Modelling and monitoring for strategic yield gap diagnosis in the South African sugar belt

► We revisit the use of modelling and monitoring in annual reviews of South African sugarcane production. ► The objective of the reviews is to explain year-to-year variations in sugarcane production. ► The reviews also contribute to improve research and co-operation between researchers and growers. ► Recent negative production trends appear related to a new pest and poor sugarcane husbandry. ► Deteriorating socio-economic conditions are indicated as the main underlying cause.