Utilization of microsatellites to determine genetic variability of the codling moth Cydia pomonella L. (Lepidoptera: Tortricidae) in Central Chile

Codling moth (Cydia pomonella L.) is the main pest of pip fruits worldwide. Despite its economic importance, little is known about the genetic structure and patterns of movement at local and regional scale, important aspects for establishing a control strategy for this pest. An analysis of genetic variability on six populations of C pomonella using microsatellite was performed in the two major apple (Malus domestica Borkh.) growing regions of Central Chile. In spite of geographic distances between some populations (aprox. 180 km), there was little genetic differentiation among populations (F-ST= 0.0-0.00097 and G(ST)=0.005-0.127), without isolation by distance, and high levels of gene flow (Nm approximate to 250). High frequencies of null alleles were found over all loci across populations (Na = 0.292) which seem to explain the significant heterozygote deficiencies found. Approximatelly 98% of the variance was found within individuals and very little at the other hierarchical levels. The high levels of genetic diversity and gene flow detected seem to indicate that the codling moth populations studied in both regions have an almost continuous distribution.