Category: Vineyard Info

By: Lorenzo Rossi and Michael G. Cook – Texas A&M AgriLife Extension Service

It is an exciting time for Texas wine, as the bustling industry is producing reds full of character, crisp and clean whites, and uniquely complex blends that are gaining international recognition. With its diverse 1,300 soil series, rainfall ranging from <10 to 60 inches a year, and over 8 AVAs (with three in progress), the Lone Star State challenges winemakers to think outside the box. From Tempranillo to Tannat, Mourvèdre, and Sagrantino, Texas wines are winning over critics and wine lovers alike. But what makes these wines so special? While climate, grape variety, and winemaking techniques all play a role, the secret to great wine is also in the soil.

A Personal Journey from Florida to Texas Wine Country

  My path into viticulture has been shaped by years of hands-on experience in both soil and fruit crop research. Before moving to Texas, I spent much of my career studying citrus production and root biology in Florida. In my time there I worked closely with commercial growers facing the realities of sandy soils, extreme weather, and persistent disease pressures. I saw how poor soil management could weaken an entire grove and how targeted soil improvements could significantly boost soil quality and tree productivity.

  Now, in my new role at Texas A&M University, I am shifting my focus to viticulture, where soil remains a key factor in producing high-quality crops. Growing grapes in Texas presents more curve balls to the mix than Florida: from the Florida-like climate and soils of South Texas and the Gulf Coast to the fractured limestone in the Hill Country, to the arid and high elevation of the High Plains where red clay and caliche lays under a layer of sand. Each region requires a different approach to soil management, and my background in soil research can help me understand how growers can make the most of their land. My goal is to aid Texas grape growers who want to refine their soil management practices enhancing vine physiology, improving fruit quality, to ultimately produce better wines.

Why Soil Matters in Winemaking

  The ideal vineyard soils strike a balance: loamy to sandy-loam textures promote proper drainage while retaining enough moisture for consistent water and nutrient uptake. A soil pH between 5.5 and 7.5 optimizes nutrient absorption, and calcium-rich substrates like fractured limestone improve root penetration. High-quality soils also contain 2–3% organic matter, which supports diverse microbial communities that enhance nutrient cycling and naturally improve disease resistance.

  To measure soil quality, vineyard growers should conduct regular soil testing, including pH, nutrient levels (such as nitrogen, phosphorus, and potassium), organic matter content, and soil texture. Tools like a soil probe or auger can be used to collect samples from various vineyard locations. Testing for soil compaction and microbial activity can also provide valuable insights into the soil characteristics. Additionally, monitoring drainage, water retention, and aeration can help identify any issues that may affect vine growth.

  When grapes are grown in soils with limiting conditions, the grower must implement a range of best management practices to improve a soil characteristic while maximizing yield and quality over the vineyard’s lifespan. These may include amending soil with organic matter and adjusting pH levels to enhance nutrient availability. When soils are well-optimized, the quality potential of the grapes increase, potentially leading to the production of richer and more complex wines.

Texas’ Unique Wine Regions

  Texas vineyards span multiple American Viticultural Areas (AVAs) and regions, each with unique soil characteristics that shape the wines they produce. Understanding these soil differences allows growers to fine-tune their management practices and maximize vine health and fruit quality.

Texas High Plains AVA: The Texas High Plains is responsible for nearly 70% of the state’s grape production. Sitting at an elevation of 3,000 to 4,000 feet, this region has sandy loam soils with red clay subsoil rich in calcium carbonate. These well-drained soils allow growers to manage vigor through irrigation. The manipulation of irrigation in these soils can also be used to alter fruit chemistry flavor and berry size, leading to greater concentration of compounds in fruit. Cover crops and organic composts can help retain moisture and improve soil biodiversity, which may provide additional benefits to grape quality. Wines from this region are known for their structure and depth, including medium bodied to full reds like Tempranillo and Cabernet Sauvignon.

Texoma AVA:  Located along the Texas-Oklahoma border, the Texoma AVA holds historical significance as the home of T.V. Munson, the horticulturist who helped save European vineyards from the phylloxera epidemic in the 19th century. The soils here range from reddish clay loam to black “gumbo” clay and fertile sandy loam, offering diverse opportunities for vineyard management. Techniques like soil aeration, addition of organic matter such as compost, and controlled irrigation help maximize grape quality. White wines, like Viognier, Blanc du Bois, and the newly planted Picpoul blanc do especially well here.

