Industry Reviews

On Target Spray Systems has been met with numerous positive reviews about the technology and results by leading industry publications.

Targeted Spraying In Apple Orchards

Feb 2014 Western Fruit Grower • Growing Produce

For many years, On Target Spray Systems, a manufacturer and distributor of electrostatic sprayers based in Mt. Angel, OR, has been focused on the grape and berry markets. Recently, however, it has turned its attention to apple orchards.
“After many discussions with apple growers, we learned that there was a need for a new way to spray in these high-density plantings,” says Willie Hartman, owner of On Target Spray Systems. “Two years ago we modified our designs for high-density tree fruit growers. " View Article →

Citrograph • Reduced costs with Electrostatic

Winter 2014; Citrograph

More and more California growers are now turning to electrostatic sprayer technology, which is enabling them to save money via reduced time, water, labor, fuel and material. Additionally, the newer spray technology is much more environmentally friendly. With standard equipment, drift is a serious problem that can affect non-targeted organisms and may occasionally be detected on plants and animals miles away from the application. " View PDF →

Electrostatic sprayer to benefit smaller growers

October 2012 • Grapegrower & Winemaker

"The latest machine by On Target Spray Systems combines the latest technology with a price that won’t send small growers running." View PDF →

Electrostatic sprayer hits the spot

October 2012 • Grapegrower & Winemaker

"A vineyard sprayer that works on the premise of ‘opposites attract’ has been given the thumbs up by one of Australia’s most respected winemakers." View PDF →

New Electrostatic Sprayers for 2012

January 2012 • Wine Business Monthly

"ON-Target had been approached by numerous small growers (5 to 8 acres) who had embraced the science of electrostatic spraying but were limited by the size of their vineyards or tractor horsepower or had narrow row spacing issues or were on a limited budget. Enter ON-Target's new design, the Cube™." View PDF →

New Narrow Row Electrostatic Sprayer

August 2010 • Wine Business Monthly

"In a September 2009 product review, I wrote in-depth about new generation electrostatic spray rigs. At the time virtually every academic I interviewed (from those in the agricultural engineering departments at the University of Georgia and UC Davis to Fresno State's director of viticulture) said the future of chemical application was electrostatic." Read more →

New Narrow Row Electrostatic Sprayer

By Bill Pregler

In a September 2009 product review, I wrote in-depth about new gen- eration electrostatic spray rigs. At the time virtually every academic I interviewed (from those in the agricultural engineering departments at the University of Georgia and UC Davis to Fresno State's director of viticulture) said the future of chemical application was electrostatic. Even the people at the California Department of Pesticide Regulation (CDPR) liked the technology.

Years ago the units had problems, but all early R&D kinks have been ironed out, and today the equipment delivers incredibly precise chemical disposition. Naturally, it was only a matter of time before even these new designs began to evolve.

Enter a new rig, On-Target sprayers from Progressive Grower Technologies, Inc. in Wilsonville, Oregon. Already a major supplier to a wide spectrum of crops from orchards to strawberries, they continue to focus design energy on vineyards. No sooner did I walk onto the exhibit floor at this year's Unified Wine & Grape Symposium than I saw their latest entry. They currently make sprayers for larger vineyards, but the new units are specific to narrow row (4 to 6 foot), high-density plantings.

At a narrow 32-inches wide, this sprayer's target market is definitely the small grower who trellises his grapes on hillsides with tight turning radiuses. It is com- pact, lightweight and carries only 70 gallons. That does not sound like enough, but with the precise spray coverage of electrostatic technology, it is plenty. Less weight also means smaller tractors. The unit I saw was compatible with a 25 Hp— PTO John Deere Model 790 tractor.

This new unit comes with either single row application (spraying left and right) or overhead booms to cover two rows at a time.

Electrostatic spraying is for those concerned about saving water, spending less on chemicals and labor, noise problems with neighbors and getting the best appli- cation possible. The concept is similar to powder-coating a car.

Automakers have been using electrostatically charged paint for some time. In the wine world, the concept is now the same. The grower gives the chemical- water spray ("paint") an electrical charge and directs it to the "grounded" vine.

It works because of Coulomb's Law, which states opposite charges attract and like charges repel. The key is to atomize the mixture to 30- to 50-micron droplets versus 250 microns for a typical air-blast sprayer. Chemical, water and air are com- bined in a shearing action from air-assist nozzles. This atomized solution emerges as a "mist" of chemical in a low pres- sure, low volume concentration.

Once inside the canopy, the spray will swirl and actually reverse direction, attaching to the backsides of the leaves. Also, since the droplets are all the same charge, they repel. They will not collect into large droplets, which typically run off onto the ground. The spray continues to circle until the entire surface is covered. The charged mist is drawn to the leaf, similar to dust on your records or metal filings to a magnet. You have essentially powder-coated your vineyard.

Hence the savings: considerably less water and chemicals without costly over- spray and runoff. According to some growers, the efficiency of electrostatic tech- nology reduces water usage by 75 percent while using only 30 percent of chemicals. This means you go further into the vineyard with one load and keep your driver spraying and not driving for refills.

The On-Target sprayer uses a quiet Kaeser blower instead of vein fans. The sound of the tractor is actually louder than the sprayer. The German-made blowers are highly reliable and use stain- less rotary lobes. Maintenance is almost none, and I was told using synthetic oils can extend operating time to 5,000 hours.

The small-aperture nozzles of electrostatic sprayers must be thoroughly flushed after use. Also, since electronics are at the heart of the system, each nozzle should be checked for proper voltage. A volt meter is included, but a simple in-field test is to turn on the spray and then alternate the on-off electrical switch. The operator will immediately see the change in the spray disposition. I personally watched as the "cloud" was immediately pulled into the canopy.

