Population Genetic Structure of Codling Moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae), in Different Localities and Host Plants in Chile

The codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae), is a major pest introduced to almost all main pome fruit production regions worldwide. This species was detected in Chile during the last decade of the 19th century, and now has a widespread distribution in all major apple-growing regions. We performed an analysis of the genetic variability and structure of codling moth populations in Chile using five microsatellite markers. We sampled the codling moth along the main distribution area in Chile on all its main host-plant species. Low genetic differentiation among the population samples (F-ST = 0.03) was found, with only slight isolation by distance. According to a Bayesian assignment test (TESS), a group of localities in the coastal mountain range from the Bio-Bio Region formed a distinct genetic cluster. Our results also suggest that the codling moth that invaded the southernmost locality (Aysen Region) had two origins from central Chile and another unknown source. We did not find significant genetic differentiation between codling moth samples from different host-plant species. Our results indicate high genetic exchange among codling moth populations between the different Chilean regions and host plants.