Texas Hill Country, Fredericksburg in the Texas Hill Country, and Bell Mountain AVAs:  Perhaps the region most often associated with Texas wine, the Hill Country AVAs, feature limestone-rich soils that are usually quite shallow, which can add a distinctive minerality to these wines. Scattered alluvial deposits of deeper loams along the Pedernales flood plain offer improved soil conditions. The high pH of these soils affects how vines take in nutrients; this makes proper soil management essential. This region is famous for Mediterranean-style grapes like Tempranillo, Sangiovese, and Mourvèdre, which thrive in the well-drained yet nutrient-challenged soils. By adding organic amendments and using chelated fertilizers growers can boost fertility and water retention.

Escondido Valley AVA: A small but promising AVA in West Texas, Escondido Valley has deep sandy loam soils with excellent drainage. The warm days and cool nights allow grapes like Cabernet Sauvignon and Merlot to ripen slowly, resulting in wines with balanced acidity and layered flavors. Here, growers can focus on moisture retention techniques like cover cropping and organic mulching to maintain soil quality in the arid climate.

Texas Davis Mountains AVA: Nestled in a rugged, high-altitude landscape, the Davis Mountains AVA boasts volcanic-derived soils with rich mineral content. These well-drained soils, combined with cooler nighttime temperatures, create an ideal environment for growing Syrah and other Rhône varieties. Organic matter enrichment, careful water management, and biodiversity conservation help vineyards thrive in this unique terroir.

Mesilla Valley AVA: Stretching into New Mexico, the Mesilla Valley AVA is one of Texas’ driest and warmest grape-growing regions. Its sandy and silty soils are highly permeable, requiring precise irrigation to prevent excessive water loss. However, these conditions are perfect for growing heat-loving grapes like Zinfandel, Syrah, and Tempranillo. The grapes, soil, and climate work together to create wines with rich flavors and smooth textures.

Gulf Coast and Lower Brazos Valley wine regions: The Gulf Coast, stretching from Houston to the Mexican border, has a warm, humid sub-tropical climate that is known for producing grape varieties like Blanc du Bois, Black Spanish (Lenoir), and, more recently, Blanc du Soleil. Because of high rainfall (and high fertility of some soils), vines have extreme vigor here. With salinity potentially being an issue along the coastline itself. The sandy loam and alluvial soils provide good drainage but require added organic matter to maintain fertility. Because of the high humidity, proper canopy management and soil aeration are essential to prevent disease and ensure high-quality fruit.

Enhancing Soil Quality for Better Wine

  Regardless of location, improving soil composition can be a game-changer for Texas viticulture. Some key strategies include increasing organic matter through compost, mulches, and cover crops. Compost can come from pomace and local cattle or poultry farms (when properly composted). Compost helps enhance soil structure. Texas soils generally have very low organic matter, ranging from 0-1%, but the target range for organic matter is 2-3%. However, excessive additions can cause issues, so it’s important to apply compost in moderation. Mulches are another option, though they are less commonly used due to costs and labor demands.

  Cover crops can be an effective strategy for improv  ing soil composition. In Texas, growers can apply seed in the row middles in September or October and terminate them in May or June. Several cover crop options are available, including clover, triticale, blue gramma, oats, wheat, annual rye, ryegrass, turnip, daikon radish, mustard, and chicory. These cover crops could enhance soil structure, increase microbial diversity, and improve water retention.

The Soil-Wine Connection

  A vineyard’s soil is the foundation for our vines, acting as a water and nutrient bank. Good quality soils that provide the necessary resources for the vines can promote more resilient growth, helping the vines endure Texas’ climate challenges. This can lead to more consistent yields and improved fruit quality over time. Additionally, well-managed soils may help reduce the need for certain chemical inputs, contributing to a more sustainable and environmentally friendly approach for Texas wine production. While soil characteristics play an important role in overall vine vigor, they can also support the vine’s ability to respond to both biotic and abiotic stresses, potentially making them better equipped to cope with certain diseases.

  As I continue my journey in Texas viticulture, I am excited to work alongside local growers to improve soil characteristics and elevate the quality of Texas wines. Just as I learned in Florida’s citrus industry, soil can play an important role in the overall vine physiology. With the right soil care, Texas wines will continue to flourish and gain the recognition they deserve.

  Feel free to reach out to me at l.rossi@tamu.edu for collaboration or discussions.

Summary of Recent Visit to San Juan Province

By: Judit Monis, Ph.D.

This year I was invited to evaluate vineyard disease issues in different grape growing regions in the province of San Juan under the auspices of the Ministry of Agriculture.  The program included the inspection of many producing vineyards (both for raisin, table, and wine grape production) as well as a grapevine nursery.  As you know my interests are in how to prevent the spread and disease development in the vineyard.   So, it will not be surprising that this article will highlight vine diseases observed in the region.

