The control of Eldana saccharina Walker (Lepidoptera: Pyrelidae) in sugarcane of KwaZulu–Natal, South Africa has proved problematical. Among various methods of control available are early harvesting and the use of insecticides. A precise and detailed simulation model is developed to investigate the effectiveness of such methods of control and in particular the optimal timing of such applications. The model is cohort–based and includes the effect of temperature on the –physiological development of individuals in each life-stage of the insect. Further, the model gives a sugarcane damage index which indicates levels of damage on any given day of the simulation. Relationships are obtained involving the damage index, timing of harvest and duration of insecticide effectiveness under selected temperature patterns.
