Devise a Home Vineyard Spray Program

So you have decided to elevate your hobby to the point of growing your own fruit for winemaking? This is a huge step that should not be taken lightly. Once you plant that first vine you have entered the world of farming. Farming is by no means something for the faint of heart. There are so many variables that can take the best of plans off course in your wine growing for a season and make for either a mediocre or completely disastrous one. It does, however, enhance your level of appreciation and bring additional understanding for what goes into making a quality bottle of wine. It is said that wine is made in the vineyard. Once you grow your own grapes you really understand why. It also helps you to truly understand what is meant when a wine connoisseur refers to a specific vintage as being a great year and another being lackluster. 

There are many things to consider and understand when having a home vineyard. One of the primary ones is your specific terroir. Terroir is a French word that refers to your specific dot on the map, so to speak. Terroir is your specific micro-climate. It is made up of things like soil types, sun exposure, slope of the land (or lack thereof), typical weather patterns, just to name a few. Your terroir will dictate what you can (or should) grow and what is necessary in your farming practices to be successful. Once you have a real understanding of your terroir you can make educated decisions with regards to varieties of grapes to plant, pruning programs to implement, fertilization and irrigation needs, seasonal vine maintenance (weed control, leaf pulling, hedging, etc.), and pest control. Pest control can come in many forms, as everything seems to want a piece of those wonderful grapes. The focus of this article will be on the smaller pests for which a proper spray program can help keep more of that wonderful fruit for your winemaking.

As terroir is so individualized, just having my perspective (I’m a cold climate grower in the state of New York) would not serve as many home winegrowers as possible. With the desire to make this discussion more valuable, I reached out via social media to fellow home winegrowers across the country to glean some of their experiences as well. I would like to thank Jeremy Fuelling and Barry Simon from Wisconsin, Greg Howard from Oklahoma, and Fred Carbone from California for taking the time to share a bit with regards to their home vineyards.

Why have a spray program for my home vineyard?

This is by far the easiest question to answer. As mentioned previously, wine is made in the vineyard. The volume, but more importantly the quality of the wine produced from year-to-year, is set to a large degree on the day of harvest. Yes, winemaking practices will influence final outcomes but that starting point of the fruit received will make the difference between a great vintage and a just palatable one. So to make the best wines we can we need the best fruit we can get. To get the best fruit, depending on our terroir, we have to compete with diseases like powdery mildew, downy mildew, Phomopsis, anthracnose, black rot, and Botrytis, to name a few. We also need to compete with pests like Japanese beetles and wasps. This is not an exhaustive list but it does provide some of the more common villains.

When should I spray?

Here is where each home winegrower needs to develop his/her specific plan. It truly is based on experience with regards to what has worked historically. The plan, however, is one that should be considered a base plan and one that will need to be varied based on the particulars of what Mother Nature decides will be our weather patterns for this season. If, for example, you have a two-week spray schedule and you spray one day and the next day you happen to get a downpour of rain, you may have to get back out the next day and reapply. 

Based on my experience, and from the input of the other winegrowers, there are some common practices here to consider. One is the application of some form of antisporulant during dormancy of the vines just following pruning/prior to bud break. This is then followed by an active program of regular spraying throughout the growing season. The timing of this spray program can and does vary widely. All of which will depend on the disease and other pest pressure that may be particular to your terroir. The other major factor that will impact the timing of your sprays will be the specific varieties you happen to be growing. Many vinifera varieties are more susceptible to diseases than hybrid and native varieties. This is a very generalized statement, however, and it is important to research the specifics of the varieties you are growing and even then only through experience in your specific terroir can you know the minimum required frequency of your spray application program. 

Try to apply your sprays either early in the morning or in the evening in calm conditions. You never want to spray during the heat of the day for fear of burning the leaves. I personally like to spray just after daybreak. I feel it gives the spray the ability to dry with the morning dew and maximizes what stays on the vines.

What should I spray?

Now that is the question. What is the recipe for your specific vineyard? First of all, research, research, research! I was very impressed at the level of effort that all of my home winegrowing colleagues have gone through to come up with what works for them. The internet, along with social media, can provide a wealth of knowledge and experience in this and most areas of winegrowing (and winemaking, for that matter). This base knowledge can also come from visiting local commercial wineries and speaking with the vineyard manager. Find out what they are growing, what they are spraying, when they are spraying, and what challenges they face. You can also reach out to your local agricultural extension to get information on what is recommended for grapes in your area.

