Decline Symptoms on Root Systems of European Beech and Oak Species Caused by Phytophthora spp. : Disease/Environment Interactions in Forest Decline. Proceedings of a Workshop of the Working Party Disease/Environment Interactions in Forest Decline IUFRO 7.02.06, Vienna, Austria, March 16-21, 1998

1999

Unselbständiges Werk

14166

200083126

The more recent literature on beech- and oak-decline has documented dead or missing feeder roots, stripe cankers on woody roots, and bleeding scars on the trunk to be a manifestation of the poor health of trees. In unison with the detection and identification of Phytophthora quercina spec nov., a highly virulent soil-borne pathogen on Quercus robur, Quercus petraea, Quercus ilex, Quercus pubescens and Quercus suber, it is conceivable, that more or less distinct above- and belowground symptoms present on roots of beech and oak have been caused by Phytophthora cambivora, and other papillate or semi-papillate species of Phytophthora associated with Pythium sp. respectively. Results indicate that mature Fagus sylvatica has contracted infection of fine roots by Phytophthora cambivora much earlier and succumb to crown rot when stressed under adverse soil conditions. Possible reasons for the occurrence of similar disorders on fine roots of conifers in Europe and the decline of indigenous trees in Alaske, eastern North America and Canada are considered.