Insights Into Cydia pomonella adaptability to different climatic conditions: voltinism characteristics and suitability of phenological models for flight predictions

The codling moth ( C. pomonella ) is a notorious pest of apples, pears and other pome fruits, causing significant economic damage during outbreaks. This study investigated the voltinism of codling moth across various climatic conditions at three distinct Moroccan apple orchards; two in the Atlas Mountains and one in the plain. Our objective was to assess the voltinism of the pest and to analyze its evolution in relation with the temperature factor through different locations. We employed phenological models to predict insect generation patterns and the onset of adult flights, and compared predictions with observed data obtained from trap catches. At all study sites, a single generation required an average accumulation of 549 DD close to some models assumptions. The study also highlighted the significant impact of temperature on the insect’s voltinism and indicated that a warmer climate could lead to an additional generation. In the mountainous regions, the pest typically occurs on three generations, with a potential fourth one if the growing season exceeds 2000 DD. In the plain, the moth completes four generations. Furthermore, the advent of flights varied among locations, highlighting the need to account for the synchrony between insect emergence and host tree phenological stages when predicting the onset of moth activity. Finally, the study suggests that different models should be used in Morocco to predict moth flights accurately as observed data were consistently aligning with specific models at each location.