Abstract We describe a method for inoculating rachises of Fraxinus excelsior (European or common ash) with Hymenoscyphus fraxineus, which is faster than previous methods and allows associated foliar symptoms to be assessed on replicate leaves. A total of ten ash seedlings were inoculated with five isolates of H. fraxineus and lesion development assessed over four weeks. A five‐point disease progress scale of symptom development was developed from no lesion (0), lesion on rachis (1), “pre‐top dead,” with curling of distal leaflets and bending of the rachis (2), top dead, with wilting and death of distal leaflets (3) to leaf abscission (4). The method revealed variation in aggressiveness of H. fraxinus isolates and may be suitable for assessing the resistance of F. excelsior and other Fraxinus species to dieback. The in vitro growth rate of H. fraxineus isolates was highly correlated with both disease progress and the length of rachis lesions on susceptible plants, indicating that it can be used as a preliminary step in selecting isolates with high aggressiveness for use in resistance screening.

中文翻译：

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评估白蜡蚴对白蜡叶致病性的通用方法

摘要 我们描述了一种用 Hymenoscyphus fraxineus 接种 Fraxinus excelsior（欧洲白蜡树或白蜡树）轴的方法，该方法比以前的方法更快，并且可以在复制的叶子上评估相关的叶面症状。总共十棵白蜡树幼苗接种了五种白蜡树菌株，并在四个星期内评估了病变的发展。症状发展的五点疾病进展量表是从无病变（0）、轴上的病变（1）、“上死前”、远端小叶卷曲和轴弯曲（2）、上死、远端小叶 (3) 枯萎和死亡，直至叶子脱落 (4)。该方法揭示了白蜡树分离株的攻击性变化，并且可能适合评估白蜡树和其他白蜡树物种对顶枯病的抗性。H. fraxineus 分离株的体外生长速率与易感植物上的疾病进展和轴病变长度高度相关，表明它可以作为选择具有高侵袭性的分离株用于抗性筛选的初步步骤。