Don’t Get Caught Off Guard During Wildfire Season: Tips For Your Winery

winery in front of a wine vineyard

Weather conditions and natural disasters occasionally take a toll on vineyards and other agricultural production systems. Due to climate change and recurring droughts, some of which are severe, the frequency and severity of wildfires is expected to increase. These risks highlight the need for winegrowers and winery owners to be as prepared as possible to reduce risk.

Putting Your Plan Together

  Many wineries may have already revisited their evacuation plans and filed them with their respective state agencies. Staying current of wildfire season developments can help enhance your ongoing planning and preparedness. Technology can also support your wildland fire planning and response. Additional planning resources by the American Red Cross are available at: www.redcross.org/get-help/how-to-prepare-for-emergencies/types-of-emergencies/wildfire.html

Steps to Take Before a Wildland Fire Event

•   Take a close look at your winery’s communication protocol for evacuations. Everyone should have a clear understanding of any community alarms that signal when you need to evacuate. Assign specific accountabilities to staff so everyone works collectively to achieve a positive outcome of protecting lives and property.

•   Work with your regional Forest Service to better understand emergency evacuation procedures in your area.

•   Coordinate with the American Red Cross, FEMA, and other emergency agencies to give them the locations of your evacuation sites. Invite your local fire department out as part of a fire pre-incident plan. They should be provided a map of your property, highlighting planned evacuation routes. They can also offer technical assistance to support your plan.

•   Prepare and post route maps for each site, including alternate routes. With a large fire, you may need to use “Plan B.”

•   Consider forming a cooperative agreement with another site to share resources and serve as an evacuation site.

•   Identify key equipment to be evacuated, including computers and other vital records. As part of your business continuity planning, programs should already have information backed up and stored remotely. But, in case you don’t, practice removing this equipment as part of your practice response.

•   Stock an ample supply of water and easily-prepared foods until rescue arrives.

Controlling Wildland Fire Exposures

  Wildland fires are one of the most catastrophic threats to wineries.  Protecting your structures from ignition and fire damage is an important program objective second only to an evacuation plan. Taking precautions ahead of time can help reduce the exposure of a wildfire intrusion. There are a number of proactive measures a winery can take to mitigate the property damage a wildland fire can cause.

  To support a fire adaptive community philosophy, the local fire department or authority having jurisdiction for your winery should require you to develop a landscape plan for your property. It is wise to seek their advice and incorporate their recommendations as you develop a plan specific to your location. You can learn more about fire adaptive community planning at the Fire Adaptive Communities, www.fireadapted.org

According to the NFPA 1144 – Reducing Structure Ignition Hazards from Wildland Fires, fire protection plans should address four zones around a property.

What are the Primary Threats to Property During a Wildfire?

  Research around property destruction vs. property survival in wildfires point to embers and small flames as the main way that the majority of properties ignite in wildfires. Embers are burning pieces of airborne wood and/or vegetation that can be carried more than a mile through the wind, they can cause spot fires and ignite structures, debris and other objects.

  There are methods for property owners to prepare their structures to withstand ember attacks and minimize the likelihood of flames or surface fire touching the structure or any attachments. Experiments, models and post-fire studies have shown structures ignite due to the condition of the structure and everything around it, up to 200’ from the foundation.  This is called the Structure Ignition Zone.

What is the Structure Ignition Zone?

  The concept of the structure ignition zone was developed by retired USDA Forest Service fire scientist Jack Cohen in the late 1990’s, following some breakthrough experimental research into how structures ignite due to the effects of radiant heat. 

The structure ignition zone is divided into three zones; immediate, intermediate and extended.

Immediate Zone

  The structure and the area 0-5’ from the furthest attached exterior point of the structure; defined as a non-combustible area. Science tells us this is the most important zone to take immediate action on as it is the most vulnerable to embers.

  START WITH THE STRUCTURES then move into the landscaping section of the Immediate Zone.

•    Clean roofs and gutters of dead leaves, debris and pine needles that could catch embers.

•    Replace or repair any loose or missing shingles or roof tiles to prevent ember penetration.

•    Reduce embers that could pass through vents in the eaves by installing 1/8” metal mesh screening.

•    Clean debris from exterior attic vents and install 1/8” metal mesh screening to reduce embers.

•    Repair or replace damaged or loose window screens and any broken windows. Screen or box-in areas below patios and decks with wire mesh to prevent debris and combustible materials from accumulating.

•    Move any flammable material away from wall exteriors – wooden pallets, mulch, flammable plants, leaves and needles, firewood piles – anything that can burn. Remove anything stored underneath decks or porches.

Intermediate Zone

  5-30’ from the furthest exterior point of the structure.  Landscaping/hardscaping – employing careful landscaping or creating breaks that can help influence and decrease fire behavior

•    Clear vegetation from under large stationary propane tanks.

•    Create fuel breaks with driveways, walkways/paths, patios, and decks.

•    Keep lawns and native grasses mowed to a height of 4”.

•    Remove ladder fuels (vegetation under trees) so a surface fire cannot reach the crowns. Prune trees up to 6-10’ from the ground; for shorter trees do not exceed 1/3 of the overall tree height.

•    Space trees to have a minimum of 18’ between crowns with the distance increasing with the percentage of slope.

•    Tree placement should be planned to ensure the mature canopy is no closer than 10’ to the edge of the structure.

•    Tree and shrubs in this zone should be limited to small clusters of a few each to break up the continuity of the vegetation across the landscape.

Extended Zone

  30-100’, out to 200’. Landscaping – the goal here is not to eliminate fire but to interrupt fire’s path and keep flames smaller and on the ground.

•    Dispose of heavy accumulations of ground litter/debris.

•    Remove dead plant and tree material.

•    Remove small conifers growing between mature trees.

•    Remove vegetation adjacent to storage sheds or other outbuildings within this area.

•    Trees 30 to 60’ from the structure should have at least 12’ between canopy tops.

•    Trees 60 to 100’ from the structure should have at least 6’ between the canopy tops.

If an Evacuation Becomes evident

•    If possible, identify the location and direction of the fire event. Remain cognizant that this can quickly change direction and speed.

•    Clearly explain your evacuation procedures to all that may be involved.

•    Identify special medical needs and gather emergency equipment and necessities, including trauma supplies for ready access.

•    Designate enough vehicles to evacuate everyone safely. Reinforce safe driving practices with all drivers.

•    Equip staff with emergency communications equipment (cell phones, walkie-talkies, whistles, flares, colored smoke canisters, etc.). Ask your local jurisdiction authority for suggestions.

•    Load key equipment, vital records, food, and water.

•    Ask qualified associates to disconnect and move LP gas tanks to a safer location, such as a gravel lot, or follow the manufacturer’s instructions to empty the tanks.

•    Warn firefighters of underground fuel storage or LP gas tanks before you leave.

  Making your facility fire resistant can help reduce property loss. However, keep in mind that these steps should be done only by assigned staff in conjunction with an evacuation and never require or allow staff to remain behind. Close and secure all doors and windows once combustible materials have been moved away from these openings.

•    Wet down buildings and roofs. There are commercial grade fire retardant products available that can help support your efforts to protect your property. But do your research ahead of time; and don’t let the application of these products reduce the priority of evacuating.

•    Have qualified personnel cut down trees in the fire path, bulldoze a firebreak, and cut field grass as short as possible.

•    Remove brush and dry vegetation near buildings.

Fire Evacuation – What You Need to Know

  During wildfire season, you may be forced to evacuate in a hurry. People are your first priority; to include guests, staff and firefighters. Most fire evacuations provide at least a three-hour notice; but due to the scope of your operation, you may need to do it sooner. Take proactive steps before and during an evacuation to reduce anxiety and avoid injuries. Plan, prepare and practice.

Filing Claims

  In the event your area experiences a wildfire event, it is highly likely it will not only be monitored by your insurance agent, in addition to your insurance company. Pre-loss documentation, such as video recordings and pictures of buildings, business personal property inventories, should be up to date and included as part of your evacuation materials. Working with your agent is a great resource to understand what might be necessary to help with documentation, if you should need it.

Ref:

•    NFPA 1144 – Reducing Structure Ignition Hazards from Wildland Fires, 2018 Edition. National Fire Protection Association. Quincy, MA 02169, 2018

•    Fire Adaptive Communities. Fire Adapted Communities Learning Network. www.fireadaptednetwork.org

•    Wildfire Safety. www.redcross.org/get-help/how-to-prepare-for-emergencies/types-of-emergencies/wildfire.html. © 2019 The American National Red Cross

  This document is intended for general information purposes only, and should not be construed as advice or opinions on any specific facts or circumstances. The content of this document is made available on an “as is” basis, without warranty of any kind. This document can’t be assumed to contain every acceptable safety and compliance procedures or that additional procedures might not be appropriate under the circumstances.  Markel does not guarantee that this information is or can be relied on for compliance with any law or regulation, assurance against preventable losses, or freedom from legal liability.  This publication is not intended to be legal, underwriting, or any other type of professional advice.  Persons requiring advice should consult an independent adviser.  Markel does not guarantee any particular outcome and makes no commitment to update any information herein, or remove any items that are no longer accurate or complete.   Furthermore, Markel does not assume any liability to any person or organization for loss of damage caused by or resulting from any reliance placed on that content.

