Das Rindensterben der Buche, Fagus sylvatica L., verursacht durch die Buchenwollschildlaus Cryptococcus fagi Bär.I. Die Anatomie der Buchenrinde als Basis-Ursache

Abstract

Beech (Fagus sylvatica L.) bark disease, caused by Cryptococcus fagi Baer. I. Anatomy of bark of Fagus sylvatica L. as a basic factor. The bark of beech possesscs broad phlocm rays which become totally sclerotic. These sclerotic phloem rays are a spcciality of Fagus sylvatica L. (and Fagus orientalis Lipsky, Fagus grandilolia Ehrh.) Thc sclerotic phloem rays act as rigid, radially running barriers which block formation of a normal rhytidome. When formation of a rhytidome is induced artificially a necrotic pathological rhytidome develops. The inability of beedi to form a normal and effectivc rhytidome due to sclerotic phloem rays is considcred to bc a basic factor in beech bark disease.