Browsing by Author "Bua, Bosco"

Now showing 1 - 5 of 5
  • Thumbnail Image
    Item
    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.
  • Thumbnail Image
    Item
    Quantification of yield loss to pineapple heart rot disease on pineapple cultivars in Uganda
    (Journal of Animal & Plant Sciences, 2019) Oculi, Jasper; Bua, Bosco; Ocwa, Akasaire
    Pineapple (Ananas comosus L. Merr) is an important fruit crop in Uganda. Pineapple production in Uganda is devastated by pineapple heart rot disease (PHRD) which is associated with serious economic and yield losses. Therefore, this study quantified yield loss on five pineapple cultivars to pineapple heart rot disease in central Uganda. Five cultivars (Smooth Cayenne, Victoria, Sasilimu, MD-2 hybrid and Red Spanish) were tested for latent infection by planting the suckers in buckets containing 10 kilograms of sterile soil for four month. Disease free suckers, four month old, of average size from the five cultivars were planted in pots containing 10 kilograms of sterile clay-loam soil in the screen house in 2016/2017 in a completely randomized design (CRD). Treatments consisted of protected pots, un-protected pots and control pots respectively. Pineapple plants in the protected pots had their suckers dipped for three minutes in a solution of Metalaxyl (Active Ingredients: methoxyacetyl)-N-(2, 6-xylyl)-DL-alaninate 8%) before planting and later sprayed with a solution of Fosetyl Al (Active Ingredients: Aluminum tris 80%) using a backpack sprayer with Hardir flat spray nozzles three weeks after planting. Pineapple plants in the unprotected pots were not treated with any fungicide. The suckers in protected and unprotected pots were inoculated with 108ml of zoospores using needle-mediated leaf base wound technique. Control pots were not inoculated. Data on pineapple heart rots caused by the pathogen was collected from all the pots and thus used to compute yield loss per cultivar. Data was analyzed usin analysis of variance (ANOVA) of the GenStat computer program (15th edition). Pineapple heart rot disease (PHRD) significantly (P<0.001) reduced pineapple yield in the un-protected pots across all the five cultivars evaluated in both trial one and trial two. Metalaxyl (Ridomil) and Fosetyl Al treatment significantly (P<0.001) reduced yield losses in all the five cultivars used in the Protected pots in trial one and trial two respectively. The highest and lowest yield loss was recorded in cultivar Victoria and Smooth Cayenne respectively. PHRD can cause 100% yield loss. Metalaxyl (Ridomill) and Fosetyl Al is recommended for the control of PHRD in Uganda
  • Thumbnail Image
    Item
    Relating Water Management Regimes and Rice Genotypes with Occurrence of Insect Pests and Diseases of Rice in Uganda
    (Journal of Global Agriculture and Ecology, 2016) Awio, Thomas; Karungi, Jeninah; Bua, Bosco; Lamo, Jimmy
    The research was conducted to assess the effect of water management regimes and/or rice genotypes on occurrence of insect pests and diseases of rice in Uganda. The study was conducted in phased field trials under natural conditions during the second rainy season of 2012 and the first rainy season of 2013. The trials were laid out in a Randomised Complete Block Design arranged as a split plot with three replications. Water management regimes (alternate wetting and drying-AWD, continuous flooding-CF and continuous drying-CD) constituted the main-plots and rice genotypes the sub-plots. Results indicated that the stalked-eyed fly (Diopsis spp) and African rice gall midge (Orseolia oryzivora) were the most encountered insect pests and both pests occurred highest in CF fields. Rice blast, brown spot, grain rot, rice yellow mottle virus (RYMV) and sheath rot were the diseases recorded in rice during the study. Rice blast and brown spot were the most prevalent diseases (>10% incidence), and brown spot was most prevalent under the AWD regime whereas RYMV was most prevalent in the CF regime. The level of occurrence of rice blast and RYMV recorded in the different water management regimes was dependent on the rice genotype. Generally, different genotypes had different insect pest/diseases occurrence profiles. The implication of these findings therefore is that for effective integrated pest management, knowledge of the most limiting pest/disease is important in deciding the appropriate water management regime. However, further experimental trials need to be conducted in different agro-ecological zones to verify these findings.
  • Thumbnail Image
    Item
    Response of Onion to Different Organic Amendments in Central Uganda
    (Journal of Agricultural Science and Technology, 2017) Bua, Bosco; Owiny, Raphael; Ocwa, Akasairi
    Onion is one of the most important vegetable crops grown in Uganda, because of its nutritional and economic value. However, production of onion in Uganda is very low due to nutritional imbalances in the soil. Therefore, soil fertility remains one of the key areas of focus in sustaining onion production. A field experiment was conducted to assess the response of onion variety Red Creole C-5 to different soil organic amendments at Kyambogo University during the period February 2016 and January 2017. The experiment was laid out in a randomized complete block design with four replications. The treatments included T0: without manure (control), T1: green manure (GM), T2: farmyard manure (FYM) and T3: compost manure (CM). Data collected included: plant height, root length, plant fresh and dry weight, number of leaves per plant, fresh and dry weight of bulbs, diameter of bulbs and commercial yield computed. Data were analysed using Genstat. There was significant response of onion to the different soil organic amendments. Onion plant height, number of leaves, root length, dry and fresh weight and bulb weight were high in farmyard manure, followed by compost manure and lastly green manure, compared to the control. The highest yield (12,000 kg/ha) was obtained from the plots amended with farmyard manure as opposed to the control. It was therefore concluded that farmyard manures had a greater effect on the agronomic and yield performance of onion. Future study with more than one onion genotype is recommended so as to widen the scope of this result.
  • Thumbnail Image
    Item
    Validating the Role of African Indigenous Vegetables for Food and Nutrition Security in Uganda
    (Journal of Food Science and Engineering, 2017) Bua, Bosco; Onang, Christopher
    African indigenous vegetables (AIVs) play an important role in house hold food and nutrition security among many communities in Uganda. However, there is limited information on the value chain. Yet, the contribution of AIVs in terms of food and nutrition security is undisputable. A cross sectional survey targeting 60 respondents including farmers, key informants and extension officers was conducted to assess the systems of production system of the AIVs, profile an inventory and diversity of the cultivated AIVs in Agweng sub-county, Lira district. Semi-structured questionnaires and direct field observation were used to gather the necessary data. The findings revealed that AIVs form a very important part of the diets of the local populace both during the normal and off seasons as well as hard times among others. However, a number of constraints were reported to hinder the AIVs value chain including lack of quality seed, competition from exotic vegetables, low market demand, pests and diseases infestation, among others. The most commonly cultivated and consumed vegetables were cowpeas, hibiscus, pumpkins and crotolaria among others. The reasons for cultivation and consumption included source of food, high nutritive value and short maturity period. Other reasons were medicinal, resistance to pests and diseases, source of cash income and resilient to harsh weather conditions. In contrast, lack of quality seeds, bitterness, low market demand and difficulty in preparation contributed to their neglected use. Therefore, in the wake of climate change and variability there is need for deliberate investment to improve adaptability and acceptance of these vegetables. There is also need for sensitization of farmers on the benefits of AIVs, developing an effective means of improved seed production and distribution to replace the farmer-to farmer seed exchange and conservation of AIVs germplasm as the strategies to improve AIVs production in the study area.