Nonlinear observer of the non-spatial dynamics of anthracnose: Case study of coffee berry disease

•An improved model of the dynamics of coffee berry disease is provided;•The fruit volume, the rot volume and the disease severity are considered;•The only outputs of the system are the fruit volume and the rot volume;•The control strategies are usually based on disease severity which is not observable;•Disease severity is efficiently estimated through the construction of an observer. In this paper, an observer for the dynamics of anthracnose disease is proposed based on a non-spatial model provided by the literature. The model is first improved in order to be more realistic. Indeed, conditions on parameters are weakened and therefore applicable to more concrete cases. There are also changes in the equations modeling the dynamics of the berry volume (v) and the rot volume (vr). A high gain observer is constructed and it is proved that it displays an exponential stability under certain conditions. The existence and the conservation of some fundamental properties of anthracnose inhibition rate are also proved. Several simulations are realized to assess the effectiveness of the observer which definitely has the expected behavior.