| Abstrakt: |
Background and objectives: Carpinus orientalis Mill is a native tree growing in the forests of northern Iran. This tree-shrub plant is shorter and more branched compared to hornbeam (Carpinus betulus L.) and thrives in sunny and rocky areas. The Cytospora genus is known as a primary agent of canker, causing damage to trees affected by stress factors such as water stress, frost stress, sunburn, or mechanical damage (caused by non-living and living agents such as insects). Disease occurrence by different species of Cytospora spp. has been reported in a wide range of hosts, including species from the genera Populus, Salix, Acer, Ulmus, Alnus, Fraxinus, Prunus, Sorbus, Cydonia, Amelanchier, and many others. Methodology: To identify the causes of oriental Hornbeam decline in Mazandaran province, samples from infected tissue were collected and transferred to the laboratory for fungal isolation. The most prominent symptoms of the disease were shoot dieback and dead or dying branches visible from a distance. In humid weather, cankers exuded clear amber resin, which eventually formed a clear white crust on the branches. In young seedlings, dried leaves remained on the branches, and the seedlings were completely desiccated, indicating the high severity of the disease. Fungal isolates were obtained by removing a mucoid spore mass from conidiomata (from the canker areas) and by disinfecting and culturing infected tissue on Potato- Dextrose-Agar (PDA) medium, incubated at 23±2°C in darkness. After purification of the fungal isolate by single spore, various morphological characteristics including spore shape and size, colony diameter, growth rate, and pigment production were evaluated on PDA medium. Results: The fungus grew rapidly on PDA and produced cream-white to hyaline, moderate to profusely cottony aerial hyphae. Conidia were hyaline, unicellular, with thin walls and no septa. A transverse section of the infected tissues showed long conidiophores inside the fungal stromata. Based on morphological characteristics, the fungus was identified as Cytospora sp. The morphological results indicated a similarity between this isolate and C. decipiens species. This is the first report of 'Carpinus orientalis decline' caused by Cytospora species in Iran. Conclusion: Investigating the epidemiology and management of cytosporic canker disease is of particular importance because its development is expected to intensify under future drought and climate stress conditions. Currently, due to increasing reports of decline caused by Cytospora, especially in Hornbeam species, the lack of information about the host range and epidemiology of the fungus, and the possible role of climate change in disease development, it is clear that this disease warrants further study. [ABSTRACT FROM AUTHOR] |
