The effect of cardinal directions on growth features and demographic changes of oak leaf-roller moth Tortrix viridana L. (Lep.: Tortricidae) in Ghabr-e-Hosein forests, Piranshahr

The oak leaf-roller moth (Tortrix viridana L.) damages the Zagros forests greatly by feeding upon leaves and sprouts of different species. The current study was carried out in 2015 in order to investigate the influence of cardinal directions on quantity features of oak tree and on the demographic changes of oak leaf-roller moth in Ghabr-e-Hosein area (Piranshahr) located in oak forests of west Azerbayjan. In every main geographical directions 30 gall oak trees (Quercus infectoria) and 30 Lebanon Oak trees (Q. libani) was measured using transect method and the pest larvae were counted from the branch tip inward and also quantity features of the host trees were recorded. Results showed that the maximum crown diameter was on the east while the minimum was on the south and north. The highest and lowest diameters at breast height (DBHs) were on the south and north, respectively. In addition, results showed significant differences (p < 0.05) between density of larvae on Q. infectoria and Q. libani. There is also significant differences between mean amounts of oak leaf-roller moth in different geographical directions. Tukey test (HSD) showed that for both of tree species the maximum and the minimum number of larvae were in the east and the west, respectively and the highest larval accumulation of the pest was on the eastern part of the tree crown. The obtained results are indicative of the fact that larvae of the leaf-roller moths’ distribution orientation can also be influenced by the direction of wind blows.