NRU :: Browsing by Author "Adipala, E."

Browsing by Author "Adipala, E."

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Characterization and Distribution of a Potyvirus Associated with Passion Fruit Woodiness Disease in Uganda
(Plant Disease, 2012) Ochwo-Ssemakula, M.; Sengooba, T.; Hakiza, J. J.; Adipala, E.; Edema, R.; Redinbaugh, M. G.; Aritua, V.; Winter, S.
This article describes the incidence and etiology of a viral disease of passion fruit in Uganda. Symptoms, including those characteristic of passion fruit woodiness disease (PWD), were observed on 32% of plants in producing areas. Electron microscopic observations of infected tissues revealed flexuous filaments of ca. 780 nm. Enzymelinked immunosorbent assays indicated a serological relationship with Cowpea aphid-borne mosaic virus (CABMV) and Passion fruit ringspot virus (PFRSV). In host range studies, only species in the families Solanaceae and Chenopodiaceae were susceptible, and neither Vigna unguiculata nor Phaseolus vulgaris became infected. Coat protein (CP) gene sequences of eight isolates exhibited features typical of potyviruses and were highly similar (88 to 100% identity). However, the sequences had limited sequence identity with CP genes of two of the three potyviruses reported to cause PWD: East Asian Passiflora virus and Passion fruit woodiness virus (PWV). Deduced amino acid sequences for the CP of isolates from Uganda had highest identity with Bean common mosaic necrosis virus (BCMNV) (72 to 79%, with evolutionary divergence values between 0.17 and 0.19) and CABMV (73 to 76%, with divergence values between 0.21 and 0.25). Based on these results and in accordance with International Committee for Taxonomy of Viruses criteria for species demarcation in the family Potyviridae, we conclude that a previously unreported virus causes viral diseases on passion fruit in Uganda. The name “Ugandan Passiflora virus” is proposed for this virus.
Comparison of damage levels caused by Radopholus similis and Helicotylenchus multicinctus on bananas in Uganda
(Annals of Applied Biology, 2000) Barekye, A.; Kashaija, N.; Tushemereirwe, W. K.; Adipala, E.
Field surveys were done in 1997 and 1998 in Masaka district, Uganda, an area which is experiencing a decline in banana production, to assess level of damage caused by nematodes Radopholus similis and Helicotylenchus multicinctus at farm level. Ten farms within a radius of 2 km were selected and nematode damage assessed. The major nematodes encountered were Pratylenchus goodeyi, R. similis and H. multicinctus. P. goodeyi and H. multicinctus were more abundant than R. similis but R. similis had a stronger and significant correlation with root damage. A subsequent pot trial examined pathogenicities of R. similis and H. multicinctus in pure and mixed cultures on tissue cultured-banana plantlets. R. similis alone and in mixed population reduced root fresh weight significantly, and the percentage of root necrosis ranged between 22.8-41.6% and 18.3-45.5% for March 1998 and March 1999 trials, respectively. The difference in damage caused by R. similis alone and in mixed population was not statistically significant, and was higher than the damage caused by H. multicinctus alone. There were no significant differences in pathogenicity among the R. similis isolates from different parts of Uganda.
Damage to Yam (Dioscorea Spp.) By Root-Knot Nematode (Meloidogyne Spp.) Under Field and Storage Conditions in Uganda
(Nematropica, 2012) Mudiope, J.; Coyne, D.L.; Adipala, E.; Talwana, H.A.L.
Although root-knot nematodes (Meloidogyne spp.) are a widely distributed pest of yam (Dioscorea spp.), the level of damage the yams incur, either alone or in association with other plant-parasitic nematodes is largely undetermined. The current study assessed the damage Meloidogyne spp. caused in the field and during storage, following inoculation onto clean seed material and also to yam planted into infested fields. In general, Meloidogyne spp. caused little galling to roots and tubers, and limited reduction in plant growth and yield. Of three species tested, D. rotundata was the most susceptible and most heavily affected by Meloidogyne spp. infection, D. alata was the least affected, and D. cayenensis was intermediately affected yam species. Meloidogyne spp. infection of tubers significantly exacerbated yam tuber weight loss during storage, particularly during the first 2 months, and moreover reduced and delayed tuber sprouting. Farmers need to select tubers free of Meloidogyne spp. symptoms prior to storage to reduce losses from tuber deterioration, and while selecting planting material for the succeeding season.
