2026-08-18
Swiss grape growers appear to be split into two nearly equal camps when it comes to cutting pesticide use, with one group adopting a broad mix of alternatives and the other still relying much more heavily on pesticides, according to a new peer-reviewed study published in the Journal of Wine Economics.
The research, by Eileen Ziehmann, Lucca Zachmann and Robert Finger of ETH Zürich, examined how winegrowers in Switzerland combine pesticide reduction measures rather than treating each practice as a separate decision. The authors said that distinction matters because vineyards often need several tools at once to reduce pesticide use without raising crop losses, and because some measures work better together.
The study used survey data collected in spring 2022 from 436 Swiss grape producers across the country’s six winegrowing regions. After excluding organic farms and outliers to make farms more comparable, the final analysis covered 313 non-organic farms. The surveyed vineyards represented 14.4% of Switzerland’s cultivated grape area, the paper said.
Viticulture is a major test case for pesticide policy because grapes are among the most pesticide-intensive crops in Europe. The paper cited previous estimates showing that vineyards often require 12 to 15 pesticide applications a year and account for 58% of fungicide use in Switzerland. In Europe, viticulture is responsible for about 70% of fungicide use, the study noted.
The researchers looked at 21 practices, including 15 pesticide reduction measures and six precision application technologies. Those measures ranged from canopy management, sanitation and fertilizer management to mechanical weed control, mulching, pheromone disruption, beneficial insects, fungus-resistant grape varieties and low-drift spraying equipment.
Their first finding was that farmers often adopt measures in bundles, especially those that are relatively cheap and less labor-intensive. Decision support tools for fungicide use, beneficial insects, preventative insect-control methods and decision support tools for insecticide use appeared most often in combinations with other practices. By contrast, measures that demand more labor or investment, such as sanitation or mechanical weeding, were less likely to show up in bundles.
That pattern suggests that labor and capital remain central barriers in Swiss viticulture, where steep slopes and intensive vineyard work already make production costly. But the study also found signs that growers are taking advantage of complementary effects between measures even when those combinations require more resources.
One example was the joint use of fungus-resistant varieties and beneficial insects. The paper said that pair may help growers reduce fungicide pressure while also supporting insect populations that contribute to pest control. Mechanical nets and traps also appeared in bundles with measures such as mulching, preventative practices and mechanical weed control.
Using a k-means clustering analysis, the researchers found that the sample could be divided into two main groups. One cluster, labeled “Low-IPM,” accounted for 52% of growers and relied more on pesticides with fewer integrated pest management practices. The other, labeled “High-IPM,” made up 48% and adopted a broader set of pesticide reduction measures.
The gap between the two groups was visible across several practices. High-IPM growers were more likely to use decision support tools, fungus-resistant varieties and pheromones, among other measures. They also differed in their use of application technology. Lower-adopting farms used hand sprayers more often, while higher-adopting farms more frequently used low-drift nozzles and spraying equipment with horizontal assistance.
The study found that these differences were not primarily geographic. According to the authors, cluster membership did not show meaningful spatial autocorrelation at the regional or cantonal level, suggesting that the divide is more closely tied to farm structure, farmer characteristics and behavior than to location alone.
High-IPM growers tended to manage larger farms and were more likely to earn most of their income from agriculture and viticulture. They were also more likely to market wine rather than unprocessed grapes and to produce under ecological cross-compliance standards. On education, the study found a notable difference in agricultural training: High-IPM growers were more likely to have completed an agricultural apprenticeship, while university education did not distinguish the two groups.
The paper also found differences in how growers seek information. High-IPM growers more often used colleagues, cantonal services and internet sources for plant protection information. In the statistical model, consulting Agroscope, the Swiss federal agricultural research body, was associated with a higher probability of belonging to the High-IPM group.
Behavior and attitudes also played a role. In a logit model measuring which traits were statistically linked to membership in the higher-adopting cluster, the strongest positive factor was marketing wine, which raised the probability of being a High-IPM grower by 32.1%. Having completed an agricultural apprenticeship increased that probability by 25.4%, and producing under ecological cross-compliance increased it by 18.4%.
The model also identified several psychological and preference-related factors. Confidence in reaching production goals was associated with a 9.8% higher probability of being in the High-IPM group. Risk aversion in the production domain increased the probability by 4.6%, while risk aversion in the market domain reduced it by 4.2%. Growers who saw high yields as their main goal were much less likely to be High-IPM adopters, with a marginal effect of -70.8%.
The authors said that result points to the importance of farmer identity and priorities, not just economics. Farmers focused mainly on output may be less willing to diversify pest-control methods if they believe pesticides remain the safer route for protecting yields. At the same time, the positive link between production risk aversion and higher IPM adoption suggests that some growers may see diversified pest management as a way to reduce production risk rather than increase it.
The paper also found that High-IPM growers were more likely to consider shifting to organic production in the future, while Low-IPM growers were more likely to consider leaving viticulture. Average disease pressure was similar across the two groups, though they reported different threats to yields. High-IPM growers more often pointed to frost, weeds and drought, while Low-IPM growers more often identified insects and hail.
The researchers said the findings carry policy implications for governments and the wine supply chain. Rather than supporting single practices in isolation, they argued that policy should encourage effective bundles of measures. They also said efforts to reduce pesticide use should not stop at the farm gate. Because growers who market wine were more likely to be strong adopters, the study suggested that wineries and retailers may help drive change through pricing, sourcing rules and other incentives that reward low-pesticide production.
The authors also called for better information and training, particularly for growers who still depend mainly on pesticides. They said workshops, peer-to-peer learning and other forms of outreach could help address perceived skill gaps around integrated pest management. The study noted that farmers who believed production success depended strongly on their own skill were less likely to be in the High-IPM group, a pattern the authors said may reflect hesitation about unfamiliar methods.
The paper also cautioned that the survey captured whether a farm used a measure, not how intensively it used it. It did not record actual pesticide quantities, meaning the study could not directly measure how much pesticide use fell on each farm. The authors said future research should track real reductions in applications and environmental risk, along with biodiversity and other on-farm outcomes, to better understand which bundles deliver the largest gains.