Yves Fotso

Context

• Coffee: important cash crop for many countries in the tropics
• Borers (Hypothenemus hampei) mostly develop and feed in coffee berries, inducing great damages (reduction in berry quality and yield) and economic losses
• Control methods: insecticides vs cropping practices (removing dropped berries, strip-picking, stump pruning), trapping, biological control (parasitoid or predator insects, entomopathogenic fungi)
• Existing model(s): simulation model with crop growth and pest control [Gutierrez et al. 1998; Rodríguez et al. 2011; Rodríguez et al. 2013]

A.P. Gutierrez, A. Villacorta, J.R. Cure, C.K. Ellis. Tritrophic analysis of the coffee (Coffea arabica)-coffee berry borer [Hypothenemus hampei (Ferrari)]- parasitoid system. Anais da Sociedade Entomológica do Brasil 27(3): 357-385, 1998. DOI: 10.1590/S0301-80591998000300005

D. Rodriguez, J.R. Cure, J.M. Cotes, A.P. Gutierrez, F. Cantor. A coffee agroecosystem model: I. Growth and development of the coffee plant. Ecological Modelling 222(19): 3626-3639, 2011. DOI: 10.1016/j.ecolmodel.2011.08.003

D. Rodriguez, J.R. Cure, A.P. Gutierrez, J.M. Cotes, F. Cantor. A coffee agroecosystem model: II. Dynamics of coffee berry borer. Ecological Modelling 248: 203-214, 2013. DOI: 10.1016/j.ecolmodel.2012.09.015

Objectives

• To develop a model representing coffee berry borer damages in various agroforestry systems
• To design and assess the efficiency of several control strategies, including alternative methods to pesticides

Work progress

Achieved

• Single-season model of the coffee berry borer dynamics, based on the insect life-cycle and including the berry availability during a cropping season
  • ODE model: local and global stability (Lyapunov functions) results for the pest-free and endemic equilibria
  • PDE extension, to integrate the berry maturation age: well-posedness and asymptotic analysis

    Yves Fotso Fotso, Suzanne Touzeau, Berge Tsanou, Frédéric Grognard, Samuel Bowong. Mathematical modelling of a pest in an age-structured crop model: The coffee berry borer case. Applied Mathematical Modelling 110:193-206, 2022. DOI: 10.1016/j.apm.2022.05.042. HAL: hal-03505679

• Optimal control problem
  • Controls: chemical control (insecticides) and/or biological control by entomopathogenic fungi such as Beauveria bassiana, traps
  • Aim: to maximise the yield at the end of the cropping season, while minimising the borer population for the next cropping season and the control costs
  • Results: existence of an optimal solution, numerical solution using the BOCOP software
    1. Bounded control, no persistence

    Y. Fotso Fotso, F. Grognard, B. Tsanou, S. Touzeau. Modelling and control of coffee berry borer infestation. Paper and oral presentation in: CARI’2018 – 14th African Conference on Research in Computer Science and Applied Mathematics, Stellenbosch, South Africa, 14-16 October 2018. HAL: hal-01871508

    Y. Fotso Fotso, S. Touzeau, S. Bowong, F. Grognard, L. Mailleret, B. Tsanou. Modelling and control of coffee berry borer infestation. Contributed talk in: ECMTB 2018 – 11th European Conference on Mathematical and Theoretical Biology, Lisbon, Portugal, 23-27 July 2018. HAL: hal-01859994

    2. Control persistence: the impact of entomopathogenic fungi (or insecticides) lasts over time

    F. Grognard, I. Tankam Chedjou, Y. Fotso Fotso, S. Touzeau. Modelling, control, and optimization for tropical agriculture. Oral presentation in: CMPD5 – Computational and Mathematical Population Dynamics, Fort Lauderdale, USA, 19-24 May 2019. HAL: hal-02139546

    Y. Fotso Fotso, F. Grognard, S. Touzeau, B. Tsanou, S. Bowong. Optimal control on a simple model of coffee berry borer infestation. Oral presentation in: BIOMATH 2019 – International Conference on Mathematical Methods and Models in Biosciences, Bȩdlewo, Poland, 16-22 June 2019. HAL: hal-02309445

    Y. Fotso Fotso, S. Touzeau, B. Tsanou, S. Bowong, F. Grognard. Modelling and optimal strategy to control coffee berry borer infestation. Mathematical Methods in the Applied Sciences 44(18):14569-14592, 2021. DOI: 10.1002/mma.7726. HAL: hal-03334090

    3. Introduction of CBB preference for mature berries (PDE model with berry age structure)

    Y. Fotso Fotso, B. Tsanou, S. Bowong, S. Touzeau, F. Grognard. Optimal impulsive control of coffee berry borers in a berry age-structured epidemiological model. Paper and oral presentation in: CARI’2022 – 16th African Conference on Research in Computer Science and Applied Mathematics, Tunisia and Cameroon, 4-7 October 2022. HAL: hal-03713440

    Yves Fotso Fotso, Suzanne Touzeau, Berge Tsanou, Frédéric Grognard, Samuel Bowong. Optimal control of coffee berry borers: synergy between bio-insecticide and traps. Journal of Optimization Theory and Applications, 196(3):882-899, 2023. DOI: 10.1007/s10957-022-02151-7. HAL: hal-03954863.

• Seasonal model to represent several cropping seasons and harvests (hybrid model)

  F. Grognard, S. Bowong, Y. Fotso Fotso, S. Touzeau, B. Tsanou. A multi-seasonal model of plant-pest interactions: the coffee berry borer. Oral presentation in: MPDEE 2022 – Conference on Mathematical Population Dynamics, Ecology and Evolution, Stellenbosch, South Africa, 13-17 June 2022. HAL: hal-03694889

• “Pré-soutenance” passed 6 October 2021, PhD defence 17 January 2022 (postponed due to pandemic)

  Yves Fotso Fotso. Modelling, analysis and control of coffee berry borer. University of Dschang, Cameroon, 2022. HAL: tel-03608463

Misc

• Participation in the École de Contrôle Optimal Numérique, Toulouse, 3-7 September 2018 (grant)
• Fellow of the AUF Collège doctoral régional de l’Afrique Centrale et des Grands Lacs « Mathématiques, Informatique, Biosciences et Géosciences de l’Environnement », June 2018 call
• Participation in the International Graduate School on Control, M18 Hybrid Control Design, L’Aquila, Italy, 13-17 May 2019 (overseas grant)