Litigation of Herbicide Drift Cases

a small helicopter in the sky

By: Brian D. Kaider, Esq

Chemical drift, the movement of herbicide/pesticide to unintended areas from the site of application, is a continuing problem in many farming areas, including vineyards.  In the Nov/Dec 2019 issue of The Grapevine Magazine, Judit Monis and I wrote an article (https://thegrapevinemagazine.net/2019/11/herbicide-drift-a-common-issue-affecting-vineyards-worldwide/) describing how herbicide drift affects vineyards and some of the legal causes of action that may be available to those who have suffered damage to their crops  

In the July/August issue, another article (https://thegrapevinemagazine.net/2020/06/liability-coverage-for-chemical-drift/) addressed insurance coverage for herbicide drift.  This article will focus on litigation of these cases, including the types of evidence needed to pursue or defend against the claims.  As with any legal issue, the details will vary from state to state and from case to case, depending upon the facts.  So, this article is not intended to convey legal advice, but rather to provide background information of the types of issues that may arise.

  To frame the discussion, we will discuss a hypothetical case in which Victoria is the owner of a vineyard who discovers damage to her vines, such as distorted leaves, defoliation of some vines, and damaged fruit.  She believes a neighboring farmer, Stephen, applied an herbicide to his soybean fields, which are adjacent to Victoria’s vineyard, that damaged her vines.  As a first step, Victoria should look to her own insurance policy to see if damage caused by third parties is covered.  If so, and if the policy covers the extend of the damage to her property, Victoria’s best option may be to simply file a claim with her insurance.  Assuming that not to be the case, Victoria may need to file a lawsuit.

  Before going to court, Victoria has to have a reasonable basis for alleging that Stephen is responsible for the damage to her vineyard.  So, when she speaks with her attorney, the litigation process begins with a “pre-suit” investigation.  Because the effects on her plants are likely to change over time, it is critical that Victoria start to document the damage as soon as she notices it.  She should take photographs and detailed notes about the condition of her vines, the location and extent of the damage on her property, as well as weather and environmental conditions, and she should update this information regularly.  If she has any knowledge or reason to believe that Stephen applied an herbicide to his soybean fields prior noticing the damage to her vines, she should document that information as thoroughly as possible. 

  Causation is always an issue in these cases.  Victoria will have to show that it was Stephen’s chemical application that caused the damage to her vines.  So, she should also attempt to collect data that would rule out any other cause of the damage.  For example, she should have thorough documentation of all chemicals that she has applied to her own property, she should note the location of farms other than Stephen’s in the area, whether she has seen them apply chemicals, and what the prevailing wind patterns are in her area.  She should also take samples from her vines to be sent for analysis to determine, if possible, to which herbicide(s) the vine has been exposed.

  Once the pre-suit investigation is complete and there is a reasonable basis to assert that Stephen caused the damage to her crop, Victoria’s attorney will prepare a Complaint and file it in the relevant court.  This begins the official litigation process. 

  When Stephen receives the complaint, he will have a certain amount of time to respond, typically with an Answer to the Complaint.  As his attorney begins to prepare the Answer, he will need to begin collecting information, as well, including documentation of the time, place, and manner of all chemicals he has applied to his land. 

  The vast majority of all lawsuits settle out-of-court rather than reaching trial.  While the parties may reach settlement at any time, there are three points at which it is most common.  The first is during the Complaint/Answer stage.  At this point, the parties have not expended a great deal of money on the litigation process and if it is very clear which party is in the wrong or if the damages are not substantial compared to the cost of litigating, it is often prudent to settle at this stage.  If the parties do not settle, the case will proceed to the “discovery” phase, and things get expensive very quickly.

  Discovery is the process by which the parties seek information from one another in order to evaluate the strength of the claims and defenses and to obtain evidence they will use at trial.  There are four main forms of discovery: document requests, interrogatories, requests for admission, and depositions.  Document requests, as the name suggests, is the process of asking the other party for documents or other tangible evidence.  Interrogatories are written questions that the other party has to answer in writing.  Requests for admission present a series of statements and require the other party to admit or deny the truth of those statements.  And depositions are a process where a person is placed under oath and asked questions to which they must respond on-the-spot.  There is typically a court reporter there taking a transcript of the questions and answers and they are often videotaped, as well.  All four of these processes take a tremendous amount of attorney time and are, therefore, very costly.  Discovery is often the most expensive part of a lawsuit.

  Whether the case involves negligence, strict liability, trespass, and/or nuisance, there are several issues that will almost certainly arise in discovery.  As the plaintiff, some of the materials that Victoria should request include:

•   documentation of the time, place, and manner of all chemical applications on Stephen’s land, including the type of chemical, who applied it, how it was applied, the quantity, and the environmental conditions at the time of application

•   copies of the labels and/or package inserts for the chemicals

•   information about crop buffer zones or setbacks on Stephen’s property and/or request permission to inspect the property to measure these areas 

•   a copy of any and all insurance policies that cover Stephen’s land

  In preparation of his defense, Stephen will not only want to seek information that undermines the case against him, but also evidence that supports his affirmative defenses and/or counterclaims.  He will want, for example:

•    documentation of all chemical applications on Victoria’s land

•    all information Victoria has on chemical applications by third parties not in the case

•    historical records about the health of Victoria’s vines and crop yields from prior years

•    detailed accounting of the number of allegedly affected vines and their condition

•    documentation of Victoria’s current and previous irrigation practices

•    documentation of insects or other pests on the land in current and prior years

•    any other information that could suggest that the damage to Victoria’s crops was caused by something other than Stephen’s chemical application

•    documentation of any and all tests Victoria has had conducted on her vines before or after the commencement of the litigation

  Discovery may also involve the services of experts.  Both sides may use experts to support or refute the theory that the damage to Victoria’s crops was caused by Stephen’s chemicals.  Each expert may submit a written report and is then likely to be deposed in order to try to undermine or discredit that report.

  The court will set a specific time period during which discovery must occur.  When that window closes, there is generally no more exchange of evidence between the parties.  This is the second point in which it is common to settle the case.  Each side is then in full possession of all of the evidence that may be presented.  Often it becomes clear from discovery that one side’s position has significant weaknesses and is likely to lose if the case goes to trial.  Since it will still require a significant investment of time and money to see the case to the end, it makes sense in that instance to reach settlement between the parties.

  If again the parties do not settle, they will begin to prepare for trial.  Typically, this involves a variety of written motions asking the court to rule on certain issues in the case.  There may be summary judgment motions requesting that the court rule in a party’s favor as a matter of law.  One or more parties may file evidentiary motions seeking to exclude certain information from the judge or jury’s consideration.  There are also many procedural issues for the court to decide, such as what instructions will be given to the jury, how much time each party will be allowed to present its case, etc.  Depending upon the outcome of these various issues, a third opportunity to settle the case often presents itself just before trial.  For example, if the court rules that a key piece of one party’s evidence is inadmissible, that party may be more inclined to throw in the towel.

  Of course, if the parties still do not settle, the case will then go to trial.  Litigation is not to be entered into lightly.  The costs for each party to take a case all the way to trial will almost certainly reach six figures and, for more complicated matters, could reach seven. 

  As always an ounce of prevention is worth a pound of cure.  If you are applying herbicides to your property, there are several precautions that can help keep you from affecting neighboring properties and exposing yourself to legal liability.  First, examine the surrounding properties to identify potentially vulnerable crops.  Some states even have listings of vulnerable crops that may help guide your choices.  Second, make sure you fully understand the chemicals you are applying and what crops may be adversely affected.  The University of Kentucky has a great resource website to cross reference herbicides, what weeds they affect, and which crops are vulnerable or resistant to the herbicide (https://www.uky.edu/Ag/Horticulture/masabni/xreflist.htm).  Third, when applying chemicals, be sure to follow the manufacturer’s instructions to the letter and document everything, including date, time, volume of chemical, manner of application, and environmental conditions.

  Brian Kaider is a principal of KaiderLaw, an intellectual property law firm with extensive experience in the craft beverage industry.  He has represented clients from the smallest of start-up breweries to Fortune 500 corporations in the navigation of regulatory requirements, drafting and negotiating contracts, prosecuting trademark and patent applications, and complex commercial litigation. 

For more information please email or call…bkaider@kaiderlaw.com

(240) 308-8032

A Review of Laboratory Methods for Grapevine Pathogen Detection and Diagnostics

By Judit Monis, Ph.D.

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, and/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 that is specific for grapevine diagnostic laboratories in USA.  Therefore, each laboratory is free to develop their own testing and sampling methodologies.    