Mendoza and San Juan are the primarily grape growing regions in Argentine

  Argentina grows over 200,000 Hectares of grapevines that are plated mainly in the provinces of Mendoza, San Juan, La Rioja, and Salta.  The industry has expanded to other areas in the provinces of Buenos Aires, Cordoba, Rio Negro, and Tucuman.  However, the majority of the vineyards are located in different regions of Mendoza and San Juan.  This is why there is a saying in Argentina that a person is between San Juan and Mendoza when drunk!  These two provinces have chosen to differentiate  their growing, Mendoza focuses on producing its famous red grape variety Malbec, while San Juan grows white wine, table and raisin grape varieties.

  Argentina ‘s viticulture is different from what I am used to seeing in Californian or Chilean grape growing regions.  Most of the vineyards in Argentina have planted vines on their own roots (i.e., these are not grafted onto a rootstock) as the phylloxera pest is not present in most Argentine grape growing regions.     Obviously, rootstocks confer resistance to phylloxera,  but also help grow grapes in areas where nematodes and salinity are a problem.  Rootstocks also control the vigor of the vines in the vineyard and many winemakers consider that there is an effect on wine quality and sensory aspects.   Consequently, more vineyards in Argentina are being planted with grafted vines, especially in Mendoza’s newer and more sophisticated growing regions such as the Valle de Uco.  

Grapevine Diseases Originate Where Vitis Species Originate

  We know that grapevine pathogens (disease causing agents) originated in the same place where Vitis (the grapevine genus) species originated.  These disease agents (bacteria, fungi, and viruses) were introduced to other places in the world with the grapevine propagation and planting material.  Specifically, the varieties and clones that are grown in vineyards around the world belong to the Vitis vinifera species (of Eastern European and Asian origin) while the rootstocks grown commercially belong to American Vitis species.  When grape cultivation started countries were not set up with quarantine programs, neither modern diagnostic tools we use today (deep sequencing, PCR, ELISA, etc.) to detect pathogens were available.  Consequently, since the early days of grapevine cultivation European and American grapevine pathogens have been moving from one site to another for many generations.

Grapevine Diseases are Found Wherever Grapevines are Grown

  When it comes to diseases, Argentine viticulture is not different from other worldwide growing areas.   The commonly known diseases caused by Leafroll viruses, Vitiviruses, Fanleaf, Agrobacterium vitis, and fungal trunk pathogens arrived on site when plant material was imported.   Even Grapevine red blotch virus (GRBV) considered an American virus has been reported to be found in Argentine vineyards.   These are important diseases that affect both grape quality, yield, and longevity of the vineyards.  In Argentina, I have witnessed the presence of Syrah Decline, a disorder that affects both grafted and non-grafted plants.  However, we now know that Syrah Decline symptoms are linked to genetic markers present in certain Syrah and Shiraz clones.  Research in France elegantly demonstrated the generic nature of the syndrome, therefore Syrah Decline can be prevented by avoiding to plant certain genotypes of this grape variety.

Growers and Nurseries Show Interest in Grapevine Certification Programs

  Grape growers and winemakers are aware of the detrimental effect of grapevine pathogens and would prefer to purchase and plant disease-tested (certified grapevines). In Argentina the grapevine certification program has gone through administrative revisions. Laboratories are being certified by an entity (INASE) to offer testing to allow vines to be part of the certification scheme.  The law allows the application of molecular (PCR, ELISA) instead of biological indexing to detect viruses in the foundation and nursery increase blocks. Interestingly, the certifying agency does not administer a foundation block.  Instead, each private nursery has their own foundation block.  The viruses excluded are Grapevine leafroll-1, -2, -3, and -4, Vitiviruses A and B, grapevine fanleaf, and grapevine fleck.  Unfortunately, even if GRBV was detected in Argentina, it is not included in the testing requirements at the moment.

Evaluation of Vineyards in the San Juan Province

  During my visit I was able to appreciate the diversity of grapevines grown in San Juan.  The vineyards evaluated included table, raisin, and wine grape variety vineyard blocks.  Some of the vineyards were mature and others were planted within the year.  As expected, the symptoms observed in the different blocks were as diverse as the varieties planted.   My visit coincided with the beginning of the fall season, in the middle of the busy harvest season in South America.  This is my favorite time to inspect vineyards since the symptoms of viral diseases (such as leafroll) are most noticeable (see Photo 1-Lead Photo).  In the table grape varieties, we were able to observe lack of color and delayed maturation of the fruit that could be due to viral infection (Photo 2). 

Vines with notable decline due to potential fungal infection were also observed.  The vines were marked and samples will be collected (after the harvest is completed and leaves fall) to test in laboratories to determine the cause of symptoms.  We will work with three different  Argentine laboratories (two of them I have helped with protocol development) to compare their proficiency (i.e., we will conduct and inter-laboratory comparison).  My week-long visit culminated with a presentation I delivered to growers, nurseries, and ministry officials focusing on suggested preventative disease strategies and discussion on the findings during the vineyard inspections and future steps that will follow.

