Trap Style, Bait, and Height Deployments in Black Walnut Tree Canopies Help Inform Monitoring Strategies for Bark and Ambrosia Beetles (Coleoptera: Curculionidae: Scolytinae)

Abstract

Knowledge about which bark and ambrosia beetle species are active and at what heights in black walnut canopies is not well understood. Neither is the role of these beetles in spreading Thousand Cankers Disease. To assist with future planned research, which will assess the extent to which these beetle species are associated with Geosmithia morbida Kolařík, Freeland, Utley, and Tisserat (Ascomycota: Hypocreales: Bionectriaceae), experiments were undertaken to monitor bark and ambrosia beetles in urban landscapes and parks in Tennessee between 2011 and 2013. Within mature walnut tree canopies, sticky panel, modified soda bottle, and Lindgren traps were deployed at different heights, with and without ethanol as an attractant and with and without walnut stem sections, or in situ limbs that had been girdled or injection with ethanol to simulate stressed tree tissues. Bark and ambrosia beetle species (Coleoptera: Curculionidae: Scolytinae) collected in greatest abundance included Ambrosiodmus rubricollis (Eichhoff), Ambrosiophilus atratus (Eichhoff), Cnestus mutilatus (Blandford), Dryoxylon onoharaense (Murayama), Euwallacea validus (Eichhoff), Monarthrum fasciatum (Say), Monarthrum mali (Fitch), Xyleborinus saxesenii (Ratzeburg), Xyleborus affinis Eichhoff, Xyleborus ferrugineus (Fabricius), Xylosandrus crassiusculus (Motschulsky), and Xylosandrus germanus (Blandford). C. mutilatus, X. saxesenii, and X. crassiusculus were more active higher in trees than most other species and were strongly attracted to ethanol via all means of lure deployment. C. mutilatus, which were captured from April through October and increased in abundance across the 3-yr study, were most abundant in late May with a second activity period in late August.

Keywords: Cnestus mutilatus; Juglans nigra; Xyleborinus saxesenii; Xylosandrus crassiusculus; trap efficiency.