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The mango tree ¿ blossom gall midge system: in-silico assessment of its functioning and management [GEN04.03]

Grechi I., Reyné B., Saint-Criq L., Memah M.M., Ratnadass A., Normand F., Boudon F.. 2019. Salzburg : ISEM, 1 p.. Biennial conference of the international society for ecological modelling (ISEM). 22, 2019-10-01/2019-10-05, Salzburg (Autriche).

Mango (Mangifera indica) is a popular fruit in tropical and subtropical regions. However, it is facing several production constraints with agronomical and phytosanitary issues. Among them, the mango blossom gall midge (BGM, Procontarinia mangiferae) is a major pest of mango tree which can cause significant yield losses by damaging mango inflorescences. Pesticide-free practices aimed at controlling BGM are required. A modelling approach is currently developed for the mango¿BGM system to assess how it works and the effect of orchard management options. Two management levers are investigated: manipulation of mango phenology to synchronize flowering, and soil mulching used as a physical barrier to break BGM life-cycle. A mango-BGM process-based model was developed from experimental data collected in a mango orchard over two years. The orchard was divided into three zones according to soil mulching treatments. The model simulates the dynamics of mango inflorescences (resources) and BGM populations within each zone of the orchard at a daily time-step during the periods of mango flowering. It accounts for i) natural development and BGM-induced mortality of inflorescences; ii) BGM life-cycle and emergence of endogenous individuals, as affected by mulching treatments; and iii) orchard colonization by BGM exogenous individuals and movements of BGM individuals between zones. The ability of the model to reproduce real patterns of inflorescences and BGM dynamics was evaluated by comparing the overall model behaviour with field data. Model simulations were performed to investigate the responses of the mango-BGM system to mulching treatments and manipulation of mango flowering dynamics, and to evaluate how sensitive these responses were to model parameters and exogenous pest pressure. The modelling approach and simulation results are presented and discussed. As a perspective, coupling the model with a functional-structural plant model describing mango tree phenology and fruit production will be useful to design sustainable mango production systems.

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