Pathogenicity tests of Phytophthora alni and Phytophthora plurivora in Fraxinus excelsior and Alnus glutinosa seedlings

Abstract

Phytophthora alni and P. plurivora have been associated to damage and death of Alnus glutinosa in Europe in recent decades. Recently, Fraxinus excelsior mortality was also associated to Phytophthora plurivora. In Spain, A. glutinosa appears with F. excelsior, creating riparian forests with a high ecological importance. The main objective of the study was to describe the susceptibility growth of Common alder and European ash from natural riparian populations in Northern Spain, using P. alni and P. plurivora isolates recovered also in Northern Spain. This study was divided into two independent experiments; Experiment I aimed at knowing the effect of soil infestation and stem inoculation with P. plurivora and P. alni on European Ash 1-year-old seedlings, and Experiment II aimed at evaluating P. plurivora infestations on different 3-month-old A. glutinosa seedlings from 5 different provenances. On Experiment I, Phytophthora plurivora and P. alni Spanish isolates didn’t prove to be pathogenic towards Fraxinus excelsior. All seedlings persisted until the end of the experiment on both treatments (Soil infestation and Stem inoculation), with no significant plant yield differences between isolates and control [...]