Effects of Concentrating Resistance to Northern Leaf Blight of Maize on Agronomic Traits
(East African Agricultural and Forestry Journal, 1995-12-09) Ojulong, H.F.; Adipala, E.; Rubaihayo, P.R.
Lack of appropriate maize varieties in Uganda has • been cited as one of the major factors limiting the production of this crop in the country. Thirty-five per cent of the maize grown in the country comprises improved open-pollinated varieties; 60% comprises unimproved open-pollinated varieties which have resulted from planting many generations of the formally improved open-pollinated varieties (Baguma, 1992). This, coupled with the introduction of susceptible cultivars from Centro International de Majeramiento de Maizy Trigo, Mexico (CIMMYT) led to an outbreak of northern leaf blight (NLB) -in 1988
Efficacy of different fungicide spray schedules for control of potato late blight in Southwestern Uganda
(Crop protection, 2003) Kankwatsa, P.; Hakiza, J.J.; Olanya, M.; Kidenamariam, H.M.; Adipala, E.
Potato cultivars grown in Uganda have low levels of general resistance to late blight. As such, most commercial potato farmers rely on fungicide applications for control of Phytophthora infestans, the causal agent of late blight. This study investigated the comparative advantages of using different frequencies of application of Ridomil (MZ 58), Ridomil once and Dithane M-45 (Mancozeb, 80% WP) subsequently, and Dithane M-45 for management of potato late blight. The highest marginal benefit was achieved by applying Ridomil once and Dithane M-45 subsequently at intervals of 14 and 21 days. The lowest marginal benefit was with sole Ridomil application at 21 day spray interval. With weekly sprays it was more economical to apply Dithane M-45 than Ridomil first followed by Dithane M-45 subsequently.
Epidemiology and population dynamics of Phytophthora Infestants in Sub-Saharan Africa: Progress and constraints
(African Crop Science Journal, 2001) Olanya, O. M.; Adipala, E.; Hakiza, J. J.; Ojiambo, P.; Mujalazi, J. M.; Forbes, G.
Global estimates of losses attributed to plant diseases are approximated at 24.8 million dollars, of this amount 3.4 million dollars has been recorded for potato. Of the potato diseases, late blight (Phytophthora infestans) is the most significant constraint in tropical Africa. Variation in losses of potato caused by late blight have been documented in several countries, and has shown that yield losses can range from 30 to 75% on susceptible varieties. In terms of disease cycle, the sources of primary inoculum have not been adequately investigated, however, the continuos cropping of potato and tomato ensures inoculum presence year-around in tropical Africa. Data on the low incidence of tuber blight and the lack of evidence for potato seed-borne infection suggests that tuber blight is not a significant source of primary inoculum in the tropics. Population studies of P. infestans in Sub-Saharan Africa (SSA) have been conducted primarily on isolates from Uganda, Kenya and S. Africa. Mating type tests with A1 tester isolates coupled with DNA analysis revealed that the fungal isolates from Uganda, Kenya and S. Afirca are of A1 mating type (US 1 clonal lineage). Variation and lack of consistency in oospore production (10 % selfing, 24 % mating, & 15 % non-oospore producers) have been detected among the isolates from Uganda and Kenya. Similarly, variability in metalaxyl sensitivity, has been detected among these isolates. Fungicide and variety reaction studies conducted in Uganda, Kenya and Ethiopia suggests that significant late blight control can be achieved when the protectant fungicide, Dithane (a.i mancozeb) is applied on a scheduled basis. On-farm research also indicates that three timely applications of a protectant or a protectant fungicide alternated with systemic fungicide can be effective for late blight management. Results of in-vitro tuber blight development and host-specificity studies imply that isolates from potato are more virulent than isolates from tomato. Studies are underway to quantify general resistance of potato varieties as well as to monitor the significance of fungal population deviations in the region. Decision support systems are in the process of being developed to optimize fungicide application and variety resistance for late blight management
Facilitating placements of graduate students to build capacity for National Agriculture Research and Extension System: The case of iAGRI in Tanzania
(RUFORUM Working Document Series, 2016) Chindime, M. S.; Uwituze, S.; Nampala, M. P.; Osiru, M.; Adipala, E.
