Models for Miridae, a cocoa insect pest. Application in control strategies

Abstract

Cocoa mirid, Sahlbergella singularis, is one of the major pests of cocoa in West Africa. It is responsible of several damages in plots. In this paper, we study the dynamics of this pest. Based on biological and ecological partial knowledge, we develop 2 cooperative mathematical models that aim to describe the time dynamics of the cocoa mirids. We first develop a cooperative stage‐structured model, derived some qualitative results, and a sensitivity analysis study in order to determine the most important parameters. Assuming that all parameters are or not periodic, we obtain conditions that allow the persistence or not of the population. We highlight the influence of cocoa pods variation along the year on the time evolution of the population. Then, we derive a 2‐stage cooperative time‐delay model, with 2 delays, that takes into account the eggs' development time and the females' maturation time. We illustrate our theoretical results with some simulations and show that the delayed system provides the best results compared with real observations. Finally, we focus on chemical control that is commonly used in Cameroon and compare it to a new biological control, mixing mating disrupting and trapping. We discuss the results and provide future perspectives based on this work.