Abundance of pests and diseases in Arabica coffee production systems in Uganda - ecological mechanisms and spatial analysis in the face of climate change

Liebig Theresa Ines. 2017. Abundance of pests and diseases in Arabica coffee production systems in Uganda - ecological mechanisms and spatial analysis in the face of climate change. Hanovre : Universität Hannover, 124 p. Doktorarbeit : Gartenbauwissenschaften : Universität Hannover

Published version - Anglais
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Encadrement : Poehling, Hans-Michael ; Borgemeister, Christian ; Maiss, Edgar

Abstract : Coffee production worldwide is threatened by a range of coffee pests and diseases (CPaD). Integrated management options require an understanding of the bioecology of CPaD and the prevalent interdependencies within the agroecological context. The comparison of different shading systems (e.g. shade-grown vs. sun-grown coffee) and the identification of trade-offs for ecosystem services is still a matter of ongoing debates. There is little quantitative knowledge of field-level investigation on shade effects and its ecological mechanisms across environmental and shading system gradients. Considering the increasingly evident effects of progressive climate change on CPaD, the need to examine the balance of shade effects under different environmental conditions becomes apparent. With the example of the coffee growing region of Mt Elgon, Uganda, this project aimed at addressing the complexity of shading effects on economically relevant CPaD using environmental and production system gradients. The approach was designed in an interdisciplinary manner, to involve the broader context of coffee agroforestry systems. The first two chapters of this thesis dealt with general aspects of coffee smallholder farming. The diversity of existing coffee production systems was characterized along an altitudinal gradient. A typology of production systems based on indicators related to the vegetation structure was generated and classified as coffee open canopy, coffee-banana inter-cropping, and densely shaded coffee systems. The typology served as the basis for comparison across the environmental and production system gradients. In the second chapter, farmers' knowledge on CPaD and the role of shade trees was contrasted with expert knowledge and field observations. Discrepancies regarding CPaD symptomatology, management and response to shade were revealed. Tackling institutional obstacles and disentangling shading effects are therefore a priority for the improvement of plant health management. The last two chapters focused more specifically on biophysical aspects of Coffee Leaf Rust (CLR, Hemileia vastatrix) and White Coffee Stem Borer (WCSB, Monochamus leuconotus). The effects of environment and production system on CLR abundance were spatio-temporally variable and either directly, interactive or indirectly mediated by microclimate. The development of white coffee stem borer was controlled by the bimodal rainfall, and by altitude and shade through their effect on minimum temperature. The findings emphasize the enormous importance of micro-environments for the ecology of CPaD, not least because of its implications in the context of climate change. (Résumé d'auteur)

Mots-clés Agrovoc : Coffea arabica, Agroforesterie, Changement climatique, Hemileia vastatrix, Monocanthus, Microclimat, Recherche interdisciplinaire, Système de culture, Petite exploitation agricole, Ombrage, Arbre d'ombrage, Altitude, Facteur du milieu, Agroécosystème, Protection des plantes, Musa, Culture intercalaire, Étude de cas

Mots-clés géographiques Agrovoc : Ouganda

Mots-clés complémentaires : Monocanthus leuconotus

Classification Agris : H01 - Protection of plants - General aspects
H10 - Pests of plants
H20 - Plant diseases
F08 - Cropping patterns and systems
P40 - Meteorology and climatology

Champ stratégique Cirad : Axe 4 (2014-2018) - Santé des animaux et des plantes

Auteurs et affiliations

  • Liebig Theresa Ines, CIRAD-BIOS-UPR Bioagresseurs (FRA)

Source : Cirad-Agritrop (

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