The attainment of sustainable food security in Africa, as elsewhere, requires the efforts of a cadre of innovative well-trained agriculture specialists who are familiar with the constraints and perspectives of national priority needs. In light of this, a USAID-sponsored partnership among six American Land Grant universities, Tanzanian Government, the Regional Universities Forum for Capacity Building in Agriculture (RUFORUM) and the Global South universities was established in 2011 to implement Innovative Agricultural Research Initiative (iAGRI). The focus was to help strengthen human and institutional capacity for agricultural research for development in Tanzania. As part of the implementation of the programme, RUFORUM was sub-contracted by the Ohio State University to coordinate the training of Tanzanians in selected universities in Africa for Master of Science and PhD Degrees in disciplines identified as priority areas for Tanzania. The iAGRI project training model involved course work at the host university and research in Tanzania under the supervision of the academic supervisors from the host university and a local supervisor from Tanzania, majority being from Sokoine University of Agriculture (SUA). The model also included a compulsory student participation in scientific conferences, skills enhancement short trainings, and travel to Tanzania by university supervisors to check on students and interact with the Tanzanian supervisors. A total of 31 students (30 MSc and 1 PhD) under RUFORUM coordination were successfully placed in nine Universities in Eastern and Southern Africa to undertake postgraduate training in 16 selected programmes of strategic interest to the Tanzania National Agricultural Research and Extension System (NARES). Of the 31 students placed, 65% have completed their degree programmes and reported back to their respective institutions in Tanzania and the rest are due to graduate by end of February 2017. The placements provided a platform for exposure and cross learning among the participating institutions and graduates have gained relevant skills to effectively contribute to the development of the agriculture sector in Tanzania. They have also been linked to close to 2,000 students and graduates across Africa. The implementation process has demonstrated the need for flexible approaches that not only take into account the needs of the sending institutions but also those of the host institutions. The additional skill enhancement trainings, field/industry attachment, regional and international exposure, and link to the wider community of graduate students and research community enhance the quality and relevance of training and wider interconnection across Africa. The iAGRI model presents learning opportunities for similar projects that are linked with academic mobility.
Farmer-participatory Evaluation of Cowpea integrated Pest Management (IPM) Technologies in Eastern Uganda
(Crop Protection, 2003) Nabirye, J.; Nampala, P.; Ogenga-Latigo, M.W.; Kyamanywa, S.; Odeke, V.; Adipala, E.
A three-season study was conducted with the goal of verifying integrated pest management (IPM) technologies developed at Makerere University for management of cowpea field pests. Ten IPM-field schools with 10–20 farmers were run for three consecutive seasons of 2000 A (first rains), 2000 B (second rains), and 2001 A. Each school evaluated seven treatments that included farmers’ practices; cowpea monoculture and cowpea/sorghum intercrop mixtures, and five varying insecticide spray regimes. The key insect pests targeted by the sprays included aphids, Aphis craccivora Koch, flower thrips, Megalurothrips sjostedi Trybom, the legume pod borer, Maruca vitrata Fabricius (formerly M. testularis Geyer), and a range of pod sucking bugs (i.e., Nezera viridula Linnaeus, Clavigralla tomentosicollis Stal., Riptortus dentipes Fab.). The experiment was a randomized complete block design with farms (i.e., field schools) as replicates. Results indicated that combining cultural practices and spraying once each at budding, flowering, and podding stages was more effective and profitable than spraying cowpea weekly throughout the growing season. An IPM practice which combined early planting, close spacing cowpea (30×20cm2), and three insecticide applications once each at budding, flowering and podding stages, had the highest yields of 791kg/ha with a 51% yield gain over the farmers’ traditional practices. Farmer evaluation over the three seasons revealed that this practice was most preferred by farmers, with a farmer preference of 46.4%, 57.1%, 71.4%, and 89.3% at planting, vegetative, flowering and harvesting evaluation stages, respectively.
