Mathematical modelling of agrochemical uptake across leaf cuticle
: (Alternative Format Thesis)

  • Jenny Delos Reyes

Student thesis: Doctoral ThesisPhD


There is global campaign for a more resilient way of farming that can withstand climate change and other food security threats in order to meet increasing demands from rising human population. Agrochemical products such as pesticides can optimise crop
yield, but due to the evolving nature within the agricultural industry, there is a continuous need for new and better refined pesticide products. However, current product development procedures are laborious and expensive. Hence, there is an increasing interest in mechanistic models as part of product development toolbox which can significantly reduce development time and resources. In this thesis, we develop a mathematical model to describe absorption of pesticide from spray droplets on the leaf surface. We use a simplified leaf structure by recognising the outer cuticle layer as the main barrier to pesticide uptake. The resulting model comprises two well-mixed compartments separated by a membrane that represents the spatio-temporal distribution of the pesticide. Moreover, effects of chemical interactions in a formulation and environmental influences are also incorporated which gives rise to a model with concentration-dependent diffusion and temporally changing domain. The importance of including two of the most important factors in modelling pesticide leaf uptake is highlighted in replicating the experimental data. Traditional techniques and more intuitive approach for parameter estimation have been explored. Finally, solving model system analytically using Laplace Transforms, and constructing a robust and accurate numerical approach are also demonstrated.
Date of Award26 Jul 2023
Original languageEnglish
Awarding Institution
  • University of Bath
SponsorsEPSRC & Syngenta Ltd
SupervisorJane White (Supervisor), Begona Delgado-Charro (Supervisor), Tony Shardlow (Supervisor) & Steven Webb (Supervisor)


  • pesticide
  • hybrid ODE-PDE model
  • parameter estimation
  • concentration-dependent diffusion
  • physico-chemical properties
  • surfactant
  • evaporation rate

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