Fruit growers are constantly looking for ways to reduce chemical sprays that control insects and diseases. But they’re slow to adopt a new practice until it’s proven to work.
A vineyard in Leelanau County is one of the first to try a spray that produces no chemical residue and only pure oxygen as a byproduct.
Naturally occurring ozone gas is produced when lightning flashes through the air. A machine that creates ozone with an electrical charge mixes those bubbles of gas with water.
That ozonated water has been used for years to disinfect containers in the bottled water industry.
It kills things such as molds, fungus and bacteria on contact.
Bill Siegmund is the owner of Pure Water Works in Traverse City. He adapted an ozonator to ride on a trailer behind a tractor with a spray tank and a generator to keep the electric charge going.
“What you’re basically doing is you’re creating an environment that it can’t live. And with ozone the beauty is that when you’re done you get pure oxygen,” he says.
He’s convinced ozonated water can replace some of the chemical sprays used routinely in vineyards.
“It’s not that we’re going to make a vineyard be able to become chemical-free. But as far as insect control, rust, blights, things like that, we’re there.”
But he still has to convince growers. So far, he’s had one taker for a spray rig he’s fabricated. It carries a price tag of $22,000.
Growers question whether this small prototype can be geared up for commercial use.
Jay Briggs says it would work well to spray a few acres. Briggs manages 45 North Winery in Leelanau County.
“Altogether with our vineyard here and our other vineyard we have 50 acres. That would take forever,” he says.
But here’s the thing: ozonated water is already being used in wineries. Briggs uses it to sanitize equipment and to keep bacteria and molds out of wine barrels.
“Peace of mind is the main thing that it does for me.”
So Briggs was intrigued by the idea of using ozone to fight molds, mildew and insects in the vineyard. He has a small section of grapes growing on a marginal site. He wasn’t planning to put much work into it or to harvest the grapes this year. So he used it to demonstrate how ozonated water would do.
The results were surprising.
“I was just out there this morning walking around and I have zero fruit infection in the ozone. There’s a touch of powdery mildew on leaves but at this point in the year, it’s easily remedied.”
Now, that’s just an observation of one small section of one vineyard in one year.
Not nearly enough to satisfy researchers such as Annamiek Schilder. She studies disease in wine grapes at Michigan State University. She’s open to the possibility that ozonated water might be a revolutionary technology.
But she says first, there needs to be several years of unbiased studies to prove it.
“We really need data. We need to show that it works,” she says.
Without that, Schilder says, MSU Extension won’t recommend the practice to growers.
On the other hand, she says, approved chemical sprays for grapes are very effective because they last a lot longer.
“You know, once they’re on the leaf they are active for a week, fourteen days, sometimes up to three weeks. And they kill any incoming spores. And ozonated water, it dissipates almost instantly.”
You’d have to spray ozone virtually every day to get the same protection.
That’s not something Jay Briggs at 45 North Winery would even consider. He doesn’t expect ozonated water by itself will ever take care of the vineyard.
But he does see potential, say, to knock back the first signs of mildew, for instance. Also, ozone can be applied a lot closer to harvest because it doesn’t leave any harmful residue.
“I mean, anything we have as a tool that can get us away from chemical dependency, I think it’s a great addition to the industry,” he says.
Briggs plans to set aside a regular section of the vineyard next year for a head-to-head comparison between ozonated water and commercial sprays.