Schadbild und Ätiologie des Tannensterbens: III. Das Vorkommen einer Phytophthora‐Fäule an Feinwurzeln der Weißtanne: (Abies alba Mill.)
1982
Blaschke, H.
The occurrence of Phytophthora causing root rot of silver‐fir (Abies alba Mill). On a number of fine root systems taken from the subsoil in affected silver fir stands extensive necrosis is reported as being caused by Phytophthora ssp. Invasion of the fungus occurred within cortical and stelar tissue of both short lateral roots and long roots. The fungus was identified by vegetative and sexual characteristics. Baiting with silver fir seedlings was a useful method for recovering the root pathogen in affected forests. SUMMARY: Symptoms and etiology of dieback of silver fir (fir dying). III. The occurrence of Phytophthora causing root rot of silver fir (Abies alba Mill.) Fine root samples taken from the subsoil in diseased silver fir stands were examined for the presence of root rot symptoms. Phytophthora ssp. was recovered for the first time as being associated with the dying of short roots and suberized partially woody long roots of silver fir. The pathogen proliferated interand intracellularly within cortical and stelar tissue. Plating of necrotic root tissue on selective agar media was used for isolation. Characteristics for the recognition of Phytophthora ssp. were the formation of distinctive mycelium, chlamydospores, sporangia together with oospores formed on agar culture or within a number of cortical cells. In addition baiting with silver fir seedlings provided indirect information on the occurrence of the pathogen in stands affected by fir dying.
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