Progressive Grower Technologies, Inc. is an O.E.M. manufacturer and therefore can custom-fabricate for specific applications. They make much larger rigs (up to 600 gallons), but these new condensed units help spread the science to the smaller grower.

What's Cool: It is terrific when a great technology continues to evolve and starts reaching out from orchards to row crops and vineyards. Even better, electrostatic spray rigs are now getting more compact and affordable for those growers with small, difficult-access vineyards.

I like the concept because it is efficient and judicious in water and chemical usage. And because the chemical application is so precise and targeted, growers report better overall results, which translate into even less spraying. It is fasci- nating to attend a demonstration and watch the mist separate and move into a canopy: No blast, no overspray and no noise.


Industry Profile: ON-Target Sprayers

May 2009 • Industry Innovation

"The ON-Target Sprayer uses a patented spray nozzle that creates the perfect spray drop. Optimal size and concentration, coupled with a high electrical charge provide unparalleled spray coverage. The unique scientific properties of electrostatic water droplets ensure consistent spraying and, as such, reduce water and chemical usage." Read more →

Industry Profile: ON-Target Sprayers


Advantages: The ON-Target Sprayer uses a patented spray nozzle that creates the perfect spray drop. Optimal size and concentration, coupled with a high electrical charge provide unparalleled spray coverage. Th e unique scientifi c properties of electrostatic water droplets ensure consistent spraying and as such, reduce water and chemical usage. In addition, the reliable chemical distribution created by the ON-Target sprayer equates to increased productivity and application effi ciency.

What Growers Have to Say:

Richard Bennett, blueberry grower - Arvin, CA

My current operation includes 100 acres of blueberries and I've been using an ON-Target sprayer. I spent quite some time looking at sprayers and found that an electrostatic machine would be the most effi cient. I researched a number of options and ultimately decided that ON-Target was the best option available.

The ON-Target sprayer produces a very fi ne mist with a consistent droplet. After using traditional spray systems over a number of years on not only blueberries but cherries and other crops, I was frustrated with the machines' inconsistencies.

Regular sprayers produce water droplets of varying sizes which means irregular chemical applications. As a result, you use a higher volume of water and chemicals, which costs time and money. Th e ON-Target sprayer eliminates that issue by providing a uniform droplet.

An added benefit is that the rig itself is very quiet and easy to maneuver, so I've been able to use it at night without having issues with neighbors. ON-Target also provides exceptional customer service. A technician came out, helped me set the sprayer up and is willing to come on-site as needed to assist with maintenance and troubleshooting.

Overall, the ON-Target sprayer has been the right decision for my operation. I plan on using it next in mandarin grove and expect to see the same consistent performance and reduction in water use and chemicals as I see now with the blueberries.

Joe Coehlo, DB Specialty Farms, strawberry grower – Santa Maria, CA

DB Specialty Farms grows 730 acres of strawberries in Santa Maria, CA, northern Santa Barbara County. One of our greatest issues has been the inconsistent delivery of water and chemicals to the underside of our strawberry leaves. In our part of the state, we battle the two-spotted spider mite and the underside of the leaf is where these pests reside.

Conventional sprayers would create a mist that resulted in defl ection off other leaves, but water was not actually hitting the under surface. As a result, in 2008 I spent upwards of $915 per acre in miticides alone. After last season, it was very apparent that I needed to consider other options.

We tested the ON-Target sprayers, along with other electrostatic systems. Going with ON-Target became a relatively easy decision given the ease of operation and maintenance, along with the rig's overall reliable performance. Other electrostatic sprayers required two to three hours of maintenance and cleaning after each use. My crew and I just don't have that kind of time.

In addition, the uniformity of the spray droplets has had a transformational impact on tackling the twospotted spider mite issue. Not only does the ON-Target sprayer ensure that the miticides reaches the underside of the leaves, but it also uses less chemicals. We had almost a 100% kill rate following our fi rst application using this new sprayer. I honestly can't say enough good things about it. It really is the best investment we've made in managing the extreme pest pressure we battle every year.

Brian Wallingford, Mesa Vineyard Management, winegrape grower - Templeton, CA

Mesa Vineyard Management oversees vineyards all along the Central Coast, in Monterey, San Luis Obispo and Santa Barbara counties. In total, we manage approximately 5,000 acres of winegrapes across the three counties. Six years ago, one of our Shandon growers began using an ON-Target 3-row sprayer and from the very beginning, had nothing but good things to say about the machine.

Since then, a number of managers have invested in ON-Target machines. Th e primary reason for switching was the system's use of ultra-low volumes of water and chemicals in correlation to the ample plant coverage. I currently operate a 300 gallon sprayer that operates at 15 gallons per acre, allowing me to cover 20 acres in one pass as opposed to just 10 acres with a traditional rig.

The electrostatic properties are key, making uniform water droplets that adhere to the plants. The efficiency correlates directly to the reduction in water use. For instance, at our San Ardo vineyard, we were battling an outbreak of the pacific mite starting back in 2004. At the time, using a conventional sprayer, we were applying treatments up to five times. Once we purchased the ON-Target sprayer, we were able to reduce applications down to three, two and now only once each year to treat for pacific mites.

We noticed the reduction in water use almost immediately. We went from applying over 100 gallons per acre down to only 30 gallons per acre. That type of decrease has meant that the machine has paid for itself in just two years. When you consider the savings from water use, that we are now using the low end rates for all fungicides - which also saves money – and our labor efficiencies, the ON-Target sprayer is well worth the up-front costs.