My expertise in grapevine disease diagnostics and my past work on developing state-of-the-art testing laboratories puts me in a position to evaluate the different choices for my clients.  The short answer is that there is no “one lab that fits all”.  In my experience, it is best to choose a lab based on the knowledge and capabilities specific to the needs of the project.  Generally speaking, choosing the lab because it offers the best prices or quicker turn-around-times might be a huge mistake.

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 the development of an accreditation of testing laboratories should be a goal for the future.

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, the grower may suspect disease in the vineyard due to specific symptoms.  Or as you may have heard me say many times, diseased vines may not always be symptomatic.  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

pipet filling up the vials
Photo 1.  A stack of plates containing a number of different fungal species isolated from declining grapevines

Fungal and bacterial pathogens can be cultured and isolated in specialized media (see fig.1).  However, microorganisms may compete among each other.  Generally, the microbe(s) with the most competitive growth capacity will overshadow microbes that grow slower, making the diagnosis difficult or even 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 (for details see NGS/HTS section).  Generally, 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, RT-PCR, qPCR

The Coronavirus pandemic has made some of the terminology that I use in my articles much easier to explain.  The general media talks about antibody tests (ELISA is one) and PCR (this is a molecular test).   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 (Fig.2 Shows the loading of an ELISA plate in the laboratory).  A positive reaction is 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 (called primers) 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 stands for reverse transcription, a molecular way of converting RNA into DNA).  PCR and RT-PCR are sensitive techniques used for the detection of grapevine pathogens.  Quantitative or Real Time PCR is a modification of PCR that can provide the relative quantitation of the pathogen present in a sample (abbreviated as qPCR).

Photo 2. The loading of an ELISA plate to determine infection status of plant material at the Bioreba AG Laboratory in Switzerland

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, ELISA has a broader spectrum of detection and can detect a range of virus variants. On the other hand, PCR is very specific, this can be an advantage but also a disadvantage.  If the detection is too specific, it could miss the detection of isolates of the same virus even when small changes (mutations) are present.  This is even more true when TaqMan, a type of qPCR that in addition to specific primers uses a specific probe is applied for the detection of viruses in grapevine samples.   This is why running both ELISA and PCR consecutively is recommended for the reliable detection of grapevine viruses, as each method is designed to detect different portions of a virus.   Since Grapevine red blotch virus is a DNA virus, and no ELISA has been developed as of yet, I recommend that PCR is performed to amplify at least two different portions of the viral genome.

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 claims it can be used for in-field testing.  However, for reliable results, the assays should be conducted by experienced technicians in a clean laboratory.  If a lay person were to attempt to run this type of assay, the instructions must be carefully followed.  The protocol includes many steps that are complicated and require measuring small quantities of reagents (microliters of components).   In my opinion, it is worthwhile to have an experienced laboratory run these tests.  Laboratory personnel are used to running different protocols and 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.

Photo 3.  Soil sample extracts being prepared at BiomeMakers Laboratory in Sacramento, CA

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 virus. Presently, this technique is being applied commercially to test plant and soil samples for the detection of bacterial and fungal microorganisms.  It is recommended that a plant pathologist with expertise in bacterial, fungal, and/or viral taxonomy be available 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 (comparative) 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 biotechnology.  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, its 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 at the nursery and on new planting material to 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.  During the Coronavirus pandemic, you can also schedule virtual vineyard consultations.  Please visit juditmonis.com for information or contact juditmonis@yahoo.com to request a consulting session.

Highlighting the Women of Washington State Wine

woman interacting with a wine enthusiast

By: Becky Garrison

A media luncheon of Washington winemakers hosted by the Washington State Wine Commis-sion during Feast Portland 2019 featured presentations by Rachael Horn of AniChe Cellars, Mari Womack of Damsel Cellars and Kent Waliser from Sagemoor Vineyards. This luncheon afford-ed a glimpse into the bounty of Washington State’s vineyards and highlighted the contributions of the state’s women winemakers.

  According to the Washington State Wine Commission, women constitute about 8% of total winemakers operating in Washington state. Given that women account for 57% of wine volume consumed in the U.S. (Nielsen Spectra 2015), why does this industry remain male-dominated? In an attempt to shed light on this question, Horn and Womack, along with a few other Washington state-based women winemakers, offered their perspectives regarding making inroads in the in-dustry.

Mari Womack, Damsel Cellars (Woodinville, WA.)

  When Mari Womack transitioned from the restaurant to the wine industry, she saw herself as a blank slate. “I didn’t feel there were any barriers for me coming into the wine industry, other than my lack of experience and knowledge about the subject.”

  After a stint working as assistant winemaker to Darby English at Woodinville, Washington’s Darby Winery, as well as managing its tasting room, Womack set off in 2012 to make her own wine. She chose to focus on Cabernet Sauvignon and Syrah. “As there isn’t a predominant varie-tal in Washington State, there’s ample room for people to experiment and implement their own style of winemaking,” Womack said.

  In Woodinville, she’s encountered a number of male allies looking for diverse perspectives, with a push towards supporting women and minority-owned businesses. Along those lines, more women appear to be designing tours specifically geared towards helping women winemakers. With more women’s voices impacting and telling the story of wine from different and original perspectives, she sees the industry becoming more diverse.

  To bring about long-lasting transformative change, Womack stresses promoting diversity in her hiring practices. “You have to see it to be it.”

  She believes female winemakers must do what they can to promote the visibility of their busi-nesses and make sure their own hiring practices are inclusive and expansive. “We just don’t see enough of it. I recommend searching for qualified candidates via different avenues and programs, as well as mentoring other women,” she said.

  Even though hers is a boutique winery, though events like Taste Washington, Womack can con-nect on a large scale with vendors and consumers beyond her immediate vicinity. Also, by par-ticipating in Feast Portland, a food festival that highlights the bounty of the Pacific Northwest food and beverage culture, she became aware of the expansive nature of the Portland food scene and was able to get her wine introduced to several restauranteurs. 

  When tasting rooms shut down due to Covid-19, Womack observed how women winemakers could utilize digital media to partner with women’s groups and produce virtual wine tastings with a women-centric focus. “I don’t think we considered that customers don’t have to come to our tasting room and physically meet us in order to have a very meaningful experience. They can order our wine in advance, taste it in a virtual setting, and then become a really loyal follower at that point,” Womack said in an interview with The Grapevine Magazine

Rachael Horn, AniChe Cellars (Underwood, Washington)

  When Rachel Horn tried her hand at fermentation in 2008, her focus was on making wines that would pair well with the foods grown in the Columbia Gorge and surrounding environs. The re-sults were reflective of her favorite European wines–blended wines with a regional focus.

  Hence, she entered this industry with no concept of any gender bias. She attributes this attitude to her upbringing and the competent, intelligent women in her social group capable of making their dreams happen. “I was like, ‘I’m going to make wine because that’s what I want to do.’”

  As the only winemaker in the Columbia Gorge at this time, Horn found she lacked access to mentors and support from the all-male winemakers in the region. Also, many growers, all men, had no interest in selling fruit to her. In her estimation, they treated her as though she was engaging in a cute little hobby. “After I was called ‘sweetie’ a few times, that lit a quickfire under my ass. I was like, ‘Okay, I’ll show you.’”

  Eventually, she found a vineyard that would sell her fruit. This vineyard was owned by an Amer-ican who had worked for two decades in France and was more accustomed to working with women in the wine industry. However, she still faced difficulties in purchasing equipment. Even though Horn visited vendor booths at trade shows with fellow women winemakers with the in-tention of spending $100,000 on equipment, they were ignored as the vendors focused on the males entering their booths.

  Furthermore, she found that her wines received a lower rating whenever she presented them for a tasting under her name. If she entered her wines in a blind tasting, her scores would go up by about seven points. This discrepancy proved her point that wine is gender-neutral. “Wine doesn’t care if you’re a female or male making it.”

  This lack of support also drove Horn to mentor other women looking to enter the industry. She found herself to be a person who asks questions such as, “So, we formed this new committee. How many women, people of color and queer people who represent our industry are on this committee?” In this quest, she does not seek preferential treatment for her wines because she is a female winemaker, but to have a fair shot selling her wines at the same price point as male winemakers producing similar wines.

  For those looking for more diversity at their wineries, Horn recommends identifying their demo-graphic and designing marketing materials to attract these consumers. “It’s kind of the Field of Dreams thing that ‘if you build it, they will come.’”

  Also, Horn said events like Taste Washington enabled her to truly understand consumers’ inter-ests. “When I went to Taste and stared creating relationships with people, these barriers didn’t melt away, but they were certainly lowered.”

Making Connections Regionally and Nationally

  Kerry Shiels, winemaker, Côte Bonneville in Sunnyside, Washington, felt fortunate to grow up with a mother who decided to start her winery along with many of the pioneering people in the Yakima Valley, such as Sara Spayd, Kay Simon and Marie Eve Gilla. “When my mom decided to start our winery, quality, consistency and continuous improvement were important attributes, and remain so to this day.” These women winemakers and viticulturists motivated her to get her graduate degree in Viticulture and Enology from the University of California Davis and work around the world before returning home.