Research the specific varieties you are growing to see if they have any intolerances to specific sprays. Check with the nursery where you purchased your grapevines for suggestions and precautions for spray materials. For example, a number of varieties are intolerant to sulfur applications. This makes it tough if you plan on being an organic grower. Another major component of determining the spray materials you will use is to find out if there happens to be any concerns with interactions of those materials. For example, if you use stylet oil, or any other horticultural oil, you have to be cautious with the use of  some common fungicides such as Manzate, Captan, as well as sulfur. Be careful to follow the precautions with any of these substances. You don’t want your combination of sprays for your vineyard to be a recipe for disaster. Remember why we spray again? We want the highest quality fruit we can get to make the best wine we can. This is hard to do if you burn all the leaves off your vines by spraying something you shouldn’t have. Now let’s look at some real life examples of backyard grape growers’ spray programs:

Fred Carbone (California)

To give some examples of spray programs I’d like to start with what Fred Carbone shared with me regarding his vineyard spray program in Santa Maria, California. “I grow Syrah and Viognier. While the Syrah is pretty bomb-proof, the Viognier is extremely difficult to farm. The translation of Viognier is actually ‘The Road through the Valley of Hell.’ It’s very prone to powdery mildew and late-season Botrytis. I find taking a preventative approach is best and I like to keep it 100% organic. After pruning in February, I do a dormant spray with a lime-sulfur mix to knock out any overwintering spores. This is actually the only time I wear protective clothing and mask because the mixture is pretty caustic. I start my sulfur sprays in the spring after bud break and stick to a two-week interval. In addition to the sulfur applied with a backpack sprayer at 1-cup-to-4-gallon ratio (237 mL-to-15-L), I also add 1⁄2-cup (118-mL) of iron/zinc mix (from Home Depot) and 1⁄2-cup (118-mL) of seaweed extract to the 4 gallons (15 L). The seaweed helps the sulfur stick and provides micronutrients. Tests of the grape tissue used to show deficiency in iron and zinc, which is why I use them. Plus, zinc helps prevent shatter. 

“Once I’ve pulled leaves to open the canopy I typically will only spray the fruit zone with the Syrah but for the Viognier I spray everything. When I do see signs of mildew I use a product called Kaligreen, which is basically potassium bicarbonate. California, in its twisted government regulation, requires an applicator license to spray this 100% organic and incredibly effective product. But damn does it kill the mildew in its tracks. The biggest challenge with the Viognier is actually not the powdery mildew but the Botrytis. It comes on every year no matter what, but I actually like about 10–20% of my fruit to be affected. Although those berries may look like hell, they taste amazing. Timing the harvest then becomes not just a measure of Brix and pH but also a handle on the Noble Rot. 

“October rains are my biggest challenge. I used to have to pick within 10 days of the first rain regardless of my other numbers because the Botrytis would run amuck. Lately, I’ve found adding just a bit of potassium metabisulfite to my Kaligreen spray after a rainfall works wonders and allows me to let the berries hang longer.”

Jerry Fuelling (Wisconsin)

As one would expect in Wisconsin, Jerry Fuelling’s spray program is different in his home vineyard where he grows Brianna, St. Pepin, Lacrosse, Itasca, Marquette, Niagara, Concord, and King of the North. “We always start off good in early spring with Mancozeb. We spray 3–4 times as time permits, or at end of April, mid-May, and mid-June. I like to spray again around the 4th of July if I can. I should be doing this every two weeks but finding the time can be an issue. After the 4th we switch to Captan. I spray this every 2–3 weeks, usually on Sunday evenings. If it’s dry I push the three weeks. If it’s rainy I do every two. For the beetles I spray with Bonide Eight now as I don’t want to kill any bees with Sevin. I spray at the first sight of beetles and will spray 2–4 times or until I don’t see many. We live in a rural subdivision and have farm fields directly behind us so some years the beetles are bad when it’s alfalfa or grass. This year it was corn so beetles were not as bad as past years. I sprayed twice. I would like to start doing a early spring spray of lime sulfur this next year. I don’t know if I do enough here but it’s what I do and seems to work for me.” 

Barry Simon (Wisconsin)

Barry Simon grows Frontenac in Wisconsin. “Early spring at bud break I use Rally fungicide for black rot control every two weeks, weather-pending, up through early June (I haven’t had black rot since 2017 when I began this routine). I start spraying Sevin starting mid-July through August for Japanese beetles. Throughout the growing season I hand pick leaves that have brown marks, odd bumps or eggs to prevent spreading. Usually the leaf picking is done in June, with some in July if warranted.” 

Greg Howard (Oklahoma)

In Oklahoma, Greg Howard grows Noble Muscadine, Lomanto, Norton, Carman, and Enchantment.

“Before bloom and near veraison I apply a mix of fungicide (Abound or Rally) with Medina Hasta Gro as a foliar spray. Then again in April and May. At 3-inch (7.5-cm) shoot growth I apply Mancozeb mixed with Rally before bloom in May. Two weeks after fruit set I apply Abound (May and June). I apply Mancozeb one more time in late May or early June. I use phosphorous acid the first time I notice downy mildew. On my Muscadines I use Captan once I cannot use Mancozeb (August and September). Two weeks after harvest I spray Rally, Captan, and phosphorous acid mixed together and then again in two weeks (September/October).” 

