Coffee

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All Coffee research conducted by NARO over the years both at National and Zonal level is housed in this collection

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Inheritance of resistance to coffee wilt disease (Fusarium xylarioides Steyaert) in Robusta coffee (Coffea canephora Pierre) and breeding perspectives
(Tree Genetics & Genomes, 2012-08-31) Pascal C. Musoli; Christian Cilas; David Pot; Agnes Nabaggala; Saleh Nakendo; James Pande; André Charrier; Thierry Leroy; Daniel Bieysse
Knowledge on heritability is essential for select- ing varieties resistant against coffee wilt disease caused by Fusarium xylarioides, which is currently devastating coffee in East and Central Africa. Variability of the resistance against coffee wilt disease in Coffea canephora and its inheritance were investigated in three experiments corresponding to a clonal trial involving 20 clones, a 10- parent partial diallel progeny, and a half-sib progeny test. There were significant quantitative genetic variations among the clones and progenies, suggesting polygenic control of the resistance. Around 50–65 % tree mortality was the optimal disease level for calculating heritability and genetic gains. General and specific combining abilities calculated within the optimal disease range for partial diallel analysis were significant. Broad-sense heritability for the same anal- ysis and same disease range was moderate (0.329), and Communicated by A. Dandekar C. Cilas (*) CIRAD, UR 106, TA A-106/02 Avenue Agropolis, 34398 Montpellier Cedex 5, France e-mail: christian.cilas@cirad.fr: A. Charrier SUPAGRO, 2 Pl. P. Viala, 34060 Montpellier Cedex 1, France D. Bieysse CIRAD, UMR BGPI, TA A-54/K Campus Baillarguet, 34398 Montpellier Cedex 5, France corresponding narrow-sense heritability was low (0.112). Broad-sense heritability from clones in the field at the same disease range was also moderate (0.333). Narrow-sense heritability from regression of half-sib progeny means onto parent means in the field and screen house was 0.183 and 0.369, respectively. Selecting tolerant clones for improve- ment against the disease is possible, and genetic gains are possible by using tolerant parents in breeding programs.
Influence of shade systems on spatial distribution and infestation of the Black Coffee Twig Borer on coffee in Uganda
(Uganda Journal of Agricultural Sciences, 2013-04-06) G.H. Kagezi; P. Kucel; J. Kobusingye; L. Nakibuule; R. Wekhaso; G. Ahumuza; P. Musoli; A. Kangire
Studies were conducted to determine spatial distribution and effects of shade systems on Xylosandrus compactus infestation on coffee. Number of twigs varied significantly (p<.0001) within canopy portions with the highest (17.7±6.1) in upper and least (9.1±4.6) in lower portions. Percentage of infested twigs and number of X. compactus entry holes varied significantly (P<.0001) within canopy and along twigs respectively. The highest percentage of infested twigs (10.7±15.9%) was in the middle whereas, the lowest (3.2±7.2%) in upper portion. The highest number of entry holes (0.9±0.7) was on basal and the lowest (0.3±0.6) on tip section of twigs. Tunneling by X. compactus was neither inclined towards base nor the tips of twigs. Percentage canopy cover varied significantly (P=0.0276) across shade tree species; with highest (60.0±26.5%) on jackfruit tree and the lowest (11.7±7.6%) on Chinese silk tree. Percentage of infested trees and twigs varied but not significantly (P<0.05) across shade categories and tree species. Coffee under full shade had the highest percentage of infested trees (70.8±27.8%) and twigs (14.8±18.3%); whereas, coffee under full sun registered the lowest (45.8±17.3 and 5.7±9.1% respectively). However, ANCOVA showed that shade and percentage canopy cover of Albizia, jackfruit and mango tree species had a significant (at P<0.05) positive influence on X. compactus infestation. The highest percentage of infested trees (77.8%) and twigs (15.7%) were observed on coffee under Ficus natalensis; whereas coffee under Maesopsis eminii had the lowest (44.4% and 1.5% respectively). These studies provided vital preliminary ecological information for designing and implementing appropriate management strategies for X. compactus.
