First report of Phaeobotryon ulmi causing decline in Ulmus glabra in Finland
In June 2025, declining Ulmus glabra trees showing shoot and branch dieback were sampled in Helsinki and later in Vantaa, Finland. Fungal isolates from symptomatic tissues were cultured and 12 were sequenced (ITS). No Ophiostoma species were detected. Instead, the associated pathogen was identified as Phaeobotryon ulmi, confirmed by ITS (identical between sites) and ß-tubulin sequencing.   In August 2025, four U. glabra branches were inoculated with P. ulmi (isolate ELM1-4). Inoculated branches developed clear necrosis, while controls remained healthy. P. ulmi was reisolated only from inoculated material, and ITS sequencing confirmed its identity.