Dominick Profaci (New York)

As for my vineyard in the Hudson Valley of New York, I begin my spray regimen when my spring shoots reach 3 inches (7.5 cm). I utilize a mix of Manzate Pro Stick with either Rally or Quintec. I utilize Rally and Quintec as a preventative for powdery mildew, as Mancozeb does not prevent this all-too-common disease in my terroir. I alternate the use of Rally and Quintec in the mix in a 7–14 day spray schedule depending on the weather conditions. Rally is a sterol inhibitor while Quintec operates on different pathways. These are applied a maximum of three times each per season so as not to allow the disease to build up tolerance to them. In July I switch over to a mix of Captan and monopotassium phosphate (MKP). I apply the MKP at a 2% solution. This foliar-based fertilizer (which enhances root growth and fruit sweetness) also acts as a preventative, along with Captan, for powdery mildew. I typically stop spraying a month prior to harvest so as to ensure little to no residual sprays on my fruit. I grow DeChaunac, Noiret, Corot Noir, Marquette, Vidal Blanc, and recently Regent.

How should I spray?

Spray application comes done to how many vines make up your home vineyard. Do you have hundreds of vines or a half dozen? Match the equipment to the need. If you have just a few vines, a pump up spot sprayer should be all that is necessary. Personally I used a pump up backpack sprayer when my vineyard consisted of less than 100 vines. It worked out fine for that. When my vineyard grew to 200 I quickly found, or my back did anyway, that I needed a different approach. Today I utilize a tow-behind spot sprayer. This has worked out to be much more efficient as I can spray my entire vineyard with one fill up of the sprayer, versus four or more of the backpack unit. Not having to carry it on my back and the unit’s built-in pump that runs off the battery of my tractor helps quite a bit too! 

We also need to be concerned with spray penetration. You can’t really protect your beautiful clusters of grapes from bunch rot if your spray can’t get to them. Back to terroir and variety. Some varieties are more vigorous than others when it comes to vegetative growth. This can also be compounded by your terroir. Do you have rich, heavy clay soils? You may end up with much more green growth than you need to ripen your fruit and that can actually increase the potential for disease. Spray application is primarily done for the prevention of disease and other pest damage. The other preventative measure that you have in your vineyard that goes hand-in-hand with a proper spray program is proper canopy management. To get proper spray penetration of your vines and to allow for air movement and sun exposure (all important in disease prevention) there are times you may need to employ leaf pulling and hedging practices.

So far we’ve been focused on protecting our grapes so we can make a quality wine. Let’s now touch on protecting ourselves from those all-important sprays; which unfortunately are not very good for our health. Let’s talk about personal protective equipment (PPE). The rule should be 0% exposure. That means protective clothing (Tyvek suit) and a full facemask respirator. Here is an area I think most of us can improve on as home winegrowers. Many of us will wear long sleeves and pants, gloves, and a half face respirator. We will also try to spray when winds are calm to minimize the over spray that will reach us. No matter what though, it is inevitable that some of that concoction that works to mitigate diseases and other pests on your vines is going to get on you. My best suggestion here is to go the extra mile that is involved with utilizing the proper PPE. In the end we need to stay healthy so we can enjoy our wines that have aged for many years.

Organic or not, having a spray program is an integral and important part of managing a successful home vineyard. As hybridists work diligently each year to try to develop “no spray required” grape varieties, it is important to remember that the need and extent of spraying required for every grape variety is terroir-dependent. Yes, a “no-spray grape” variety may be more disease-resistant than other varieties, and that’s a good thing. But, like other “marketing,” take it with a grain of salt and remember that in the end our pursuit is the highest quality grape we can produce in order to make great wine. If it requires you to spray something to protect that fruit, as long as you do it properly, it’s OK. 

Common Sprays for Viticulturists

Fungicides

JMS Stylet Oil
JMS Stylet Oil provides post-infection, antisporulant, and eradicant activity, and modest protectant activity, against powdery mildew, with low risk of disease-resistance development. Use in a 1 to 2% solution, and do not concentrate beyond 2% (2 gallons product per 100 gallons water/7.6 L per 380 L). JMS Stylet Oil provides significant eradicant activity against existing powdery mildew infections, but thorough spray coverage is essential for effective control. Should not be used within two weeks of sulfur application. Other brands may be labeled “horticultural oil,” read the label for details. Some oils are listed by the Organic Materials Review Institute (OMRI) as suitable for use in organic growing.

Sulfur
Sulfur is an organic plant fungicide that is a finely ground wettable powder. It is effective against powdery mildew, rust, scab, brown rot, black spot, and many more.

