The occurrence of Hymenoscyphus pseudoalbidus apothecia in the leaf litter of Fraxinus excelsior stands with ash dieback symptoms in southern Poland

Abstract

The paper presents the results of a study performed in 28 ash stands located in Myśleniece and Dynów Forest Districts in southern Poland. The intensity of Fraxinus excelsior disease process was estimated based on the disease symptoms analysis of 1400 trees. The amount of infectious material of Hymenoscyphus pseudoalbidus (anamorph Chalara fraxinea) was estimated by the leaf litter examination on 166 square (0.5 × 0.5 m) plots. The total number of ash leaf rachises and apothecia were counted. The analysis shows that the estimated number of H. pseudoalbidus apothecia may reach from 370 thousand to over 13 million per hectare at a time.