Monitoring population density and fluctuations of Anisandrus dispar and Xyleborinus saxesenii (Coleoptera: Scolytinae, Curculionidae) in hazelnut orchards

Abstract

Bark (Anisandrus dispar) and ambrosia beetles (Xyleborinus saxesenii) (Coleoptera: Curculionidae: Scolytinae) include many important pest species of forest and fruit trees. These beetles prefer physiologically stressed trees for colonization but some species also attack healthy trees. Bark and ambrosia beetles consist of two main ecological groups; bark beetles settle in the phloem, whereas ambrosia beetles bore in the xylem (sapwood). The latter are very detrimental in Turkish hazelnut orchards. This study was carried out between 2005 to 2007 to monitor populations of A. dispar and X. saxesenii (Coleoptera: Scolytinae, Curculionidae), causing considerable damage in hazelnut (Corylus avellana L.) orchards in Ordu and Samsun Provinces. Populations of bark beetles were monitored using sticky traps with red wings used to capture these pests. Ethanol (96%) was used as the attractant in the traps. The results of the three-year study indicated that both pest species emerged at different times in Ordu and Samsun. A. dispar emerged in large numbers in spring (March - May) as overwintered adults; X. saxesenii emerged in large numbers in summer (June - August). Population density of A. dispar on the 15^th of May, 2007 was 398 adult/trap whereas population density of X. saxesenii on the 1^st of September, 2005 was 383 adult/trap. The highest catch was recorded in Samsun province.

Key words: Hazelnut, population monitoring, Anisandrus dispar, Xyleborinus saxesenii, red winged sticky traps.