  Jody Elsom, winemaker and owner of Elsom Cellars in Seattle, benefited from making connec-tions with local women winemakers. In particular, her interests lie in the rise of women getting their hands dirty by hanging out in the vineyard and the cellar. She recalled that when she started in the industry, she would show up to vineyards in her minivan to purchase fruit with a newborn baby and pregnant with another one. The vineyard manager would come up to her van and knock on her window, suggesting that perhaps she took a wrong turn. “It was an interesting experience for me being in that situation. I was a single mom and had to take my kids with me,” Elsom said.

  She found support with the Sisters of the Vinifera Revolution, a group of women based in western Washington who serve as a resource for female winemakers trying to break into what she describes as the “good ole boys club.” “The camaraderie has really grown, and it’s like we’ve cre-ated our own little support network–bouncing these stupid questions off of one another without feeling stupid.” 

  Elsom also benefited from bringing together female business owners from other industries and exposing them to SOVR’s wine and what they’re doing. “We all can see we have similar chal-lenges regardless of our particular industry.”

  Like Elsom, Anna Schafer, winemaker at àMaurice Vineyard in Walla Walla, Washington, found it challenging to make wine while young and pregnant, and then after having a newborn. Since her father and other male growers supported her, Schafer did not perceive her role as a winemak-er as unique. She credits her fellow winemakers in the Walla Walla Wine Alliance as wanting her to succeed, being supportive and willing to help. “If you’re there to listen, people are there to help you,” Schafer said.

  Holly Turner, winemaker at Three Rivers Winery, also found support among her fellow winemakers in the Walla Walla AVA. She, too, acknowledged the challenges still inherent in the in-dustry. “I’m pretty sure most women in the wine industry have a bit of feisty grit that has gotten them to where they are today.”

Resources for Women Winemakers

Bâtonnage Community

Winewomen.net

Womenofthevine.com

Preparing for a Successful Harvest

By Dana Hinders

Most vineyards in North America and Europe will harvest grapes in August, September, and October. Typically, sparkling wine grapes are harvested first to ensure lower sugar levels, followed by the white wine grapes. Red wine grapes take a bit longer to reach full maturation, so they’re harvested later in the season. Finally, the grapes for ice wines make their way to crush, as it’s desirable they dehydrate on the vine to create a raisin-like grape with highly concentrated sugars.

  In most cases, a vineyard manager will check the grapes every day during the week or two before the scheduled harvest date because each part of the vineyard must be harvested at precisely the right moment. Matthew Clark, Assistant Professor of Grape Breeding and Enology at the University of Minnesota, says that understanding basic juice chemistry isn’t as difficult as it sounds. “The question is ‘Do I have enough sugar to make my wine product?’ Higher sugar grapes provide you with higher alcohol content in your wine. If there’s not enough sugar in your grapes, you can’t make wine without adding additional sugar. The best way to test sugar levels is with a handheld refractometer, either analog or digital. Each variety has a known point at which sugar levels won’t increase.”

  It’s usually preferable to harvest when temperatures are coolest. The cooler temperatures during the evening hours make grapes firmer and easier to de-stem, as well as creating better working conditions for those in the field. And, by harvesting at night, your grapes will already be closer to the temperature needed during the cold soaking process. “In order to reduce high fruit temperatures during harvest, which accelerates deterioration and demands more energy to cool fruit down further, harvest should be carried out early in the morning when temperatures are cooler or at night if a grower has sufficient lighting,” according to Elizabeth Wahle of the University of Illinois Extension Office. “Morning harvested grapes should be kept shaded until moved to a cooling unit.”

Choosing a Harvest Method

  Traditionally, all vineyards were harvested by hand. Hand harvesting gives you more control over the process and has the advantage of doing a better job of protecting the grape’s juice content from the oxidation caused by damaged skins. Mosbah Kushad, Postharvest Horticulturist at the University of Illinois, recommends hand harvesting if possible. “The biggest concern is fruit injury,” he said. “Damaged fruits enhance the rate of fungal and bacterial growth due to the seepage of their sugars. Damaged fruits also attract insects that could affect the quality of the finished product. For a small grower, hand harvesting is the way to go.”

  The main disadvantage of hand harvesting is the amount of labor required. If you can’t recruit temporary laborers or volunteers from the community, you may need to advertise on a site such as WineBusiness.com. However, Clark stresses that your labor force has to be flexible. “The biggest mistake I see smaller growers making is picking when labor’s available,” he said. “If you arbitrarily schedule harvest for Saturday and the grapes aren’t ready until the following Wednesday, you won’t happy with the results. Garbage in, garbage out is a computer science mantra with relevance to winemaking. For quality wine, you need quality fruit.”

  When hand harvesting, you’ll need to make sure your buckets are cleaned and sanitized before the big day. Sharpen your picking slips and lubricate them with a bit of olive oil. Provide cotton picking gloves for all your workers to protect against small cuts as well as the risk of bee stings.

  Mechanical harvesting is efficient and cost-effective. “Labor availability and quality is a big factor in choosing mechanical harvesting,” says Eric T. Stafne, an Associate Extension/Research Professor at Mississippi State University. “Economics is another. There is a certain economy of scale that makes it worthwhile to have harvest equipment. The market for the fruit may also dictate which method is used.”

  The mechanical harvest method works best for large vineyards that lay on a flat patch of ground, where the rows have been laid out straight, and the posts are of uniform height.  Additionally, harvesters shouldn’t be operated near ditches, embankments, holes, steep slopes, or within 15 feet of electrical wires.  Even for vineyards prepared with mechanical harvesting in mind, it’s always a good idea to do a pre-harvest survey for low hanging limbs, wires, or any obstacle that could obstruct the path of the harvester.

Post-Harvest Essentials

  As a winemaker, you want to avoid “reinventing the wheel” with each vintage you produce. This is why it’s crucial that you keep accurate records throughout the harvest process. Don’t expect to rely on your memory to recall the exact brix and pH you want or your average crop load per vine. Jot down relevant details on a notebook in your pocket or use a voice recording app on your smartphone. When the harvest is over, transfer everything to a spreadsheet so you’re ready for the following year.

  “At a minimum, records should be maintained to monitor vine balance: dormant pruning weights and yields are used to calculate crop load (Ravaz index),” Wahle said. “Over the years, this helps determine the impact of management and fruit quality. Yield can be estimated by keeping track of the number of vines per block, the average number of clusters per vine, and average cluster weights annually at harvest.”

  You’ll also need to tend to your field after your grapes have been picked. “Don’t forget the vines after harvest,” Stafne said. “They may need fungicide and insecticide applications to retain leaves, irrigation during dry periods, etc. to reduce vine stress and promote good health going into fall and winter. This will reduce chance for winter injury and encourage bud fruitfulness in the following year.”

  Vines should be pruned in winter when they are fully dormant. Without the leaves in the way, it’s easier to see the structure of the plant. When pruning, promptly remove and dispose of any diseased wood with lesions or sap, grapes that didn’t ripen, mold, and discolored leaves. Sterilize your pruning equipment by dipping the cutting blades in a solution of isopropyl alcohol after you’ve finished with each vine.

Harvest Time at Adelaida

  Located just 14 miles from the Pacific Ocean, Adelaida’s family-owned vineyards are in the mountainous terrain of Paso Robles’ Adelaida District. “We are one of the oldest wineries in Paso Robles, established in 1981,” explained Glen Mitton, winery and vineyard ambassador. “Our estate vineyards are planted between 1,650 ft. and 1,980 ft. We own the oldest continually producing Pinot Noir Vineyard in the Central Coast, planted in 1964. Our soil is a diverse combination of limestone, chalk, and clay with amazing water retention properties to enable us to dry farm 30% of our vineyards and also 100% of our 700 plus acres of walnuts.”

  The vineyards are farmed with Earth-friendly practices, which earned Adelaida the honor of being named a Certified California Sustainable Winegrowing Winery & Vineyard (CCSW) in 2015. “We pick our grapes based on flavors and condition of plant, as our winemaker is in the vineyard daily,” remarked Mitton. “We hand harvest all of our 157 acres of estate vineyards at night usually starting at midnight. Grapes are placed and transported from vineyard to winery in 20 lb. trays. While each year is different, we find our estate vineyard is a four to six weeks harvest process.”

Harvest Time at Laurita Winery

  Central New Jersey’s Laurita Winery is committed to creating wines that derive as much character from the fruit as possible. They pride themselves on being responsible stewards of the land, with 43 fully cultivated acres of vineyards and 200 acres of woodlands, meadows, and pasture. “We hand pick based on what varieties are ripe at the time,” noted Nicolaas Opdam, Oenologist/Vineyard Manager. “The process is monitored carefully. We take samples for two to three weeks to monitor sugar levels and pH. Since each grape variety ripens at its own pace, we usually have a few days between harvest sessions. This makes us fortunate to have a little flexibility in scheduling our labor force.”

