Damage assessment of the acorn pests in Arasbaran Forests

The oak trees density are very high in Arasbaran Forests and accounted as the second most abundant tree species after horn beam, Carpinus betulus L. trees. The most important acorn pests in this area include oak weevil, Curculio glandium Marsh. and the moths of Cydia genus specially Laspeyresia fagiglandana Zell. (Lep.: Tortricidae). Their larvae feed inside acorn and cause great damage to oak trees annually. Thus they lower renewal and reproductive rate of oak seeds. In the cause of a 2 year studies, carried out in Ainalo and MakidiForests pests and non-pests damages affecting acorns were investigated. The emergence hole of acorn weevil and tortricid moths are somehow different in shape, it is circular for acorn weevil and oval shape in the tortricid moths. In addition their excretion (frass) are some how different and can be used to separate them. The tortricid moth larvae excretion is granular and its feeding canal is large, while the acorn weevil larva excretion is powder microlithic and its feeding canal is very small at first which leads to acorn destruction. The loss measure of acorn weevil, tortricid moth and the other destructive agents on acorns were 34/8, 17/1 & 14/6 percentage respectively and the healthy acorns was 33/6 percentage. The data combinated analyses of variance carried out with MSTATC soft ware and there is a significant difference between two acorn pests and the acorn weevil damage was more than the tortricid moth. The pests' interaction with regard to the year has a significant difference but there isn’t any significant difference on pests' damage in the area.