بيماري پوسيدگي رايزوكتونيايي ريشه و طوقه گياه دارويي رزماري (.Rosmarinus officinalis L ) در شهرستان كرج

Rhizoctonia root and crown rot disease of rosemary medicinal plant {Rosmarinus officinalis L.) in Karaj

Rosemary is a perennial succulent plant that culture of this plant for pharmacy and cosmetic industries is most important in Iran and scientific name of rosemary is Rosmarinus officinalis. A major product of Rosemary is cultured in Tehran province. Major pathogen of this plant is Rhizoctonia solani Kuehn. Plant disease samples were taken from Karaj (Institute of Medicinal Plants, Iranian Academic Center for Education, Culture and Research). Symptoms on original plant included root and crown rot, canker and vascular tissue darkening and pith and root hallow and eventual darkening in order to isolate disease agent(s), symptomatic root and crown tissues after surface sterilization with sodium hypochlorite (1%), were cultured on PDA medium in petri dishes. Fungal colonies grew from tissue segments and were subsequently culture. Hyphal tip was removed from colony of rhizoctonia margin placed on PDA medium and incubated in dark stained hyphal diameter of about one hundred hyphae measured. After nuclear staining of rhizoctonia single hyphae contained several nuclei. The fungal isolate identified as Rhizoctonia solani based on the following test. From the results of this study it is concluded that Rhizoctonia solani is the causal agent of root and crown rot disease of Rosmarinus officinalis in Karaj.