On synergistic co-infection in crop diseases. The case of the maize lethal necrosis disease

Abstract

Crops are often subject to intense attacks by pests and diseases. Among them, Maize Lethal Necrosis (MLN) is a serious disease that impact maize crops in many Southern countries. It results from the synergistic interaction of two plant viruses, transmitted by two vectors. In this paper, we develop a general deterministic epidemic model of crop-vector-borne disease for synergistic co-infection, with a particular focus on MLN disease. A theoretical analysis shows that different thresholds exists that drive the dynamics of the system: the well known basic reproduction numbers and also invasion reproduction numbers. The latter are essential for the emergence or not of the MLN disease. After a global sensitivity analysis, we illustrate our results through numerical simulations and discuss potential control methods such as vector control and roguing.