Summary Dothistroma needle blight (DNB), caused by Dothistroma septosporum and Dothistroma pini, and brown spot needle blight (BSNB), caused by Lecanosticta acicola, are some of the most serious and damaging foliar diseases of pines (Pinus spp.). Lecanosticta acicola is reported for the first time from Ireland and Portugal and confirmed from the Black Sea coast of Russia (Krasnodar region, Sochi). It has also been recovered from the first, and only, reported site in Latvia 4 years after efforts to eradicate it were undertaken. Dothistroma septosporum is reported for the first time from Ireland on Pinus sylvestris and Pinus radiata. It was also found in Comunitat Valenciana, Spain, and confirmed as the causal agent of the disease in Bulgaria. Dothistroma pini was found in Aragon, Spain, and in Arkansas, USA, where it was found on Pinus elliottii, a new host for this pathogen. A new ITS haplotype of D. septosporum is reported from the Bulgarian isolates and a new ITS haplotype of D. pini from the Arkansas isolates. These new country and regional reports extend the geographical and host range of these pathogenic fungi and continue a trend seen since the 1990s. Of particular concern are the geographically widespread new reports of L. acicola from the most north‐ and south‐westerly (Ireland and Portugal) to the most south‐easterly (Russia) regions in Europe, suggesting that not only is this pathogen continuing to spread in Europe but also is well adapted to a wide range of climatic conditions.

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Global warming affects the abiotic and biotic growth environment of plants, including the spread of fungal diseases such as Dutch elm disease (DED). Dutch elm disease-resistance of different Ulmus species varies, but how this is reflected in leaf-level physiological pathogen responses has not been investigated. We studied the impacts of mechanical injury alone and mechanical injury plus inoculation with the DED-causing pathogens Ophiostoma novo-ulmi subsp. novo-ulmi and O. novo-ulmi subsp. americana on Ulmus glabra, a more vulnerable species, and U. laevis, a more resistant species. Plant stress responses were evaluated for 12 days after stress application by monitoring leaf net CO2 assimilation rate (A), stomatal conductance (gs), ratio of ambient to intercellular CO2 concentration (Ca/Ci) and intrinsic water-use efficiency (A/gs), and by measuring biogenic volatile (VOC) release by plant leaves. In U. glabra and U. laevis, A was not affected by time, stressors or their interaction. Only in U. glabra, gs and Ca/Ci decreased in time, yet recovered by the end of the experiment. Although the emission compositions were affected in both species, the stress treatments enhanced VOC emission rates only in U. laevis. In this species, mechanical injury especially when combined with the pathogens increased the emission of lipoxygenase pathway volatiles and dimethylallyl diphosphate and geranyl diphosphate pathway volatiles. In conclusion, the more resistant species U. laevis had a more stable photosynthesis, but stronger pathogen-elicited volatile response, especially after inoculation by O. novo-ulmi subsp. novo-ulmi. Thus, stronger activation of defenses might underlay higher DED-resistance in this species.

Potential Dutch elm disease vector beetle species were caught with pheromone bottle traps and handpicked in 2019: in total, seven species and 261 specimens were collected. The most common was Scolytus triarmatus, but by percent, the incidence of Ophiostoma novo-ulmi was highest in Scolytus scolytus, followed by Xyleborinus saxesenii and S. triarmatus. We analysed the beetles’ DNA using PacBio sequencing to determine vector beetles of Ophiostoma novo-ulmi. Ophiostoma novo-ulmi was found on six out of seven analysed beetle species: Scolytus scolytus, S. triarmatus, S. multistriatus, S. laevis, Xyleborinus saxesenii and Xyleborus dispar. The last two beetles were detected as vectors for Ophiostoma novo-ulmi for the first time. Previous knowledge on the spread of beetles is discussed.