Conclusions

  My involvement with the San Juan province project will continue as we work with the growers, nurseries, and laboratories to develop sampling and testing protocols.  I am also planning to help the nurseries develop sanitation and testing programs to allow them to propagate only plants that are not infected with pathogens of concern.  It is my hope that, with time, future changes will include the availability of certified pathogen free tested and true-to-type scion and rootstock planting material.  Only with clean planting grapevine material these important grape growing areas will see an improvement on the health and longevity of their 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: Judit Monis, Ph.D.

This year I was invited to do a presentation at the Southern Interior Horticultural Show in Penticton, British Columbia (Canada).  The growers in British Columbia are experiencing problems due to diseases and need to replant their vineyards. I was so glad that my audience was interested in plant health and procuring material that is not infected with pathogens (disease causing agents). There are so many articles and books that focus on planting a new vineyard.  These describe soil preparation, setting up irrigation, trellis systems, etc. but rarely focus on plant health.  The best way to avoid disease in a vineyard is prevention.  It is known that diseased plants are more susceptible to environmental stress such as heat, cold, drought.  Further, once infected vines are planted, it is too late to fix the problem.  In this article, I will describe guidelines and best practices to assure that the vineyard planting material is healthy and remains healthy during its lifetime.

Available Nursery Material

  In the spring. Nurseries are busy grafting the cuttings of rootstock and scion varieties that were collected in the winter.  Most nurseries in California propagate and grow material from the California Certification and Registration (R&C) program.  This R&C program was revised in 2010 to include testing for specific pathogens (mainly viruses and Xylella fastidiosa, the causal agent of Pierce’s disease).  After the discovery of Grapevine red blotch virus (GRBV), the regulations were revised once more in 2016 to include the exclusion of this detrimental virus in the certification program.  Canadian growers procure plants from the Canadian Certification program but also purchase plants from California nurseries.

  Some growers and winemakers already have a favorite nursery they have worked with and have had good success with the planting material. Others may had had a bad experience and likely will avoid working with that nursery.  In every case, it is important to develop a good working relationship with the nursery that will produce the grafted vines to be purchased. Prior to placing an order, there is important information to request from the nursery that will help determine the quality and health of the plants they produce. 

  Most growers will be interested in purchasing certified grafted vines as they have an extra level of assurance (the foundation mother blocks are tested regularly for certain pathogens).  However, growers must be aware that grapevine plants are still being propagated in nurseries from the old California R&C program (material from the early 1980s Since many diseases are transmitted and spread in the vineyard you can expect that the older the block the higher the chances of being infected with one or more pathogens!).  It is also important to know when was the nursery increase block planted. As starting in 2017, the new U. C. Davis foundation block was found to be progressively infected with GRBV to the point that it had to be abandoned and replaced with plants grown in greenhouses.

  Even if the nursery propagates material from the certification program you should ask if the nursery has a disease testing and sanitation plan.  The nursery personnel can provide their quality assurance protocol.  Questions to ask include the following: how old are the mother blocks? how many vines are tested in each block? Does the nursery perform random testing or do they have a plan and test all vines on a rotation basis?  Which pathogens are tested for, how often, and why do they not test for others?  Do they test single vines or composites of many vines?  What do they do when a composite sample tests positive for a detrimental virus (i.e., Grapevine leafroll, fanleaf, or red blotch)?  Would they allow you or your consultant to take samples of the varieties or clones of interest and base your purchase on the laboratory results? The answers to these questions will reflect the seriousness of the nursery operation and give some idea of the overall health of the increase blocks and nursery rows.   In addition, I strongly recommend to request reports of the analyzed vines to learn about testing schedules and health history of the nursery’s increase blocks. If the reports are not clear, talk to the nursery personnel or a plant pathologist to help you understand the testing schedule and/or results. It is important to visit the grafting and propagation facilities to perform your own inspection. Finaly, inspecting the plant material and performing a random test prior to delivery and planting will avoid planting material infected with trunk disease causing fungi and Allorhizobium vitis (previously known as Agrobacterium vitis, the causal agent of grapevine crown gall).  If you do not have the required knowledge to understand what to look for, I recommend you hire an expert who can help. 

Testing Requirements of Plant Material

  To increase the assurance of freedom of disease, representative samples from blocks of the rootstock and scion material should collected and submitted to a testing laboratory to determine their health status.  If the vines are field finished (i.e., not potted), testing after growing in the nursery rows or after cold storage is recommended to assure freedom of disease-causing agents.  Is it possible to develop a testing plan depending on the number of vines to be produced, either by testing individual mother plants or using statistical sampling.  The more samples that are submitted for testing, the better confidence in results.

