Uganda Journal of Agricultural Science (UJAS)
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Growth performance of 5-year old Pinus caribaea var. hondurensis (Barr. and Golf.) in selected districts of Uganda
Get PDFVariation in growth characteristics of Pinus caribaea var. hondurensis (PCH) has been reported across the major pine growing areas of Uganda. We assessed the growth performance of PCH from July 2012 to August 2013 in order to generate information needed to guide future interventions for improved pine management in the country. Growth parameters of 5-year-old PCH plantations were assessed in terms of height, diameter at breast height (DBH) and foxtailing in six districts. Data were analysed in the R statistical environment (version 3.1.1). Results showed that the pine trees registered good growth rates in Gulu and Mubende districts and poor growth rates in Nakasongola District. In Gulu and Mubende districts, the mean DBH was 17.29 cm and 14.44 cm, respectively, while the corresponding mean height was 12.39 m and 11.38 m. Growth of the pine trees in Nakasongola District was substantially slower, with mean DBH of 9.89 cm and mean height of 9.01 m. These growth rates correspond to mean annual increments (over bark) of between 15 and 19 m3 ha-1 y-1 on sites in Gulu and Mubende districts and 4.6 m3 ha-1 y-1 on sites in Nakasongola district. The percentage of foxtailing in all the study districts was 7.1. We recommend a longer time study of about 20 years to the age when the trees are expected to achieve full maturity. This will provide a more elaborate understanding of the influence of site and stand factors on growth performance of PCH in Uganda
Relative abundance of sweetpotato whitefly in orange-fleshed sweetpotato cultivars at Umudike, south-east Nigeria
Get PDFField experiments were conducted to evaluate the relative abundance of sweetpotato whitefly, Bemisia tabaci (Gennadius) on selected orange-fleshed sweetpotato (OFSP) cultivars namely: NRSP/05/022, CIP440293, Centennial, CIP199034.1, CIP199004.2, Shaba, Ex-Oyinga, SPK004 and one white fleshed (TIS87/0087) as a check at National Root Crops Research Institute (NRCRI), Umudike during the 2010 and 2011 cropping seasons. The experiments were laid out in a Randomised Complete Block Design replicated three times. Sampling for adult B. tabaci was done in the early hours of the morning (0700-0900h) starting five weeks after planting (WAP) and operated at weekly intervals from three inner plants of the middle row of each plot for a period of three months. The study revealed that selected OFSP cultivars tested were colonised by B. tabaci. The preponderance of B. tabaci on OFSP cultivars: NRSP/05/022, CIP440293 and Centennial gave mean values of 15.33, 12.83 and 10.47, respectively; which is an indication of their susceptibility to the sweetpotato chlorotic stunt virus infection, a precursor of sweetpotato virus disease
Can protected areas work in artisanal fisheries of Uganda? The case of Lakes Edward-George and Kazinga Channel
Get PDFThe Ecosystem Approach to Fisheries Management agitates for provision of Marine Protected Areas (MPAs) which seem to be effective in developed countries. However, efforts to control artisanal fisheries through protection have not been adequately assessed. The Uganda portion of Lake Edward, Kazinga channel and half of Lake George are located in Queen Elizabeth National Park, controlled and managed by the Uganda Wild Life Authority (UWA). Three of the seven recognised landing sites on Lake George occur outside the park, and by proxy are unprotected. The objective of this study was to compare fishing efforts, gears and fishery yield of the protected and unprotected lake areas and landing sites of Uganda during 2011 and 2013. Fishing effort data sets were generated through periodic census of fishing inputs, in addition to the yield. Of the total annual fish production (9,200 metric tonnes) from the Edward-George system on the Uganda portion, protected areas contributed 87% and were markedly higher than the unprotected area (13%). The number of illegal gillnets in the protected area increased by 88% relative to 12% in the unprotected area, over the same period. The principle of MPAs in conservation in artisanal fisheries may not be effective and achievable in these regions
Fruit fly infestation in mango: A threat to the Horticultural sector in Uganda
