Déterminants de l'hétérogénéité temporelle et spatiale de la pression de foreurs de tige sur maïs dans une région agricole du Kenya

Harignordoquy Miren. 2011. Déterminants de l'hétérogénéité temporelle et spatiale de la pression de foreurs de tige sur maïs dans une région agricole du Kenya. Paris : AgroParisTech, 45 p. Mémoire de master : Sciences et technologie du vivant et de l'environnement. De l'agronomie à l'agroécologie : AgroParisTech

Résumé : This study is integrated in a context of research on ecosystem services on pest regulation. In the context of high population rural area in mid altitude Kenya, smallholders have diversified production systems and intensification is based on labor. In this situation, human pressure shapes a complex landscape with a very small grain. The study was carried in Kajulu location in western Kenya, during 2011's long rainy season. We investigated the ability of such landscape to deliver pest regulation services. We studied the spatial and temporal heterogeneity of maize stemborers pressure, based on spatial monitoring of insect flight and damages at the field level, as well as surveys of farmers. Landscape was described in scale units, from the natural elements framing the area to intercropped species in the field. A very low infestation of stemborers was observed in the 27 fields spread in the whole area. Busseola fusca was the dominant stemborer, confirming its climatic and altitudinal preferences. Due to this low density of stemborers, natural regulation by parasitoids could not be observed. Long rainy season started with a gap of more than one month; as a consequence, sowing dates and Busseola fusca flights were shifted. Fight peak was observed in June, with a high variability of caches among traps. Surveys of farmers revealed that stemborers are not considered as a main pest in the area contrary to birds, rodents or baboons. There is no direct pest control against stemborers but cultural methods as tillage are employed against insects more widely. In this situation, it has not been possible to observe heterogeneity in stemborer pressure and to relate it to landscape traits and agricultural practices. Applied methodology and results are discussed in this report, with critical discussion and outlooks.

Mots-clés Agrovoc : insecte déprédateur des tiges, Zea mays

Mots-clés géographiques Agrovoc : Kenya

Classification Agris : H10 - Ravageurs des plantes

Auteurs et affiliations

• Harignordoquy Miren, CIRAD-PERSYST-UPR SCA (FRA)

Source : Cirad - Agritrop (https://agritrop.cirad.fr/560739/)

Métriques

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