  Laurita Winery employs staff members, their families or friends, and seasonal labor to pick the grapes. The pickers are taught to pay close attention to the vines, only picking the highest quality grapes. A second sorting occurs after picking to make sure damaged grapes or foreign material is removed. Opdam commented, “We’re an old school winemaker.  We watch the weather forecast and the condition of the vines carefully, but there’s a family feel to the whole harvest process.”

Harvest Time at Garvin Heights Vineyards

  In Winona, Minnesota, Garvin Heights Vineyards specializes in the growing of cold climate grapes developed by the University of Minnesota and Elmer Swenson. Made by cross breeding native American varieties with those from Europe, their grapes can withstand Minnesota’s colder temperatures while producing wine similar to what you might find in more traditional growing areas.

  According to co-owner Linda Seppanen, deciding when to harvest involves several factors. “Our primary chemistry considerations are the brix (sugar level) plus the acid level for the style of wine that we are intending to make,” she shared. “Along with this is when we can get a picking crew, what the weather will be, if we are having a lot of bird pressure even through the netting, and when the Asian Lady Beetles numbers are getting bad.”

  To find supplemental labor for their hand picking, Garvin Heights Vineyards enlists the help of local students. They also work with clubs that want to earn money for extracurricular activities, thereby streamlining the harvest process while also helping to support the community.

The Unexpected is Growing in Niagara

grape leave crops

By: Alyssa Andres

As a cool climate wine region, the Niagara Peninsula in Ontario, Canada, is traditionally known for planting specific grape varietals that thrive in a colder climate. The region is known for its delicate Riesling and Cabernet Franc with a distinct note of green pepper. Chardonnay and Pinot Noir are planted widely across the Peninsula and flourish. This is unsurprising since Niagara is situated at the same 43-degree latitude as Burgundy, France. However, that is not all that is being planted in Niagara. Within the region, winemakers and grape growers are experimenting with the unexpected, taking on grape varietals that have never before been grown in Canada.

  It’s true; Niagara is technically a cool climate wine region, but the weather varies dramatically from year-to-year,  just as in Bordeaux. In certain years, temperatures start rising as early as April or May, and early bud bursts allow for an extremely long ripening season. Other years the region can be devastated by frost shortly after temperatures start to rise, and winemakers are at risk of losing entire crops. Summers are warm and even Mediterranean, with days reaching over 100 degrees Fahrenheit. Long, sunny periods leading into the winter let even late-ripening grapes become quite juicy in the warmest of vintages and allow winemakers to create single-varietal expressions of grapes typically known to be hot climate varietals.

  J-L (Jean-Laurent) Groux of Stratus Vineyards is one winemaker that began experimenting with warm climate varietals as soon as he started his vineyard in Niagara-on-the-Lake in 2006. Known for his mastery of the Old World Art of assemblage, when Groux planted his first vines, he included half an acre each of Sangiovese, Tempranillo, Tannat and Mourvedre. He wanted to experiment with what was possible in Ontario, and use this unique combination of grapes to create his Stratus Red blend, an annual release that Groux deems the perfect combination of aromatics, mouthfeel, length and complexity.

  Of the four unexpected varietals, the only one that did not survive the Canadian climate was Mourvedre. Even after being left on the vine until December 21st, the berries were still not ripe enough. However, the other three grapes were successful, including Tannat, which is known to be extremely late-ripening. Traditionally grown in the South of France and now the national grape of Uruguay, Tannat requires excessive heat and sun to avoid being overly acidic and astringent. This means that in Ontario, a lot of maintenance is needed in the vineyard to achieve success with Tannat, and, as a result, it is an expensive varietal to produce.

  All of the leaf removal, pruning, crop thinning and picking of the Tannat is done by hand with the goal of creating the best expression of the grape as possible. Unlike in hot climate wine regions, there is no risk of sunburn for the grapes in Ontario. Pruning must be done early; most of the leaves are removed from the vines in the spring to allow grape clusters complete exposure to the sun. After leaf removal, the crops must undergo a complete adjustment, with the majority of the fruit getting dropped to the ground, reducing yields from approximately six tons an acre down to just two. Yield reduction encourages more quality grapes that are at less risk of being underripe. Frost eliminates most of the leaves by late October or November, but the winter can still see lots of sunshine during the daytime and can lengthen the harvest substantially. The grapes are left on the vine to ripen for as long as possible; most years, Tannat will not be harvested until the second week of November.

  Groux typically uses the Tannat in his Stratus Red Blend to add acidity, tannin and alcohol. If the Tannat is needed for the blend, 100% of harvested grapes will go into it. In some years, however, Groux has been able to produce a single varietal expression of the grape. In 2017, an early budburst and a late harvest meant an amazing yield for Tannat, and Stratus was able to release a 2017 single varietal expression. 2018 brought heavy rainfall during harvest, and, as a result, was a bad vintage for Tannat. However, Stratus managed to produce a 2018 single varietal Petit Verdot that was just bottled this past July. It won’t be until May 2021 that Stratus winemakers decide if the 2019 Tannat grapes will be used in a blend or on their own. This year looks promising for the hot climate grape, with lots of heat and sunshine sweeping across the Niagara-on-the-Lake region so far this summer.

  This year’s weather is also helpful at Ridgepoint Wines in Vineland on the Niagara Escarpment, where winemaker Mauro Scarsellone has been growing Nebbiolo since 1999. The warm weather is a relief for Scarsellone after experiencing harsh winters in Ontario the past couple of years. Cold weather is the biggest issue for Nebbiolo grapes, which need to spend more time on the vine to ripen fully. While the vines can survive the cold, it is challenging to produce a reliable Nebbiolo every year in the Niagara region. To achieve a quality product requires a lot of thought in the vineyard. The yield of the vines will have a significant impact on the wine, so Scarsellone will thin clusters to as few as one or two per shoot. During veraison, if he sees clusters that have not significantly started to ripen, he will drop the fruit to the ground, reducing the yield to as little as one and a half tons per acre. 

  In the hottest years, Ridgepoint can produce single-varietal Nebbiolo that is reminiscent of a Barolo. In cooler vintages, the Nebbiolo starts to resemble a Barbaresco, a softer expression with more elegant, floral notes. The winery is currently offering its 2010 Nebbiolo in the tasting room, a big and bold wine with smooth tannins and a lengthy finish. However, this is not their only unexpected offering.

   Ridgepoint is also offering a sparkling wine made from what could be the only Glera growing in North America. Glera is a Northern Italian grape that is the dominant grape used in Prosecco. By definition, Prosecco must be made using 85% or more Glera and made in the Charmat method. Scarsellone wanted to make his own version of Prosecco from Ontario but could not find Glera vines growing anywhere within the region. He started asking around in British Columbia and even California to no avail. After an intense search, he discovered a grape grower in Stoney Creek, Ontario, whose father was born in Friuli, Italy, and had brought Glera vines over to Canada 20 years prior. Scarsellone bought all the grapes the farmer produced in 2019 to use in his version of Prosecco. The resulting sparkling wine is bright and fruity with notes of mandarin orange, ripe peach and even tropical notes of guava and passionfruit. While technically the wine cannot be bottled under the classification of Prosecco because of labeling laws surrounding the term, it’s an exciting first for the Niagara Peninsula and Ridgepoint Wines. Equally as exciting, 2020 is the first year the winery will grow Glera on-site.

  Scarsellone plans to continue experimenting with classic Italian grapes in his vineyard. He is growing Rondinella and Corvina for use in an authentic style Appassimento, but he says he has to be careful. He currently uses approximately 25% of the vineyard for “sensitive” varieties that run the risk of not making it through to harvest. It’s a balance between an art and a business for him, and each year brings new challenges. This year, he says, he almost put up a “for sale” sign after temperatures dropped and snow hit in mid-May, forcing him to use wind machines to keep frost off the newly budding vines. However, he managed to pull through and is cautiously optimistic about the 2020 vintage. With lots of sunshine, heat and a lack of moisture so far this summer, the berries should be ripe and concentrated as long as there isn’t too much rain throughout harvest. September and October can be tumultuous months for the wine region and can make or break a vintage. 

  Grape growers and winemakers in the Niagara Peninsula can only hold their breath and wait to see what kind of weather the rest of 2020 will bring. Temperatures might rise or fall, and winemakers will have to react accordingly to ensure the quality of their crops. By planting a diverse variety of grapes that thrive well under different circumstances, winemakers can ensure they have a successful harvest each year. From Tannat and Nebbiolo to Corvina, Malbec, Aglianico and Old Vine Foch, it is all growing in Ontario. As this New World wine region continues to grow and blossom, it is becoming more apparent that Niagara is capable of more than just ice wine—it is becoming a world-class wine region for the unexpected.

