Two Vineyards, Two Risk Profiles: What Frost in Ticino Teaches Us About Smarter Variety Choice

Climate Change Is Changing the Variety Decision

Climate change is reshaping viticulture, but not in a simple way. Warmer seasons do not automatically make farming easier, and a resistant variety does not automatically mean a resilient vineyard. Grapevines respond differently to the same weather, the same site, and the same disease pressure. For farmers and decision-makers, that means one thing: variety choice has to be made with both field observation and historical data in mind. Recent research shows that varietal selection is an important adaptation strategy, but also that grapevine performance needs to be understood through a holistic, multi-stress lens rather than through one variable alone. (MDPI)

A Simple Observation from Ticino

That message becomes very clear in a simple field observation from Ticino. On 31 March, two vineyards located close to each other showed two different realities. In the PIWI block, buds had already moved into a more advanced stage, which means higher exposure if frost arrives. In the nearby Merlot block, buds were still less advanced, so the immediate frost risk was lower. Same region, same period, but a very different level of vulnerability.

From the databaum side, we have seen frost warnings in many Swiss cantons over the last 10 days through the databaum weather station network. This is exactly why local observation matters: frost damage is never only about air temperature on its own, but about temperature meeting plant stage at the wrong moment.

PIWI: Strong on Disease, Not Automatically Safe from Frost

PIWI varieties bring real value to modern viticulture because they were developed for improved resistance to major fungal diseases such as downy mildew and powdery mildew, helping reduce disease pressure and the need for fungicide applications. But disease resistance is not the same as frost resilience. Research on grapevine cold hardiness and spring phenology shows that budburst timing is closely tied to spring frost exposure, and earlier development can leave young tissues more vulnerable when cold nights return. (Frontiers)

Merlot: Beauty, Identity, and Trade-Offs

Merlot has a special beauty in Ticino. It is not just a grape variety, but part of the visual and cultural identity of the region, where Merlot is the defining face of local wine production. That makes it an important point of reference for growers and wine lovers alike. At the same time, classic Vitis vinifera cultivars such as Merlot generally require closer disease monitoring under fungal pressure than resistant PIWI cultivars. In practice, this means Merlot may look safer during a frost window in one moment, while still demanding more careful fungal management over the season. (swisswine.com)

Frost Risk Does Not Disappear in a Warmer Climate

Swiss research makes this especially relevant. A study from the Swiss Rhône Valley showed that warming can advance budburst by roughly a week, but that does not automatically remove frost risk, because the timing of plant development and the timing of the last frost do not always shift together. In other words, climate change can move the risk window rather than eliminate it. (Springer)

Why Farmers Need to Read the Whole System Together

This is why variety selection should never be based only on market preference, wine style, or one attractive trait. Farmers and decision-makers need to look at previous years’ phenology, frost events, disease pressure, spray history, rainfall, elevation, slope position, and short-term weather alerts together. Research also shows strong inter-varietal differences in the thermal requirements needed to reach budburst, which means two cultivars under similar weather can still enter risk windows at different times. The best decisions come from combining site history, weather patterns, and variety characteristics into one view.

How databaum Helps Growers Act Earlier

This is exactly where databaum becomes useful in day-to-day vineyard management. At databaum, growers can view weather station data from multiple stations, compare local conditions, and set frost alerts so they can react earlier when risk begins to rise. That matters especially in cases like this, where neighboring vineyards can behave very differently depending on variety and phenological stage.

Just as importantly, many of these tools are available free of cost, so more farmers can benefit from timely weather intelligence and practical decision support. In a changing climate, better access to field-level data can make a real difference not only for large operations, but for smaller growers as well.

The Takeaway

The Ticino observation is simple, but the lesson is powerful. A PIWI block may be better protected against fungal attack, yet more exposed to frost because it has already moved further ahead in development. A Merlot block may need closer disease management, yet be safer on a given cold night because its buds are still behind. In a changing climate, the best results come from combining frost risk, disease resistance, varietal behavior, and local weather data instead of treating any one factor in isolation. That is the kind of connected view databaum aims to make accessible to more farmers. (MDPI)

Bibliography

1. Baltazar, M., Castro, I., & Gonçalves, B. (2025). Adaptation to Climate Change in Viticulture: The Role of Varietal Selection—A Review. Plants, 14(1), 104. doi: 10.3390/plants14010104. (MDPI)
2. Martínez-Lüscher, J., Matus, J. T., Gomès, E., & Pascual, I. (2025). Toward understanding grapevine responses to climate change: a multi-stress and holistic approach. Journal of Experimental Botany, 76(11), 2949–2969. doi: 10.1093/jxb/erae482. (OUP Academic)
3. De Rosa, V., Vizzotto, G., & Falchi, R. (2021). Cold Hardiness Dynamics and Spring Phenology: Climate-Driven Changes and New Molecular Insights Into Grapevine Adaptive Potential. Frontiers in Plant Science, 12, 644528. doi: 10.3389/fpls.2021.644528. (Frontiers)
4. Meier, M., Fuhrer, J., & Holzkämper, A. (2018). Changing risk of spring frost damage in grapevines due to climate change? A case study in the Swiss Rhone Valley. International Journal of Biometeorology, 62, 991–1002. doi: 10.1007/s00484-018-1501-y. (Springer)
5. Salotti, I., Bove, F., Ji, T., & Rossi, V. (2022). Information on disease resistance patterns of grape varieties may improve disease management. Frontiers in Plant Science, 13, 1017658. doi: 10.3389/fpls.2022.1017658. (Frontiers)
6. Faralli, M., Martintoni, S., Dotti Giberti, F., & Bertamini, M. (2024). Dynamic of bud ecodormancy release in Vitis vinifera: Genotypic variation and late frost tolerance traits monitored via chlorophyll fluorescence emission. Scientia Horticulturae, 331, 113169. doi: 10.1016/j.scienta.2024.113169. (ScienceDirect)
7. Swiss Wine. Ticino Wine Region: The Home of Swiss Merlot. Used here for regional context on Merlot in Ticino. Accessed 2 April 2026. (swisswine.com)