In the elegant dance between nature and winemaking, the vineyard is the stage where tradition meets technology, and where ecological idealism often grapples with agricultural reality. In recent years, biocontrol—the use of natural organisms or substances to combat vine diseases and pests—has been heralded as a cornerstone of sustainable viticulture. But in 2025, the story is shifting.
Faced with economic pressures and unpredictable weather patterns, many French winegrowers are scaling back or abandoning biocontrol methods, citing uncertain efficacy, high costs, and complex application protocols. Only a handful of well-proven, resilient solutions remain in use—raising new questions about the future of eco-friendly viticulture in a world increasingly shaped by volatility.
A Promising Vision, Challenged by Reality
Biocontrol products once captured the imagination of the wine world as a natural, environmentally responsible alternative to synthetic chemicals. From Bacillus thuringiensis to orange essential oils and clay powders, these tools promised harmony with the vine’s ecosystem—resilient soils, balanced microbial life, and lower environmental impact.
But recent seasons have tested that vision. In both the Gironde and Hérault regions, the 2025 growing year was marked by a dramatic increase in pest pressure, particularly from snails and slugs. Organic growers were left with only one authorized option: iron phosphate pellets, a biocontrol solution with limited effect. Meanwhile, conventional growers, though nominally allowed more potent substances such as metaldehyde, found themselves unable to access these products due to national supply shortages.
This left winegrowers with few viable choices—and reinforced a broader perception that biocontrol is ill-equipped for high-pressure years.
Down but Not Out: Biocontrol’s Uneven Role in Disease Management
The use of biocontrol today is nuanced. For diseases like mildew, where yield losses can be catastrophic, both conventional and organic producers remain cautious. In conventional vineyards, biocontrol products make up roughly 30% of protection strategies, while in organic settings, the share is closer to 45%. Still, for high-stakes diseases like downy mildew, growers rarely take chances. Products like phosphonates, although technically biocontrol agents, represent just a small share (10%) of fungicide usage for this disease.
When it comes to powdery mildew, the calculus changes. Here, sulphur—a time-honored and effective biocontrol agent—dominates usage, accounting for around 70% of treatments. Other biocontrol products may be deployed strategically, but typically only as dose reducers or stopgaps when no better alternatives are available.
Biocontrol’s Mechanical and Logistical Costs
The practicalities of biocontrol can be daunting. Take, for instance, the management of green leafhoppers—tiny, persistent pests that can wreak havoc on grapevines. Conventional chemical solutions exist but often carry high ecotoxicological risks. Biocontrol is preferred here, but comes with considerable logistical demands. One widely used method requires spraying 20 kilograms of kaolin clay per hectare, in multiple passes, before the adult insects begin laying eggs. This demands precise timing, continuous population monitoring, and heavy machinery equipped with advanced filtration systems to avoid damaging pumps and sprayers.
The situation is similar with Bacillus thuringiensis (Bt), a microbial biocontrol agent applied against grape moths. While Bt offers the advantage of a short pre-harvest interval (just three days), its efficacy is highly dependent on timing: the application must coincide precisely with the blackhead egg stage, a window that is both brief and difficult to detect. Miss it, and the treatment fails.
Preventive—but Pricey
Some biocontrol products have demonstrated strong potential—particularly those based on compounds like Cos-Oga, applied in early stages to stimulate plant defenses. These have shown encouraging results in reducing treatment frequency and improving yields. But they remain preventive, not curative, and are often cost-prohibitive for growers navigating a challenging financial climate.
Similarly, Taegro, a Bacillus-based product by Syngenta, continues to see selective use, especially late in the season between bunch closure and véraison. But it is only deployed on less sensitive grape varieties, such as Syrah or Merlot, and only in years of moderate disease pressure. On more vulnerable grapes like Chardonnay or Carignan, its effectiveness is too limited to rely on.
A Fragmented Landscape with Few Survivors
In Champagne, biocontrol’s reputation is particularly guarded. Only a few substances—phosphonates, sweet orange oil, and Armicarb—are considered trustworthy enough for consistent use, and even then, always in combination with copper or sulphur. The industry remembers past disappointments: for example, Armicarb’s earlier trials against botrytis produced underwhelming results. Yet, more recent experiments against powdery mildew have shown promise, a sign that biocontrol’s reputation can evolve—but only through rigorous, repeated, and successful field trials.
What the Future Demands
The biocontrol market is clearly at a crossroads. While certain methods, like sexual confusion pheromones, remain foundational to organic pest management, others are faltering under the weight of practical complexity and inconsistent results. To survive and thrive, biocontrol products must meet the same high standards that the wine industry demands from every input: consistency, efficiency, and economic viability.
The burden now falls to manufacturers to invest in long-term field validation—not just laboratory efficacy claims—and to create tools that are as user-friendly and reliable as they are sustainable.
Toward a Sustainable Synthesis
For luxury wine producers, the conversation around biocontrol is no longer simply about ecological ideals. It’s about strategic resilience: how to protect vine health, preserve yield quality, and maintain brand integrity in an increasingly erratic climate.
Biocontrol is not disappearing, but it is being recalibrated. In the years ahead, the most successful products will be those that prove their worth not only in principle, but in the practical crucible of the vineyard. Those that do may yet earn a central place in the next chapter of high-end, ecologically balanced winemaking.
Because in the end, even the most storied terroirs need guardians—and the future may depend on the smallest among them.