Fungicide application and host-resistance for potato late blight management: benefits assessment from on-farm studies in S.W. Uganda
(Crop Protection, 2004) Namanda, S.; Olanya, O.M.; Adipala, E.; Hakiza, J.J.; El-Bedewy, R.; Baghsarif, A.S.; Ewell, P.
Late blight caused by Phytophthora infestans, is one of the most significant constraints to potato production in Uganda and other regions of the world. Fungicides and host plant resistance are among the most efficient control options available to growers. Field trials were conducted in 1999 and 2000 in South-western Uganda to evaluate the cost effectiveness of fungicide application regimes on six potato varieties. A factorial experiment with five fungicide application intervals (weekly, fortnightly, IPM, no spray and farmers’ practice) and six potato varieties was established. Late blight infection was prevalent in both years, and a significant amount of disease was detected (P<0.05). Application of fungicide treatments considerably reduced late blight progress, with a corresponding increase in tuber yield. Based on monitoring of late blight disease occurrence and weather variables, two applications of the contact fungicide mancozeb on a moderately resistant variety was the most economical. Marginal rates of return and net benefits were significantly affected by fungicide applications. In the IPM treatment, late blight disease monitoring or scouting prior to first fungicide applications resulted in significant economic gains compared to scheduled applications of weekly and biweekly or no application (control) treatments.
Genetic Diversity of Phytophthora infestans (Mont.) de Bary in the Eastern and Western Highlands of Uganda
(Journal of Phytopathology, 2002-10-16) Ochwo, M. K. N.; Adipala, E.; Rubaihayo, P. R.; Olanya, M.
Eight isolates of Phytophthora infestans were recovered from late blight infected samples collected from the districts of Mbale and Mbarara in the Eastern and Western highlands of Uganda in 2001 and analysed using mitochondrial deoxyribonucleic acid (DNA) haplotype and Amplified Fragment Length Polymorphism (AFLP) markers. Polymerase chain reaction amplification with the P2 primer followed by digestion with MspI yielded a three-fragment pattern characteristic of isolates belonging to the US-1 clonal lineage; the polymorphism was confirmed by DNA sequencing. AFLP analysis yielded 60 markers, analysis of which clustered the Ugandan isolates with reference to US-1 isolates (US930258 and US940501). These results suggest that the examined Ugandan isolates belong to the US-1 clonage lineage
Impact of Fungicide Application and Late Blight Development on Potato Growth Parameters and Yield in the Tropical Highlands of Kenya and Uganda
(African Crop Science Journal, 2001) Ojiambo, P. S.; Namanda, S.; Olanya, O. M.; El-Bedewy, R.; Hakiza, J. J.; Adipala, E.; Forbes, G.
