The Occurrence of Stereum hirsutum Associated with Wood Rotting of Olive Trees in Iran

In summer 2021 (June–July), disease symptoms on trunks and shoots were observed in olive groves in the Tarom Sofla region, Qazvin province, Iran. The symptoms were light-pink discoloration and surface depression in the external layers of the wood. As the disease progressed, brown streaks of tissue appeared on the longitudinal sections of the wood. The identification of fungus was made based on PCR amplification of the rDNA-ITS region with the universal fungal primers ITS5 and ITS4. BLAST searches revealed 99.52% identity to Stereum hirsutum. Several species of basidiomycetes are known to live on wood as saprobionts or parasites. On olive trees, they cause white rot symptoms. Although they are not directly responsible for tree mortality; however, they can lead to structural deterioration of woody tissues. To the best of our knowledge, this is the first report of S. hirsutum associated with wood rotting of olive trees in the world.