  The grower may decide to propagate and graft material from their own or a neighbor’s vineyard. This choice can be based on early performance of the specific variety or clone in the winery.  However, caution must be taken to assure that the field selection is not infected with detrimental pathogens.  A field selection that performs well in one vineyard may not perform the same way in a newly planted vineyard.   For example, it is known that some pathogens may not display symptoms until a stress factor is present.  Also, some varieties display more symptoms when grafted to a specific rootstock.  In summary, regardless of where the plants originate, it is a good practice to test the mother vines for the presence of pathogens.

Prevention of Infection in the Newly Planted Vineyard

  Procuring certified and/or disease-free tested vines, is just the start.    The newly planted vines have the potential to become infected during their life span. This is especially possible if a diseased vineyard block was removed and replaced with “clean planting stock” or nearby blocks are infected with a virus that is able to spread (e.g., some Grapevine leafroll associated virus species are transmitted by mealybugs; Grapevine fanleaf virus is specifically transmitted by nematodes).

  The new blocks and adjacent vineyards should be monitored for insect vectors and/or suspicious symptoms.  It is always a good idea to determine the cause for suspicious symptoms as viruses and other pathogens can spread from adjacent vineyards.   The knowledge of a positive finding of a virus that is transmissible and the presence of the insect that transmits it will turn on a warning sign.  For example: Grapevine leafroll associated virus-3 or other related Ampeloviruses (GLRaV-1, or -4) and the mealybugs that can transmit these viruses should alert the vineyard manager of a disease prevention strategy that will help avoid the spread of these viruses. I have observed instances in which a vineyard owner removes (and replaces with tested vines) only half of the infected vineyard block to avoid production losses.

A new vineyard planted with vines infected with Allorhizobium vitis (cluse up)

  The other half of the infected vines are removed after the newly planted vineyard block starts to produce grapes.  This is not recommended.   In these cases, I have seen that by the time the infected older plants are removed, the newer plants have become infected with the same pathogens that were present in the original block.

  Some important fungal and bacterial pathogens are soil-born and can be transmitted to the new planting after the infected vines were removed.  But it is also possible to bring these pathogens with the new planting material.  In many cases, a simple visual inspection can indicate that the planting material is infected with A. vitis. Either way, with no symptoms present, sophisticated tests are available to test the vineyard soil and planting material to allow the grower to make informed decisions on planting and disease management.

Conclusions

  In summary, new vineyard development is a critical task that should be taken seriously.  My recommendation is not to hurry.  Do not just purchase the only material left at the nursery or propagate your next-door neighbor’s budwood because you made last minute decisions.  Take the time to make sure that the planting material will meet the quality standards that will produce the best grapes for optimal wine or table production.  You probably heard me say many times that the only way to avoid disease in the vineyard is to prevent the introduction of harmful pathogens.

   By far the most efficient way of pathogen introduction in a vineyard is by planting material that is already infected (one infected mother plant can produce 200-300 infected daughter plants!).   Currently there is no cure for graft-transmissible diseases once established in the vineyard.     This urges you to apply special care when selecting planting material prior to developing a new block.   With these simple guidelines, it is my hope that you will develop a vineyard that will be healthy and productive. 

  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: Michael Cook and Justin Scheiner, Ph.D. – Texas A&M AgriLife Extension Service

As grape growers, we know how important water is for profitable production. Water is involved in pretty much every physiological activity inside a grapevine. We also realize that water is a precious resource and no matter how you slice it, it costs us money. It is not only expensive to apply, but the indirect costs of over or under watering can lead to negative impacts on our bottom line.

  Most climate models predict future growing seasons will be warmer, which will increase water use by grapevines and vegetation in vineyards. This may be good for our friends in Canada, “eh”, but for growers and grapevines in more arid and hot areas on the West Coast as well as in the warm continental and humid climates east of the Rockies, it would spell trouble. These trends mean that it’s increasingly important for commercial producers to adopt data driven technology to monitor water in the soil and in the vine to help guide our decisions. Long gone are the days when the small producer could say there are no sensors in their price range.

  Thanks to advances in technology and manufacturing, there are sensors of all shapes and prices available to today’s grape grower. Having accurate, intuitive data about water use can save a grower serious money. Soil moisture sensors can be very useful in determining when to start irrigating and when to stop. Those that dry farm often irrigate the first few years of vineyard establishment and soil sensors can even be useful in these more temporary situations. Here we’ll briefly discuss soil sensor types and how even the smallest grower can benefit by adopting this technology as part of their irrigation management plan. In a future article, we’ll discuss monitoring vine water status directly and weather-based modelling for irrigation scheduling.

