Programme REID 2012x - Inra

LE CHANGEMENT DE CLIMAT A-T-IL FAVORISE L'EMERGENCEDU DEPERISSEMENT DES AULNES A PHYTOPHTHORA ALNI ?J Aguayo, C Husson & B MarçaisUMR1136 Interactions arbres/microoganismes,INRA-Nancy, ChampenouxEmerging infectious diseases have become a major threat for forest ecosystem. Several factorsmay cause these emergences, among which evolution of sylviculture practices, environnementalchanges, or introduction of alien pathogen by international trade. Those causes often can occurtogether and precisely assessing their importance is an important scientific question.In France, Alnus glutinosa is threatened by the development of the epidemic caused byPhytophthora alni. This pathogen is known to have been invasive in part of Europe and is the resultof an interspecific hybridation event between Phytophthora alni subsp. uniformis and Phytophthoraalni subsp multiformis. The aim of this study was to assess whether the climate warming of the lastdecades might have participated in the disease emergence. For that, P. alni soil inoculum andincidence of the crown decline and of canker were monitored on 16 sites located along a altitudinalgradient in NE France used as an proxi for a temperature gradient. The results show that the diseaseincidence, i.e. the likelihood of new disease case in the sites, was positively correlated with the meantemperature of the winter. Evolution of past river temperature in the last 40 years suggest thatclimate warming could by one of the cause explaining the emergence of P. alni alder decline.Mots-clés : maladies végétales; milieux naturel; émergence; changement climatique44