The green oak leaf roller moth, Tortrix viridana, is one of the most harmful pests of Quercus spp. in Zagros oak forests. The young larvae develop inside flushing buds and feed on the leaves of oak trees and sometimes cause significant damage to the oak forests by increasing defoliation in the target forests. The aim of this study was to understand which factors (geographical distances, oak species) influence the genetic structure of the pest using six microsatellite markers (SSRs). Therefore, we collected 72 genotypes of T. viridana from 17 oak forest stations located in Kurdistan, West Azarbaijan, Kermanshah and Lorestan provinces based on geographical distances and host oak species Quercus brantii and Quercus infectoria. All loci showed polymorphism from a total of 202 alleles produced by six microsatellite primers. In addition, analysis of molecular variance (AMOVA) showed a very high genetic diversity within the populations (98%) than among the populations (2%), which indicated the existence of high gene flow among the geographical populations. Further on, the distribution of T. viridana in the geographical areas studied using principal coordinate analysis (PCoA) and based on the genetic distance matrix (Nei) showed that the populations of Kurdistan and West Azarbaijan provinces very similar and the populations of Kermanshah and Lorestan provinces are separated from other populations genetically. Nevertheless, the dendrogram obtained from the XLSTAT software and Ward's method showed that the geographical region and the host oak species did not affect the clustering of genotypes. However, the results of this research showed a very strong gene flow among populations, which can be useful in the planning of integrated management of the pest in forests of northern Zagros in future.
