Biological study of oak weevil, Balaninus glandium Marsh. and determination of its natural enemies in Arasbaran forests.

The oak trees density are very high in Arasbaran Forests and place in second degreeas compared with horn beam Carpius betulus L.trees .One of the most important acorn pest in the area is acorn weevile, Curculio glandium Marsh. that its larva feeds in acorn contents annually create a great damage on oak trees and therefore it cause difficult on live renewal and reproductive of oak seeds. Acorn weevile is recorded from France, England, Northamerica, Spain, Yugoslavia, Czech Oslovakia and the republics of the last Russia.It also is reported from Western Westernsouth provinces such as Fars, Kordestan and Azarbaijan in Iran, It is seen in most oak distribution aeras in Arasbaran Forests and the main host of the pest is the oak trees but it sometimes feeds on hazel- nut. In attention to there is an other pest of oak seeds that called Laspeyresia fagiglandana (Lep. Tortricidae)in the mentioned aeras the primary investigations indicated that average damage of these pests in Makidi and Ainalo Forests had any significantly different between them and the percentage of weevil damage was more than the Tortricid moth s damage in the both of aeras. Overwintering of this acorn weevil is the last instar larva in the soil and adults appear in the spring in Arasbaran mostly and the activity period of them continue from early May to mid- October.After mating the femals begin their oviposition from last june they continue to early october . Larval activity period and creation of damage start from mid-july and they last to mid- octaber (When the fruitfalling is begun). After the fruitfalling larvae exist of the infested fruits and enter to the soil and then they are changed to the pupa at the following Spring.The larvae spend five instar in Arasbaran and the pest has only one generation per year. Study on the natural enemies of the acorn weevile indicated that there are five species of Arthropods including two predators Centipedes, one predator, Spider a parasitoid wasp and kind of entomopathogenic fungi in Arasbaran Forests.Every one of them effects on life stages of the pest specially larval stage.The livestocks and some birds feed on fruits contains larvae therefore they are important factors in decreas of the pest population. Key words: Arasbaran forests , Curculio glandium , Oak , Quercus