S15 - Session O1 - Effect of cultural practices and landscape on the entomological biodiversity of agro-ecosystems in Senegal

Authors: Karamoko Diarra *, Mamadou Diatte, El Hadji Serign Sylla, Babacar Labou, Etienne Tendeng, Seydina O. Seydi, Amadou Balde, Pape Diop, Serigne O. Sene, Issa A. Ndiaye

Insect's pests cause significant damage to horticultural crops in Senegal. They are often difficult to control using insecticides. The increasing and non-reasoned use of insecticides directly contributes to the destruction natural enemies and causes the development of resistant insect populations. In the same way, the cultural practices and the characteristics of the landscape probably have a determining role in the regulation of the populations. The objective of this work is to determine the effect of cultural practices and landscape context on the abundance of insect pests and the impact of natural enemies. The study sites are located in the northern, central and southern zones of Senegal. The target pests were monitored in the field and in the laboratory to assess the associated parasitism. Results showed that the incidence of H. armigera and T. absoluta was negatively correlated with distance from the sea. Plant density in the plots and duration of plants in the nursery were negatively correlated with the intensity of H. armigera and T. absoluta attacks. The number of insecticide treatments was negatively correlated with T. absoluta infestation. Soil preparation type influenced T. absoluta infestations. H. armigera attacks vary with irrigation type. Strong impacts of practices on the population levels of these two insects were noted. The characterization of the orchards allowed correlations to be made between the characteristics of the orchard and the communities of ants, the characteristics of the orchard and the populations of pests (fruit flies) and the characteristics of the orchard and the populations of its natural enemy ( Oecophylla longinoda ). The results obtained contribute to the identification of levers for prevention and integrated management of pest populations at risk and insecticide resistance for the design of sustainable horticultural production systems.