Investigation on oak charcoal disease in dieback affected forests of Ilam province

In recent years, widespread tree dieback simultaneously with charcoal oak disease have occurred in Zagros forest especially in Ilam province. They dramatically caused damage to oak trees. This research was carried out to identify pathogenic fungi, to prove the pathogenicity and to investigate their pathogenic behavior during 2012-2015 in the forests of Ilam province. After several field observations across the forests of Ilam province, several samples were collected from infected parts of Persian Oak trees and transferred to the laboratory. Then, the samples were cultured to screen the pathogenic agents identified using morphological traits and validated by fungi keys. In order to prove the pathogenicity of the identified fungi, they were inoculated on two-year-old oak seedlings. In the final stage, the pathogenic behavior of fungi was studied. The results showed that fungi causing charcoal diseases in the forests of Ilam province were Biscogniauxia mediterranea and Obolarina persica. Furthermore, the fungi caused the disease on oak seedlings with dieback symptoms on the sections areas above the inoculum site. The study of the pathogenicity behavior of these fungi showed that their contamination began from inoculation site and developed in the wood, in addition to longitudinal extension, the hyphae colonized in transverse and radial directions towards the heartwood, so that it affects the xylem and phloem vessels. Considering the pathogenicity prove of these fungi and their contribution to the weakness and dieback of Persian oak trees, it would be possible to reduce the oak losses by eradicating the dead trees to prevent fungal spore spreading in the region.