Get PDFFruit flies (Diptera: Tephtritidae) are one of the most important insect pests to fruits worldwide. In Uganda, fruit flies have inflicted considerable yield losses especially in mangos (Mangifera indica L.), However, there has been no recent assessment of the associated economic damage impact despite the outcries from the farming communities. The objective of this study was to assess fruit fly prevalence and infestation in mango and other hosts, to guide the development and improvement of fruit fly control measures in the mango industry in Uganda. A survey was conducted in the major mango producing areas of the country. Four fruit fly (Diptera: Tephritidae) species were recovered from various field-collected fruits; namely Bactrocera invadens, Ceratitis cosyra, Ceratitis rosa and Ceratitis capitata. Bactrocera invadens was the most prevalent species (98%), while C. capitata was the populous. A total of 73% of the mango fruit samples collected from seven agro-ecological zones was found infested with fruit fly larvae. Fruit samples from West Nile had the highest infestation (83%), followed by Northern Moist, Lake Victoria Crescent, and Western Medium High Farmland, with 78, 75 and 73% fruit fly infestation, respectively. It was common to experience 100% fruit losses across the agro-ecological zones in the absence of control measures. The situation was increasingly severest with exotic commercial varieties. Besides mangoes, over 15 other cultivated and wild fruits acted as alternative hosts to the fruit flies
Reaching out to farmers with plant health clinics in Uganda
Get PDFUgandan farmers experience low farm level productivity attributed to various factors that include poor management practices, use of unimproved varieties, poor soil fertility and losses to pests and diseases. Pests and diseases cause 30-40% pre-harvest and post-harvest losses. The Plantwise initiative aims at improving the availability of knowledge and information on pest and disease management to farmers through strengthening existing in-country plant health systems and providing a knowledge bank that supports the country’s knowledge base. Farmers receive free extension advice based on their specific crop problems presented at 145 plant clinics that have been established in 70 districts and run by more than 200 trained plant doctors. The plant clinic approach will be beneficial to farmers if aspects of increased access, gender concerns and capacity are addressed. It can yield success when embedded in national systems and organisations thereby building the links and relationships necessary for a functioning plant health system that adequately links research, extension, farmers, agro-dealers and regulatory bodies
Proximate composition and mineral contents of Pebbly fish, Alestes baremoze (Joannis, 1835) fillets in relation to fish size
Get PDFAlestes baremoze (Joannis, 1835), locally known as Angara in Uganda, is native to fresh water systems in Africa, thriving well in both lacustrine and riverine conditions. It is part of the routine diets of families in northern Uganda, South Sudan, the Sudan and the Democratic Republic of Congo. The objective of this study was to determine the proximate composition and mineral contents of A. baremoze fillets according to fish size. The mineral contents of A. baremoze from Lake Albert were analysed using standard procedures. The fish samples were categorised into three size-groups; <1 kg (880–990g), 1-1.5 kg and 1.6-2.5 kg. On wet weight basis, there were no significant differences (p>0.05) in crude protein and ash content among the different fish sizes. However, there were significant differences (p<0.05) in crude fat, carbohydrate, gross energy and vitamin A. Crude fat (0.35%), carbohydrate (0.37%) and gross energy (597.6 Kcal/100 g) were significantly higher in medium sized fish (1 to 1.5 kg) compared with the larger fish category. Vitamin A contents of different fish sizes ranged from 55.1 to75.3 μg RAE/100g. The contents of magnesium and iron were highest in sizes <1 kg (5.34 mg/100 g) and (3.58 mg/100 g), respectively. It was observed that potassium content (339.33 mg/100 g) and calcium (29.75 mg/100 g) were significantly higher (p<0.05) in fish >1.5 kg. These findings suggest that taste, freshness and other related external appearances should not be the only factors to be considered in making choice for marketing and consumption of Alestes baremoze
Common fish diseases and parasites affecting wild and farmed Tilapia and catfish in Central and Western Uganda