Eventually, as rigs wear out and need to be replaced, we'll outfit the entire company with ON-Target sprayers. It just makes good business sense since nothing else works like it.

James Deville, J&L Farms, winegrape grower - Bradley, CA

J&L Farms is currently growing 1,600 acres of winegrapes for Lockwood Vineyard and another 1,300 acres for Diageo Chateau Estate and Wines. We've got 5 ON-Target sprayers used on all of the vineyards. Given the number of plots we manage, it was important that we have a system that was efficient, easy to transport from location to location and worked reliably.

We currently operate on a 10-day spray schedule, 60 acres per day per machine, for a total of 300 acres each day. The ON-Target system enables us to maintain our schedule without wasting time, water or materials. The coverage of the machines is unlike anything else. The electrical charge ensures that the drop sticks to the bottom of the plant's leaves, ensuring the water and applied chemicals are properly absorbed.

The current machine uses 15 gallons per acre of water and chemicals. At one point, we conducted our own test to determine the highest efficiency and ran 15 gallons per acre, 20 gallons per acre and 50 gallons per acre through our machines. Ultimately, at 15 gallons per acre we saw the needed results without compromising the plants. This saves time and money for water, chemicals and labor.

For some growers, the cost up front can be a factor in not considering ON-Target. In the end, I think you come out ahead by having this sprayer. The amount of money you save in fertilizer and other chemicals, water, man-power and maintenance makes it worth it. These machines require about 20 hours of upkeep each year, which may seem like a lot compared to other rigs, but again, the time is worth it for the results. Even taking more time to maintain them, you still save more money in the long run by reducing the number of times and amount you spray. I haven't found anything that works better.

ON - Target Testimonials

Clos du Bois Vineyards / Doug Price, Viticulturist Keith Horn, Vineyard Manager

"We started testing the ON-Target spray nozzles in the 1990's and now have three systems," said Doug Price. We now get better coverage and use less water than in the past," added Keith Horn. "We reduced water use from 50 gallons per acre to 20." Horn also stated that this also reduces labor costs since there are fewer re-fill trips needed. How does Clos du Bois feel about ON-Target's effectiveness? "We are using it for all our fungicides and some insecticides," said Horn. Recently, the vineyard has been very successful controlling powdery mildew, a serious California grape disease. He credits the system's better coverage, even on the leaf's underside, for improving their control of the mildew. They also use the sprayer on their two leading insect pests, the leafhopper and mites, though the later is not a problem every year. They have seen hopper populations drop 80-90% with ON-Target system's coverage.

Chalk Hill Winery / Kevin Koebsell, Manager

"In order to foster better relations with those living close to our operations, we felt it imperative that we minimize both the spray drift and the noise generated by our spraying. The ON-Target sprayer we purchased did both jobs beautifully. Not only was drift virtually eliminated but the noise of the sprayer could not be heard above the tractor's engine. Couple this with the fact that we have reduced our spray rates by 25 to 30% as opposed to our conventional sprayers and you have a classic win-win situation."

Jackson Family Wines / Brandon Axell, Manager

We have been very impressed by the spray coverage that is provided with the ON-Target electrostatic system. Progressive Grower Technologies helped us build a full three row sprayer and we are able to cover acreage fast with great spray penetration and low water volume usage. We have used the lower recommended rates with all products and have been successful in having no mildew or botrytis issues. This system is also a plus to use for our neighbor relationships, there is minimal drift potential and noise is basically no louder than the tractor engine.

Michel-Schlumberger Wine Estate / Mike Brunson

Mike Brunson finds the ON-Target nozzle a perfect fit with their more sustainable approach to growing. "This is exactly the product we were looking for," said Brunson. He is even using the system for materials he never imagined. The first success was controlling diseases such as botrytis, phomopsis, and mildew.


Vineyard Showcase - Progressive Grower Technologies, Inc.

March/April 2009 • Practical Winery & Vineyard

"ON-Target offers electrically-charged sprayers for growers in the vineyard, orchard, row crop, and nursery industries. For more than 10 years, Progressive Grower Technologies (PGT) has improved the sprayers and expanded to include the western U.S., Australia, and South America." Read more →

Vineyard Showcase - Progressive Grower Technologies, Inc.

On-Target offers electrically-charged sprayers for growers in the vineyard, orchard, row-crop, and nursery industries. For more than 10 years, Progressive Grower Technologies (PGT) has improved the sprayers and expanded to include the western U.S., Australia, and South America.

On-Target sprayers produce billions of electrically-charged spray drops per minute. All charged-drops are attracted to a plant, resulting in unequaled coverage and uniformity, and radically reducing drift and runoff, which are the most wasteful and costly elements in any spray program.

On-Target sprayers are designed and fabricated in Oregon. The stainless steel construction is compact and of the highest quality. With this design comes flexibility; unlimited adjustment capabilities for single - or double - row, running parallel with any trellis system for uniform coverage.

Growers have experienced reduced application time, pesticide quantity, and risk to employees - a great advantage over traditional spraying methods.

The On-Target system has proved itself to be efficient and reliable, spraying more acres in one day than any other sprayer.


Sulfur-free in Alexander Valley

March/April 2006 by Mark Greenspan • Practical Winery & Vineyard

"Sulfur has not been applied in the vineyards managed by Jim Cuneo, assistant vineyard manager, during the past three years. He does not miss it one bit. Cuneo manages the pesticide program on 317 planted acres in the Alexander Valley for Robert Young Vineyards (Geyserville, CA)." Read more →

Sulfur-free in Alexander Valley

By Mark Greenspan

Sulfur has not been applied in the vineyards managed by Jim Cuneo, assistant vineyard manager, during the past three years. He does not miss it one bit. Cuneo manages the pesticide program on 317 planted acres in the Alexander Valley for Robert Young Vineyards (Geyserville, CA).