Ecological factors influencing incidence and severity of Coffee Leaf Rust and Coffee Berry Disease in major Arabica coffee growing districts of Uganda
(Uganda Journal of Agricultural Sciences, 2013-04-09) R.J. Matovu; A. Kangire; N.A. Phiri; G.J. Hakiza; G.H. Kagezi; P.C. Musoli
Coffee Leaf Rust and Coffee Berry Disease are the most devastating diseases of Arabica coffee in Africa. The importance of coffee in economies of many African countries like Uganda, presents urgent need for cost-effective disease control strategies. In this study, 192 coffee farms were surveyed and their corresponding incidence and severity recorded. Nebbi district had the highest CLR incidence (90.2%) and severity (2.2%) followed by Sironko (67.9% and 1.9%) and least in Kapchorwa (20.4% and 1.3%) respectively. CBD incidence was highest in Kapchorwa (6.0%) followed by Nebbi (1.7%).There was no CBD incidence observed in Sironko. There was a significant (pd”0.05) interaction between altitude and disease severity. Thin and medium shade intensity had highest CLR incidence followed by thick and no-shade levels. CLR was highest in farms under mono-shade followed by farms under mixed-shade and least in open-farms. CLR severity was found to be highest at very steep slopes and medium slopes and least on gentle slopes. In conclusion, CLR was present in all surveyed districts while CBDoccurred in Kapchorwa and Nebbi districts at intensity levels enough to trigger economic losses.
Immunodiagnostic potential of a 27 kDa protein of Fusarium xylarioides, the cause of coffee wilt disease in Robusta coffee in Uganda
(African Journal of Biotechnology, 2014-07-10) Olal, S.; Atuhaire, K. D.; Ochwo, S.; Kiiza, L.; Kangire, A.; Musoli, P.; Olaho-Mukani, W.; Lubega, G. W.; Hakiza, G. J.
Several Fusarium species infect Robusta coffee; these Fusarium xylarioides Steyaert (Gibberella xylarioides Heim and Saccas) are the most virulent and responsible for the destructive Robusta coffee wilt disease in Uganda. To date, F. xylarioides has not been isolated directly from soil, though the pathogen can persist in soil for a short time. In this study, a promising diagnostic target which can be developed into a serological test for F. xylarioides in coffee plants and soil has been identified and validated for identification. Water-soluble extracts of mycelia from six Fusaruim species were resolved by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The different protein profiles from the other five Fusarium species were compared and contrasted with that of F. xylarioides. Protein bands that appeared peculiar to F. xylarioides were cut and injected into rabbits to produce polyclonal antibodies. Dot blot and Western blot analyses showed one immunodominant antigen (27 kDa) common to all F. xylarioides isolates analyzed. No cross-reactivity of anti-27 kDa antibodies were observed in the entire test Fusarium species. The results suggest that polyclonal antibodies raised against the endoantigens from F. xylarioides of 27 kDa, is a promising tool for the rapid, sensitive, and accurate detection of pathogen in soil and plant parts.
In vitro inhibitory effect of selected fungicides on mycelial growth of ambrosia fungus associated with the black coffee twig borer, Xylosandrus compactus Eichhoff (Coleoptera: Curculionidae) in Uganda
(African Journal of Agricultural Research, 2015-06-04) Godfrey Kagezi; Patrick Kucel; Sammy Olal; Fabrice Pinard; Joseph Seruyange; Pascal Musoli; Africano Kangire
Black coffee twig borer is a new but rapidly spreading insect pest of coffee in Uganda. Female beetles bore into primary branches/twigs and cultivate an ambrosia fungus for feeding their larvae. Thus, controlling the fungus means depriving the brood a source of food. Three fungicides, chlorothalonil (Glider), tebuconazole (Orius 25EW) and dimethomorph + mancozeb (Volar) were evaluated in vitro for their effectiveness in inhibiting mycelial growth of ambrosia fungus associated with the beetle. The pathogen was exposed to four concentrations (1.5x, 1.25x, 1.0x and 0.5x times the manufacturer recommended rate) incorporated into potato dextrose agar using inhibition and food poisoning techniques. The three fungicides inhibited fungal growth to some extent, even at the lowest concentration (0.5x) and percentage inhibition was significantly different (P≤0.05) from each other. Tebucozanole caused 100% growth inhibition irrespective of concentration and technique used while chlorothalonil and dimethomorph + mancozeb caused less than 40% inhibition for both techniques. Therefore, research should determine effectiveness of tebucozanole for suppressing fungal growth under field conditions for diminishing beetle incidence and fungal pathogenic effects in infested branches. This will pave way for integration of use of tebucozanole into overall Integrated Pest Management package (IPM) for the beetle in Uganda.
