Fusarium wilts on native silk trees (Albizia julibrissin Durz) in the north of Iran, Gorgan

In this study vascular wilt symptoms were observed on silk trees during ‏‏2010-2011. Stems with symptoms were transferred to the laboratory and cut into smaller pieces. The small pieces were disinfected with alcohol 70% for 30 seconds. After drying on the filter paper, four of these pieces were cultured on a PDA culture medium into each petri dish. After ten days, fungal colonies provided by slide were examined under the microscope and found that the funguses are related to the genus Fusarium. The characteristics of the colonies and conidia of the fungus were investigated with Nelson Fusarium key. The colony and conidia, characteristics were consistent with Fusarium oxysporum species of Nelson Fusarium key. To prove the pathogenicity of fungi, the one year old silk three seedlings were inoculated with three days old mycelia on agar block of the fungi. After 20 days of treatment, the wilt symptoms and yellowing gradually appeared. The petioles with symptoms have been removed and the after disinfection and drying were cultured on a PDA culture medium. After a week, fungal the colonies and conidia appeared in the previous specifications.