Project’s finishing event
On Friday, November 28, 2025, we presented the results of the targeted research project CRP V4-2225 “Measures to Prevent Further Spread of Grapevine Flavescence Dorée (FD-GamePlan Project)” at the Grand Hall of the Chamber of Agriculture and Forestry of Slovenia in Ljubljana. The event was very well attended, filling the lecture hall.
Flavescence dorée (FD), caused by the quarantine phytoplasma Grapevine flavescence dorée, is an incurable grapevine disease that spreads rapidly in vineyards, primarily via the American grapevine leafhopper (Scaphoideus titanus). Understanding its epidemiology and applying reliable diagnostics are crucial for early detection and effective management. The project (2022–2025), funded by Slovenian Research and Innovation Agency (ARIS) and Ministry of Agriculture, Forestry and Food, focused on vector biology, alternative hosts, and innovative detection methods. Researchers from the National Institute of Biology, Institute of agriculture and forestry Nova Gorica, Institute of agriculture and forestry Maribor, the Agricultural Institute of Slovenia, and the Slovenian Institute of Hop Research and Brewing collaborated on this effort. Leader of the project Nataša Mehle presented what was done at NIB in the Microbiology research group.
Key findings
- FD phytoplasma was detected in pre-imaginal stages of Scaphoideus titanus only in a small fraction of samples, making this approach unsuitable for routine early detection.
- The main vector among grapevines is Scaphoideus titanus. The mosaic leafhopper (Orientus ishidae) likely plays an important role in transmission and is common in hazelnut orchards and edge vegetation. Other potential vectors seem limited but cannot be excluded.
- Hazelnuts are not a primary source of FD problems in Slovenian vineyards, but they may serve as a reservoir of genetic diversity.
- Transmission of FD phytoplasma by Orientus ishidae from hazelnut to grapevine has not yet been confirmed, as the ongoing experiments include only a limited number of insects introduced into the trials, and only a small proportion of them were infected.
- Some insecticides containing pyrethrin or deltamethrin, permitted for hazelnut pest control, could affect Orientus ishidae, but systematic control requires regulatory extension and further efficacy studies.
- Airborne hyperspectral imaging is a promising method for early and spatially precise detection of FD infections. Detection is most reliable in autumn; spring detection is possible but less accurate. Robust prediction requires advanced data processing and model adaptation by variety and location.
These results provide valuable insights into FD epidemiology and support improved management strategies.
👉 Learn more and access presentation materials: https://projects.nib.si/fdgameplan/