Soil-Based Approaches

  Getting the most out of soil sensors requires some basic knowledge of soil water dynamics. A thorough treatment of these principles is beyond the scope of this article, but we’ll highlight a couple of key concepts here. The foundation for using soil-based water availability measurements, which are ultimately an indirect method of monitoring vine water status, is that we want to maintain some level (e.g., 50-80%) of plant available water (PAW) to vines throughout the growing season. Plant available water is the amount of the water in the soil that vines can actually take up versus the total amount present. While it can be represented as a percentage, we can also express PAW as a volumetric measurement (e.g., inches per acre). Once the soil begins to dry out and the moisture content decreases below a threshold, typically 40-50% of PAW, vines experience drought stress. The specific minimum depletion level that a grower may allow, often called the management or maximum allowable depletion (MAD), may be fine-tuned where a water deficit is allowed to persist over key phenological stages. However, once the soil moisture level approaches 50% most growers will opt to turn the irrigation on.

  Plant available water for a given site or vineyard block can be easily estimated based on soil type, texture, and depth (Table 1). These soil qualities can be investigated by consulting USDA Natural Resources Conservation Service soil maps, collecting soil samples for soil texture and chemical analysis and by simply digging soil pits with an excavator to observe soil horizons, potential rooting depth for new vineyards, and actual rooting depth for mature vineyards.

  Although we still need to get out and scout our vineyard blocks for visual cues throughout the season, soil sensors provide actual data about what is happening in the plant’s root zone. These sensors can be categorized by their function, including those that measure soil tension (qualitative) and those that measure soil moisture content or volume (quantitative).

  There are a number of things to consider when choosing a soil sensor. One is determining the number of sensors to utilize as many can only provide a single point of measurement. Even when using multi-depth sensors, vineyard sites or individual blocks with higher soil variability and with greater topographical changes will require more sensors to accurately determine irrigation needs. The tradeoff for this is higher data resolution leading to more informed decision making. The viticulturist should also consider installing soil sensors at multiple depths in the soil profile so that water infiltration through the soil can be monitored (Image 1). This is also useful for determining if deep soil moisture is available during periods when irrigation may not be routinely applied such as near bud break. With so many soil sensor options available, cost, convenience and accuracy should be weighed to identify the best option.

  No matter which soil sensor you choose, pay particular attention to the placement, installation, and maintenance protocol as each soil sensor type has different requirements. No soil sensor will provide accurate data if it is installed and maintained improperly. Sensors must maintain constant contact with the soil and should be located under the trellis in an area that would normally be wetted by the irrigation system but not immediately underneath an emitter. Make sure to flag soil sensors in the field, secure any cabling, and map locations for future reference as they can easily become lost or damaged.

Qualitative-Based Soil Sensors

Qualitative-based soil sensors, also called water potential sensors, matric potential sensors, or water suction sensors, measure how tightly moisture is bound to soil particles. These measurements are described in tension units (often as centibars, or cbars). Data can reflect suction or negative pressure as with a tensiometer or electrical conductance/resistance as with electrical resistance blocks. Water potential readings are higher (less negative) in fully saturated soil and become more negative as soil begins to dry due to the increase in soil water tension. In other words, there is still water in the soil, but the plant can’t use it because the soil won’t give it up. Soil tension sensors are generally soil-specific and can be inaccurate if the correct model, calibration and installation instructions are not followed.

  These sensors are useful to indicate when to irrigate, but it typically requires some time to understand roughly how much water to apply to bring soil moisture up to an appropriate level.

Quantitative-Based Soil Sensors

  Quantitative-based soil sensors, also called volumetric water content (VWC) sensors are the most used sensors in commercial vineyards. Based on a calibration, they measure how much water in liquid form is present relative to the amount of soil (i.e. volumetric). Measurements are generally in units like percent volume of water to volume of soil or cubic inches of water per cubic inches of soil. For example, a sensor giving a reading of 25% volumetric water content is the same as 0.25 cubic inches of water per cubic inch of soil. When compared to the water content at field capacity, VWC deficits can be used to drive irrigation scheduling decisions. Although the information provided by VWC sensors can be highly valuable, it does not provide any insight into other pertinent information such as water adherence to the soil or ease of extractability by the vine.

  Two classes of quantitative-based soil sensors include Neutron probes and dielectric sensors. Neutron probes are primarily used by researchers and irrigation specialists, requiring bulky and expensive equipment and licensing. Dielectric sensors include Time Domain Reflectometry (TDR) and Frequency Domain Reflectometry (FDR), often referred to as capacitance sensors (Image 2). Of all the soil sensors currently on the market, FDR sensors are the newest and fastest developing area of technology. They can be cost effective, accurate, reliable, low maintenance, and easily integrated into other sensor-based modules like weather stations (Table 2). As with all sensor types, consult the manufacturers recommended installation and maintenance protocol for proper placement, density and depth per block.

