start of the season but also throughout, to understand what worked and what should be remedied. Watch helpful instructional pruning videos from Fritz Westover.

  “I do a lot of post-pruning site visits with growers, and it’s always informative to learn what you did wrong after you did it!” Westover joked. “The number one mistake I correct is the retention of small wood, followed by the retention of too many buds per vine. Both can result in an inefficient canopy, poor fruit quality and overall less balanced vines. The good news is that it’s easier to take buds off than to put them back on.”

Spur and Cane Pruning: Reasons for Each

  “Ideally, the decision to spur or cane prune should be made before designing and planting a vineyard,” Westover said. “However, most varieties can adapt to either a cane- or spur-pruned system. Also, I’ve found both vertical shoot positions or high-fruiting wire training systems can adapt to spur or cane pruning.”

  “A lot of our decisions regarding spur vs. cane pruning is based upon varietal,” Kim Myers told The Grapevine Magazine. Myers , co-owner, Laurel Gray Vineyards and Yadkin Valley Wine Company, along with her husband, Ben, co-stewards land in North Carolina that’s been in the family for 10 generations. Their 10.5-acre vineyard, Laurel Gray, features estate French vinifera vines such as Chardonnay, Viognier, Pinot Gris, Merlot, Cabernet Sauvignon, Cabernet Franc and Petit Verdot. Their winery, Yadkin Valley Wine Company, produces award-winning selections, including a signature Bourdeaux blend, Scarlet Mountain; Estate Barrel Fermented Chardonnay; and Estate Cabernet Sauvignon, Merlot and Viognier.

  “Spur pruning is used for varieties that show high fruitfulness on basal buds. For example, Cabernet Sauvignon works very well on spur pruning—until it’s time to renew the cordons. When renewing, we cane prune in order to establish a new healthy cordon,” she said. “Viognier produced best when cane-pruned because this technique allows more light on to the cordon and into the canopy.”

  “Generally, spur pruning, once established, is less labor-intensive. It’s easy to do and easy to teach, especially for vines that are trained on fences or trellises,” Myers added.

  Westover provided further recommendations. “In general, sites that require in-row vine spacing wider than four feet are better adapted to a cordon/spur-pruning system to best utilize the space in the fruiting zone, as laying canes longer than 18-24 inches can result in poor shoot size uniformity in many varieties,” he said.

  “Cane pruning, on the other hand, results in a vine that has a lower number of pruning wounds than a vine that is spur-pruned. Therefore, there might be less opportunity for certain fungal diseases that infect pruning wounds and cause grapevine trunk diseases,” he said. “Additionally, there’s less old wood on a cane-pruned vine and less potential area for disease spores to overwinter, such as phomopsis or other GTD-associated pathogens. Some varieties are also known to be more fruitful when cane-pruned, such as Nebbiolo or Malvasia Bianca.”

  “Cane pruning requires a high level of expertise, is more expensive and takes more time,” Myers added. “You have to make very educated choices about each and every vine. However, cane pruning has many advantages: frost protection, even production and even spacing of growing shoots in the spring.”

  Similar to what Myers does at Laurel Gray, Westover incorporates both methods for individual vines on some of his clients’ properties. “This isn’t typical, but can help increase the yield on vines that have high vigor but low yields due to small cluster size or shading of lower bud position of the spurs,” he said. “Careful consideration should be made as to where to use this practice, as the extra buds can cause crowding in the canopy, which can increase disease pressure in wet, humid climates.”

  Another mitigating factor for following a pruning method is the rumbling advance of mechanized or “no-touch” vineyard operations. The University of California Agriculture and Natural Resources Department released data in 2019 from a 53-acre Merlot research vineyard in the San Joaquin Valley—where more than half of all California grapes are grown— that indicated mechanical pruning “reduced labor costs by 90%, resulted in increased grape yields and had no impact on the grape berry’s anthocyanin content.”

  Kaan Kurtural, UC Cooperative Extension specialist in the UC Davis Department of Viticulture and Enology; and George Zhuang, UCCE viticulture advisor in Fresno County; conduct conference panels and webinars about the process, which they say is the future of pruning for operations of 150–300 acres.

  So keep in mind as you strategize production growth and processes, “one of the greatest disadvantages to cane pruning in our future shift to mechanization is that it cannot be easily machine-pruned,” Westover said.

