Modelling the epidemiology of Flavescence dorée in relation to its alternate host plants and vectors (Flavid)

• Forschungsstelle: BLW
• Projektnummer: 18.02

Schlüsselwörter (Deutsch)

Goldgelbe Vergilbung, Flavescence dorée, Rebe, Quarantäneorganismus, Risikobewertung, Überwachung, Best Practices, Insektizidreduktion

Schlüsselwörter (Englisch)

Flavescence dorée, vine, quarantine organism, risk assessment, monitoring, best practices, insecticide reduction

Schlüsselwörter (Französisch)

Flavescence dorée, vigne, organisme de quarantaine, évaluation des risques, surveillance, meilleures pratiques, réduction des insecticides

Kurzbeschreibung (Deutsch)

Die Goldgelbe Vergilbung (flavescence dorée, FDp) ist eine durch Phytoplasmen verursachte Rebkrankheit, die lange Zeit mit einem einzigen Vektor, der Amerikanischen Rebzikade (Scaphoideus titanus), und ihrer Übertragungsaktivität von Rebe zu Rebe in Verbindung gesetzt wurde. Vor Kurzem wurden sowohl zusätzliche Vektoren wie auch neue Gastgehölze entdeckt, die auf einen viel komplexeren Krankheitszyklus der FDp hinweisen.

Vorliegendes Forschungsprojekt bezweckt ein besseres Verständnis der FDp Ökologie und eine Verbesserung der Bekämpfungs- und Überwachungsstrategien dieses Quarantäne-Organismus, um den Einsatz von Pestiziden zu minimieren und gleichzeitig die Biodiversität und die Überlebenschancen der Rebpflanzen auf ein Höchstmass zu bringen.

Dazu wird man ein detailliertes Vegetationskartierungsprotokoll entwickeln, die Rolle von ausgewählten Gehölzen als potentielle FDp Wirtspflanze testen, ein entsprechendes Risiko-Analysen Modell entwickeln und die angepassten Bekämpfungs- und Überwachungsansätze für die Schweizer Rebberg-Landschaft empfehlen. Die Autoren werden ausserdem das Projekt in enger Zusammenarbeit mit dem Konsortium der Euphresco-Initiative abwickeln.

Kurzbeschreibung (Englisch)

The Flavescence Dorée (FDp) is a phytoplasma disease and its epidemic has been long time exclusively associated with the transmission from vine to vine by a single vector, the leafhopper Scaphoideus titanus. In recent time, the existence of alternative vectors and related host woody plants have been reported, highlighting a much more complex epidemiological cycle of FDp.
The present project aims at understanding the FDp ecology and improving the control and monitoring strategies, as well as the limitation of this quarantine organism.
We will develop detailed vegetation mapping approaches, monitor the potential role of selected woody species in the surroundings of the vineyard as FDp host species, develop a risk modeling approach, and suggest risk-adapted monitoring and FDp control measures. In this context, we will also collaborate with the FDp consortium of the Euphresco initiative (see annex 1). This will allow to develop a method for providing a realistic risk of the FDp epidemic in the ecological context of the Swiss vineyards and adopting suited preventive measures to prevent the FDp arrival and diffusion. This will result in practical tools for monitoring and assessing the FDp risk and undertaking most suitable control measures, which, in turn, will allow to reduce insecticide applications, preserve biodiversity, minimize the management impact and maximize plant health and survival.

Kurzbeschreibung (Französisch)

La flavescence dorée (FD) est une maladie de la vigne due à un phytoplasme qui a longtemps été associée à un unique vecteur, la cicadelle des vignes américaine (Scaphoideus titanus), et à son activité de transmission de vigne en vigne. Récemment, on a découvert tant des vecteurs supplémentaires que de nouvelles plantes ligneuses hôtes, qui renvoient à un cycle de maladie de la FD bien plus complexe. Flavid vise à parvenir à une meilleure compréhension de l’écologie de la FD et à améliorer les stratégies de lutte et de surveillance de cet organisme de quarantaine, pour réduire à un minimum l’emploi de pesticides et, simultanément, pour maximiser la biodiversité et les chances de survie des vignes.

Projektziele (Englisch)

Our team will use the Euphresco network and the related information exchange in order to set up and refine the detailed research plan that aims at:
1. Develop a detailed protocol for mapping the vegetation surroundings the vineyards in order to provide spatial-explicit cartographies of possible FDp hosting plant species;
2. Monitoring the potential role as host species for selected woody species presenting possible phytoplasma symptoms (e.g. Alnus sp., Corylus avellana, Clematis vitalba) by checking their distribution and the presence of FDp, AldY or PGY strains in selected vineyards of the Southern Alps.
3. Collect data and build a database on the putative FDp alternative vectors;
4. Suggest risk-adapted monitoring and FDp control measures in order to minimize the environmental impact by maximizing the plant health and survival.
Points 1 and 4 aim at developing important tools and best practices for evaluating and assessing the real risk in the ecological context of the Swiss vineyards and to consequently adopt preventive
measures to prevent the FDp arrival and diffusion, to reducing insecticide applications, to preserve biodiversity, and to minimize their impact at landscape level.
Points 2 and 3 aim at creating a database for the risk model that takes in account also possible future evolutions in the leafhopper population as a consequence of climate and land-use changes.
Finally, the acquired information could be integrated in existing modeling approaches  for developing sustainable control strategies of the FDp.

Publikationen / Ergebnisse (Englisch)

The project allowed us to gain very important scientific and practical insights to improve the man-agement approach of the FD epidemic.

We confirmed that suspending insecticides treatments for the control of the S. titanus population is indeed feasible without leading to a significant increase of infected grapevines. However, we also remarked the importance of following the recommendations of the authorities. In the case of vector population’s management, a treatments suspension is in fact indicated only in case of low initial population.

We furthermore highlighted the importance of analyzing the landscape surrounding vineyards, which can represent a possible source and maintenance spot for the FDp inoculum and has a significant effect on the occurrence of alternative and putative FDp vectors, such as O. ishidae and J. hyalinus. Landscape management may thus represent an integral component of adaptive management strategies.

We finally set up a database and developed a standardized protocol for monitoring different FD epidemic aspects such as insect vectors, emergence of symptomatic grapevines, and vegetation and landscape components. This information is essential in order to fine-tune the adaptive management strategies.

All main scientific results of the project has been submitted and partially already published in international peer reviewed journals.