Bleeding Canker of European Beech in Southeastern New York State: Phytophthora Species, Spatial Analysis of Disease, and Periodic Growth of Affected Trees

Abstract

The epidemiology of bleeding canker, a Phytophthora-associated disease, on European beech remains unclear. Pathogen surveys as well as dendrological and spatial point pattern analyses (SPPA) were conducted to identify factors contributing to disease progress on beech at the Green-Wood Cemetery (GWC) and Planting Fields Arboretum (PFA) in southeastern New York State. Phytophthora pini was the predominant Phytophthora isolated from cankers as well as soil under asymptomatic and diseased (canker bearing) European beech at each site. No significant differences existed between asymptomatic and Phytophthora-infected trees according to diameter breast height, elevation, and the Phytophthora spp. The radial growth (25-yr chronology for 1986 to 2010) of infected European beech at GWC and PFA, however, was significantly less when compared to asymptomatic beech; yet, residual growth was similar among the latter cohorts, providing no evidence for the instigatory effect(s) of environmental stressors on disease progress. SPPA demonstrated all beech at GWC and PFA were planted in non-random aggregates, whereas the distribution of diseased European beech did not deviate from random. Collectively, results indicated bleeding canker is a slow, chronic disease and the overland tree-to-tree spread of P. pini, and accompanying Phytophthora spp., is rare or does not occur at GWC or PFA.