A presentation by an agricultural chemical distributor early in 2001 piqued Cuneo's interest in using JMS Stylet-Oil for powdery mildew control. Previously, micronized sulfur was applied at a rate of two pounds per acre per application.

Cuneo and Jim Young (owner), were interested in reducing or eliminating dusting sulfur to control powdery mildew disease, out of concerns by winemakers of sulfur residues in their grapes. Jim Young set a goal in 2000 to eliminate all dusting sulfur, due to concerns about drift when sulfur-dusting. Not to mention that Cuneo is somewhat sensitive to sulfur as are members of the vineyard-crew. This is a situation that many of us are in, but tend to keep quiet about it, thinking that sulfur is just a fact of life in vineyard management.

JMS Stylet-Oil is a highly refined mineral oil that controls powdery mildew disease by smothering the fungus, Uncinula necator, which causes the disease. The product is very simple - just the oil along with emulsifying materials. There are both organic (listed by the Organic Materials Review Institute) and non-organic formulations of JMS Stylet-Oil. For grapes, it can be applied as a 1% to 2% emulsification with water.

Dr. Doug Gubler, Extension Plant Pathologist at U.C. Davis, has compared Stylet-Oil against sulfur and other chemical fungicides and found Stylet-Oil to be highly effective when used at a 14-day interval at a 2% concentration. Cuneo chose to use it at the lowest recommended concentration (1%) at a rate of 30 gallons of water spray per acre.

"Many oils are registered including OMNI oil and SAF-T-CIDE," says Gubier. "However, even through these work, they have higher phytotoxicity risks. A new product very similar to JMS Stylet-Oil is "Green" that works just as well and is also highly purified."

First trial in 2001

While mineral oil provides an opportunity to reduce or eliminate sulfur application, Robert Young Vineyards has a strict zero-tolerance policy on powdery mildew, so they did not want to take the plunge into mineral oil before testing it. JMS Stylet-Oil was applied in the 2001 growing season in a 20-acre block of Chardonnay, which had a history of being a bit of a problem with regard to powdery mildew.

"Beginning at budbreak, we applied the material at 14-day intervals, adding copper to the spray tank for the first three passes in the growing season," explains Cuneo. "Copper provides additional mildew control, and helps with frost protection. After the first three applications and up through veraison, JMS Stylet-Oil was mixed with a rotation of systemic demethylation (sterol) inhibitors (DMI's) or maintaining a 14-day application interval."

They have two Adcon weather stations that monitor weather and canopy conditions on the ranch. The data is entered into the UC Davis Powdery Mildew Risk Assessment Model that determines the risk of mildew infection based on the pathogen's reproductive rate. The model allows Cuneo to decide if and for how long to stretch spray intervals. However, Cuneo feels the 14-day interval has worked well as a rule of thumb and that it facilitates manpower and equipment scheduling.

In other vineyard blocks that did not receive oil applications, the fungicides were mixed with elemental (micronized) sulfur materials at 2 pounds per acre, per their standard practice. The result: no mildew problems in the test block. Nor were there any mildew problems in the sulfur-treated blocks, indicating that the mineral oil performed as well as the sulfur did that season.

2002: Expansion to larger acreage

Their positive experience in 2001 led them to expand their no-sulfur program to all of the vineyard acreage at one property on the east side of Alexander Valley. The 67-acre ranch has Merlot, Chardonnay, and Syrah and includes the original 20-acre trial block. It was largely successful that year. there were some powdery mildew outbreaks in many of their vineyards that year, regardless of whether sulfur or mineral oil was applied.

"Outbreaks consisted of a cluster or berry here and there," reports Cuneo, "and an occassional vine where many clusters were infected." Bottom line: JMS Stylet-Oil performed at least as well as the sulfur did in 2002.

Spraying equipment

A lightweight spray rig was purchased to allow all-season access with less soil compaction. They purchased a Rears 100-gallon sprayer (which they generally do not fill completely to reduce the weight). They customized an over-the-row boom to adjust for 6-foot or 8-foot tractor-row spacings. Two of these sprayers are used today, each pulled by a Polaris 6x6 all-terrain vehicle (ATV).

The Rears sprayers can cover two rows in one pass. They are pulled with either a six-wheel Polaris ATV with tracks in valley floor vineyards or with a crawler tractor on hillside vineyards. These sprayers are used up until 18 inches of shoot growth.

They switch to a 200-gallon electrostatic sprayer (for the valley floor vineyards) with On-Target nozzle assemblies, which can be adjusted to spray only the extent of the vine growth at that time of year. the manifolds are adjusted to spray only the extent of foliage and a wider band as shoot growth continues. Cuneo has been very pleased with the coverage that this nozzle arrangement has provided. They began using an On-Target sprayer in 1995 and upgraded the system in 2001.

2003-2005: No more sulfur

Success in their trials led them to expand mineral oil application to the entire vineyard acreage. The previous wettable sulfur and fungicide program was substituted with JMS Stylet-Oil and fungicide applications in 2003.

Cuneo reports a complete success. Not a miracle, mind you; they still have some spot outbreaks of powdery mildew, which they deal with by dropping fruit or by washing with Kaligreen. (In retrospect, the oil could have been used as an eradicant "wash" instead of applying Kaligreen.) But that had been their experience with sulfur also. Net gain: no sulfur drift, no respiratory irritation, and no sulfur residue on the fruit.