Get PDFIntensification of aquaculture production in Uganda is likely to result into disease out-breaks leading to economic losses to commercial fish farms and associated natural aquatic ecosystems. This survey assessed health profiles of selected commercial fish farms and adjacent natural aquatic ecosystemsto identify fish diseases and parasites affecting Nile tilapia (Oreochroms niloticus) and African catfish (Clarias gariepinus) in aquaculture systems in Uganda. Fish farms encounter disease out-breaks that cause low survival rates (0 - 30%), especially catfish hatcheries. Health management issues are not well understood by fish farmers, with some unable to detect diseased fish. Current control strategies to control aquatic pathogens include use of chemo- therapeutants and antibiotics. Bacterial pathogens isolated included Flavobacterium columnare, Aeromonas sp., Edwardsiella sp., Psuedomonus sp., Steptococcus sp., Staphylococcus sp., Proteus sp., and Vibrio sp. A high occurrence of Flavobacterium columnare exists in both asymptomatic and symptomatic fish was observed. Parasites included protozoans (Ichthyopthirius multiphilis, Trichodina sp. and Icthyobodo sp.) and trematodes (Cleidodiscus sp. and Gyrodactylus sp.). Diagnosis and control of diseases and parasites in aquaculture production systems requires adoption of a regional comprehensive biosecurity strategy: the East African (EAC) region unto which this study directly contributes
Response of banana hybrids to the banana weevil (Cosmopolites sordidus Germar) (Coleoptera: Curculionidae) in Uganda
Get PDFBanana weevil (Cosmopolites sordidus (Germar) is one of the major constraints to banana production in Uganda. A field screening experimentwas undertaken at Kawanda to determine the response of 18 hybrids to the banana weevil (Cosmopolites sordidus (Germar).Based on total cross-sectional damage, results indicated that there was improved resistance to banana weevil in the hybrids tested. Damage scores for all the tested hybrids were significantly different from the susceptible check (Atwalira). Except M4, M5, M6 and M8, the rest of the hybrids showed significant difference from the resistant cultivar (Yangambi KM 5). Data on mat disappearance showed that hybrids were more stable than the susceptible check, while findings from weevil trap catches suggested no relationship between attraction and weevil damage. Resultsshowed that some hybrids have superior agronomic and yield characteristics, however due to high weevil infestation, the findings of the study were not representative of maximum yield potential that may be achieved under good management practices
Implications of Black Coffee Twig Borer on cocoa in Uganda
Get PDFCocoa (Theobroma cacao L.) is one of Uganda’s major cash crops. It is grown by 15,000-18,000 smallholder households on an estimated 20,000 hectares. Cocoa contributes about US$65 million annually to the country’s foreign exchange earnings. On account of its perennial nature and robust vegetative growth, cocoa harbors a wide range of insect pests which affect its production. Here, we report for the first time an outbreak of the Black Coffee Twig Borer (BCTB), Xylosandrus compactus (Eichhoff), a new pest on cocoa in Uganda. To determine its spread and impact, we surveyed 20 households in Bundibugyo, Kibaale and Hoima districts in January 2014. On each field, 10 cocoa trees were examined for BCTB infestation along a transect. Overall, more than half of the cocoa plantations, 13% of trees and 3.8% of primary branches were infested. At district level, Kibaale had the highest proportions of infested fields (100%), trees (30%) and primary branches (8.5%). The seriousness of BCTB prevalence is likely to complicate the current BCTB spray programme on coffee in the country
Assessment of farmers knowledge and preferences for planting materials to fill-gaps in banana plantations in southwestern Uganda
Get PDFBanana (Musa spp.) plantations in central Uganda used to be productive for 30-100 years. Due to prevalence of the banana weevil (Cosmopolites sordidus L.), life spans have fallen to only <5 years. This forces farmers to establish new plantations or replant existing ones, usually using infested materials. To determine farmers’ knowledge and sources of planting materials and the cleaning techniques used, a household survey was conducted in southwestern Uganda. Up to 99% of the farmers reported C. sordidus as their major pest, and at least 50% reported gap-filling mainly due to land and banana weevil pressure. Most farmers (>80%) obtained planting materials from home/neighbours’ gardens. Corm paring (recommended for cleaning) was minimal, with 87% of farmers just trimming a few roots from the suckers. Most (90%) farmers preferred maiden suckers for gap-filling, believing that they establish and mature faster, and withstand weevil damage compared with other planting materials. Based on farmers’ experience and the results of an on-station study at the National Agricultural Research Laboratories (NARL), Kawanda, we recommend the use of maiden suckers when replanting in already infested plantations or those at risk