Carbon Farming for Successful Vineyard Systems

row of vineyard

By: Becky Garrison

At the Oregon Wine Symposium held in Portland, Oregon from February 11-12, 2020, Dr. David Montgomery, MacArthur Fellow and University of Washington professor of geomorphology, presented his work researching and writing about farming methods that use less fossil fuel, fertilizer and pesticides than traditional farming. In his books, “Dirt: The Erosion of Civilizations” and “Growing a Revolution: Bringing Our Soil Back to Life,” Dr. Montgomery digs into the history of traditional farming methods and how these practices negatively impact the health of vineyard workers, the vigor of the soil and profitability.

  Dr. Montgomery advocates that, if we want to feed people in the next century, we need to change agriculture in this century. He cited the United Nation’s 2015 State of the Soil Assessment, which presented a global review of the world’s soils. According to this assessment, each year, the world loses 0.3% of net agricultural production capaci-ty to ongoing soil loss and separation.

  “If we play this out for the next hundred years, we are slated to lose about a third of our agricultural production capacity at a global scale. Our population is slated to rise by about a third,” Montgomery said. Furthermore, about a third of the world’s cropland has been degraded to the point where it’s no longer in production. 

The History of Soil Erosion

  While working on several continents, Dr. Montgomery noticed the connection between the degraded state of soils and the impoverished state of people living in different landscapes. He observed how soil erosion contributed to undermining civilizations around the world, starting with the earliest agricultural civilizations such as Neolithic Europe, Classical Greece, the southern United States Neolithic and more.

  In a review of over 1,500 scientific studies, soil erodes at the rate of one inch every twenty years. At this rate, the soil of a large civilization outside major river flood plains depletes in roughly 500 to 1,000 years. Dr. Montgomery described how flood plains like the Tigris and Euphrates bring sediment and silt, tires, school buses and whatever is coming down the river. “These places can maintain balance, as what the plow takes away on average is replenished by flooding. Nature is fixing the damaged of the plow.”

  His findings debunk the traditional theory of soil erosion found in environment history textbooks, that deforestation led to erosion, which undermined civilizations. “I found out it was the plow that followed that did it. The villain of this tale is tillage.”

  He described soil as akin to a bank account, whereby it is the natural capital that fi-nances civilizations, as it’s used to grow food, wine and everything else people grow from the ground.

  According to Dr. Montgomery, the plow leads to soil degradation because, by design, it inverts soil. “It provides incredibly good weed control, which is why it’s often used in organic systems. A plow takes those nasty weeds upside down and makes fertilizer out of them.”

  In addition, tillage accelerates the breakdown of the organic matter in the soil by stimu-lating microbial activity. In effect, this draws down the batteries of the soil by degrading its organic matter. Also, tillage leaves the soil vulnerable to erosion until the next crop. If this process goes on for long enough, the soil’s organic matter can deteriorate to the point of impacting the fertility of the land, negatively affecting the health of the crop.

Is Soil Restoration Possible?

  “The problem with long-term soil degradation is not that we farm. The problem is the way we’ve been farming. Tillage has been a major destructive element in human histo-ry,” said Dr. Montgomery.

  While traditional farming methods account for the loss of a millimeter to a millimeter and a half of soil each year, no-till farming only erodes less than a tenth of a millimeter of soil during the same period.

  When Anne Biklé, Dr. Montgomery’s biologist wife, turned their degraded yard into a garden, she added organic matter consisting of compost and mulch. After a decade, their yard went from 1% organic matter to 12% in some places. In their book, “The Hidden Half of Nature,” they attributed this shift to the work done by trillions of micro-organisms that were feeding underground. This zone, called the rhizosphere, is one of the most life dense areas on the planet. Dr. Montgomery described the rhizosphere as “a biological bazaar where microbes and plants trade nutrients, metabolites and exu-dates.” Like any living organism that consumes something, the plants metabolize the organic matter and produce waste products like growth hormones.

  Understanding the symbiotic relationships between soil microbiota and plants presents farmers with two very different diets for feeding their plants. The first is the fertilizer diet, where if you give a plant enough fertilizer, even bad soil can produce big yields. How-ever, as Dr. Montgomery assessed, once the plants get all the significant elements they need for growth, they stop investing in their root system. “This means they’re not get-ting as many micronutrients, like zinc and copper, that they need for health, which those microbial partners provide.”

  In comparison, growing plants in healthy, fertile soils that have more organic matter to feed those microbes will produce comparable growth. In addition, farmers get the ben-efits of mineral micronutrients and microbial metabolites. Simply put, organic matter produces higher carbon in the soil.

Principles of Conservation Agriculture

  To assess if these theories could be implemented on a large scale, Dr. Montgomery visited farms in Equatorial Africa, Central America and all across North America. What he found was a common recipe for rebuilding soils.

  First, he said, ditch the plow. Minimal tilling can produce better results, but more car-bon generates when not using a tiller. Second, cover up the soil by maintaining perma-nent ground cover using cover crops and retaining crop residues. Finally, grow diversi-ty. Rotating three to four crops will break up pathogen carryover. In a vineyard, one can achieve this by rotating what’s growing between the vines.

  According to Dr. Montgomery, these principles could be scaled up or down, depending on the farm, within two decades. Restoring agricultural soils in this manner can help increase farm profitability, feed the world, help with climate change and prevent envi-ronmental degradation through non-chemical practices.

How Microbes Relate to the Wine World

  Discussions about terroir focus on climate and soil; however, Dr. Montgomery sug-gests rethinking terroir in terms of the microbes, which are related to climate, soil and geology. “As we examine the relationship between the soil, the vines and the wines people enjoy, we should think about how the microbial ecology is a big part of that foundation.”

  Recent journal articles have begun to cover the landscape of microclimates, including those of a particular vineyard. Microclimates affect the microbes that live in the rhizo-sphere around the roots of grapevines and can carry through to the winemaking pro-cess.

  “Microbial abundance and diversity come into play on leaves, roots and fruit, and then carries on into the fermentation process. How you operate your vineyard will determine what you will have in terms of the fungal community,” said Dr. Montgomery. “Hence, understanding the role of microbial ecology is important for rebuilding soil organically, but also in understanding every step of the wine production process.”

  Addressing the practicalities of soil management in the vineyard, Dan Rinke, proprietor of Roshambo ArtFarm and Director of Vineyard Operations at Johan Vineyards, said, “If you are continuously tilling and depleting organic matter from the soil, those resultant soils are going to be more prone to compaction. But you can have more resilient soil through no-till systems.”

  In Rinke’s estimation, the best way to rotate cover crops is to use a no-till seed drill, which can be rented from some soil and water conservation districts. However, he added that he’d like to see research done in this area to see more comprehensive re-sults using conventional, reduced and no-till means specifically for vineyards.

  More research is needed to confirm Dr. Montgomery’s findings and develop and under-stand the implications for vineyards. For biodynamic farmers like Barbara Steele of Cowhorn Vineyard & Garden, carbon farming is not unique. “Carbon cycling in the soil is the basis of successful dirt farming,” she said.

  Biodynamic practices include building a fresh compost pile every year and growing plants whose sole purpose is to create carbon. “By increasing organic matter in the soil, we slowly increase the cation exchange capacity or CEC (the measure of the soil’s ability to hold positively charged ions), and thus the carbon cycling in the soil,” said Steele.

  For more information about soil health, check out the resources available from the USDA National Resource Conservation Service at…https://www.nrcs.usda.gov/wps/portal/nrcs) and www.dig2grow.com

Liability Coverage for Chemical Drift

helicopter spraying pesticides on crops

Protecting your vineyard from damaging pests and grapevine diseases with pesticides may be an essential part of your vineyard management.  Keeping these chemicals on your property can be challenging even if you have followed all the required procedures.  Nationwide, the EPA estimates up to 70 million pounds of pesticides valued up to $640 million are lost to drift each year .  Drift is the movement of chemicals off your vineyard, through the air away from the intended target, and can be in the form of liquid droplets, vapors, and particles.  You have reason to want to limit drift simply because of the economic consequences, and these chemicals are too expensive to just blow in the wind.  Furthermore, drift that damages a neighbor’s property may lead to litigation. In certain instances, liability insurance specifically designed for chemical spray drift may allow you to mitigate this risk. 

  You have seen examples of herbicide and pesticide drift from agricultural application in the news recently.  Stories abound of alleged damage to neighboring crops, communities, and even bird habitats. If you are growing the same crop as your neighbor is on their vineyard, you may have limited or no impact. However, in certain instances there can be a more substantial impact when your neighbors are raising other crops or livestock, operating an organic farm, or you are adjacent to other susceptible properties like a golf course, an apiary, or a residential community.  Damage has occurred miles away from a farm, so even if one is not next door, one may be nearby.

Why Does Spray Drift Occur?

  Spray drift often occurs when wind or application equipment blows the chemicals off your property.  You may think that drift will only occur when applications are done improperly.  However, even if properly applied, drift may ultimately be unavoidable. Drift can happen days after application when chemicals volatize into gas naturally or due to higher temperatures.  You can minimize drift by using the correct chemicals, properly maintaining equipment, always following manufacturer labels, factoring in the weather, and training employees.

