Insect Pest Alert – Granulated Ambrosia Beetles

In recent weeks, the Extension office has received several calls about trees being damaged or killed by Ambrosia Beetles. This beetle was introduced from Asia in the 1970s and attacks a variety of deciduous trees and some shrubs. Although they attack healthy trees, trees that are stressed in any way are at greater risk. Female beetles bore into wood and excavate galleries for their young. Beetles also inoculate the trees with fungus, from which the adults and young feed.

According to Michelle Wallace, Durham Co. Extension Agent,

“Some of the characteristic symptoms of an Ambrosia Beetle Infestation include:

1)      Tiny holes in the bark of the tree
2)      Sawdust that looks like little toothpicks sticking out of the tree
3)      Dieback of the upper branches of the tree

Once the infestation occurs death always follows – there is no cure. 

However, action must be taken to remove and destroy the infested wood.  This insect has many hosts and is particularly attracted to trees under stress – though can and will attack healthy trees as well.”

Sawdust plugs pushed from a tunnel. Photo: C. S. Gorsuch

Sawdust plugs pushed from a tunnel. Photo: C. S. Gorsuch

Adult Granulated Ambrosia Beetle (formerly Asian Ambrosia Beetle). Photo: NSCU.edu

Adult Granulated Ambrosia Beetle (formerly Asian Ambrosia Beetle). Photo: NSCU.edu

Control of this pest is difficult. Infested plants should be removed and destroyed. Monitor trees for signs of pests, and avoid conditions that will cause stress. For more information, please see the following links:

http://www.ces.ncsu.edu/depts/ent/notes/O&T/trees/note111/note111.html

http://www.clemson.edu/cafls/departments/esps/factsheets/turforn/ambrosia_beetles_to22.html

http://entnemdept.ufl.edu/creatures/trees/asian_ambrosia_beetle.htm

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