Georgia Invasive Species Task Force

Xyleborus glabratus

James K. Johnson, Coordinator, Georgia Forestry Commission, Forest Health Accomplishment Report 2004

Statesboro has been dealing with a massive die off of Red Bay trees since last summer and they are now seeing Sassafras dying in a similar manner (these 2 trees are in the same family - Lauraceae). A similar factor in this mortality is the presence of a newly introduced insect (Xyleborus glabratus) an Asian ambrosia beetle. The GFC survey person (Wesley Wells) trapped several of these insects in 2002 at Port Wentworth and they were sent to an expert in Maryland for identification. They were identified as Xg but little was known about the insect except that it is native to India / Borneo region of the world and this was the first find in North America. This insect bores into the tree and has a fungus on its body which grows in the wood and the insect feeds upon the fungus. There are several researchers looking at various aspects of this mortality. They are in the process of isolating the fungus that actually kills the tree and they know it is an aggressive species in the same genus as the fungus that causes Dutch Elm Disease. They are trying to prove that this fungus occurs on the bodies of Xg found in the wood. There are other insects found in these dying trees and these could be the carrier for the fungus also so there is more work to do to prove what is causing this mortality.

Chip Bates has been providing excellent leadership with this ongoing problem and even planted some Avocado trees (sent to us by the Florida Department of Agriculture) in stands suffering severe red bay mortality. Avocado share the same genus (Persea) with Red Bay so it is very closely related and these trees are grown commercially in south Florida. So far the Avocados are unaffected.

NOTE: There has been another species of Asian Ambrosia Beetle established in our state since the mid 1970's and the 2 have a very distinctive damage characteristic. When they bore into the tree, the frass tubes stick out from these holes looking like tiny toothpicks.