  Despite your best efforts, what happens if your pesticides do drift and damages your neighbor’s crop?  As the growing season approaches, consider ways to properly protect your business from this exposure.

  This article will not address the legal theories surrounding the liability of vineyard operators applying or hiring an applicator.  Courts have differed on finding liability so we will leave the intricacies of the law to others.  Elements of liability aside, if you are alleged to be negligent, you will need a defense.  If found liable, you will want indemnification.  Let’s discuss where to find that coverage with liability insurance.

Insurance

  Every insurance policy is different, so it is important that you read the terms of your policy and discuss them with a professional insurance advisor.  Winery and vineyard policies may include multiple coverage parts including a Commercial General Liability (CGL) part and a Basic Farm Premises Liability (FL) part.

  Standard commercial general liability coverage forms  may contain an exclusion for pollution coverage for ‘bodily injury’ or ‘property damage’ related to the actual, alleged or threatened discharge, dispersal, seepage, migration, release, or escape of pollutants or some similar pollution-related exclusion.  Such exclusions could apply to spray drift claims. Accordingly, consider obtaining an endorsement that provides coverage specifically for chemicals drifting off of your property resulting in damage to someone else’s property, such as their crops or livestock. The specific language in these endorsements vary so it is important that you read the endorsement terms carefully and discuss them with a professional insurance advisor.

  Certain farm premises liability coverages include a limited amount of coverage for damage from chemical drift, which may include drifts that naturally occur during normal farm operations.  However, the coverage may not include drift from aircraft, loss of market, or loss of use of soil and crops. Some farm premises liability coverage forms also exclude discharge from aircraft, which may be a concern if you contract for crop dusting services. Other coverage limitations to the farm premises liability coverages may also apply.

  Commercial general liability and the farm premises liability coverages can be amended to include certain pollution-related coverages.  However, this pollution coverage may require the release of chemicals to be “sudden and accidental” and take place while in “storage or being transported”. Such language may affect the application of the coverage to a drift claim.  Accordingly, you may consider an endorsement specifically designed for chemical spray drift.

Chemical Drift Liability

 A chemical drift liability endorsement may provide coverage for damage to other’s crops and livestock, but an endorsement may also contain policy conditions, limitations, and exclusions.  For example, a chemical drift liability endorsement may not provide coverage for the following:

•    Damage to your own property, crops, or animals.

•    Damage you expected or intended to occur

•    Bodily injury to people

•    Government mandated testing or clean-up of pollutants

  Other limitations and exclusions may also apply. It is important to read the policy and any potential endorsements carefully.

  To obtain chemical drift coverage and to increase the liability limits, your insurance company may require additional information, such as:

•    Demonstrating you have a strong risk management program in place to include proper documentation, employee training, and record retention for at least five years. 

•    A list of chemicals used to determine if any are restricted. 

•    If you are hiring an applicator, they may ask for a list contractors, the total annual cost for those services, and will want to confirm that each is properly licensed. 

•    A review of high risk surrounding exposures (organic farms, public parks, golf courses, schools, churches, apiaries (bees), or other public facilities) neighboring any of the farm locations where chemicals are applied.

  If you are operating a tasting room or holding events at your vineyard, you may be asked to confirm that you are limiting access to the vineyard after an application, and that you are observing re-entry time intervals.

  As with any other winery process, documenting your operations is a good management practice. In the event of a negligence claim, do you know:

•    What brand or product name was used?  Consider keeping a copy of the label. 

•    How much was applied and using what equipment? 

•    Where on the vineyard were chemicals were applied?

•    What crops received the pesticide?

•    The time the application started and stopped?  A best practice would be to document the temperature, humidity, and rainfall too.

  You may also want to review the level of worker training and supervision and ask:

•    Are supervisors experienced with pesticide application?

•    Be sure to document what specific employee training was completed.  Have you kept records to show that you have trained them on the directions for applying each type of chemical used? 

•    Do they know how to use the equipment properly? 

•    Are you doing this each season with each new cohort of workers?

  Spray drift of chemicals is a potential risk for vineyard operators.  Liability insurance specifically designed for chemical spray drift may allow you to mitigate certain types of risk.  For additional questions on chemical drift liability contact your professional insurance advisor.

  This document is intended for general information purposes only, and should not be construed as advice or opinions on any specific facts or circumstances. The content of this document is made available on an “as is” basis, without warranty of any kind. This document can’t be assumed to contain every acceptable safety and compliance procedures or that additional procedures might not be appropriate under the circumstances. 

  Markel does not guarantee that this information is or can be relied on for compliance with any law or regulation, assurance against preventable losses, or freedom from legal liability.  This publication is not intended to be legal, underwriting, or any other type of professional advice.  Persons requiring advice should consult an independent adviser.  Markel does not guarantee any particular outcome and makes no commitment to update any information herein, or remove any items that are no longer accurate or complete.   Furthermore, Markel does not assume any liability to any person or organization for loss of damage caused by or resulting from any reliance placed on that content.

Grapevine Plant Quarantine and Certification Programs

harvest secured with fence
Apparently healthy grapevines growing at the nursery.

By: Judit Monis, Ph. D.

As I write this article, the world is experiencing the SARS-COV-2 pandemic responsible for causing COVID-19 disease.  Generally, I find it difficult to explain quarantine measures.  Today, I am sure that all of my readers might had practiced some sort of “sheltering in place” or “social distancing”.  Therefore, the concept of quarantine will feel closer to home at this time. I am revisiting the quarantine and certification topic as this time; it is expected that my audience will be more receptive to the concepts.

Years ago, when I worked at the United States Department of Agriculture – Animal and Plant Health Inspection Services- Plant Protection and Quarantine (USDA APHIS PPQ), my group learned about the interception of citrus cuttings (intended for planting) that were packed pretending a box of chocolates was in the shipment.  I am sure that you have heard before about “suitcase clones”.  These are grapevine clones that people have brought from abroad before or after quarantine measures were developed  It is my hope, that what we learned about the introduction and spread of SARS-COV-2 world-wide will provide a lesson to people to think twice before breaking the law by introducing plant material without import permits or respecting quarantines. 

  Plant quarantine programs have been developed worldwide to reduce the risk of introducing plant pests and/or pathogens that do not occur in a country or region.  My expertise is plant pathology and throughout my career I have specialized in the study of bacteria, fungi, and viruses that affect the vineyard and fruit orchards.  In spite of the current existence of plant quarantine programs, all grapevine pathogens with rare exceptions occur in all grape growing areas worldwide.  The reason for this is that in most cases, quarantine programs were implemented after the introduction of the infected plant material.  In addition, modern techniques for the detection of these pathogens were developed after the plant material was introduced. In other words, the majority of grapevine pests and pathogens were moved unknowingly. 

  The advancement of science and the use of sophisticated detection methods for grapevine pathogens has helped keep certain viruses outside of Australia.  For example, Grapevine fanleaf (GFLV) and Grapevine red blotch viruses (GRBV) have not been reported in Australia as of yet. But even now with the use of advanced methodologies, pathogens continue to be discovered. As science progresses with the development of more refined technology (e.g., next generation sequencing also known as high throughput sequencing), it is expected that new (or unknown and established) pathogens will be discovered. In practice, most grapevine pathogens have originated at the centers of origin of the Vitis (a plant genus that includes both table, wine, and rootstock grapevine varieties) species and moved to many grapevine growing regions in the word when plant material was introduced. 

  In the United States, the USDA APHIS PPQ regulates the introduction of plant material for planting from foreign countries.  However, the USDA does not have a centralized government plant quarantine system.  Instead, APHIS issues permits to specific clean plant centers with proper containment facilities and approved protocols to manage the quarantine of specific crops. For grapevines, two import centers are available for introducing quarantined planting material: The Foundation Plant Services (FPS) at the University of California at Davis and the Clean Plant Center at Cornel University in Geneva, New York.  

  Since pathogens are present in most grapevine growing areas, certification programs are needed to produce tested plant material that is free of known important pathogen.  These plants are be distributed to nurseries that further propagate and sell them to growers.   In the United States, certification programs are voluntary and are managed by individual states.  I am most familiar with the certification program in California, and many US grapevine growing regions purchase planting material from California nurseries. 

  The Grapevine California Registration and Certification (R&C) Program was first written into law in the 1980’s.   The Grapevine R&C Program is administered by the California Department of Agriculture (CDFA) and provides for the testing of source vines for grapevine viruses that cause important diseases. Registered sources and certified nursery stock are periodically inspected by the CDFA staff and are maintained by the participant nurseries.   Starting in 1996, I participated and provided input at the industry meetings that lead to the revision of the California Grapevine R&C program many years later.   In 2010 the Grapevine R&C program was revised to include testing of foundation mother vines for the presence of a comprehensive list of viruses. With funding from the National Clean Plant Network, a new of foundation block “Russel Ranch” was started at the University of California at Davis in 2009.  

