Asian Ambrosia Beetles Of Maple

Disease Information

Asian Ambrosia Beetles


Symptomsand damage

Japanese maples are among the more common hosts of the granulate ambrosia beetle (Xylosandruscrassiusculus), with other hosts including styrax, ornamental cherry (especially Yoshino), pecan, peach, plum, dogwood, persimmon, sweetgum, magnolia, fig, Chinese elm and azalea. This pest is attracted not only to damaged, stressed or transplanted trees, but to seemingly healthy trees as well. The beetle becomes active in early March (or earlier), and the female beetles bore into trunks or branch wood of thin-barked hardwood trees. Once a tree has been attacked, it becomes more attractive to further attack. Often these trees are less than four inches in diameter.

Visible symptoms include wilted foliage, as well as the toothpick-like strands of boring dust (frass) that protrude from these small, pencil-lead size holes.

Management

 infested plants should be removed. If only a few branches are infested they may be cut out. The life cycle takes approximately 55 days until the emergence of the next generation of beetles, so prompt removal or burning of the wood is important. Protective sprays on other susceptible plants may reduce their spread. Permethrin may be used as a trunk and scaffold limb spray beginning in March ,Thoroughly wet the bark. Multiple treatments may be needed during a season. Research indicates that spraying the infested trunks with permethrin may cause the beetles to leave the galleries they have already created. Since the beetles do not consume the host plant material, dinotefuran and imidacloprid treatments are ineffective.

 



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