Variability in Pine Pitch Canker Susceptibility among Scots Pine (Pinus sylvestris) Provenances in Eastern Europe

Pine pitch canker, caused by the ascomycete Fusarium circinatum, poses a substantial threat to pine trees and Douglas firs (Pseudotsuga menziesii), and has been identified as a pervasive issue in forests and nurseries worldwide, particularly in regions where susceptible conifers are cultivated. Given its prevalence in the Iberian Peninsula, assessments of the susceptibility of diverse European provenances of Scots pine (Pinus sylvestris)-specifically those from Poland, Lithuania, and Ukraine-have been conducted. Preliminary evaluations of Polish provenances have raised concerns about the potential threat to Scots pine stands in Poland posed by pitch canker. Under controlled conditions, we examined the impact of F. circinatum inoculation on the survival of seeds and seedlings from ten provenances of Scots pine. In response, the initial assessment of F. circinatum pathogenicity was undertaken in a controlled greenhouse environment. This evaluation uncovered a heightened susceptibility of pine seedlings to pitch canker among the tested provenances. Notably, one Lithuanian provenance demonstrated superior resistance to pitch canker, while two Polish provenances exhibited a higher prevalence of symptomless seedlings. These findings underscore the need for further exploration and identification of resilient individuals within these provenances, offering valuable insights for developing strategies to mitigate the impact of pitch canker on Scots pine in Europe.