Questions of the Advisor

  Since Westover consults for dozens of vineyards east of the Rocky Mountains through his onsite visits and victual academy, we asked him to provide answers to the top three questions he gets regarding pruning. They are:

1.   When should I start pruning?

      A: Depending on vineyard size, time and labor, if a grower in the Northern Hemisphere uses pre-pruning or partial pruning, I encourage them to start in January and move to final pruning at a time that allows them to complete it prior to budburst. So, for example, a small grower may be able to prune in a week and can start the process 10-to-14 days before the historical average budburst date in their area. Larger vineyards obviously need more time and may be pruning steady until budburst.

2.   Do I need to protect pruning wounds from GTDs?

      A: Fungal diseases associated with GTDs are primarily spread by splashing rain. Therefore, it’s important not to prune when it’s raining or when rain is predicted within the next few days—I advise my growers to wait until after the rain. In some cases, registered fungicides can be applied to protect pruning wounds from infection, such as Topsin M—check your state registry status. If pruning wounds have healed over, or if no rain is predicted, then protective sprays can be avoided. There are also products available now that can be painted over the top of larger pruning wounds to create a physical boundary against pruning wounds, such as VitiSeal.

3.   What if I don’t finish before budburst?

      A: Ideally, all final pruning will be completed a week or so before budburst. When shoots begin to grow, they first emerge on the most distal part of a cane, which is referred to as “apical dominance” of shoots across a cane. Some growers intentionally hold off final pruning until the onset of budburst on distal bud positions, as this can delay the budburst of the lower buds retained as spurs near the cordon. This small delay in budburst can result in the avoidance of a late spring freeze by 7-to-14 days, depending on site and variety. However, if a grower doesn’t complete final pruning before the shoots on the distal nodes reach greater than two inches in length, the lower bud positions can lose fruitfulness. The bottom line: pruning needs to be completed by bud swell—and not later.

Education, Sterilization, and Clean-Up Ensures Successful Results

  Many vineyard managers hire crews with pruning experience, while some do a crash course each season with trusted volunteers. In either scenario, Westover said, you need to ensure people do what your vines require.

  “Cut-and-paste pruning strategies won’t address the needs of each block. A pruning crew is only as good as its instructor, and it’s often necessary to have a lot of supervision the first few days of pruning—and again any time the pruning strategy changes between vineyard blocks,” he said. “Educate your crew and stick with them until the end. I share videos with my clients from my website, and on a rainy day, the crew watches those. Repetition of key pruning concepts is a great way to empower your crew to make decisions on their own and quickly.”

  One example he provides is that vigorous vines with large cane diameters can retain spurs with two-count buds, whereas smaller vines or vines with some small canes may need to have several spur positions pruned back to a one-count bud. “The motto I use in my academy is ‘no wimpy wood’—which seems to resonate with growers and results in less wimpy shoots that produce inferior fruit,” Westover of Virtual Viticulture Academy told The Grapevine Magazine.

  “Weather can also cause a shift in a standard pruning protocol. For instance, in a year with high primary bud death due to freeze conditions, a grower needs to first assess the percentage of bud death in the vineyard, and then adjust the final number of count buds per vine to compensate,” he said. “This isn’t easy to do, but it can certainly help keep a vineyard in business through a tough season if done properly—and some live buds remain!”

  Myers’ pruning team includes two people on staff for a 40–plus workweek who are in the vineyard daily. One of her primary takeaway tips is proper sterilization. “Clean pruning tools at the end of each row, and especially when changing varietals.”

  Westover agreed. “This is an area of research that we have little information on at this time, but sterilizing shears after each row and—at a minimum—between blocks is a good practice. Solutions of 10% bleach or 70% isopropyl alcohol are inexpensive options to spray on shears,” he said.

  So is the work done once buds break? Not necessarily. “Stay proactive on your vineyard management programs from pruning until frost to avoid uncontrollable problems,” said Myers of Laurel Gray Vineyards. “Watch for split vines that may have happened due to extreme cold weather when the sap was rising. Remove all cut wood from the vineyard floor and spray while still dormant with lime sulfur to kill any disease spores that overwintered in mummified fruit, dead wood or old leaves.”

