Abstract: Effects of the temperature on immature stage developmental times of the medfly Ceratitis capitata (Diptera; Tephritidae) were used to study the dynamics of population with FRUFLY model. To test the model in the field, flight activity was studied using para-pheromone traps. The FRUFLY model simulations agree with experimental data results of the insect collected by para-pheromone traps and predicts the appearance of the various generations of adults with time FRUFLY simulation modelling is an important tool for identifying insect pest population's size and can help to determine the urgency of action and evaluating options for management.