Benefits beyond mildew control

While the goal of using mineral oil was control of powdery mildew, the product also has beneficial insecticidal properties. Pacific mites had been a problem in many of their blocks, usually requiring one or two applications of miticide for control. In the 2001 trial block, mites were not a problem where treated with mineral oil and that block required no miticide treatment, unlike some of the sulfur-treated blocks, some of which did require miticide applications.

In the years preceding the trial, agrimek and/or Nexter were needed as applied twice to control mites, 100 acres being treated in 2001 and 30 acres in 2002. In subsequent years, when mineral oil was used in all of their vineyards, it was found that mite populations were much less of a concern compared to previous experiences.

There were some mite hotspots in 2003 and in 2005 (but none in 2004) which required one or two miticide applications. Twelve acres required miticide treatment in 2003 and 50 acres in 2005. But the hotspots were well-defined and the mite infestations less severe than in previous experiences or in comparison to what their neighbors encountered during those same episodes.

Although it appeared that JMS Stylet-Oil seemed to have some suppressive effect on mite populations, they wanted to know if it could be relied upon for that purpose. They tested this by applying mineral oil at a 2% rate on a few mite-infested rows in 2005. To their dismay, it did not suppress the population sufficiently to justify use as a miticide. However, they remain encouraged that it helped to reduce their overall need for miticides in the vineyards.

Another benefit found was that of leafhopper suppression. The mineral oil suppressed populations of leafhoppers, minimizing the need for a pre-harvest application of Provado.

Downside to mineral oil

There are caveats to mineral oil application - sulfur cannot be applied within 14 days of JMS Stylet-Oil application or vice versa, or any potential hot weather that could toast the leaves to a crispy crunch. That is clearly stated on the product's label.

With or without sulfur, spraying in hot weather can cause over-heating and burn of oil-treated foliage. Cuneo's crew begins spraying at midnight and continues until morning in order to apply the material under the coolest conditions. Spraying is halted at 11 am, or earlier if the temperature reaches 800F as a precaution.

Cuneo reports using the lowest recommended concentration (1%) in their spray, and he thinks that the lower concentration helps to avoid heat-related foliar damage. He has seen no foliar damage in their oil-treated vineyards with temperatures into the 90's when spraying is has been halted before 800F is reached.

Another minor downside to mineral oil was that spray volume by electrostatic sprayer increased 50%, from 20 gallons per acre to 30 gallons per acre. This would necessitate more spray-tank refills, but did not seem to be a serious issue to Cuneo. Also, material cost is somewhat higher with mineral oil than sulfur. Cuneo's material costs increased about $1.50/acre per application when changing from micronized sulfur to JMS Stylet-Oil. Growers using a higher rate of sulfur than two lbs per acre will see less of an increase in material cost.

Cuneo mentions another downside to using mineral oil - it tends to coat some of the waxy bloom on berries, giving it the appearance of having water spots. Neither he nor the winemaker are concerned about this cosmetic effect. In his lab, Dr. Gubler found that the presence of residual oil had no negative effects on yeast growth during fermentation.

It appears that, for Jim Cuneo and Robert Young Vineyards, the advantages of using JMS Stylet-Oil for mildew control far outweigh the negatives.

NOTE: While Robert Young Vineyards has shared their positive experience with using JMS Stylet-Oil for powdery mildew control, there is no expressed or implied recommendation for its use. Please conduct your own investigation and experimentation before embarking on a similar program.

Dr. Mark Greenspan is the founder of Advanced Viticulture LLC (Santa Rosa, CA) [] providing consulting services to wineries, winemakers and winegrowers interested in producing premium wine products. He has 17 years of scientific research and viticultural experience, and specializes in irrigation and nutrition management, yield and canopy management, fruit maturation and vineyard technology. He may be contracted at or tel: 707/568-5256.

For more information on disease control and fermentation, and sulfur residue and wine quality, readers are invited to pursue the following research published by Dr. Doug Gubler and cooperating researchers:

  1. 1997 Dell, K.J., W.D. Gubler, R. Krueger, M. Sanger, and L.J. Bettiga. "The efficacy of JMS Stylet oil on grape powdery mildew and Botrytis bunch rot and effects on fermentation." Am. J. Enol. & Vitic. 49(1): 11-16.
  2. 1993 Thomas, C.S., R.B. Boulton, M.W. Silacci, and W.D. Gubler. "The effect of elemental sulfur, yeast strain, and fermentation medium on hydrogen sulfide production during fermentation." Am. J. Enol. & Vitic. 44(2):211-216.

No sulfur application at Fanucchi Vineyards

Much like Robert Young Vineyards, neighboring winegrower David Fanucchi has not used sulfur on his vineyards for three years. The Fanucchi family has been farming their Alexander Valley property since 1948 and currently farms 57 acres of Syrah, Merlot, and Cabernet Sauvignon.

Like Cuneo, he wanted to eliminate sulfur drift, mite flare-ups, and irritation to his vineyard crew and made the switch to JMS Stylet-Oil during the 2002 season. Fanucchi is aggressive with the oil, appliying it to some prolematic blocks even before budbreak if there was a mildew problem during the prior season.

Fanucchi mixes other registered fungicides along with the mineral oil, but far less frequently than Cuneo. He feels that Stylet-Oil provides sufficient control. But if weather conditions promote high powdery mildew pressure or if there is an outbreak of powdery mildew, one or two applications of fungicide are made along with the mineral oil. It has never been necessary to do this more than twice per season.

