Browsing by Author "Lambon, J.B."
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Item Importance, etiology and management of the tear stain disease symptoms of mango fruits in Ghana(Springer, 2022) Honger, J.O.; Narh, S.; Lambon, J.B.The tear stain symptom refers to slightly raised blisters which reduce the aesthetic value of mango fruits in Ghana. The dis ease incidence, severity and percentage of exportable mango fruits on infected mango trees were determined in the coastal savannah zone of Ghana in 2019. Samples of disease fruits were collected and the causative agent isolated and identified using phenotypic and genotypic characteristics. Selected copper based fungicides, namely, Cuprous oxide (750 g/kg), Copper oxychloride (500 g/kg) and Mancozeb (800 g/kg) either solely or in combination with Acibenzolar-S-methyl were applied in the field to determine their effect on the disease incidence and severity and on the percentage of exportable fruits. The disease incidence ranged from 9.4% to 11.0% in the major season and 37.3% to 45.0% in the minor season. Severity ranged from 0.08 to 0.1 in the major season and 1.4 to 2.1 in the minor season. The fungus isolated showed the characteristic short conical spores with rounded edges, an indication that it was C. gloeosporioides. The combination of gene sequences of the ITS region and the partial actin gene identified the fungus as C. siamense. All fungicides evaluated were able to reduce the disease incidence and severity on treated trees and resulted in a higher percentage of exportable fruits compared to non treatment control trees.Item Molecular characterization, pathogenicity and copper sensitivity of Xanthomonas citri pv mangiferaeindicae, the causal agent of mango bacterial black spot disease in Ghana(Taylor & Francis Group, 2021) Honger, J.O.; Osabutey, S.; Nyaku, S.T.; Lambon, J.B.Recent outbreak of the mango bacterial black spot disease has resulted in massive damages to the Ghanaian mango industry. Research was carried out to confirm the etiology of the disease. Diseased mango fruits and leaves were collected from Greater Accra (Asutuare and Dodowa), Eastern (Akuse, Somanya) and Volta (Juapong) regions, and the sus pected causal bacterium was isolated. The pathogen was identified as Xanthomonas citri pv mangiferaeindicae based on cultural and morphological characteristics and sequence analysis of the cpn60 gene. The pathogenicity of the bacterial pathogen on mango and cashew was determined and its sensitivity to some selected copper based fungicides available in Ghana was evaluated by the agar diffusion bio-assay. All strains of the pathogen were able to cause disease symptoms on artificially inoculated mango and cashew leaves. The pathogen was highly sensitive to Copper oxychloride, Copper hydroxide and Coprous oxide at very low concentrations.