Tree spatial structure, host composition and resource availability influence mirid density orbBlack pod prevalence in cacao agroforests in Cameroon

Gidoin Cynthia, Babin Régis, Bagny-Beilhe Leïla, Cilas Christian, Ten Hoopen Gerben Martijn, Ngo Bieng Marie-Ange. 2014. Tree spatial structure, host composition and resource availability influence mirid density orbBlack pod prevalence in cacao agroforests in Cameroon. PloS One, 9 (10):e109405, 12 p.

Quartile : Q1, Sujet : MULTIDISCIPLINARY SCIENCES

Liste HCERES des revues (en SHS) : oui

Thème(s) HCERES des revues (en SHS) : Psychologie-éthologie-ergonomie; Staps

Résumé : Combining crop plants with other plant species in agro-ecosystems is one way to enhance ecological pest and disease regulation mechanisms. Resource availability and microclimatic variation mechanisms affect processes related to pest and pathogen life cycles. These mechanisms are supported both by empirical research and by epidemiological models, yet their relative importance in a real complex agro-ecosystem is still not known. Our aim was thus to assess the independent effects and the relative importance of different variables related to resource availability and microclimatic variation that explain pest and disease occurrence at the plot scale in real complex agro-ecosystems. The study was conducted in cacao (Theobroma cacao) agroforests in Cameroon, where cocoa production is mainly impacted by the mirid bug, Sahlbergella singularis, and black pod disease, caused by Phytophthora megakarya. Vegetation composition and spatial structure, resource availability and pest and disease occurrence were characterized in 20 real agroforest plots. Hierarchical partitioning was used to identify the causal variables that explain mirid density and black pod prevalence. The results of this study show that cacao agroforests can be differentiated on the basis of vegetation composition and spatial structure. This original approach revealed that mirid density decreased when a minimum number of randomly distributed forest trees were present compared with the aggregated distribution of forest trees, or when forest tree density was low. Moreover, a decrease in mirid density was also related to decreased availability of sensitive tissue, independently of the effect of forest tree structure. Contrary to expectations, black pod prevalence decreased with increasing cacao tree abundance. By revealing the effects of vegetation composition and spatial structure on mirids and black pod, this study opens new perspectives for the joint agro-ecological management of cacao pests and diseases at the plot scale, through the optimization of the spatial structure and composition of the vegetation.

Mots-clés Agrovoc : Theobroma cacao, agroforesterie, agroécosystème, méthode de lutte, facteur climatique, microclimat, Sahlbergella, Phytophthora megasperma

Mots-clés géographiques Agrovoc : Cameroun

Mots-clés complémentaires : Sahlbergella singularis

Classification Agris : H20 - Maladies des plantes
H10 - Ravageurs des plantes
F08 - Systèmes et modes de culture
F40 - Écologie végétale
K10 - Production forestière

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

Auteurs et affiliations

• Gidoin Cynthia, Montpellier SupAgro (FRA)
• Babin Régis, CIRAD-BIOS-UPR Bioagresseurs (KEN) ORCID: 0000-0002-3753-1193
• Bagny-Beilhe Leïla, CIRAD-BIOS-UPR Bioagresseurs (CMR)
• Cilas Christian, CIRAD-BIOS-UPR Bioagresseurs (FRA)
• Ten Hoopen Gerben Martijn, CIRAD-BIOS-UPR Bioagresseurs (CMR) ORCID: 0000-0003-2133-3130
• Ngo Bieng Marie-Ange, CIRAD-PERSYST-UMR SYSTEM (FRA)

Source : Cirad - Agritrop (https://agritrop.cirad.fr/574240/)

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