الملخص الإنجليزي
Oman Botanic Garden (OBG) was established in 2006 to conserve, display and research the plants and ethnobotany of Oman. However, over one thousand seedlings and plants were killed over the previous years due to diseases of unknown etiology. This study was conducted to characterize the main fungal pathogens associated with foliar and root diseases of six native plants at OBG. A survey over 2008 to 2010 which covered all OBG plants and seedlings showed that root rot, soft rot of stems, wilt symptoms, die back, leaf spots, canker and galls are the main disease symptoms associated with plants at OBG. Incidence of leaf spot disease in Aloe dhufarensis, Cissus quadrangularis and Ficus sycomorus was 100%, 95% and 30%, respectively. Mortality in Crotalaria saltiana, Echidnopsis scutellata and Caralluma quadrangular due to root rot and/or wilt diseases reached 75%, 60% and 45%, respectively. Isolations followed by molecular-based identification of fungal pathogens showed that Cladosporium cladosporioides and Alternaria alternata were the most common pathogens associated with leaf spot diseases of the three native Plants. Rhizoctonia solani, Fusarium solani and Pythium aphanidermatum were the most common pathogens associated with root diseases of the other three native Plants. Investigating potting media, soil and water samples used at OBG for contamination with fungal and oomycete pathogens provided evidence that some wilt and leaf spot inducing fungi can be transmitted via potting media.
This is the first report of association of these pathogens with diseases in these six plants. The study recommends applying strict quarantine measures in OBG nursery, investigating management options for these diseases and doing further studies to know the pathogens associated with other native Omani plants.
