Modelling in cassava production and pest management under biotic and abiotic constraints

Many pests and diseases affect the production of cassava leading to considerable yield losses. For over 30 years, experimental and theoretical studies have sought to better understand the epidemiology cassava pests and diseases, to result in more effective detection and control. In this review, we consider the contribution that modelling studies have had on understanding the epidemiology and management of a number of cassava pests. This review summarises modelling studies for the most economically important cassava pests and diseases including cassava mosaic disease, cassava brown streak disease, the cassava mealybug and the cassava green mite. We focus on conceptual models of system dynamics rather than statistical methods. Through our analysis we identified four key areas where modelling could contribute. First, by taking a more holistic approach and considering multiple pest-threats at a time, modelling could further advance strategies for surveillance, detection and control of cassava pests. Second a more comprehensive assessment of the agricultural crop production system could be achieved by taking a systems approach to modelling and linking the crop, pest, and environmental conditions. Third, greater insights into the impacts and uncertainties of climate change could be achieved through novel modelling applications. Finally, with recent advances in understanding molecular mechanisms of plant defence, there is a great opportunity to further develop models at the molecular and cellular level to describe plant and pest population dynamics so increasing the understanding of the impacts these mechanisms have.