Wine-growers are losing the war on fungi

2026-02-10 - 16:00

Comment: As New Zealand’s wine-growers head into a harvest plagued by the relentless humidity and rain of a wild La Niña summer, an uncomfortable truth has been laid bare – our vineyards remain dangerously dependent on pesticides, and the systems we’ve built around them are far more fragile than we like to admit. In a paper recently published in Gastronomica, Nick Lewis, Emma Sharp and I explored experiments with alternative modes of agriculture, and what this means for the future of farming and particularly the problem with fungi. What we found suggests the future of farming may lie not in more efficient chemical warfare, but in abandoning the battlefield entirely. Much of our farming in New Zealand is an exercise in chemical warfare. Wine-growing is no exception. Fungal diseases such as powdery mildew, botrytis, and downy mildew pose major threats. Although 98 percent of New Zealand vineyards are certified sustainable through the industry’s sustainable wine-growing programme, wine-growers use a lot of fungicides. Whether wine-growers call themselves organic, biodynamic, conventional, sustainable, or regenerative, New Zealand’s approach to protecting vines is almost always premised on the same model: apply fungicides to kill off the microbes that cause vine and grape diseases. As one grower in our research bluntly put it: “Organics is killing too”. The standard approach is to spray fungicides at 7-14 day intervals throughout the growing season. In practice, this means creating (and then maintaining) a microbial vacuum, a sterile environment, but one that doesn’t remain sterile. We now know how much human health depends on a diversity of bacteria and other organisms, and the same is true for vineyards. This drive toward sterility impedes the development of a diverse microflora, and risks creating an ideal environment for “bad” fungi to proliferate. It locks farmers into a vicious cycle of chemical dependence, and an ever-intensifying battle as pesticide resistance rises and climate change brings less predictable weather patterns. This scorched earth warfare is becoming harder to justify as fungicide residues accumulate in soils, human bodies, and our environment, and the carbon footprint of spraying pesticides translates into greenhouse gas emissions. The economic model driving much of New Zealand wine doesn’t help. The growth in low‐value bulk wine exports encourages high yields. High yields mean thicker canopies, more moisture retention, and increased risk of fungal diseases, which demands increased use of fungicides. Increased use of fungicides is the antithesis of an ecological approach. The bad economy of exporting wine in bulk is locking in a system where value is added elsewhere and goes hand in hand with bad biology, which locks in ever-increasing dependence on fungicides. From biodynamic to probiotic wine-growing We do have alternatives. Efforts to develop non-chemical approaches to plant protection can be found in many places. Some of the more radical alternatives are being developed within the biodynamic wine-growing community. Biodynamics offers a fundamentally different worldview, one of interconnection between all manner of human, environmental, and even cosmic forces and activities. It’s a systems approach, where the farm, vineyard, orchard, or garden is viewed as a living whole and each activity affects everything else. In our study, we followed a small group of biodynamic wine-growers in South Africa going beyond farming with pesticides to use ecological alternatives that work with, rather than against, living systems. They are selectively cultivating a diverse microflora that will suppress fungal disease and boost the plant’s own “immunity”. By seeking to enhance life rather than eliminate it, they have adopted a “probiotic” form of farming, which is supported by a vineyard-wide ecosystem management approach. Their approach includes cultivating local microbes, making changes to vineyard layouts, and using canopy management to channel airflow and sunlight in disease-fighting ways. It is premised on thinking more deeply about where and how they grow different types of vines and other crops and working more carefully with local environments rather than against them. What this means for us One example of the potential value of probiotic farming in New Zealand is the drier environments that typically have larger diurnal temperature ranges, such as those of Central Otago. These environments are characterised by reduced disease pressure, making it much easier to farm grapes organically. Why would any wine grower want to spray vines in such conditions? We would blame the dominance of a spraying mentality and the business models and research structures that support and encourage it. The virtues of a probiotic approach are clear. It would also allow for value-added opportunities for small to medium-sized wineries to grow and market high-quality, high-price wines on the back of place-based provenance. Though the Central Otago environment is an outlier in New Zealand, it illustrates the potential of more appropriate ecological knowledges that will enhance and protect life, as well as alternative business models that will generate greater value for all those involved in wine economies and communities. The imperatives of short-term investors, land speculators, executive managers, and growth-based narratives can obscure good economic sense. But these are the challenges that we must face, as wine-growers, communities, and nations. Will we learn what we must learn? The La Niña summer of 2025–26 is yet another reminder of the growing difficulties and costs of waging an antimicrobial war. Incremental sustainability tweaks will not help this vintage and will not ultimately stop the oncoming forces of climate change, biodiversity loss, and antimicrobial resistance. We must move beyond sustainability, organics, or pesticide innovation to a strategy of rethinking farming systems from first principles. South Africa’s pioneering probiotic wine-growers show what can be achieved by moving away from the narrow focus of techno-scientific measurement and the self-interests of external (business and viticultural) consultants. Probiotic approaches question the shibboleths of growth models and bio-economy innovation, as well as the spray calendar freebies from the pesticide companies. They replace farming by numbers and from a distance, with place-based and embodied ways of knowing and managing plants. They emphasise learning how to grow and make distinctive and excellent wines from specific places over the medium term while protecting and enhancing both winemaking conditions and qualities that match the right land and environments with the right varieties and viticultural and oenological techniques. This is precisely what the French mean by terroir. Although defiled by the marketing and promotional strategies of industrial wine producers, terroir is still a defining discourse of value attribution in wine economy that describes the profound relationships between land, climate, microbes, and human skill. Perhaps rethinking farming can start with wine and wine can start with terroir.