The effects of fungicide application and late blight development on potato varieties with different levels of resistance to late blight were quantified in Kenya and Uganda during the 1999 cropping seasons. Experiments were laid out in a randomised complete block design with three replications in three sites, Loreto and Kabete in Kenya and Kalengyere Research Station in Uganda. At each experimental site, plots consisted of 4 m rows with plants spaced at 0.75m x 0.3 m. Treatments consisted of three potato varieties and four application intervals of Dithane M-45 arranged in a factorial combination. Areas under disease progress curves (AUDPCs) was significantly lower in the sprayed plots than in the unsprayed plots. Disease levels were lower in plots with 7 days application interval and most severe in plots of 21 days spray interval. Yields were higher in the 7 days intervals and lower in the 14, 21-days intervals and in the unsprayed plots. Fresh tuber weights and dry tuber weights were higher in the sprayed plots and lower in the unsprayed plots, respectively. At Kabete, Kerr's Pink had the highest AUDPC value of 2139.3 and disease was least on Asante with an AUDPC value of 409.4. The corresponding AUDPC values for the control plots were 671.5, 945.6 and 2367.8 for Asante, Tigoni and Kerr's Pink, respectively. At Loreto, disease was also most severe on Kerr's Pink with an AUDPC value of 2076.3 and least severe on Tigoni that had an AUDPC value of 444.8. The corresponding AUDPC values for the control plots were 840.4, 1000.2 and 2740.0, for Tigoni, Asante and Kerr's Pink, respectively. The highest tuber yield of 41.3 t ha-1 recorded at Kabete for Asante was significantly higher than yields of Kerr's Pink (22.0 t ha-1) but was not different from the yields of Tigoni (39.9 t ha-1). At Loreto, Tigoni had the highest yields of 34.6 t ha-1 that was significantly different from that of Kerr's Pink (6.2 t ha-1) in the sprayed plots. At Kalengyere, disease levels were significantly (P = 0.05) lower in the sprayed plots than in the control plots and disease severity was least on variety Rutuku (AUDPC value of 17.9) in 7 day spray interval. Tuber yields were significantly (P = 0.05) higher in the sprayed plots and highest tuber yield was recorded on variety Kabale (39.5 t ha-1) in plots with 7 day spraying interval.
Initial Efficiency of Commonly Used Practices to Control Soil, Runoff and Nutrient Losses from Maize and Banana Based Systems in the Lake Kivu Basin
(Journal of Great Lakes Research, 2016) Adidja, M. W.; Majaliwa, J. G. M.; Tenywa, M. M.; Bashwira, S.; Adipala, E.
This study was carried out to determine the initial efficiency of commonly used practices to control soil erosion from Maize and Banana based cropping systems in Lwiro micro catchment in the Lake Kivu basin. Soil, runoff and nutrient losses were determined using runoff plot approach. Instrumentalised runoff plots of 2X15m were installed on maize intercropped with beans and banana gardens. Two soil erosion management practices, namely; Tithonia and contour bunds were tested on Maize intercrop with Beans and mulch for Banana. The experiment included a control practice for each crop. Each treatment and control was replicated four times. Runoff and soil loss were estimated for each rainfall event and aggregated on seasonal basis. Nutrient (N, P and K) losses were estimated per season. Results of the long and short rains of the first year of experimentation show that soil and runoff losses did not significantly change with practices and seasons (P>0.05) for both banana and maize based systems. Soil and runoff losses ranged from 15.73 to 32.93 Mg/ha, and from 168.14 to 322.17 m3; respectively. Nutrient losses varied with practices and seasons (P<0.05) and ranged from 54.68 to 112.34 Kg/ha, 87.7 to 409.4 Kg/ha; 24.5 to 94.22 Kg/ha for K, N and P; respectively. Soil and runoff losses ranged from 8.99 to 20.6 t/ha, and from 85 to 152 m3; respectively. Only K losses changed significantly with season (P<0.05) and ranged from 17.8 to 53.9 Kg/ha under Banana cropping system.
Insecticide application to reduce pest infestation and damage on cowpea in Uganda
(African Plant Protection, 1998-08-05) Omongo, C.A.; Adipala, E.; Ogenga-Latigo, M.W.; Kyamanywa, S.