Ecological and genomic vulnerability to climate change across native populations of Robusta coffee (Coffea canephora)
(Global Change Biology, 2022-05-08) Rémi Tournebize; Leyli Borner; Stéphanie Manel; Christine N. Meynard; Yves Vigouroux; Dominique Crouzillat; Coralie Fournier; Mohamed Kassam; Patrick Descombes; Christine Tranchant-Dubreuil; Hugues Parrinello; Catherine Kiwuka; Ucu Sumirat; Hyacinthe Legnate; Jean-Léon Kambale; Bonaventure Sonké; Jose Cassule Mahinga; Pascal Musoli; Steven B. Janssens; Piet Stoffelen; Alexandre de Kochko; Valérie Poncet
The assessment of population vulnerability under climate change is crucial for planning conservation as well as for ensuring food security. Coffea canephora is, in its native habitat, an understorey tree that is mainly distributed in the lowland rainforests of tropical Africa. Also known as Robusta, its commercial value constitutes a significant revenue for many human populations in tropical countries. Comparing ecological and genomic vulnerabilities within the species’ native range can provide valuable insights about habitat loss and the species’ adaptive potential, allowing to identify genotypes that may act as a resource for varietal improvement. By applying species distribution models, we assessed ecological vulnerability as the decrease in climatic suitability under future climatic conditions from 492 occurrences. We then quantified genomic vulnerability (or risk of maladaptation) as the allelic composition change required to keep pace with predicted climate change. Genomic vulnerability was estimated from genomic environmental correlations throughout the native range. Suitable habitat was predicted to diminish to half its size by 2050, with populations near coastlines and around the Congo River being the most vulnerable. Whole-genome sequencing revealed 165 candidate SNPs associated with climatic adaptation in C. canephora, which were located in genes involved in plant response to biotic and abiotic stressors. Genomic vulnerability was higher for populations in West Africa and in the region at the border between DRC and Uganda. Despite an overall low correlation between genomic and ecological vulnerability at broad scale, these two components of vulnerability overlap spatially in ways that may become damaging. Genomic vulnerability was estimated to be 23% higher in populations where habitat will be lost in 2050 compared to regions where habitat will remain suitable. These results highlight how ecological and genomic vulnerabilities are relevant when planning on how to cope with climate change regarding an economically important species.
A review of the indigenous coffee resources of Uganda and their potential for coffee sector sustainability and development
(Frontiers in Plant Science, 2023-02-17) Aaron P. Davis; Catherine Kiwuka; Aisyah Faruk; John Mulumba; James Kalema
Uganda is a major global coffee exporter and home to key indigenous (wild) coffee resources. A comprehensive survey of Uganda’s wild coffee species was undertaken more than 80 years ago (in 1938) and thus a contemporary evaluation is required, which is provided here. We enumerate four indigenous coffee species for Uganda: Coffea canephora, C. eugenioides, C. liberica (var. dewevrei) and C. neoleroyi. Based on ground point data from various sources, survey of natural forests, and literature reviews we summarise taxonomy, geographical distribution, ecology, conservation, and basic climate characteristics, for each species. Using literature review and farm survey we also provide information on the prior and exiting uses of Uganda’s wild coffee resources for coffee production. Three of the indigenous species (excluding C. neoleroyi) represent useful genetic resources for coffee crop development (e.g. via breeding, or selection), including: adaptation to a changing climate, pest and disease resistance, improved agronomic performance, and market differentiation. Indigenous C. canephora has already been pivotal in the establishment and sustainability of the robusta coffee sector in Uganda and worldwide, and has further potential for the development of this crop species. Coffea liberica var. dewevrei (excelsa coffee) is emerging as a commercially viable coffee crop plant in its own right, and may offer substantial potential for lowland coffee farmers, i.e. in robusta coffee growing areas. It may also provide useful stock material for the grafting of robusta and Arabica coffee, and possibly other species. Preliminary conservation assessments indicate that C. liberica var. dewevrei and C. neoleroyi are at risk of extinction at the country-level (Uganda). Adequate protection of Uganda’s humid forests, and thus its coffee natural capital, is identified as a conservation priority for Uganda and the coffee sector in general.