  The planting material (both scion and rootstock varieties) included in the new foundation block had to pass a rigorous testing program and have been propagated using the “apical micro-shoot tip culture” technique.   The apical micro-shoot tip culture process is a plant tissue culture technique that is used to eliminate pathogens from vegetative propagated plant material.  The testing program is known as Protocol 2010.  The maintenance and testing of the scion and rootstock mother blocks are performed by UC Davis FPS personnel.  Shortly after the update of the California Grapevine R&C Program, GRBV, a virus of significant importance for the vineyard industry, was discovered.  Consequently, the California Grapevine R&C Program was revised again to include the testing of foundation and nursery increase blocks for the presence of GRBV.  

  The California Grapevine R&C Program rules can be found in CDFA’s website:  https://www.cdfa.ca.gov/plant/pe/nsc/nursery/regcert.html

  The testing of the foundation mother plants includes a list of well characterized viruses, Xylella fastidiosa, and phytoplasmas using biological, serological, and molecular testing techniques (https://fps.ucdavis.edu/fgr2010.cfm).  The nursery increase blocks are inspected and tested by CDFA personnel.  The nursery increase blocks are only tested for GFLV, Tomato ring spot (ToRSV), and Grapevine leafroll (GLRaV)-1and -3 using the Enzyme linked Immuno assay (ELISA). The updated Grapevine R&C added the testing for the detection of GRBV using the polymerase chain reaction (PCR) to vines in the foundation and nursery increase blocks. 

  Unfortunately, other insect vectored viruses such as GLRaV-4, Grapevine virus A (GVA), GVB are not being tested at the nursery.  Related to nursery certified plants, the rules are vague and state that these plants may be tested (particularly if after inspection suspected symptoms are observed). 

  According to CDFA, the goal is to test a statistical sample with a 95% confidence level assuming a 1 % disease incidence.  It is disappointing that in spite of the importance of the decline and canker diseases caused by fungal pathogens (and how easily the pathogens can be transmitted by activities carried out at the nursery), the regulations do not include inspection or testing for fungal pathogens in mother or increase blocks.  

  In the past few years, the Russell Ranch foundation block became progressively infected with GRBV.  The infection status is so high that last year FPS suspended the sale of plant material to nurseries.  I will not elaborate on this issue as I have recently written about this topic.

  Obviously, in spite of the limitations of the R&C program mentioned above, the use of certified material is expected to be less risky than planting field selections of unknown infection status.  However, it is always prudent to consult with me to assure that the planting material meets the expected cleanliness standards.

  An important piece of advice when working on the procurement of clean planting stock is to plan in advance.  Most nurseries in California collect cuttings for bud wood as soon as the vines are dormant.  However, grafting activities are performed during the spring of the following year.  Planning with time will allow for inspection of the increase blocks early in the fall before a freeze.   Being familiar with the nursery’s operations and their staff is important.  Good communication will help with scheduling inspections and testing of the increase blocks from which bud wood and rootstock cuttings will be collected. 

  Diseases, pathogens, and/or their vectors do not know or respect the borders between vineyard blocks (at the nursery, foundation block, or your vineyard).  Even if the planting material came from a reputable certification program, paying attention to the surrounding vineyards as well as having knowledge of the potential presence of disease prior to planting is important. 

  The planning of a new vineyard is not trivial and requires specialized knowledge.  I am available to help look for suspicious symptoms (inspect scion and rootstock source blocks), evaluate the planting site, develop a testing plan based on science and statistics, and review nursery and vineyard disease testing history.  

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

Grapevines and Water Stress, a Key to Quality

rows of vineyard

By: Dr. Richard Smart, vinedoctor@smartvit.com.au, www.smartvit.com.au

Where is the best place to grow wine grapes,” I am often asked. The answer I give surprises many people. I say, “A cool desert, that is where! Deserts are typically sunny, but should be cool, and with sustainable supplies of irrigation water.” A desert is preferred because rainfall can be a problem for quality wine production.

  There are two significant problems associated with rainfall, both relating to how difficult it is to control, in terms of timing and quantity. Firstly, rainfall induces many fungal diseases on leaves, shoots and fruit, which may have direct or indirect effects on fruit ripening and wine quality. Secondly, and often less appreciated, is that water supply is a principal means of regulating vine growth and physiology to maximize fruit ripening and potential wine quality.

  In brief, we prefer to have slight moisture stress during the period of active shoot growth after flowering to inhibit lateral shoot growth and to limit leaf expansion and size. In association with an appropriate training system, this will help maintain a light, porous canopy—essential for wine quality. Secondly, and critically, we can use moisture stress to stop shoot tip growth in the period just before veraison. This is essential to avoid carbohydrate competition between the active growing shoot tip and the ripening berries.

  If grapes are grown in a desert, of course, we need to irrigate. This gives us a chance to manipulate vine water stress at our will, in the absence of rainfall. The rest of this article discusses how to manage the desired level of water stress.

Irrigated Vineyards

  Irrigation research was one of my first projects when I started a viticulture career in the mid-1960s in Australia. Then, drip irrigation was very new, and I published one of the first studies on the method with wine grapes, comparing drip to flood irrigation.

  This was also a time of new technology for measuring plant and soil moisture. Gypsum block and tensiometers were common then, and soon soil capacitance meters were to be introduced to measure soil moisture.

Evaluating the Pressure Bomb

  In the late 1960s, pressure bombs used to measure leaf and stem water potential were introduced. The pressure bomb was a powerful tool to directly measure plant water stress, and help understand how grapevines respond to soil moisture conditions and the daily pattern of weather conditions.

  After sunset, grapevines recover gradually from the water stress of the day before. Then, at sunrise, the plants begin to experience mild water stress. As air temperature increases, and as humidity decreases, so water stress experienced by the plant increases, being at a maximum in early afternoon. As sunlight levels decrease towards late afternoon, the water stress experienced by the grapevine recovers somewhat, again declining substantially after sunset.

  Our published studies determined a major impact of current weather conditions on grapevine water stress. Grapevines experience the most water stress with bright sunlight, high temperatures, low humidity and high wind speed. These are all conditions that cause the most rapid water loss from the vines.

  As soils dry out, the level of plant water stress is higher during the morning and in the afternoon. However, one must be careful to distinguish the effects of soil moisture from those of higher sunlight, temperature, wind speed and lower humidity. It is challenging to take spot measurements with the pressure bomb during the day to predict soil moisture conditions. Direct measurement of soil moisture profiles is preferred, which are much less variable over the day.

Use of Plant Appearance

  I had almost side-by-side vines with different soil moisture conditions in an irrigation trial I conducted, and I soon learned how the appearance of vines change as they develop water stress. One of the most obvious symptoms is that shoot tips stop rapid growth, and eventually, they stop growth altogether. This symptom relates to moisture stress over several week’s duration.

  Another of the visual effects of water stress is on leaf inclination. Initially, the petioles droop a little, and as stress continues and becomes worse, the leaves first hang vertically and then begin to cup by folding inwards along the main vein.  When very stressed, you will see the backs of several leaves if you look along the row. I was working with the Shiraz (Syrah) variety, and the leaf backs are hairier than the front, so they are easy to distinguish. These symptoms may take several days or a week to develop.

Leaf Temperature Assessment

  This assessment relates to present vine water stress. When vines are water-stressed, stomata (leaf pores controlling water loss on the leaf underside) partially or fully close, and so the loss of water from the leaf ceases. Transpiration (like evaporation) acts to cool leaves. So a sunlit leaf will have a temperature not so different from that of the air, perhaps a little warmer or cooler. However, when the vine is water-stressed, sun-exposed leaves are noticeably hotter than air temperature because the stomata close, and shade leaves are around air temperature.

  I proposed a leaf temperature-based water stress index, which is in Table 1 (Below).  Measurement is suggested in the early afternoon, or when it is sunny and air temperature reaches its maximum. Mid-shoot leaves well exposed to the sun are tested. I suggest pressing the leaf blade between fingertips and palm and quickly sensing leaf temperature on the palm. One must take an instantaneous impression of leaf temperature, as holding a leaf will quickly bring its temperature to that of your hand!

  The reader might be thinking, “Why not use an infrared thermometer to measure air temperature as we have seen used recently to indicate forehead temperature with Covid-19 virus detection?” Indeed, such devices are now quite cheap, portable and accurate, but be careful always to measure leaves with the same angle to the sun.

Conclusion

  Leaf temperature will give an instantaneous measure of vine water stress. In contrast, leaf inclination and shoot tip growth assessment will indicate water stress over the previous two weeks or longer. Therefore, leaf temperature can give a better indication of water stress, and so, irrigation needs, while shoot growth will advise how effective the irrigation has been.

  The clever vine irrigator might believe these visual guides more than those of randomly taken pressure bomb tests to manage vineyards to optimize wine quality. Modern irrigation monitoring is developing systems based on thermal images, either close up or remote, related to my simple system of using one’s hand!