Institut für Biologischen Pflanzenschutz
Codling moth (Cydia pomonella) is a major pest to apples. The larvae are highly dependent on fruits as a food source. The caterpillars bore into fruit and cause severe fruit damage. Since decades, various means of control, including chemical, biological, and preventive, have been implemented to prevent the damages caused by the caterpillar. C. pomonella is present in temperate climates suitable for pome fruit production and is thus a severe threat to apple cultivation worldwide. Adaptive behavior such as diapause and multiple generations allow C. pomonella to persist in regions of different climatic conditions. The diapause is a period of interrupted development. It can occur to outlast unfavorable climatic conditions, or periods of reduced food supply. In diapause larvae of C. pomonella enter a phase of low metabolic activity and can persist in this state, for up to two years without feeding. The diapause behavior within a C. pomonella field population is heterogenous, i.e. some individuals finish the diapause in early spring around the end of March, whereas other pupate late, up to the middle of June.Individuals that finish the diapause early in spring are able to complete two or more generations and thus pose a higher pest pressure than individuals that pupate later and are only able to complete one generation per year. Climate change accompanied with longer and warmer seasons will push C. pomonella to more generations per year.Diapause of C. pomonella is regulated by the photoperiod and temperature and progression through diapause phases is based on unknown physiological processes. In other Lepidoptera some recent progress has been made in elucidating markers important for latitudinal regulation of voltinism, genetic factors involved in the diapause regulation of C. pomonella need to be determined. The heterogenous diapause behaviour within certain C. pomonella populations from the same sites (i.e. under the same environmental conditions) indicates that diapause is not only triggered by environmental cues, but also intrinsically controlled and genetically determined. Determining these factors will be eminent for appropriate risk assessment and optimal phytosanitary measures. It is thus important to understand the diapause dynamics and their genetic regulation in C. pomonella.
Versuchszentrum Laimburg
