%0 Journal Article
%J New Phytologist
%D 2003
%T Pathogenicity of Swedish isolates of Phytophthora quercina to Quercus robur in two different soils
%A Jönsson, Ulrika
%A Thomas Jung
%A Rosengren, Ulrika
%A Nihlgård, Bengt
%A Sonesson, Kerstin
%X
Several studies have demonstrated the involvement of soil-borne Phytophthora species, especially Phytophthora quercina, in European oak decline. However, knowledge about the pathogenicity of P. quercina in natural forest soils is limited.
The short-term effects of two south-Swedish isolates of P. quercina on root vitality of Quercus robur seedlings grown in two different soils, one high pH, nutrient-rich peat–sand mixture and one acid, nitrogen-rich but otherwise nutrient-poor forest soil are described. Pathogenicity of P. quercina was tested using a soil infestation method under a restricted mesic water regime without prolonged flooding of the seedlings.
There was a significant difference in dead fine-root length between control seedlings and seedlings grown in soil infested with P. quercina. Trends were similar for both soil types and isolates, but there was a higher percentage of fine-root die-back and more severe damage on coarse roots in the acid forest soil. No effects on above-ground growth or leaf nutrient concentration between control seedlings and infected seedlings were found.
The results confirm the pathogenicity of south-Swedish isolates of P. quercina in acid forest soils under restricted water availability. Stress-induced susceptibility of the seedlings and/or increased aggressiveness of the pathogen in the forest soil are discussed as key factors to explain the difference in root die-back between soil types.
%B New Phytologist
%V 158
%P 355 - 364
%8 05/2003
%G eng
%N 2
%! New Phytol
%R 10.1046/j.1469-8137.2003.00734.x