Trunk injury and fungal transport by Agrilus bilineatus, Chrysobothris femorata, and Xyloterinus sp. in oak wilt infected trees in Texas

Abstract

Examinations for trunk borers revealed that over 95% of the oak wilt (Ceratocystis fagacearum) infected trees in Texas were infested with twolined chestnut borers (Agrilus bilineatus) and flatheaded appletree borers (Chrysobothris femorata). Infestations by the ambrosia beetle (Xyloterinus sp.) were also common. The amount of borer injury varied, but in some trees it was sufficient to cause additional stress to trees already weakened by oak wilt. Variations in the amount of xylem injury by these two borers might help explain why some trees die more rapidly than others following oak wilt infections. In Texas, adult twolined chestnut Dorets were emerging during the first week of March, and a peak number was collected on sticky traps in oak wilt infection centers in June. Isolations from 81 adult ambrosia beetles, 40 twolined chestnut borers (22 larvae and 18 adults), and 17 flatheaded appletree borers (larvae) did not yield C. fagacearum, even though the fungus was isolated from the wood from which these insects were collected. These insects are not likely vectors of C. fagacearum because they carry faster growing fungi and attack trees already stressed by oak wilt or other diseases.

Citation

Lewis, R., JR. 1987. Trunk injury and fungal transport by Agrilus bilineatus, Chrysobothris femorata, and Xyloterinus sp. in oak wilt infected trees in Texas. Journal of the Mississippi Academy of Sciences 32:41-46.