California’s Largest Certified Organic Winegrower Scales Autonomous UV-C Technology Across the Central Coast
May 12, 2026 (Paso Robles, CA) — Castoro Cellars, California’s largest certified organic winegrower, today announced a major expansion of its partnership with Saga Robotics – scaling the Norwegian company’s “Farming with Light™” technology to more than 600 acres of certified organic vineyards across the Central Coast. After three years of deploying the Thorvald platform with measurable results, Castoro has rapidly expanded its treated acreage, making it one of the largest autonomous UV-C disease management programs in American viticulture. The Thorvald platform delivers precision UV-C light to manage powdery mildew and fungal disease without chemical sprays. This is done autonomously, through the night, across Castoro’s estate vineyards.
“Farming with Light™”: A New Standard for Disease Management
Rather than applying chemicals to fight fungal pressure, the Thorvald platform delivers a low dose of UV-C light directly to the vine canopy under cover of darkness – disrupting the reproductive cycle of powdery mildew and disease spores at the source. The result: disease control efficacy comparable to conventional spray programs, without the chemical residue, soil disruption, compaction or ecological side effects.
For Castoro, managing rigorous disease pressure across 600-plus certified organic acres has always been one of the hardest realities of large-scale organic farming. Sulphur and oil-based treatments, even those permitted under organic certification, carry real ecological costs: impacts on soil microbiomes, beneficial insect populations, worker exposure, and atmospheric loading. Three years of Thorvald results have proven a better path is possible.
From Pilot to Scale: 600 Acres Farmed with Light
What began as a pioneering commitment has grown into one of the most ambitious deployments of light-based crop protection on a U.S. wine estate. Castoro’s rapid expansion reflects confidence in the technology and a decisive move to replace chemical inputs across its entire certified organic program.
“After three years with the Thorvald platform, the results were clear and the right move was to scale. What we are seeing across our vineyards is what happens when you take the chemical burden off the land and let the vines express what the site is truly capable of cleaner fruit, healthier ecosystems, and wines that reflect that. This is farming that works with the biology of the plant and the ecology of the farm. We believe it is the beginning of a much larger shift for growers across California and beyond.” Niels Udsen, Co-Founder, Castoro Cellars
A Legacy of Organic Leadership on the Central Coast
Castoro has farmed organically long before sustainability became an industry talking point, consistently proving that great wine and responsible farming are the same ambition. The Thorvald expansion follows years of investment in regenerative practices: cover cropping, composting, habitat restoration, and reduced tillage combined with reducing chemical inputs which is enhancing quality.
“What Castoro has built over three years with the Thorvald platform is exactly the kind of partnership that accelerates this technology’s impact. They tested, measured what mattered, and when the results spoke, they moved decisively. Farming more than 600 acres with light is a landmark moment for autonomous, chemical-free disease management in American viticulture, and the fruit quality coming off these vineyards is a testament to what this approach can achieve for the vine, the land, and the wine. We are proud to grow alongside them.” Pål Johan From, Founder, Saga Robotics
Advancing Organic Viticulture Across California
Castoro intends to share data and learnings from its multi-year Thorvald program with the broader grower community at upcoming demo days, consistent with its advocacy for organic transition across the Central Coast. Saga Robotics will continue expanding the Thorvald platform’s availability to U.S. winegrowers, building on the data generated through partnerships with growers like Castoro Cellars.
About Castoro Cellars
Founded in 1983 by Niels and Bimmer Udsen, Castoro Cellars is an estate winery on the Westside of Paso Robles, California. California’s largest certified organic winegrower, Castoro is committed to farming practices that protect and restore the land for future generations. www.castorocellars.com
About Saga Robotics
Saga Robotics is leading the transition from chemical- and carbon-intensive agriculture to clean and autonomous farming. Its Thorvald platform replaces sprays with light, reduces chemical inputs and carbon emissions, and brings continuous field intelligence to every acre. Purpose-built for vineyards and soft fruit, Thorvald elevates crop quality while preserving the ecosystem. This is a redefinition of how food is grown: cleaner, lighter, and built for the future of farming. www.sagarobotics.com
