شناسایی قارچ بیماری‌زای کاج در شهر تهران

In order to identify the fungal agent involved in the red rot of pine trees in Tehran in different seasons of 1402, sampling and isolation of fungi were done from pine trees in several parks with disease symptoms. The samples sent to the laboratory were thoroughly washed with running water, and in order to separate the fungi, parts of the root, crown, leaf, and stem areas between healthy and infected tissue were separated and immersed in sodium hypochlorite solution for 3-5 minutes. The percentage of surface disinfection and then they were washed three times with sterile distilled water and their moisture was taken by sterile filter paper. Then these parts were cultured on PDA (potato-dextrose-agar) medium and purified in WA (water-agar) medium. After purification, a piece of the active margin of the growing mycelium was cultivated in a petri dish containing PDA (potato-dextrose-agar) and placed in an incubator for ten days at 25 degrees Celsius. Identification of fungal isolates using the mycological key of Nelson et al. (1983) and Seifert (1996) by preparing microscopic slides and based on microscopic characteristics such as: shape, size, presence or absence of microconidia and its shape, presence and Absence of chlamydospore, presence or absence of microconidia chain and appearance characteristics of mushroom colony color especially from the bottom surface and colony growth rate were done. As a result, 10 fungal isolates of Fusarium solani species were obtained. The proof of the pathogenicity of the disease agent was done by infecting one-year-old pine seedlings in the open air, in such a way that several discs of the growing fungus were placed in the soil of the pots (around the crown and root of the seedling). Pathogenicity was proved after two months by the formation of wounds in the crown, roots and yellowing and drying in the needles of the seedlings. The mentioned fungus was isolated and identified from the inoculated seedlings that had disease symptoms. The correctness of the isolates identified by molecular identification method was also confirmed by ITS-rDNA sequencing.