Viability of Deficit Irrigation Pre-Exposure in Adapting Robusta Coffee to Drought Stress
(Agronomy, 2023-02-25) Godfrey Sseremba; Pangirayi Bernard Tongoona; Pascal Musoli; John Saviour Yaw Eleblu; Leander Dede Melomey; Daphne Nyachaki Bitalo; Evans Atwijukire; Joseph Mulindwa; Naome Aryatwijuka; Edgar Muhumuza; Judith Kobusinge; Betty Magambo; Godfrey Hubby Kagezi; Eric Yirenkyi Danquah; Elizabeth Balyejusa Kizito; Gerald Kyalo; Emmanuel Iyamulemye; Geofrey Arinaitwe
Coffea canephora has high but inadequately exploited genetic diversity. This diversity, if well exploited, can sustain coffee productivity amidst climate change effects. Drought and heat stress are major global threats to coffee productivity, quality, and tradable volumes. It is not well understood if there is a selectable variation for drought stress tolerance in Robusta coffee half-sibs as a result of watering deficit pre-exposure at the germination stage. Half-sib seeds from selected commercial clones (KR5, KR6, KR7) and a pipeline clone X1 were primed with deficit watering at two growth stages followed by recovery and later evaluated for tolerance to watering deficit stress in three different temperature environments by estimation of plant growth and wilt parameters. Overall, the KR7 family performed the best in terms of the number of individuals excelling for tolerance to deficit watering. In order of decreasing tolerance, the 10 most promising individuals for drought and heat tolerance were identified as: 14.KR7.2, 25.X1.1, 35.KR5.5, 36.KR5.6, 41.KR7.5, 46.KR6.4, 47.KR6.5, 291.X1.3, 318.X1.3, and 15.KR7.3. This is the first prospect into the potential of C. canephora half-sibs’ diversity as an unbound source of genetic variation for abiotic stress tolerance breeding.
Potential of Moisture Conservation Practices to Improve Soil Properties and Nutrient Status of Robusta Coffee Plant
(Agronomy, 2023-04-18) Judith Kobusinge; Geofrey Gabiri; Godfrey H. Kagezi; Godfrey Sseremba; Alice Nakitende; Geofrey Arinaitwe; Charles K. Twesigye
Soil moisture conservation practices (SMCPs) have been adopted in Uganda to adapt to the effects of climate variability. However, limited information exists on how conservation measures influence the physico-chemical properties of soil and coffee leaf nutrient concentrations. Thus, we determined the effects of selected SMCPs on the soil physio-chemical properties and leaf nutrient concentrations in Robusta coffee in a randomized incomplete block design, replicated three times, in Kituza, Uganda. Soil samples were collected from 0 to 20 cm and 20 to 40 cm depths, and analyzed in the laboratory following standard procedures for selected physio-chemical properties. Coffee leaf samples were picked from each treatment (open sun coffee (COSS), coffee cover crop, Desmodium intortum (CCS), coffee mulch, Miscanthidium violoceum (CMS), and coffee A. coriaria (ACS)). Bulk density was significantly (p < 0.001) the highest under ACS (1.61 gcm−3) and lowest under CCS (1.29 gcm−3), and it significantly (p < 0.001) increased with depth. The soil organic matter was higher than the optimum range of 1–3% at the 0–20 cm depth across different SMCPs, but within the optimum range at the 20–40 cm depth. Leaf nitrogen was significantly the highest under ACS (3.19%) and lowest under COSS (2.30%). Overall, the findings suggest that SMCPs improve the soil physio-chemical attributes and leaf nutrients for sustainable coffee productivity. However, ACS improved the leaf plant nutrition better compared to other SMCPs.
Coffee Berry Moth, Prophantis smaragdina (Butler) (Lepidoptera: Pyralidae): Another threat to Robusta coffee, Coffea canephora production in Uganda
(National Agricultural Research Organisation, 2023-09-01) Kagezi G.H.; Kyalo G.; Twesigye V.; Helerimana C.; Anyijuka M.; Musasizi J.K.; Ssenoga G.; Kobusinge J.; Sseremba G.; Arinaitwe G.; Niyibigira E.I.