  Consider incorporating soil sensors in your water management plan to improve your confidence in irrigation decisions.

 Table 1. Plant available water based on soil texture. (Adapted from Goldammer, T. 2018)

Table 2. Major soil sensor types suitable for vineyard use.

¹based off 2025 MSRP for the sensor itself. $ low cost, $$ moderate cost, $$$ high cost.

²maintenance requirement rated from 1-3, with 1 being the lowest maintenance to 3 being highest maintenance.

Image 1. A single soil sensor monitoring moisture placed in the topsoil and another installed in the sub-soil at the same location.

Image 2. A capacitance type sensor being installed in a vineyard.

By: Alyssa L. Ochs, Staff Writer

Animals of all sizes and types can have devastating impacts on grapes growing in a vineyard. There are direct economic impacts when animals eat, trample or otherwise damage grapes, which leads to yield losses and additional expenditures for pest control measures.

It is essential for vineyard owners to find a balance between the costs and labor involved in wildlife control and the benefits of a healthy harvest. We connected with leading vineyard wildlife control companies to learn more about the effects of wildlife and how to manage grapevine damage caused by wild animals.

How Wildlife Affects Vineyards

  There are many ways in which animals can affect grapevines in a vineyard. For example, they can cause direct crop damage by eating grapes, especially when grapes mature right before harvest. Wildlife can contaminate grapes by leaving behind fungus and bacteria from their fecal matter. This residue often leads to off-flavors and bunch rot.

Vine damage occurs when animals gnaw on vines’ bark or dig around the base of plants, impacting current and future grape growth. There is also the possibility of soil erosion caused by wildlife trampling through the vines and damage to irrigation systems.

  Some vineyards are faced with increasing costs for pest control because they need to address the damage already caused and then take more effective action to protect future crops. Changing weather conditions and increasing extreme weather events may also impact pests’ natural behaviors, requiring shifts in vineyard pest control strategies to accommodate new patterns of infestation.

Factors Affecting Wildlife Damage

  A vineyard’s geographic location matters regarding wildlife damage to grapes. Some areas are more prone to animal activity, so it is important to understand the prevalence of wildlife populations and their feeding patterns where you are. You may experience more or less wildlife due to the availability of food and shelter, as well as your vineyard’s terrain and proximity to wild habitats and urban areas.

  The type of wildlife present in your area also determines how much damage is likely to be caused, as some pests cause more harm than others. Fortunately, customized solutions are available to help vineyards improve their management practices and be proactive about minimizing wildlife activity.

Types of Damage Caused by Wildlife

  Birds cause substantial damage by eating copious quantities of grapes, thereby reducing a vineyard’s yield. Starlings, sparrows, and blackbirds are problematic in many vineyards. You may notice pecking damage from birds on grapes, which leaves them susceptible to rot and disease.

  Jon Stone from Avian Enterprises told The Grapevine Magazine, “While grapes that are consumed are a direct loss, pecked grapes may release juice, which can lead to bunch rot and even greater levels of loss. The juice can also attract drosophila flies and wasps, which can spread the rot to otherwise untouched bunches.”

  Based in Sylvan Lake, Michigan, Avian Enterprises offers an EPA-registered solution to eradicate pest birds without causing harm to the birds, other animals, or humans.

  Rodents are common in vineyards, including mice, rats, and voles. These animals are notorious for gnawing on vine roots and bark, which weakens or kills the vines. Rodents can contaminate grapes and vineyard equipment with their fecal droppings, creating risks for food safety and sanitation.

  Deer are known for causing vine damage as they move through vine shoots, leaves and grapes. The movement of deer in vineyard rows reduces the plants’ ability to successfully photosynthesize and produce grapes. Because of their generous size, deer commonly damage vines and soil by trampling through the rows, causing root damage, soil compaction and trellis and fence damage.

  George Horetsky, senior sales representative at Trident Enterprises, told The Grapevine Magazine that bucks also cause damage by rubbing their antlers on young vines, which can kill or weaken them. Based in Waynesboro, Pennsylvania, Trident Enterprises has been a wildlife exclusion expert for over 30 years and is a leading distributor of fence supplies.

  In some areas, wild boars are a problem for vineyard owners. They eat grapes, leading to significant crop loss. Wild boars have rooting behaviors that uproot vines and damage irrigation systems. Predatory animals like coyotes and foxes can also disrupt vineyard operations and scare away beneficial wildlife and insects as they search for food.