He applies the mineral oil at 14-day intervals, but will stretch the interval a bit if the weather heats up. Fanucchi does that to avoid heat damage to the foliage, but also because powdery mildew pressure is low during heat events (above 900F). Fanucchi's vineyards have a northwest-southeast row orientation, which exposes the vines to direct sunlight during the afternoon.

Fanucchi tries not to spray if temperatures reach 870F, because that usually means that temperatures in the afternoon will be outside his comfort zone. If the weather service forecast is 1000F or higher, he will hold off all spraying until the heat wave subsides. He will then increase irrigation and wait one or two days after the heat event has passed before resuming oil sprays to allow the vines to rehydrate. While all of this precaution may seem daunting, it should be noted that sulfur requires similar precautions against application during hot weather.

Fanucchi applies the product with a Turbomist sprayer fitted with a tower and feels that he gets good coverage with that system. he applies a 1% emulsion of oi at rates varying from 75 to 150 gallons of water per acre. The lowest volume is applied early in the season and the highest volume applied late in the season if there is a mite infestation. The mineral oil is applied from budbreak until the last berry has gone through veraison.

In the cool spring, he feels that the mineral oil is more effective than sulfur, because unlike sulfur, mineral oil does not need to be volatilized to be effective. Likewise, there is no concern of residue on the fruit affecting wine quality, so he is not afraid to apply mineral oil a bit later in the season than he would sulfur.

Fanucchi's efforts at eliminating sulfur have been seccessful. he has had mildew outbreaks (especially in 2005 which was a high-pressure year), but feels that these outbreaks are similar in incidence and severity to sulfur-wielding neighbors.

Fanucchi has seen significant benefit of mineral oil against insect pests. The mineral oil regime suppresses both leafhopper and mite populations. He has had some success at using mineral oil for mite control, but has found that, while it suppresses mite populations, it does not completely eradicate them. He has had success against mites by distributing predatory mites in his vineyard a few days after a mineral oil application.

Fanucchi feels that beneficial mites are less affected by the oil spray, as they are predominantly found in more sheltered portions of the leaves. All-in-all, he is optimistic that the mineral oil program will eliminate his need for chemical miticide treatment.

Fanucchi cautions against applying mineral oil on severely water-stressed vineyards. He has observed some leaf scorch in vineyards that have been temporarily water-stressed. To avoid the problem, he attempts to maintain his vineyards between -12 and -13 bars of midday leaf water potential.


Advantages of electrostatic sprayers

March/April 2004 by Doug Price, Keith Horn • Practical Winery & Vineyard

"In 1999, our vineyard management team at Clos du Bois (Geyserville, CA) purchased the company's first electrostatic sprayer from Randell Equipment (Woodlake, CA). The advantages of the electrostatic sprayer were reported to include a low volume of 12 to 20 gallons of water per acre, and an electrostatic charge of the spray particles, which helps minimize drift. Given the better spray coverage and the attractant nature of the spray particles, the unit also uses less chemical per acre than did previous technologies." Read more →

Advantages of electrostatic sprayers

By Doug Price, Viticulturist
Keith Horn, Vineyard Manager
Clos du Bois Vineyards, Geyserville, CA

In 1999, our vineyard management team at Clos du Bois (Geyserville, CA) purchased the company's first electrostatic sprayer from Randell Equipment (Woodlake, CA). The advantages of the electrostatic sprayer were reported to include a low volume of 12 to 20 gallons of water per acre, and an electrostatic charge of the spray particles, which helps minimize drift. Given the better spray coverage and the attractant nature of the spray particles, the unit also uses less chemical per acre than did previous technologies.

Our experience with the sprayer showed that it also increased work efficiency, because less time filling the tank yielded more spraying time. Also, by turning the outside spray boom 180 degrees and aligning the nozzles parallel to the cordons or canes, we were able to cover three vine rows with a two-row sprayer, or five rows with a three-row sprayer. (After our positive initial experience, we have added to our sprayer equipment, which now includes two 2-row sprayers and one 3-row unit.) This has greatly increased spray coverage on the 800 acres we farm in Alexander Valley.

As the vine canopies get larger through the growing season the spray heads are returned to their original position, with coverage of only two or three vine rows per pass. One to three early season spray-passes can be made in this manner, depending on the growing season and variety.

With the electrostatic sprayer's ability to spray two or three vone rows with full foliage in one pass, simple calculations indicate its advantages. Spraying a 26-acre block at 3-mph with a two-row electrostatic sprayer at 20 gallons per acre (gpa) requires filling the spray tank 2.5 times for a total 3.75 hours of spray time. A three-row sprayer at 20 gpa requires filling the spray tank once for a total of 2.5 hours of spray time. Compare this to a single tractor-row sprayer at 60 gpa requiring filling the spray tank 5.25 times for a total of 7.5 hours of spray time.

Another important benefit of the reduced amount of chemical used and rate of discharge is that there is less time spent mixing and filling the spray tank. This not only increases efficiency, but also reduces exposure of the spray operator/mixer loader to the concentrated form of the spray, which presents the highest health risk.

Drift issues are not dramatically different with electrostatic technology. Standard drift prevention applies when spraying with the Randell spray equipment (RSE). Close attention must be paid to weather, wind, and environmentally sensitive areas. However, with the electrostatic sprayer there is certainly less drift. By using less air pressure and having the water/spray droplets electrically-charged, the spray contacts the target with greater accuracy.

We have found that the electrostatic sprayers function well in applications that do not require high volumes of spray, such as horticultural oils, mildew eradicants, and certain miticides, as the volume of material is restricted to a maximum of 20 gpa. Attention to tank mixes is important to these spray programs in order to prevent problems with nozzle clogging. We find that most fungicides and wetable sulfur are compatible in a spray tank mix, but careful testing of micro-nutrient mixing, especially flowable calcium, is a critical consideration prior to spraying.

