Browsing by Author "Akasairi, Ocwa"

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    Diagnostic Survey of Pineapple Heart Rot Disease in Lake Victoria Crescent of Uganda
    (International Journal of Phytopathology, 2018) Bosco, Bua; Akasairi, Ocwa; Jasper, Oculi
    Pineapple (Ananas comosus L. Merril) is a key horticultural crop in tropical and sub-tropical countries valued for its economic and nutritional importance. However, the recent outbreak of pineapple heart rot disease (PHRD) in Uganda is a serious threat to production. Yet, information on the prevalence, incidence and severity is limited and scanty. This study, therefore, assessed the prevalence, incidence and severity of pineapple heart rot disease in the districts of Masaka, Luwero, Kayunga and Mukono in the Lake Victoria crescent of Uganda in 2015. Semi-structured questionnaires were used to solicit information from 216 respondents. Data collected was analyzed using descriptive statistics of SPSS computer package versions 16.0. Varying incidences and severities of pineapple heart rot disease was observed in all fields surveyed. The disease was more prevalent in Kayunga than Masaka districts, respectively. Overall, 48% and 05% pineapple fields were infected with pineapple heart rot disease in Kayunga and Masaka district, respectively. Similarly, the highest and the lowest disease incidence were recorded in Kayunga and Masaka district, respectively. Overall, the incidence and severity varied from field to field. The findings have therefore shown that pineapple heart rot disease is widespread and devastating in central Uganda. Therefore, there is a need for the policymakers to priorities resources to develop an appropriate disease management strategy to combat this devastating epidemic to save the pineapple industry.
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    Morphological Identification of Phytophthora a Causal Organism of Pineapple Heart Rot Disease in Uganda
    (International Journal of Phytopathology, 2018) Akasairi, Ocwa; Bua, Bosco; Oculi, Jasper; Tusiime, Geoffrey
    Pineapple (Ananas comosus L. Merr) is an economic horticultural crop in Uganda. However, pineapple production is currently being threatened by the latest outbreak of pineapple heart rot disease in Uganda. Yet, information on pineapple heart rot disease causal pathogen is unknown. Therefore, the objective of this study was to identify the pathogen causing pineapple heart rot disease (PHRD) in Uganda. Samples of pineapple leaves with symptoms of PHRD were collected from four districts of Masaka, Luwero, Mukono and Kayunga. Pathogen isolation was done using corn meal agar (CMA) amended with Pimaricin, Ampicillin, Rifampicin Pentachloronitrobenzene, Hymexazol and Benomyl (PARPHB). Macro- and micro- morphological characteristics of the isolates were assessed using Potato dextrose agar (PDA) and V8 media, respectively. Pathogenicity of the isolates was tested using healthy pineapple plants based on Koch’s postulate. The results showed a significant difference (P<0.05) in the growth rates, hyphae diameter and asexual structure dimensions of the isolates. Isolates were characterized by a dense rosette and stoloniferous mycelial growth pattern in PDA media. Although, sporangia were non-caduceus, terminal, papillate and mostly ovoid, obpyriform and limoniform sporangia (32-56μm) with a mean length/breadth ratio of 1.32:1μm were observed. Chlamydospores were spherical and thick-walled (25-42μm diameter) while Sporangiophores branching was sympodial. Based on the morphological characteristics of isolates, it was concluded that Phytophthora nicotianae is the species causing pineapple heart rot disease in Uganda. This study, therefore, represents the first comprehensive information in Uganda. However, molecular identification of the pathogen is recommended to confirm the genetic identity of the species.