A structured questionnaire eliciting farmers’ knowledge of Coffee Berry Moth (CBM) was administered to 10 coffee farmers selected in the villages surrounding Kaweri. Additionally, 10 coffee trees were assessed for CBM infestation in farmers’ gardens and at Kaweri. Half of the farmers knew CBM and >50% of them first observed it on their coffee recently. However, 42.8% of them thought CBM causes no effect on coffee yields. Furthermore, 57.2% of them could identify the pest by the characteristic silk webs and the same percentage was aware that CBM causes more damage during the dry season. Majority (71.2%) of them did not know the effect of shade on its infestation while all of them were not aware of any alternative host for it. Lastly, only 14.2% of the farmers mentioned that they were managing CBM. At plot level, CBM was observed in all the Kaweri sections and farmers’ gardens assessed and the infestation was significantly (p≤0.05) higher at Kaweri than in farmers’ gardens. Infestation decreased significantly (p≤0.05) with increase in pruning and intercropping. The results showed that CBM is gaining economic importance as a pest of Robusta coffee in Uganda. However, limited farmers’ knowledge about its management, coupled with scanty literature, points to urgent need for research towards developing integrated management strategies for it.
Coffee Berry Moth, Prophantis smaragdina (Butler) (Lepidoptera: Pyralidae): Another threat to Robusta coffee, Coffea canephora production in Uganda
(Uganda Journal of Agricultural Sciences, 2023-09-15) Kagezi G.H.; Kyalo G.; Twesigye V.; Helerimana C.; Anyijuka M.; Musasizi J.K.; Ssenoga G.; Kobusinge J.; Sseremba G.; Arinaitwe G.; Niyibigira E.I.
A structured questionnaire eliciting farmers’ knowledge of Coffee Berry Moth (CBM) was administered to 10 coffee farmers selected in the villages surrounding Kaweri. Additionally, 10 coffee trees were assessed for CBM infestation in farmers’ gardens and at Kaweri. Half of the farmers knew CBM and >50% of them first observed it on their coffee recently. However, 42.8% of them thought CBM causes no effect on coffee yields. Furthermore, 57.2% of them could identify the pest by the characteristic silk webs and the same percentage was aware that CBM causes more damage during the dry season. Majority (71.2%) of them did not know the effect of shade on its infestation while all of them were not aware of any alternative host for it. Lastly, only 14.2% of the farmers mentioned that they were managing CBM. At plot level, CBM was observed in all the Kaweri sections and farmers’ gardens assessed and the infestation was significantly (p≤0.05) higher at Kaweri than in farmers’ gardens. Infestation decreased significantly (p≤0.05) with increase in pruning and intercropping. The results showed that CBM is gaining economic importance as a pest of Robusta coffee in Uganda. However, limited farmers’ knowledge about its management, coupled with scanty literature, points to urgent need for research towards developing integrated management strategies for it.
Characterisation and Mapping of Soils in Major Coffee Growing Regions of Uganda
(Journal of Agricultural Science, 2023-12-15) Gerald Kyalo; Peter Charles Apunyo; Majaliwa Mwanjalolo; Charles Kizza Luswata; Ronald Kawooya; Emmanuel Iyamulemye Niyibigira
There is limited information on the soil nutrient status, site specific fertilizer and agronomic recommendations for coffee in Uganda hence limiting its production and productivity. Therefore, this study was undertaken to characterize the soils under coffee farms and provide fertilizer and land management recommendations for coffee farming in selected districts in Uganda. 717 soil samples were collected from 45 coffee growing districts that were purposively selected to represent the major coffee growing regions of Eastern, Northern, Western, Mid-west and West Nile. 35 districts were sampled from Robusta coffee growing areas and 10 districts from Arabica coffee growing areas. Parameters considered in the laboratory analysis included; pH, total organic carbon, total nitrogen, available P, exchangeable Calcium (Ca), Sodium (Na), Magnesium (Mg), and Potassium (K) and micro elements: Iron (Fe), Zinc (Zn), Copper (Cu), Manganese (Mn) and Boron, soil texture, bulk density and hydraulic conductivity. Soil nutrient levels distribution maps for Robusta and Arabica coffee growing regions were generated in ArcGIS for the entire country. The soil chemical and physical properties were subjected to analysis of variance using Genstat 14th edition. The soil mapping results showed that, the overall average soil macro-nutrients concentrations were significantly different across regions (p < 0.05) with Eastern having the highest levels of macro elements (CEC of 19.28 meq/100 g, Base Saturation (BS) of 43.40%, pH of 5.78, N of 0.20%, K of 1.64 meq/100 g, P of 107.68 mg/kg and OM of 3.31%) followed by Western region. No significant difference (p > 0.05) was recorded for the micronutrients across the different regions, except Zn (p < 0.05). This study showed that Phosphorus and Potassium were generally moderate to high levels in most of the regions sampled while Nitrogen and organic matter were moderate to low. Results from this study provide a general picture of the nutrient status across all coffee growing regions in Uganda and highlight the required modifications for increased production and productivity.
