Investigating the presence of oak leaf-roller (Tortrix viridana L.) at different altitude in oak forests of West-Azerbaijan province

One of the main destruction factors of oak forests is the oak leaf roller Tortrix viridana L. which causes a lot of damage to these woods by feeding leaves and buds of oak trees. The purpose of study was to investigate the population changes of this pest in different altitudes. This research was conducted in 2018 in Perdanan and Mirabad. In each region, in three elevation classes, transects with 100 meters’ intervals, and in each elevation class, 30 individuals of Quercus infectoria Olivier, which were located along the specific transect and in terms of appearance approximately similar, measured. In each tree, four branches were selected in four main directions (each direction of a length of 50 cm) and the pest larvae counted and the diameter of the branches were measured. Data were analyzed by SPSS 18 software and comparison of means was performed using Duncan's multiple range test. Results showed that according to the climatic diversity of two regions, the number of T. viridana larvae in the Perdanan was higher than Mirabad. Also, the number of larvae was recorded for both areas in the 1200-1300 meters’ elevation, which shows that the favorable conditions for larvae activity. The elevation class had no effect on distribution of pest in directions of the tree crown. The highest number of larvae in all three elevation classes was recorded in the eastern direction of the tree and its lowest amount were recorded in the west direction.