Economic Impacts of Wildlife Damage

  Horetsky from Trident Enterprises explained to us how wildlife damage, especially from deer, can lead to substantial economic losses for vineyards.

“Reduced yields from damaged vines directly impact revenue, while the cost of repairing physical damage and replacing plants adds to the expense,” he said. “In some regions, studies suggest wildlife damage can result in a five to 10 percent loss in total vineyard productivity annually. Beyond crop loss, vineyards may face increased operational costs for pest management and implementing preventative measures. Trident Fence’s wildlife control solutions are designed to help mitigate these losses by offering durable, long-lasting fencing options tailored to vineyard needs.”

  Stone from Avian Enterprises shared with us, “The USDA has estimated that bird damage may result in a loss of up to an average of 40 percent of the crop. In a recently published article, Michigan State University states that losses can be as high as 95 percent and 60 percent in red and white varieties, respectively. Losses of over $100 per acre are possible. Clients who have used Avian Control® Bird Repellent have reported significant reduction in the level of loss, at times less than 10 percent.”

How to Prevent Wildlife in the Vineyard

  According to Horetsky from Trident Enterprises, one of the best ways to control wildlife is to install effective fencing.

  “High-quality fencing is the cornerstone of wildlife prevention,” Horetsky said. “Our fencing solutions, including poly and metal mesh options, are designed to withstand wildlife pressure, providing reliable protection for vines. Customizable features ensure the fencing fits the specific needs of the vineyard, whether it is a large-scale acreage or a boutique operation.”

  Horetsky also recommended creating physical barriers to reinforce vulnerable areas like vineyard perimeters and entry points. He suggested pairing fencing with complementary measures like motion-activated sprinklers or repellents during peak wildlife activity. He also shared that inspecting fencing regularly is essential to identify and repair damage.

  “By investing in durable, scalable fencing solutions and adopting best practices for wildlife deterrence, vineyards can focus on cultivating healthy vines and maximizing their yields, year after year,” Horetsky said.

  Stone from Avian Enterprises explained that rather than trying to manage and repair damage already done, crop loss to foraging birds can be significantly reduced by taking a proactive approach to bird control.

  “Frightening devices like cannons, distress calls and streamers have proven to be somewhat effective, while netting is effective but costly to use and very labor intensive,” Stone said. “Avian Control® Bird Repellent is a non-toxic liquid spray that, when used as directed, irritates birds, teaching the birds to avoid any treated areas.”

  Stone said that Avian Control® has no effect on people, pets, or livestock. Also, it does not affect the taste of grapes and biodegrades rapidly.

“The key to successfully bird control is to begin applying Avian Control® Bird Repellent at the first signs of birds in the vineyard, usually around veraison,” Stone said. “Avian Control® can be used up to the day of harvest.”

Best Practices for Vineyard Wildlife Control

  Stone at Avian Enterprises stressed that growers who have experienced the highest level of success with their company’s products have begun their applications early. 

  “Waiting to see how serious the damage will be allowed the birds to establish themselves in the vineyard, making it more difficult to repel them and ensuring ongoing damage until the birds leave,” Stone said. “Avian Control® works at it best when applied by itself. Tank mixing is discouraged, as the presence of other chemicals has been shown to reduce effectiveness, and a pH that is below 6.5 causes premature breakdown of the product. Properly applied, an application of Avian Control® can last up to two weeks.”

  Meanwhile, Horetsky from Trident Enterprises provided several tips for effectively using his company’s wildlife control solutions in a vineyard. His advice can be broken down into the following: site assessment, proper installation, maintenance, complementary measures, and custom solutions.

  “Conduct a thorough assessment of the vineyard to identify vulnerable areas, such as borders near forests or water sources,” Horetsky recommended. “Ensure fencing is installed at the correct height and depth. For deer, fencing should be at least 7.5 feet tall to prevent jumping.”

  “Regularly inspect fences for damage or wear, especially after storms or during peak wildlife activity,” he continued. “Combine fencing with other deterrents like motion-activated sprinklers or repellents for a multi-layered approach. Finally, utilize fencing systems designed for vineyards, such as those with easy access points for equipment and workers, while maintaining robust protection.”

  Vineyards can preserve their immediate productivity and long-term sustainability by incorporating these measures and investing wisely in wildlife control solutions with the help of trusted companies that understand the industry well.

  “Wildlife pressure can be unpredictable, but proactive measures like high-quality fencing reduce risks and provide peace of mind,” Horetsky said. “Trident Fence is committed to helping vineyard owners find practical, cost-effective solutions tailored to their unique needs, ensuring their vines — and bottom lines — are protected season after season.”