Contrasting Effects of Shade Tree Species Diversity on Incidence and Damage of Pests and Diseases of Robusta Coffee
(Journal of Biology, Agriculture and Healthcare, 2024-01-31) Winnie Nanjego; Godfrey H. Kagezi; Samuel Kyamanywa; Judith Kobusinge; Geofrey Arinaitwe
In Uganda, most farmers grow their Robusta coffee, Coffea canephora in association with a diversity of shade tree species. Shade tree species diversity and density influence abiotic variables particularly, temperature and relative humidity. In turn, these may negatively or positively influence the population dynamics and damage caused by pest and diseases. Understanding these relationships is therefore vital for informing selection of shade tree species for ecological management of pests and diseases. We thus conducted a study in Kaweri Coffee Plantation Limited located in central Uganda to determine the effect of shade tree species diversity on the incidence and damage caused by pests and diseases on Robusta coffee. One plot measuring 100 x 100 m was demarcated in each of the four sections of the plantation: Kitagweta, Kyamutuma, Luwunga and Nonve. All the shade trees/shrubs and saplings (≤3 m) in the plot were counted and identified to species level. Additionally, incidence and damage of pests and diseases were assessed on 20 Robusta coffee trees selected along two diagonals in the plots. We recorded a total of 299 trees comprising of 22 species, with Solanum giganteum being the most abundant shrub (19.8 shrubs/ha) whereas, the most abundant shade tree species were Albizia chinensis (9.3 trees/ha) and Markhamia lutea (6.0 tree/ha). Eight (8) insect pests and two (2) diseases were recorded on Robusta coffee. These included, Xylosandrus compactus, Leucoptera coffeella, Leucoplema dohertyi, Epicampoptera andersoni, Prophantis smaragdina, Planococcus spp., Hypothenemus hampei, leaf eating beetles, Hemilleia vastatrix and Cercospora coffeicola. Our results further showed contrasting effects of shade tree species diversity on the incidence and damage of pests and diseases of Robusta coffee. Damage caused by X. compactus and E. andersoni as well as the incidence of H. vastatrix and C. coffeicola decreased significantly (p≤0.05) with increasing shade tree species diversity. Contrary, damage caused by all the other insect pests increased with increasing shade tree species diversity but, only significant (p≤0.05) in case of P. smaragdina, and Planococcus spp. There is therefore a need to thoroughly understand these dynamics if agroforestry systems are to be utilized as a strategy for ecological management of pests and diseases of Robusta coffee.