However, we also found that the usage directions from Randell spray equipment need to be followed. Clos du Bois tractor drivers flush the nozzles hourly with an adjustable rinse cycle built into the Randell sprayer.

End-of-shift maintenance is also very important. The tractor drivers spray all night, and when they finish their shifts, they are tired, so we send them home. We dedicate one person to the task of flushing, washing, and reporting any malfunctions to the mechanic of all spray rigs. This is an important step. An electrostatic sprayer not properly cared for can lead to breakdowns and downtime, which we can ill afford during the spray season.

The electrostatic sprayer is inherently more complicated than a standard pressure/air sprayer, and it requires electrical and mechanical knowledge. Attention to electrical connections and wires is key. The electrical elements of the sprayer are exposed to an environment similar to the marine environment (highly corrosive). We have borrowed some preventive elements of marine wiring by using waterproof connections with a heat shrink on all electrical connections and repairs.

Mechanically, the hydraulics and support structure are similar to any over-the-row implement; fatigue on the outside booms is exaggerated by the increased leverage of the arm. Attention to the structure is necessary. This often requires adding extra strength by gusseting welds on the booms and swing arms, and then carefully inspecting fatigue points.


Clos du Bois has found cost benefits to using electrostatic sprayers. These benefits result from reduced usage/rate of chemicals and time savings from reducing the hours for mixing and loading of spray solutions.

The use of electrostatic sprayers has allowed us to reduce the per-acre rate of early season post-bud break applications with wetable sulfur and copper sprays. Since purchase of the electrostatic sprayers, the spray quantity per acre has been steadily reduced. For early season applications, we find these rates have provided excellent protection for powdery mildew. Minimal late season incidents of powdery mildew have increased our confidence in the electrostatic spraying technology.


Electrostatic Spraying Gains Ground

August 2001 by Jeremy Hay • Wine Business Monthly

"In grape growers' eternal battle against vineyard pests, electrostatic spraying has been slow to gain a foothold as a weapon of choice." Read more →

Electrostatic Spraying Gains Ground

By Jeremy Hay

In grape growers' eternal battle against vineyard pests, electrostatic spraying has been slow to gain a foothold as a weapon of choice.

"The old technology didn't always perform as advertised," says Dennis Culver, Phd, an independent integrated pest management consultant who has spent the last 30 years in California's farms and vineyards seeing what does and doesn't work. The theory and use of electrostatic spraying in agriculture has existed since the 1970's when it was first used to treat orchards. But Culver says that even five years ago, the electrostatic sprayer technologies available were too unreliable and expensive. "I think it left a bad taste in a lot of people's mouths," he says of the experience many wine grape growers had at the time.

However, say manufacturers and distributors, as well as vineyard managers, recent advances seem to be slowly reversing that first unfavorable impression.

"I'm really pleased with it; I love the thing," at Dehlinger Winery in Sonoma County, says of the electrostatic sprayer he purchased last year.

"They keep on improving the technology, making them more dependable and effective," says Davey Pina, general manager of Pina Vineyard Management in Rutherford, Calif., who oversees 1,000 acres of Napa County vineyards. Pina says that three years ago, buying his first electrostatic sprayer "was kind of a leap of faith." Now, he says, the likelihood is that he will one day convert to a fleet of entirely electrostatic sprayers, once his crews are more familiar and expert with the technology.

Going to Ground

Electrostatic spraying involves charging the liquid spray of pesticides or fungicides with electricity as they are being applied. The idea is that the spray of charged drops, or particles, will be attracted to and then cling to a grounded object, in this case the grapevine. The result, says supporters of the technology, is a more efficient application - better, faster coverage - that requires a lower water to chemical ration than conventional sprayers.

"The basic goal is to provide better, more uniform coverage to kill your pests," says Jack Buffington, chairman of Randell Equipment Company, in Woodlake, Calif., which has been making sprayers since the 1940's and electrostatic sprayers since 1995.

The same type of technology - with the same goal of uniform coverage - has been applied to the painting of cars and many household appliances since the mid 1970's. But those tasks are carried out under considerably more controlled conditions than those of a vineyard.

"The hard part has always been to transfer this kind of technology to agriculture. You have to deal with having very high voltage and electrical components out in very rough environments that are exposed to the elements and are using a lot of different types of chemicals," says Willie Hartman, owner of Progressive Grower Technologies. The Canby, Oregon-based company is a leading player in electrostatic spraying technologies. (The other major name in electrostatic sprayers for the wine industry is Spectrum Electrostatic Sprayers, of Houston, Texas.)

Hartman, who was trained as a physicist but also studied agriculture, founded Progressive Grower Technologies in 1994. The company introduced its first On-Target charge-spray system in 1995 and is now manufacturing its third generation of electrostatic sprayer nozzles. The company manufactures the nozzles for sale to companies like Randell Equipment, who then build their own model of sprayer.

"The technology has come a long, long way, and it's much more consistent in performance," Culver says of the current crop of electrostatic nozzles.

Progressive Grower Technologies sells On-Target nozzles to six sprayer manufacturers and since its first product, Hartman says, has managed to cut the cost of its product by half, to about $300 a nozzle. He says the real improvements in performance came about when the company began sheathing all of the system components in Schedule 80 urethane tubing, which greatly improved the durability of the system.

The On-Target nozzles use compressed air to surround the stream of liquid chemical mix and atomize the liquid into droplets of from 40 to 80 microns in size; as the same air propels the liquid stream through the nozzle tip, each droplet passes through a high voltage field created by a stainless steel jacket and is charged with approximately 1,000 volts. For the sake of convenience, the system is designed to run on 12 volts provided by the tractor battery, and uses its own power supply to ramp up the current at the nozzle end.