  Also remember that not removing enough canes “will cause over-production with a too-dense canopy, under-ripe fruit and conditions for disease,” she said. “These conditions require more labor through the growing season because the vineyard manager is constantly trying to combat these issues through summer hedging, spraying and leaf removal.”

By: Gerald Dlubala

  From pruning, shoot thinning and positioning, leaf and lateral care to hands-on vine training, canopy management is the best way for a vineyard to achieve optimal, mature fruit from their vines. Good canopy management, partnered with the proper trellis and row spacing, allows vineyards to better combat fruit loss due to disease or pest damage while providing an overall protective and nurturing environment.

Canopy Management Is An Evolving Science

  “It’s always been evolving, but it seems to be moving along at a more deliberate pace now,” said Duff Bevill, founder and partner of Bevill Vineyard Management in Healdsburg, California. “We’ve come a long way in the past 30 years from when it was fashionable just to have the California flop, meaning the grapes were grown-up vertically, and the canopy was left to flop over. When increased production was needed, and European varieties were introduced, it became apparent that we needed to provide better light and greater air circulation for the fruit. Around the 1980s came the push to reduce or eliminate bunch rot and mold, and after a particularly wet season, the practice of leafing began. Then around the mid-1980s, Dr. Richard Smart, an Australian viticulturist, revolutionized our way of grape growing with his Smart-Dyson trellis system.”

  Smart’s trellis system helps canopy management by finding the balance in leaving enough foliage to facilitate the necessary photosynthesis process without causing excessive shading that would negatively impact fruit ripening or promote disease.

  “His style of trellis system is still the way to go,” said Bevill. “We see the Vertical Shoot Position trellis or modified VSP trellis with movable wires used the most because it traditionally results in a high-quality first crop. Another popular configuration is the high wire system, with the first wire 42 to 48 inches above the ground and then a secondary wire hanging about six inches above that first one. The downside to the high wire system is that it creates a need for manual shoot training for about the first five years. But if done properly, subsequent pruning can be done mechanically, with manual pruning only necessary for mechanical misses. Suckering is also minimal.”

  Bevill told The Grapevine Magazine that hand labor can eat up to 60% of a vineyard’s expenses, so that is an area of canopy management that is drawing extra attention. In an industry looking toward a mechanized future but, in the meantime, still requires hand labor, the VSP trellis remains the best all-around canopy management trellis for fruit production.

  “First, that hand labor has to be available,” said Bevill, “and it needs to be available when needed, frequently and for extended times to get the fruit picked on time and during prime harvest conditions. That’s getting harder to come by and more expensive to utilize. We offer bunkhouses and higher wages to our immigrant workers here on H2A visas to ensure our labor availability. But if things keep going the way they are, I would estimate that such extensive use of hand labor will end within the next five or six years in favor of mechanical labor. Compatible trellis design, along with smart canopy management, has a lot to do with this, allowing your trellis systems and vine configurations to grow in a manner that is favorable to mechanical picking, pruning and leafing. It’s better if you can accomplish these tasks with the off-the-shelf mechanical implements available today.”

  Bevill has already seen this in action. By applying the principles of trellis placement and design with well-planned canopy management, the cabernet sauvignon vineyards have shown a dramatic decrease in farming costs associated with labor.

  “Only one man is needed per ten acres here in Sonoma County,” said Bevill. “That figure matches what we believe is necessary, and that’s also what we have and use. Currently, only about 50% of farms are mechanically harvested. Many older ones can’t take advantage of mechanized farming because of how they were originally planned. Some leafing and mechanical harvesting can be done, but much of the canopy management has to be done by hand. Some older vineyards with their original planted vine systems are still entirely managed using hand labor. We are seeing a lot of these vineyards now being pulled out and replanted to use a flat-faced trellis system more conducive to mechanical farming.”

  Bevill told The Grapevine Magazine that mechanized farming will likely be the focus for the foreseeable future. There is nothing new on the horizon regarding the mechanical aspect of agriculture. All the advancements are within farming technology, things like devices to better detect the best times and amounts for irrigation, and increased uses for drone mapping. The yields and performance of high wire trellises are showing promise, but it will be another 10 years before any data can be confidently identified as reliable.

