ARS | Publication request: Xylosandrus germanus: A long-established but emerging invasive pest in U.S. nurseries

Submitted to: Proceedings, XXI International Congress of Entomology
Publication Type: Proceedings
Publication Acceptance Date: February 28, 2008
Publication Date: July 8, 2008
Citation: Ranger, C.M., Reding, M.E. 2008. Xylosandrus germanus: A long-established but emerging invasive pest in U.S. nurseries. Proceedings, XXI International Congress of Entomology.Available: http://www.ice2008.org.za/pdf/proceedings.pdf

Technical Abstract: Since first being detected in the U.S in 1932, the exotic ambrosia beetle Xylosandrus germanus is increasingly being recognized as a key pest of nursery trees, particularly deciduous hosts. Despite being mainly considered as a secondary attacker, a growing body of evidence indicates X. germanus will colonize apparently-healthy trees. A series of experiments were conducted to elucidate the influence of abiotic and biotic factors on the colonization strategy of X. germanus. The impact of prolonged winter dormancy on host-attraction to X. germanus was assessed using kousa dogwoods, Cornus kousa. Groups of dormant C. kousa trees were held for varying lengths of time in cold storage to experimentally-induce progressive phenological stages. Cornus kousa trees ranging from dormant to post-dormant were then simultaneously placed adjacent to woodlots just prior to X. germanus peak flight activity. The influence of phenological stage on host-attractiveness and colonization by X. germanus will be described. Complementary experiments focused on the interaction between flood stress and pathogenicity of X. germanus fungal symbionts. Sweetbay magnolia, Magnolia virginiana, trees under adequate and flood-stress irrigation conditions were inoculated with either Ambrosiella hartigii or a second unidentified Ambrosiella sp. isolated from the mycangium of X. germanus. Volatiles collected and identified from the M. virginiana treatments were subsequently assessed for their attractiveness to X. germanus. Fungal pathogenicity and the attractiveness of host-plant volatiles to X. germanus will also be described. Understanding the influence and interaction among these factors is critical to improving the management and detection of X. germanus in the nursery agroecosystem.