Assessment of tree vigor parameters in successful establishment of dendroctonus micans on picea orientalis in Turkey

Dendroctonus micans (Kugelann) (Coleoptera: Curculionidae) has caused severe outbreaks and killed millions of oriental spruce (Picea orientalis (L.) Link.) trees in the Black Sea Region of Turkey since its discovery in 1966. Besides wounded and overthrown trees, apparently healthy trees are also attacked by the beetle. In infested stands, repeatedly attacked trees and unattacked trees or trees with aborted attacks are reported. In this study, we experimentally investigated the role of some tree vigor parameters in the beetle’s successful establishment on its host. Phloem thickness, recent tree growth rate and tree size were used as tree vigor parameters. Beetle insertions were made at four cardinal points on each tree and establishment success of the beetles was investigated by ten replicates. In our experiment, D. micans females were successfully established more often on thicker phloem and they also tended to be successful on vigorously growing trees. Stressed or destroyed vigorous trees may produce epidemic populations in stand