  “Overall, farming knowledge is constantly increasing, and as a vineyard management company, we are always looking at new and better planting standards and goals. They’re all tied into making mechanized farming as friendly as possible,” said Bevill. “Acquiring and using machinery to do the work is certainly the way of the future. It’s much cheaper and more reliable than hand labor, and let’s face it, it’s there when you need it.”

Seeing Each Vineyard As A Unique Environment

  “I literally have a different protocol for every vineyard depending on the winemaker’s desires for his product and the environment that we’re growing in,” said Mike Loconto, viticulturist for Barbour Vineyards, a vineyard management and development company in Napa, California. “You know, we do all the normal tasks, like suckering, tucking, shoot positioning and hedging, but the winemaker’s end goal determines the amount and timing of these tasks and the best canopy management practices for their situation. For example, we like to leave 12, 14, or 16 leaves per shoot to get two clusters of fruit out of each one, but when to remove those leaves is different for each client. We always like to open up the fruit zone, including below the clusters, but you have to leave just enough shade to baffle the sunlight and produce a great environment all around the fruit zone. It’s about getting sunlight and airflow to that bloom at the right time to deter disease and increase the quality of the fruit.”

  Loconto told The Grapevine Magazine that canopy management in Napa is all about controlling the heat and sun exposure to provide the highest quality fruit and the highest volume of product. When some of the older vineyards were installed, they preferred open, wide spacing between the rows. Over time, in an attempt to increase grape production, the vineyards started tightening up and leaving less and less spacing between the rows. Some were tightened to the point that they lost volume, quality, or both by inadvertently limiting light and decreasing airflow, increasing heat retention and inferior growing conditions. 

  “Heat prevention here in Napa is big and proven to directly affect quality, so now we try to stay around the seven-foot mark for row spacing and utilize cross arms to provide shade and heat prevention for the fruit,” said Loconto. “In any vineyard installation, you want to be smart about canopy management and factor in the ability to mechanize the farming now or in the future. Labor is so expensive that even if you can find it, you may not be able to afford the amount you’ll need to get the tasks done on time. Canopy size and row spacing need to be used jointly so that at some point, mechanized tools can be used for leafing, pruning and harvesting. By using between eight and 12-inch cross arms, you make more effective use of available mechanized tools.”

  Loconto works mostly with high-end cabernet growers, and over the past five to 10 years, he’s seen the customary canopy management practices start to change.

  “Call it climate change or whatever, but we’re starting to see a fundamental change,” said Loconto. “There’s still a high use of VSP or modified VSP trellis systems, but any newly planted, replaced or moved rows are being repositioned and spun in a better and more precise North-South orientation. This makes better use of the natural path of the sun and maximizes and better balances the use of morning and afternoon for both sides of the canopy. After that, it’s about timing and the goals of the vineyard regarding their fruit and vine quality and desired yield. If you have weak or younger vines, it may be better to sucker sooner and perform your fruit thinning. For stronger and older vines, you can thin fruit and sucker later for maximum sugar loading. Open zones are beneficial for more aromatic profiles, and they can help with the amount of acidity and tannin development with simple vine management. You always want warm days and good sap flow for pruning.”

  Different environments require different management and trellis considerations. Vineyards located in volatile weather settings have to be willing to use netting, shades or some other blocking material in case of severe weather, extreme winds or hailstorms. Some colder climate vineyards make use of buried canes, green growing vines that are pulled down and buried in the vine row. The Geneva Double Curtain trellis is a popular choice for increased frost protection because of its downward growing, split canopy system. Still, being bulky and top-heavy, it is a liability in areas experiencing frequent windy situations.

  “Our biggest challenge here in Napa is to develop mechanized vineyards that retain the quality we’re known for, while also controlling heat and sun exposure issues,” said Loconto. “Everywhere you go, you’ll see misters and shade cloth used to combat sun exposure. For those older vineyards that are still orientated to have unequal amounts of sun in the morning and afternoon, there is a noticeable difference on the contrasting sides of the vine. Any issues we address have to be solved with the idea of optimizing our vineyards for mechanical farming. Plain and simple, labor is just hard to come by and getting harder. Some equipment manufacturers are helping by developing machines that are comparable to hand labor, gently pulling the right amount of leaves while being relatively gentle on the fruit and soft on the clusters. That trend has to continue to move towards the mechanized vineyard.”