Browsing by Author "G.H. Kagezi"

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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.
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.