Assessment of lesion development in Fraxinus excelsior cultivars Altena, Atlas and Westhof's Glorie inoculated with different isolates of Hymenoscyphus fraxineus

Hinke Wiersma, Joukje Buiteveld, Jelle Hiemstra, Paul Copini*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

Ash dieback caused by the invasive fungus Hymenoscyphus fraxineus leads to massive mortality among common ash (Fraxinus excelsior) in Europe. To select tolerant genotypes, inoculation experiments are frequently conducted with isolates of the fungus. The aim of this study was to improve the inoculation methodology for evaluating susceptibility of ash genotypes to ash dieback through (i) testing the virulence of different isolates of Hymenoscyphus fraxineus and (ii) investigating temporal lesion development using three widely applied cultivars: Altena, Atlas and Westhof's Glorie. First, an experiment was conducted with a repeated measure design in which virulence of five different isolates was tested. Second, a subset of two isolates that induced the longest downward lesion length in experiment one was used in combination with a slightly adjusted inoculum protocol. Significant differences were found between isolates for downward lesion length, but a significant interaction effect of isolates and cultivars was absent. Also, the inoculation position within the stem affected lesion length; the largest lesions were found on the highest inoculation position within the stem. Furthermore, we found that cryopreserved isolates can remain virulent over years. The timing of inoculation at the end of the growing season was effective as large lesions already occurred during winter dormancy. For future inoculation studies, we propose to use: (i) isolates that induce large lesions, as less virulent isolates induced not only shorter but also fewer lesions; (ii) a similar inoculation position to better compare inoculations within and between experiments; (iii) cryopreserved isolates for testing over years; (iv) mycelial suspensions for inoculum preparation to cover wood chips more evenly; (v) reference clone—like the studied cultivars—to standardize research outcomes between years and research groups.

Original languageEnglish
JournalForest Pathology
Volume52
Issue number5
Early online dateSept 2022
DOIs
Publication statusPublished - Oct 2022

Keywords

  • cultivar susceptibility
  • Fraxinus excelsior
  • Hymenoscyphus fraxineus
  • inoculation experiments
  • lesion development
  • virulence

Fingerprint

Dive into the research topics of 'Assessment of lesion development in Fraxinus excelsior cultivars Altena, Atlas and Westhof's Glorie inoculated with different isolates of Hymenoscyphus fraxineus'. Together they form a unique fingerprint.

Cite this