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Ambrosia beetle is a generic term used to refer to a number of genera of insects, including various species, which are found throughout the southern United States. The ambrosia beetle may cause significant damage to green logs and unseasoned lumber, and occasionally to dead, dying, or severly stressed trees. As the insect chews through the bark and into the wood, the insects create a series of winding tunnels called galleries. The insect does not use the xylem as food, but uses the galleries that are created as a place for a fungus to grow. The fungus becomes the source of food for the insects. Interestingly, because of this dependence on the fungus, |
 Boring dust at base of tree Photo credit: USDA Forest Service |
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the insect carries spores of the fungus with it as it moves from
one tree to the other. This gurantees a food supply. The wood debris from the galleries appears as fine sawdust and is pushed out of the galleries where it accumulates around the entrance hole or at the base of the tree. This insect can only survive in very weakened or dying trees, or in wood prodcuts that have not been dried. The moisture is needed to allow the fungus to grow. |
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Ambrosia beetle attack can be recognized by piles of fine, whitish dust found around the 1/16" entrance holes or at the base of the tree. In lumber, the fungus darkly stains the galleries and these stains can easily be seen. |
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Adult beetles are long and thin, usually about 1/4" long. They are reddish brown in color with sharp spines at the back end of their bodies. Fully-grown larvae and pupae are the same size as the adult beetles but are yellowish white in color. |
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Ambrosia beetles attack most tree species. The beetles target very weakened, dying trees, green logs, and unseasoned lumber. The beetles will only attack trees and logs with high moisture content. |
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 Adult Photo credit: USDA Forest Service |
| [Forest Health] |
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