JANUARY 2026
CELEBRATING 147 YEARS AS CANADA’S PREMIER HORTICULTURAL PUBLICATION
THEGROWER.ORG
RADICAL THINKING
Outside-the-box science delivers inside the spray box
After three years of trials, winegrower Brian Schmidt (L) and Clean Works entrepreneur Paul Moyer along with his partner Court Holdings, are confident that a misting machine using hydrogen peroxide, ozone and UV-light can combat one of the biggest problems in the vineyard: powdery and downy mildew. Now that mechanical issues have been solved, a pull-type machine is in development that could be used by 75 hp tractors. The trial machine was demonstrated at a summer 2025 grape tailgate tour at Vineland Estates Winery, Vineland, Ontario. Photo by Karen Davidson.
KAREN DAVIDSON Imagine you could sanitize your crops against disease the same way apples are sanitized before being shipped to your local grocer. And that the entire process is sustainable, with water being the treatment’s sole residue. Third-generation winegrower Brian Schmidt thinks it’s more than possible. Bringing expertise acquired over 36 harvests, he’s collaborated with Clean Works of St. Catharines, Ontario, to do field trials for the past two seasons on his 100-acre vineyard near Vineland, Ontario. The Clean Works equipment passes over the vines, bathing them with a hydrogen peroxide and ozone fog in the presence of UV light. These three treatments have a history of being used successfully as individual sanitizers in many other
Québec’s Outstanding Young Farmers PG 4 Volume 76 Number 01 P.M. 40012319
$3.00 CDN
industries. The key element for each of these treatments is the sanitizing effect of hydroxy radicals, and research shows that when combined into one application, the efficacy increases almost a hundredfold. For Brian Schmidt’s grape vines, the gain has been a significant reduction in powdery and downy mildew during trials. Although the chemistry of this treatment has been well established and broadly used, innovation was needed to take the technology out of the warehouse and into the field. That is, to make it transportable. Denise VanderVeen, director of business development for Clean Works, explains how their fogging machine works. Hydrogen peroxide is atomized into a clean flow chamber while ozone is being released into the chamber. As the machine moves along the vine row, the fog envelops the entire plant while being irradiated by ultra-violet light, which in turn exponentially accelerates hydroxy radical production on the plant’s surfaces. Since
Potatoes pile up PG 10 @growernews
these radicals only have a half-life of about one nanosecond and can’t travel far, maximum surface saturation is required to ensure optimal effectiveness in killing the mildew fungus. And voilà, within seconds of application, the fungus is dead, depositing water as the end by-product. The treatment is an attractive solution from several perspectives. Fog or vapour diffusion throughout the vine achieves instant mildew eradication on most of the plant’s surface, not just the surfaces reached by typical spraying. It costs less than a comparable fungicide application. And it can be applied right up to harvest since there are no re-entry interval limitations. But most significantly from a sustainability perspective, there are no negative impacts on pollinators, water sources, or soil.
Continued on page 3
Focus: Grapes, vineyards & berries PG 12