Field assessments were carried out in seven districts of eastern and northern Uganda to establish pest infestation of cowpea (Vigna unguiculata) and the extent of insecticide usage to control these pests. More than 60 % of the farmers in eastern Uganda applied insecticides to control cowpea pests whereas no farmers in the northern region used chemieels for this purpose. The extent of pest infestation at different crop growth stages appeared to influence pesticide application, with mostlarmers spraying during the vegetative (30 %) and flowering (50 %) stages. and only a few at podding (10 %). There was evidence 01 ineffective/uneconomical use of insecticides. On-farm trials indicated that insecticide protection at all crop growth stages gave the best control. leading to yield gains 01 more than 50 %. Spraying during vegetative and flowering stages was also effective. giving yield gains of about 40 %. A three-spray programme (at vegetative growth. flowering and podding) was most profitable in the short rainy season at Serere (marginal return = 6.08) and second best in the long rainy season at Kabanyolo (marginal return = 4.35).
Metalaxyl resistance, mating type and pathogenicity of Phytophthora infestans in Uganda
(Crop Protection, 2001) Mukalazi, J.; Adipala, E.; Sengooba, T.; Hakiza, J.J.; Olanya, M.; Kidanemariam, H.M.
A total of 81 isolates of Phytophthora infestans (Mont.) de Bary were recovered from late blight infected samples collected from different areas of Uganda in 1998/1999. They were analyzed for their resistance to metalaxyl fungicide, mating types, and cross infection between potato and tomato hosts. Sensitivity to metalaxyl was determined by growing isolates on 10% V8 medium amended with 0, 5 and 100μg/ml metalaxyl. Overall 44.4% of the isolates tested were resistant to metalaxyl, 23.5% were intermediate and 31.2% were sensitive. Mating type was determined on 80 isolates using an A1 (1724) isolate and by growing the same isolates in pure culture (selfing). Fifty percent of the isolates produced oospores by matings and selfings, 22.5% by mating only and 10% by selfing only; 18% did not produce oospores in the two tests. Twenty seven of the P. infestans isolates from potato-infected tomato. The majority of these isolates were highly resistant to metalaxyl and produced oospores by either mating or selfing or both.
Pests and diseases on cowpea in Uganda: Experiences from a diagnostic survey
(African Crop Science Journal, 1999) Adipala, E.; Omongo, C.A.; Sabiti, A.; Obuo, J.E.; Edema, R.; Bua, B.; Atyang, A.; Nsubuga, E.N.; Ogenga-latigo, M.W.
A diagnostic survey (DS) using a questionnaire covering 525 farm households was conducted in 1993/94 to determine the status of cowpea (Vigna unguiculata L. Walp) and its production constraints in Uganda. Subsequent on-farm assessments were made during the two rainy seasons of 1994 to verify and quantify the survey information. Additionally, on-station trials were conducted to address issues arising from the information. Insect pests, low plant population densities, poor weed management and labour bottlenecks are the most important constraints to cowpea production in Uganda. Insect pest damage, particularly by bruchids, is most important. Research to develop integrated pest management (IPM) strategies based on the finding of this study are in progress.
Potential for soybean rust tolerance among elite soybean lines in Uganda
(Crop protection, 2009) Oloka, Herbert K.; Tukamuhabwa, P.; Sengooba, T.; Adipala, E.; Kabayi, P.
Soybean rust, (Phakopsora pachyrhizi), currently the most devastating disease of soybeans worldwide, is known to challenge single resistance genes deployed against it and therefore, disease tolerance is indisputably the most viable measure in controlling the pathogen. Studies were conducted at Namulonge in Central Uganda to assess the level of tolerance to soybean rust among selected elite soybean lines. Seven elite lines together with three local checks were tested in a split-plot design where some plots were protected with fungicide to estimate the level of tolerance to soybean rust. The experimentwas conducted for three cropping seasons beginning second rains of 2005. A rust tolerance index (RTI) was computed for each test line as the ratio of yield from unprotected plots to yield from protected plots. The study showed that high levels of tolerance to soybean rust were present in the test lines. The soybean lines that showed high levels of tolerance included MNG 10.3 and MNG 3.26 all showing RTIs higher than 0.93. These lines also out-yielded the local checks by about 400 kg ha 1 and are recommended for multi-location testing.

Browsing by Author "Adipala, E."

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