Quality Coverage

The key point, Hartman notes, is that each spray droplet contains a like charge - it can be either positive or negative so long as all the drops are the same - which means that as they are shot from the nozzle they repel each other, dispersing as they are drawn to the grounded grapevine. This electrically engineered dispersal is what enables the type of uniform and complete coverage that is creating fans of electrostatic sprayers.

"The coverage we're getting is great," Kevin Merrill, president of the Central Coast Wine Growers Association, says of his experience with two Spectrum sprayers that he is using for the first time this year. Spectrum sprayers use a different method than the On-Target system to apply the electrical charge; called air shear, it directs the liquid stream into the path of a high-velocity air-stream in order to create and then charge the droplets. Spectrum Sprayers are built by Progressive Ag of Modesto, Calif., which has also released a new generation of air-shear charged particle system this year.

"The bottom line is that electrostatic spraying does a better job," says Bruce Clark, who oversees new products and market development for the sprayer division of Moxee, Wash. based Blueline Mfg. Blueline builds sprayers using both the "On-Target" system and Blueline's own version of an air-shear charge particle system.

Time is Money

Converts to electrostatic spraying say the benefits extend well beyond the issue of coverage. Merrill, a vineyard manager with Mesa Vineyard Management who oversees some 1,200 acres of vineyard, says, "What I think is really great is that we can use so much less water per acre." Merrill, who uses his Spectrum sprayers solely for applying fungicides, says that with the electrostatic sprayers he is using 30 gallons of water per acre as compared to the 100 gallons per acre a conventional sprayer would require.

Using less water to cover more ground also means reducing the number of times a sprayer needs to be refilled - something that several vineyard managers spoke of with great enthusiasm.

"What I think is great, is that we're able in a day's time to cover ninety to one hundred acres, as opposed to the other sprayers covering sixty to sixty five acres in the same time," says Bill Hammond, Kendall Jackson Wine Estates' vineyard manager in Monterey County. Hammond says this is the first full year of operation for the three sprayers Randell helped to convert from the conventional method to electrostatic technology, and they will be used on 400 of the 2,400 acres he's responsible for. "With the reduced water, we've been able to get the same or better coverage," he says.

In Sonoma County, Dehlinger Winery's Hedlund says he has cut in half the time it takes him to spray the winery's 45 acres of vineyard. As for materials and cost savings, he says he now can cover eight acres using 100 gallons, where before, his conventional model sprayer used 100 gallons an acre. Also, he says he is confident enough in the coverage the electrostatic spray nozzle provides to drive half a mile per hour faster than he previously did.

All in all, Hedlund says that after factoring in the time of scheduling spray rotations, filling up the tanks, and recovering from the noise and strain of the hours spent actually applying the chemicals is factored in, the savings are "priceless, they cannot be quantified."

Randell's Buffington says electrostatic sprayers enable farmers to reduce the amount of chemicals per application by 40 percent to 75 percent depending on the chemical used. Hammond says that after reconfiguring the layout of the nozzles on his sprayers so that they are arranged on the perpendicular, he has achieved savings of 50 percent on the use of certain pesticides.

In the end, argues Spectrum Electrostatic Sprayers' founder, Blake Dobbins, "When you look at the economics, it's always the right chice; it's always going to cost less with an electrostatic sprayers."

Vineyard manager Davey Pina agrees: "It comes back to using less water, less chemicals, having better coverage - the economics are definitely there."

Less Drift

Another major advantage to electrostatic sprayers, say supporters of the technology, is that wind drift is reduced.

Hammond says that to date, he has found that, "With these sprayers we're able to control that issue so much better."

Of the On-Target system, Culver says, "This unit significantly reduces drift. When you run the unit and turn the electrics on and off, the difference in the cloud and how it moves in the vineyard is really amazing."

Hartman also notes that because the spray particles are "forced" to cling to the plant, the runoff from plant to ground is drastically cut.

Those and other environmental concerns, often highlighted by encroaching development, are among the reasons why Merrill, Culver, Hedlund and others predict that along with economics, it will be one of the reasons the industry will have to increasingly - if slowly - go the way of electrostatic spraying.

New Labels Needed

But before electrostatic sprayers do become the industry standard, they will have to overcome a major obstacle in the minimum water per acre requirements issued by many chemical companies and supported by the state's agricultural authorities.

As it stands, the label requirements on many vineyard chemicals require a minimum 50 gallons of water use per acre-which works directly against the intent and capabilities of the electrostatic sprayer systems, which are designed to use far less water.

"We have to get the chemical manufacturers to understand that the technology is changing and they're going to have to change their labels to reflect that," Merrill says.

Jeremy Hay is a freelance writer based in Santa Rosa, California.


Blueline Mfg. Co.
Bruce Clark, Sprayer Division

Tel: 800-477-8449,

Poso Ag Equipment
Bob Pettis
Tel: 661-399-7462,

Progressive Ag
Sales Rep: Mark Ryckman
Tel: 800-351-8101,

Progressive Grower Technologies
Owner: Willie Hartman
Tel: 503-263-1795,

Rainbow Agricultural Services
President: Jim Mayfield
Tel: 800-427-2404,

Randell Equipment
Chairman: Jack Buffington
Tel: 559-564-3396,

Redwood Equipment Company
President: Bill Souber
Tel: 707-586-1790


"Our significant decrease of water usage has meant that the machine has paid for itself in just two years."

— Brian Wallingford, Mesa Vineyard