Details on the situation of the Phytophthora disease of alder in France
In France, the Phytophthora disease of alder (EPPO Alert List - EPPO RS 99/134) was first detected in 1996 in the south-west and the north-east. Surveys have been carried, and so far the alder disease mainly occurs in three zones: 1) south west: the fungus was isolated in the départements of Gironde and Landes; 2) west: three foci were detected in Deux-Sèvres, Vendée, Maine et Loire; and 3) north east: the disease has caused tree mortality on more than 50 locations in 11 départements. The pathogen was found on alders along the main rivers but also along smaller rivers, lakes and in easily flooded zones in forests. The pathogen was also detected in surface water, in particular in the river Moselle during floods in spring. In other parts of France, dieback symptoms of alder have been sporadically observed but have not been attributed to the Phytophthora disease as no systematic surveys were done in these areas.
Sources
Streito, J-C.; de Villartay, G.; Tabary, F. (1999) Une nouvelle espèce de Phytophthora s'attaque à l'aulne.
Phytoma - La Défense des Végétaux, no. 519, 38-41.
Web site of the Laboratoire National de la Protection des Végétaux, Nancy (FR)
Le Phytophthora de l'aulne.
http://perso.wanadoo.fr/lnpv/nancy/aldphyt.htm