Annual monitoring of wilt pathogens on elm trees in Alberta is part of a provincially-regulated prevention and control program for Dutch elm disease. Over the past eight years (2016–2023), twig samples with wilt symptoms from 200 elm trees across Alberta were tested for the presence of wilt pathogens. Plenodomus tracheiphilus, the causal agent of Mal secco disease of citrus trees, was isolated from 116 out of the 200 elm trees. The identification of this fungus was confirmed morphologically by comparison with the type culture, and sequencing the internal transcribed spacer region, the β-tubulin gene, the DNA-directed RNA polymerase II second largest subunit gene, the actin gene and eight protein-coding genes exclusively present in the P. tracheiphilus genome. The pathogenicity of P. tracheiphilus isolated from Alberta was tested by artificial inoculation on elm trees to fulfill Koch's postulates based on symptom observation and fungal re-isolation. Our data indicated that P. tracheiphilus is commonly present in Alberta’s elm trees especially in the Edmonton area and that the previously described Dothiorella elm wilt is actually caused by P. tracheiphilus and not Dothiorella ulmi.

对艾伯塔省榆树枯萎病原体的年度监测是省级荷兰榆树病预防和控制计划的一部分。在过去八年（2016 年至 2023 年）中，我们对艾伯塔省 200 棵榆树出现枯萎症状的树枝样本进行了检测，以确定是否存在枯萎病原体。Plendomus tracheiphilus是柑橘树 Mal secco 病的病原体，从 200 棵榆树中的 116 棵中分离出来。通过与典型培养物比较，并对内转录间隔区、β-微管蛋白基因、DNA引导的RNA聚合酶II第二大亚基基因、肌动蛋白基因和八个蛋白质编码基因进行测序，从形态学上证实了该真菌的鉴定。只存在于P. tracheiphilus基因组中。通过在榆树上人工接种来测试从阿尔伯塔省分离出的气管假单胞菌的致病性，以满足基于症状观察和真菌重新分离的科赫假设。我们的数据表明，P. tracheiphilus普遍存在于艾伯塔省的榆树中，特别是在埃德蒙顿地区，并且之前描述的 Dothiorella 榆树枯萎病实际上是由P. tracheiphilus而不是Dothiorella ulmi引起的。