Inspection of ornamental cut-flower plantation in Cairo, Giza and Qalubyia governorates revealed a considerable occurrence of root-rot, wilt and/or damping-ofif infection in carnation (Dianthus caryophyllus), gerbera (G. jamesonii) and marigold (Tagetes spp.). Infection was found to be gradually increased year by year. Based on symptomatology, morphological and cultural characteristics, the fungal agents of these diseases were identified. Fusarium spp., Rhizoctonia solani & Pythium sp. (carnation), as well as Fusarium spp. & Phytophthora sp. (gerbera and marigolds) were the highest frequent fungi in isolation trials. Fusarium isolates of carnation and gerbera were identified as: F. equiseti, F. oxysporum (or f.sp. dianthi), F. semitectum & F. solani. while those of marigolds were: F. moniliforme, F. oxysporum & F. solani. According to the available literature, the recorded diseases of gerbera and marigolds and their fungal pathogens arc reported for the first time in Egypt.
In infested soil, pathogenicity tests indicated that F. oxysporum f.sp. dianthi & R. solani (carnation), Phytophthora sp. & F. oxysporum (gerbera) and Phytophthora sp., F. moniliforme & F. oxysporum (marigold) were the most aggressive fungi. Whereas, F. solani & Pythium sp. (carnation), F. semitectum & F. solani (gerbera) and Sclerotinia sclerotiorum (marigold) were less aggressive. On the other hand, distinct disease symptoms for several pathogenic fungi were fully described. F. oxysporum (or f.sp. dianthi) showed, however, a characteristic features of wilt symptoms on the infected plants characterized with dark brown discoloration on vascular system and often accompanied with reduction in root system formation. Also, the infection by fungi causing root and/or collar rots were usually associated with yellowing, browning or dryness on leaves. |
