African Journal of Wood Science and Forestry

African Journal of Wood Science and Forestry ISSN 2375-0979 Vol. 12 (8), pp. 001-008, August, 2024. Available online at www.internationalscholarsjournals.org © International Scholars Journals

Full Length Research Paper

Impact of Hymenoscyphus pseudoalbidus on Fraxinus excelsior Seed Plantations in Austria

Thomas Kirisits* and Christian Freinschlag

Institute of Forest Entomology, Forest Pathology and Forest Protection (IFFF), Department of Forest and Soil Sciences, University of Natural Resources and Life Sciences, Vienna (BOKU), Hasenauerstraße 38, A-1190 Vienna, Austria.

Accepted 30 April, 2024

Abstract

Ash dieback, an emerging fungal disease incited by Hymenoscyphus pseudoalbidus (anamorph Chalara fraxinea), causes immense damage to Fraxinus excelsior in many parts of Europe. There is hope that some individuals of this tree species display high levels of resistance to the disease. In 2009 and 2010, the intensity of ash dieback was investigated in an ash seed plantation in Upper Austria, consisting of 51 clones of local provenance. A specific rating system for visual inspections was developed to assess shoot, twig and branch dieback as well as leaf shedding. Considering all 187 evaluated trees, mean ash dieback intensity was 18.1% in July 2009 and 17.6% in July 2010. Disease intensity varied greatly between clones, ranging in both years from almost no dieback to more than 80% dieback in the most severely affected clone. Likewise, levels of leaf shedding in July and September differed considerably between clones. However, no clear relationship between leaf shedding and dieback intensity was observed. The results indicate that F. excelsior clones in the seed plantation may indeed differ substantially in their resistance to H. pseudoalbidus.

Key words: Chalara fraxinea, common ash, disease assessments, emerging fungal disease, resistance.