The project entiteld “Emerging infectious diseases on alder and ash in riparian ecosystems” \u00a0and coordinated by C. Husson has been granted by the\u00a0Agence de l\u2019Eau Rhin-Meuse et INRA<\/p>\n
Maladie \u00e9mergente sur aulne et fr\u00eane en ripisylve<\/b><\/p>\n
Financement\u00a0: Agence de l\u2019Eau Rhin-Meuse et INRA<\/p>\n
D\u00e9but du programme\u00a0: juin 2013<\/p>\n
Dur\u00e9e\u00a0: 3 ans<\/p>\n
Les maladies \u00e9mergentes sont tr\u00e8s pr\u00e9occupantes aujourd\u2019hui pour la soci\u00e9t\u00e9 et les professionnels. Une des causes majeures de ces \u00e9mergences est l\u2019introduction de parasites exotiques favoris\u00e9e par la multiplication des \u00e9changes commerciaux internationaux. Les arbres n\u2019\u00e9chappent pas \u00e0 ce ph\u00e9nom\u00e8ne et les ripisylves sont directement concern\u00e9es. En effet, deux nouvelles maladies l\u00e9tales et invasives sont apparues ces derni\u00e8res d\u00e9cennies sur l\u2019aulne glutineux et le fr\u00eane commun, esp\u00e8ces majeures pour l\u2019\u00e9cologie des berges de cours d\u2019eau dans le bassin Rhin-Meuse. Elles sont caus\u00e9es par Phytophthora alni<\/em> et Chalara fraxinea<\/em>, respectivement. Face \u00e0 ses maladies \u00e9mergentes, trois questions importantes se posent : quelle sera leur impact sur les populations h\u00f4tes ? Les h\u00f4tes disposent-ils de suffisamment de r\u00e9sistance pour lutter contre les agents pathog\u00e8nes impliqu\u00e9s ? Peut-on pr\u00e9dire l\u2019avenir des aulnes et fr\u00eanes en milieu naturel et ripicole ?<\/p>\n Ainsi, concernant la chalarose du fr\u00eane, nos objectifs sont dans un premier temps de mettre en place des dispositifs de suivis de fr\u00eanes en Lorraine sur diff\u00e9rents cours d\u2019eau, de mesurer la fr\u00e9quence puis l\u2019incidence de maladie dans cet environnement (\u00e9volution) et d\u2019estimer le r\u00f4le du cours d\u2019eau dans l\u2019\u00e9pid\u00e9mie.<\/p>\n Concernant le d\u00e9p\u00e9rissement des aulnes, notre recul est plus important car nous disposons d\u2019un dispositif de 2000 arbres ou c\u00e9p\u00e9es le long de la Sarre que nous suivons depuis 2002 (croissance, \u00e9tat sanitaire). Nous savons que la temp\u00e9rature hivernale moyenne est un facteur de risque de maladie. Pour finaliser un mod\u00e8le d\u2019\u00e9volution de la d\u00e9mographie des aulnes sous la contrainte de P. alni <\/i>et du climat, nous avons besoin de poursuivre le suivi sanitaire. Par ailleurs, nous souhaitons d\u00e9terminer quelle pression de s\u00e9lection le pathog\u00e8ne exerce sur la population h\u00f4te et quelle est la r\u00e9sistance disponible chez l\u2019aulne en terme de fr\u00e9quence et de niveau.<\/p>\n Ce projet permettra de mieux comprendre le fonctionnement de ces deux pathosyst\u00e8mes, d\u2019estimer l\u2019impact des deux maladies sur la d\u00e9mographie des arbres en ripisylves et de proposer des indications de gestions.<\/p>\n \u00a0<\/b><\/p>\n Emerging infectious diseases on alder and ash in riparian ecosystems<\/b><\/p>\n This study is funded by the Agence de l\u2019Eau Rhin-Meuse and INRA and started in June 2013 (3 years)<\/p>\n Emerging infectious diseases are economically and ecologically a major concern for managers. One of the major causes of these new diseases is the introduction of exotic pathogens due to the increase of international trade. Forest or riparian trees are infected by introduced pathogens, in particular by fungi. Indeed, two new lethal and invasive diseases have emerged during the last decades in Europe on common alder (Alnus glutinosa<\/i>) and ash (Fraxinus excelsior<\/i>), that are both important species for ecology of riverbanks in Lorraine. They are caused by Phytophthora alni<\/i> and Chalara fraxinea<\/i>, respectively. These threats have raised important questions: What about their impact on demography of host populations? What about host resistance for disease management? What about the future of alder and ash trees in natural and riparian ecosystems?<\/p>\n Concerning ash dieback, our objectives are to conduct an epidemiological survey along rivers throughout the Lorraine region, to estimate disease prevalence and incidence and to evaluate the role of rivers in the epidemic.<\/p>\n Concerning alder decline, we have conducted an epidemiological survey since 2002 on a plot along the Sarre river containing 2\u00a0000 trees. Growth and health status of all alder trees have been recorded each year. Our results showed that mean winter temperatures are linked to disease incidence and recovery of declining trees. To improve a SIR model that we developed to understand and forecast the effect of environmental characteristics and climate on the behavior of annual alder Phytophthora <\/i>outbreaks, disease monitoring has to be prolonged during few years. In addition, our aim is to determine whether specific pathogen selection pressure is exerted on host population and to determine frequency and level of resistance in host populations by performing susceptibility tests.<\/p>\n This study allows us to better understand the epidemiology of both pathosystems, to estimate their impact on riparian trees demography and to recommend managements for controlling the spread of the diseases.<\/p>\n","protected":false},"excerpt":{"rendered":" The project entiteld “Emerging infectious diseases on alder and ash in riparian ecosystems” \u00a0and coordinated by C. Husson has been granted by the\u00a0Agence de l\u2019Eau Rhin-Meuse et INRA Maladie \u00e9mergente sur aulne et fr\u00eane en ripisylve Financement\u00a0: Agence de l\u2019Eau … Continue reading