01510nas a2200133 4500008004100000245006100041210006000102300001200162490000700174520111200181100001601293700002101309856004601330 1999 eng d00aPhytophthora species in oak forests of north-east France0 aPhytophthora species in oak forests of northeast France a539-5470 v563 a

Phytophthora species were surveyed from the end of 1997 through July 1998 in oak forests in NE France. Healthy (Amance) or declining (Illwald) forests were compared. The Phytophthora population in both was diverse and locally abundant. At least eight species were present at Amance and six at Illwald. At Amance Phytophthora species had a localized distribution in water and low-lying soils. At Illwald distribution was more uniform apparently due to flooding events. Most often recovered were P. citricola, P. gonapodyides and P. quercina. P. gonapodyides was ubiquitous in water and colonized leaf debris. P. quercina was widely distributed in soil but not abundant, and was found in sites that did not otherwise appear to favor Phytophthora. No correlation was detected between presence of Phytophthora in soil and health of trees. Unusual combinations of environmental factors may be required for resident Phytophthora to have a detrimental impact on oaks. © 1999 Editions scientifiques et médicales Elsevier SAS.

1 aHansen, E M1 aDelatour, Claude uhttp://dx.doi.org/10.1051/forest:19990702