First detection of Neoscytalidium dimidiatum associated with canker disease in Egyptian Ficus trees

Abstract

In September 2013, a canker disease of Ficus nitida and F. benjamina was reported for the first time in Assiut governorate, Egypt. Infected samples were collected from various locations. Pure cultures of a fungus were isolated on potato dextrose agar at 25°C from diseased plants. Morphological investigation and DNA sequencing showed that the causal agent was Neoscytalidium dimidiatum. A pathogenicity test conducted using 2-year-old plants of each host gave 70%-80% infection, and the pathogen was reisolated from the inoculated plants. A pure culture of N. dimidiatum was deposited in the culture collection of the Assiut University Mycological Centre (AUMC) under the code AUMC 9293 and the ITS sequence was placed in NCBI under accession number KX985929.

Molecular Characterization and Disease Control of Stem Canker on Royal Poinciana (Delonix regia) Caused by Neoscytalidium dimidiatum in the United Arab Emirates

“…For that reason, phylogenetic analysis using TEF1-α sequence (MN447201) was generated and proved the identity of the fungus as N. dimidiatum. N. dimidiatum was closely related to both N. novaehollandiae [33] and N. hyalinum [34], confirming previous findings [13,35]. Our data indicated that the isolate of N. dimidiatum in the current study was morphologically and genetically similar to other isolates of N. dimidiatum from Juglan regia, Prunus sp., mango and others.…”

“…The results obtained from the greenhouse experiment on young healthy plants after inoculation were similar to the disease symptoms on trees of royal poinciana located in the field, and that was confirmed by Koch's postulates when N. dimidiatum was frequently recovered from the inoculated seedlings. Our data match those in other trials using artificial inoculation of the same pathogen on royal poinciana [16] or other plant species [13][14][15]20,28]. Pathogenicity assays on seedlings of royal poinciana (Figure 4), F. benjamina and F. nitida [13] and eucalyptus, poplar and olive [30] clearly described that discoloration of vascular tissues, and drying and defoliation of leaves, were symptoms associated with stem canker caused by N. dimidiatum.…”

“…Our data match those in other trials using artificial inoculation of the same pathogen on royal poinciana [16] or other plant species [13][14][15]20,28]. Pathogenicity assays on seedlings of royal poinciana (Figure 4), F. benjamina and F. nitida [13] and eucalyptus, poplar and olive [30] clearly described that discoloration of vascular tissues, and drying and defoliation of leaves, were symptoms associated with stem canker caused by N. dimidiatum. There has been a rise in reports about N. dimidiatum causing diseases on fruits of pitahaya, plum and almond [12,14,15].…”

“…In general, we noticed dieback, canker and gummosis, which ultimately led to complete dryness and death of royal poinciana trees (Figure 1). Although some studies have reported several fungi to cause cankers on plant species [5][6][7][8], others have recorded N. dimidiatum on almond, dragon fruit, eucalyptus, fig and plum, displaying disease symptoms of canker and dieback in different places of the world [13][14][15]28]. In general, environmental stress has negative impact on the severity of disease, depending on the level and duration of the stress, and the sensitivity and developmental stage of the plant species.…”

“…Neoscytalidium dimidiatum is another fungal pathogen that causes cankers and has a wide geographical and host range, including plum, almond (Prunus dulcis), mango (Mangifera indica), pitahaya (Hylocereus undatus), Citrus, Musa, Populus, and Ficus spp. in Australia, China, Egypt, Niger, Tunisia and the USA [9][10][11][12][13][14][15].…”