11- Cydia pomonella L. causes significant economic loss in the global fruit-growing industry. Its biology is influenced by environmental factors which have an impact on its voltinism in relation to its habitat. 22- The influence of the altitudinal gradient on the number and duration of C. pomonella populations on walnut trees grown at latitudes below 29° was determined. The relation between temperature and population curves was evaluated by an altitudinal gradient. 33- A higher number of generations was quantitatively recorded in a shorter time on orchards located at lower altitudes. Walnut trees grown at higher altitudes, with lower temperatures, showed less pest pressure. The “Predictive Extension Timing Estimator”, used in several regions for the management of C. pomonella, does not accurately predict the length of the generation time in plantation crops at lower altitudes, requiring further studies in this area. 44- The results are relevant for designing of management strategies for walnut trees grown at latitudes below 29°, where environmental conditions differ considerably from other latitudes that were studied, impacting on the population dynamics of C. pomonella.