Published in the July/August 2017 edition of The Grapevine Magazine, Agrothermal Systems was featured in an article titled “The Heat is On: Grape Growers Look for New Answers to an Old Problem”. Fewer pests, healthier vines, and more grapes at a lower cost are just a few of the benefits highlighted by writer Jim Offner. You can read the an excerpt of the article below or download the pdf.
The Heat is On: Grape Growers Look for New Answers to an Old Problem
By: Jim Offner
Mark Seifert says he has found a way to save a lot of cold cash by applying heat to his vineyards.
Agrothermal Systems, based in Napa, California, has pioneered the use of Thermaculture treatment services, a new methodology for managing crops through the application of heat with substantial, proven results, the company said. Applied to plants by their trademarked Agrotherm XT, a tractor pulled machine, the heat treatment can by applied at various stages throughout the growing cycle.
Seifert, vineyard manager of Foley Family Wines and Sebastiani Vineyards in Sonoma, California, has found success in Thermaculture trials at two of his vineyards. The results: fewer pests and more grapes at a lower cost.
“We measured increased numbers of berries per bunch, increased bunch weight, increased Brix, clean fruit, and improved phenolics in the grape juice measured in the lab,” Seifert said.
The idea of applying heat to grapevines is relatively recent. The concept was developed and patented by Florencio Lazo, a Chilean grower, in 2006. Lazo came up with an idea to apply heat for frost control then began to experiment with the notion as a potential tool for pest control.
That’s when Marty Fischer stepped in. Fischer, who now runs Agrothermal Systems, says he heard about Lazo’s work and started working with the Chilean grower to develop applications for the idea on commercial ranches.
“Thermaculture...is used for numerous grape crop benefits, including increased fruit set, creating higher levels of phenol and antioxidant, drying off vines after rains,” Fischer says. “Some of our growers have experimented with pest control for both insects and fungus – using heat by itself, and in combination with fungicide. The results have been quite encouraging, and we have begun more scientific examinations of the pest control benefit and protocol experimentation.”
Fischer notes that it has become clear that the heat blast at 300-350 degrees Fahrenheit increases plant surface temperature instantaneously and this leads to a form of thermal shock. The result is higher levels of phenol and antioxidant in the wine.
“These chemicals/ compounds are the flags that the heat has activated the natural self-defense system of the plant,” said Fischer. “At the same time, the heat level is way beyond what insects can withstand if they are in the open parts of the canopy. They heat up and, in some cases, either are damaged or just leave. The smaller the insect, the more it heats up, so tiny insects like mite and thrip populations cease to find their homes in the canopy. Those insects that are large or are protected by bark or other cover are not affected.”
Fungal control is a bit more complex, but some growers report success controlling powdery mildew, especially in rotation with sulfur compounds, Fischer notes.
“This has resulted in some producers being able to cut 50% or more of their fungicide use. We believe that the heat and natural plant self-defense component work together to accomplish this resistance.”
Heat Treatment Saves Cold Cash?
Heat treatment can save growers money, although how much can vary according to grape variety, weather conditions, and other factors. Fischer said, in general, the technology leads to more grapes at harvest time.
“Typically, if you add up the cost of the propane, the cost of the machine depreciated over 100 acres and five years, the cost of labor, the cost of depreciating a tractor and the cost of diesel – and you’re assuming you’re doing 100 acres, it ends up about $30 (per-acre) for everything,” Fischer said. “That would compare to much larger amounts of money for a pesticide treatment because of the cost of the materials. We use roughly three gallons of propane per acre. That’s $5-6 per acre. If you contrast that with the cost of pesticide, you’ll find a very big price difference. And again, it depends on the pesticide you’re using. Sulfur is quite inexpensive, but some of these other [chemicals] are costlier. It’s cheaper per pass. Historically, we’ve done eight to 10 passes per season.”
In addition heat treatments have added about 24% more berries per bunch during the fruit set period, and the average yield is about 16% more.
“So, if you’re a typical vineyard and you’re doing three tons per acre, you could pick four tons – that’s about 15 percent more revenue,” said Fischer.
Seifert says he’s not yet sure about the cost savings, however, he notes, that’s not a “big-picture” consideration. “I think when all things are said and done, there may not be much cost savings, but we had disease-free plants and fruit that rivaled plants that had conventional pesticides applied, and we increased yields and improved wine quality without the use or potential dangers or side effects of chemicals.”
The idea of applying heat to plants might seem discordant to a novice of the treatment system. It’s a relatively safe procedure though, Seifert said.
“The only danger of using heat on the plants might be if the machine operator stopped forward movement of the equipment and were to scorch the plants, or if the operator were to use too high of temperature,” he said.
Seifert also warns that Thermaculture might not fit every ranch in every climate; he only knows that it has worked for him. “We are told that if there are plants that have insects this technology is a good erradicant,” he said. “Fortunately, we have not been able to prove that as of yet because we don’t have too many insect problems.”
Fischer acknowledges that heat treatments might not be an ideal fit for all growers. Not yet, anyway.
“I don’t know where we’ll ever get to the point where it’s 100 percent of a solution for either insects or fungus. If you try to treat fungus in an environment on the East coast or in Canada, where they get more rain, it’s much more complex than trying it in the West coast, where it’s drier. So, there’s much more work that needs to be done,” said Fischer.
Heat can kill insects instantly, but it doesn’t prevent another wave of pests from doing damage. “We don’t leave any killing residue, so if it’s a highly mobile insect, it might come back a second time,” Fischer said.
A Sustainable Solution
Thermaculture is a sustainable system that is suitable to a variety of scenarios, including organic production.
”I think the use of this technology can be expanded in the agriculture industry – not just limited to wine grapes – as it becomes more widely used and experimented with. Because it is a clean technology, there are no known side effects. I would tend to believe there would be no problems in certified organic situations,” Fischer said.
Potentially growers applying heat could get healthier or stronger plants because of the stress response mechanism in the plants as they are heat shocked.
“If anything, I think this technology can be used in a lot of colder climate locations or in years when the weather is cooler than normal to promote growth,” said Fischer.
Seifert believes that Thermaculture will find wider use across the industry, even if it doesn’t push pesticides out of the picture. “In the end, this is another very valuable tool in the toolbox,” said Seifert.
Besides those going on at Seifert’s vineyards, several trials of Thermaculture are underway this season, Fischer said.
“Buoyed by grower experiences, we have initiated several trials this season to evaluate pest-control effects from Thermaculture. These are under the management of well-respected scientists. Thus, we hope to develop effective protocols whereby the effects of heat shock in combination with fungicide can improve overall pest control and with lower levels of pesticide use. In the meantime, our growers are also developing experience with their own experimentation,” said Fischer.
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