Mancozeb
Mancozeb provides protectant control of black rot, downy mildew, and Phomopsis. Mancozeb is a combination of two other dithiocarbamate fungicides, maneb and zineb. It is a broad-spectrum fungicide with low risk of disease-resistance development. Applications of mancozeb should end a minimum of 66 days prior to harvest.

Captan
Captan provides protective control of Phomopsis, downy mildew, and various “summer rots.” It is a broad-spectrum fungicide with low risk of disease-resistance development. Captan can cause plant injury if applied with other oils, liquid insecticides, and some surfactants. Do not apply with or following a spray of JMS Stylet Oil, and do not apply JMS Stylet Oil within 10 days of application.

Abound
Abound provides very effective control of powdery mildew, downy mildew, and black rot; moderate control of Phomopsis; and slight control of Botrytis, with a high risk of disease-resistance development. Abound is a strobilurin fungicide, and powdery mildew and downy mildew resistance to the strobilurins is known to occur widely in the Eastern United States.

Rally
Rally provides effective control of powdery mildew, black rot, and anthracnose with post-infection, antisporulant, and limited protectant activity, with moderate risk of disease-resistance development. Apply on a protectant schedule that does not exceed 14 days, or within 72 hours of a black rot infection period. Rally is a sterol inhibitor (DMI) fungicide, and powdery mildew resistance to the DMI fungicides is common where they have been used for several years. Use a good resistance management strategy in your vineyard by limiting the number of DMI applications to a maximum of three per year, and use a rotational program with other non-DMI powdery mildew fungicides. Rotating with other DMI fungicides is NOT an effective disease-resistance management approach. It has a 12-hour re-entry interval, and should not be applied within 14 days to harvest.

Quintec
Quintec provides excellent protectant control but no post-infection or eradicant control of powdery mildew. Quintec is unrelated to any other grape fungicide registered in North America, so it controls powdery mildew colonies that are resistant to other fungicides and is useful in a powdery mildew resistance-management program. However, Quintec is at risk for disease-resistance development, so it should be used no more than 2–3 times per season in a rotational program with other effective powdery mildew fungicides. It has a 12-hour re-entry interval, and should not be applied within 14 days to harvest.

Kaligreen
Kaligreen is a contact-type fungicide for the control of powdery mildew. It contains microencapsulated potassium bicarbonate as the active ingredient and direct contact with the fungus is absolutely necessary for control. Potassium ion balance in the fungus cell is broken by Kaligreen; cell walls collapse, shrinking the cells and destroying the fungus. Kaligreen is OMRI-listed.

Phosphorous Acid
Phosphorous acid fungicides provide moderate protectant, post-infection, and antisporulant control of downy mildew. Protective activity against infections is limited to 3–5 days after application, with significant post-infection and antisporulant activity; spray intervals should not exceed 10 days during periods of wet weather. Downy mildew resistance is known to occur in many growing regions. Do not apply in more than two consecutive applications before rotating with another downy mildew fungicide, and do not apply more than four times per season. Some varieties are susceptible to leaf burn so test for sensitivity prior to use. It has a 4-hour re-entry interval and can be used up until harvest.

Medina Hasta Gro
Three products in one, Medina Hasta Gro contains high-quality N-P-K plant food plus Medina Soil Activator to stimulate biological activity, and HuMate humic acid to improve the soil structure by improving nutrient uptake, and seaweed extracts to stimulate fruiting and blooming. It is ideal for foliar applications where nutrients are absorbed directly by the plant. Low-salt, low-chemical formulation prevents leaf burn. Nitrogen is derived from clean urea sources and is complexed with humic acid.

Monopotassium Phosphate
Monopotassium phosphate 0-52-34, MKP, (also potassium dihydrogenphosphate, KDP, or monobasic potassium phosphate), KH₂PO₄, is a soluble salt of potassium and the dihydrogen phosphate ion. It is a source of phosphorus and potassium as well as a buffering agent. It contains 52% phosphorous and 34% potassium, and is water-soluble. Can also be used as a fungicide at a 2% solution.

Pesticides

Sevin
Sevin Concentrate insecticide utilizes the active ingredient of Zeta-Cypermethrin that kills upon contact and visible results are seen within minutes, while having a residual kill of up to 3 months. (Older versions of the pesticide named Sevin employed the active ingredient carbaryl.)

Eight
Eight Insect Control is a permethrin concentrate for insect control. It controls over 100 different pests. A drawback is that it is lethal to bees.

Assail
Assail controls many insects including leafhoppers, grape berry moths, mealybugs, grape Phylloxera (aerial form only), banded grape bugs, rose chafers, and Japanese beetles. It is a neonicotinoid insecticide, a class of products that represent risk to butterflies and bees. Do not make more than two applications per season, do not apply more than once every 14 days, and do not use spray adjuvants. It has a 12-hour re-entry interval and should not be used within three days of harvest.