Fungus-resistant grape cultivars have up to threefold lower environmental impacts than traditional varieties

Fungus-resistant grape cultivars, commonly referred to as PIWIs (an abbreviation of the German term pilzwiderstandsfähig), are hybrids of Vitis vinifera with other Vitis species that exhibit low susceptibility to powdery mildew (Erysiphe necator) and downy mildew (Plasmopara viticola), the major fungal diseases in viticulture. In contrast, traditional grape cultivars are highly susceptible and require frequent fungicide applications during the growing season. The reduced number of fungicide treatments required by PIWIs lead to significant environmental and economic advantages, including fewer tractor passes, lower fuel and water consumption, and reduced pesticide-related waste. However, these benefits are rarely quantified. This study compares two fungus-resistant cultivars (Cabaret noir and Sauvignac) with two traditional ones (Pinot noir and Rivaner), using data from an experimental vineyard in Luxembourg. Environmental impacts are assessed using Life Cycle Assessment (LCA), and economic costs analysed both from a private and social perspective, accounting for direct production costs and environmental externalities. Results show that fungus-resistant cultivars can reduce environmental impacts by up to a factor of three, particularly in the climate change and freshwater ecotoxicity categories. Economically, growing PIWI cultivars allowed average savings of €685/ha/year at the level of the winery (mostly driven by lower fungicides use) compared to traditional cultivars. The estimated environmental costs in PIWI systems were €157/ha, compared to €406/ha for traditional systems. Sensitivity analyses confirmed the robustness of these findings across variations in disease pressure, yield and input prices, while showing that additional fertilizer inputs can reduce the relative magnitude of the environmental advantage. Altogether, the findings highlight the strong potential of fungus-resistant cultivars to lower both the environmental and economic burden of viticulture, supporting their broader adoption as a sustainable alternative.