Within-Canopy Distribution of Incidence and Damage of Pests and Diseases of Robusta Coffee, Coffea Canephora and Implications for their Management
(International Journal of Sciences: Basic and Applied Research, 2024-03-03) Winnie Nanjego; Godfrey H. Kagezi; Samuel Kyamanywa; Judith Kobusinge; Geofrey Arinaitwe
Due to its perennial and robust vegetative growth nature, the Robusta coffee harbors a diversity of pests and diseases that are not necessarily evenly distributed within the coffee canopy and this has management implications. We thus, conducted a study in a Kaweri Coffee Plantation Limited in central Uganda to determine the distribution of incidence and damage caused by the pests and diseases within the Robusta coffee canopy. In each of the four section of plantation (Kitagweta, Kyamutuma Luwunga and Nonve), a plot measuring 100 x 100 m was demarcated and 20 Robusta coffee trees were systematically selected along two diagonals in each of the plots. All the stems on each of the selected coffee tree were assessed for pest and disease incidence and damage on the leaves, berry clusters and berries. The coffee canopy was divided into three sections (lower, middle and upper) and incidence and damage of the pests and diseases were determined on coffee leaves, berry clusters and berries. Results showed that the pests and diseases were not evenly distributed within the canopy. On the leaves, the incidence and damage caused by Leucoptera coffeella, Leucoplema dohertyi and Hemilleia vastatrix varied significantly (p≤0.05) across the canopy sections, with the highest levels (23.1, 36.1 and 30.5%) being recorded in the lower section. On the other hand, though the damage caused by Epicampoptera andersoni and the leaf eating beetles was not significantly (p≥0.05) different within the canopy, the highest infestation was recorded in the upper (26.9%) and middle (19.3%) sections, respectively. For the berry cluster, only damage caused by Planococcus spp. varied significantly (p=0.0188) across the canopy, with the highest infestation (18.6%) being recorded in lower section. However, incidence and damage caused by Prophantis smaragdina and Cercospora coffeicola were not significantly (p≥0.05) different within the canopy but, the highest levels were recorded in the upper section of the canopy (15.8 and 24.4%, respectively). On the coffee berries, the incidence and damage of both Hypothenemus hampei and Cercospora coffeicola did not significantly (p≥0.05) across the canopy sections but the highest levels were recorded in the lower (28.5%) and upper (20.7%), respectively. Our findings enlightened the understanding of the vertical distribution of the incidence and damage of pest and disease within the Robusta coffee canopy. This information will contribute to developing and implementing monitoring techniques and regimes as well as ecologically-informed management strategies for these pests and diseases.
Impact of tree management on coffee and common bean productivity in smallholder agroforestry systems in Uganda
(National Agricultural Research Organisation, 2024-11-02) Joel Buyinza; Catherine W. Muthuri; Matthew D. Denton; Ian K. Nuberg
In this study, we hypothesized that tree canopy pruning would positively influence the relative growth performance and productivity of coffee (Coffea arabica L.) and common beans (Phaseolus vulgaris L.) growing under Cordia africana and Albizia coriaria trees. The trees were subjected to a 50% pruning regime at a 6-month interval over a period of 20 months (July 2018 - February 2020), and common beans were introduced following local planting seasons. Yields of parchment coffee were highest under pruned Albizia (949 kg/ha). Unshaded coffee produced the least yield at 402 kg/ha and 422 kg/ha in the Albizia and Cordia sites respectively. While the highest common beans yields (708 kg/ha) were obtained from open field sites, beans that were planted under unpruned Cordia gave the least yield of 420 kg/ha. Unlike coffee, there was a significant variation in yield of common beans across the different management options (P<0.05). The results show that agroforestry tree canopy pruning is an important on-farm management decision for controlling competition while prolonging the period of intercropping in intensive farming systems. Farmers should deliberately prune agroforestry shade trees to minimize the negative effects of dense shading.
Distribution and Severity of Coffee Pests and Diseases in Central Uganda
(2024-11-03) Olango N.D.K.; Kagezi G.; Olal S.; Kucel P.; Ekwaru R.; Judith K.; Arinaitwe G.
This study aimed to determine the incidence and severity of coffee pests and diseases and any relationships between them. Five coffee producing districts in Uganda, namely, Masaka, Mubende, Mpigi, Kayunga and Luwero were selected. 10 coffee farms were evaluated per district. Pest and disease incidence were determined as the percentage of trees with the disease or pest. Disease severity was evaluated on a 1-5 scale while pest damage was expressed as a percentage of tissue damaged. Results showed significant differences in incidence and damage/severity among all the major pests and diseases in the region except foliage beetles. The most damaging pest was the BCTB with an incidence between 15% and 26%. The next most damaging pests were the tailed caterpillars and Skeletonisers, both lepidoptera with incidence of 20.4% and 16% respectively. The most severe disease was Red blister (Cercospora coffeicola) with a severity score 2.0 and incidence 51.6%. No novel pests or diseases were discovered. Further studies are recommended to understand factors proliferating the pests and diseases.

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