Cocoa plant mirids

  • PhD: Myriam Djoukwe Tapi, University of Douala, 2014-June 2020
  • Supervisors: S. Bowong, Y. Dumont, L. Bagny-Beilhe (CIRAD)
  • Partners: CIRAD, IRAD

Context

  • Cocoa: major cash crop – Cameroon: 5th largest producer
  • Mirids (Sahlbergella singularis) feed on and damage young pods and shoots, most dangerous insects
  • Control methods: insecticides (efficient but costly) vs cropping practices, mating disruption, trapping
  • Existing model(s): complex production model [Zuidema et al. 2005], no dynamical models for mirids

P.A. Zuidema, P.A Leffelaar, W. Gerritsma, L. Mommer N.P.R. Anten. A physiological production model for cocoa (Theobroma cacao): model presentation, validation and application. Agricultural Systems 84(2): 195-225, 2005. DOI: 10.1016/j.agsy.2004.06.015

Objectives

  • To represent the spatio-temporal evolution of damages caused by mirids in a cocoa plot
  • To compare (bio)control strategies to reduce the pest population and the damages
  • To set up new experiments and observations to validate hypotheses or estimate model parameters

Work progress

Achieved

  • Mirid population stage-structured dynamic models: with or without periodic parameters, without or with time-delays
  • Model analysis: based on cooperative system theory, conditions for mirid persistence
  • Mirid control: insecticide use could be reduced if applied at the appropriate period of the year; alternative methods, i.e. mating disruption and trapping, could also reduce the pest population

M. Djoukwe Tapi, L. Bagny Beihle, S. Bowong, Y. Dumont. Modeling mirid population, a cocoa pest. Analysis and simulation. Poster in: BIOMATH 2017 – International conference on Mathematical Methods and Models in Biosciences, Kruger Park, South Africa, 25-30 June 2017.

M. Djoukwe tapi, L. Bagny Beihle, S. Bowong, Y. Dumont. Models for Miridae, a cocoa insect pest. Application in control strategies. Mathematical Methods in the Applied Sciences 41(18): 8673-8696, 2018. DOI: 10.1002/mma.5063

  • Refined model, in order to capture more complex dynamics observed in the field
  • Representation of alternative control strategies: mating disruption and trapping

M. Djoukwe Tapi, L. Bagny Beihle, Y. Dumont. Miridae control using sex-pheromone traps. Modeling, analysis and simulations. Nonlinear Analysis: Real World Applications 54: 103082, 2020. DOI: 10.1016/j.nonrwa.2019.103082

PhD defence, 19th June 2020

Myriam Djoukwe Tapi. Mathematical modelling, analysis and simulations to improve the control of Miridae, a cocoa pest. PhD in Applied Mathematics, University of Douala, June 2020. HAL Id: tel-03122705

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