Monday, June 29, 2015

Experimental Biocontrol Agent Released for Hemlock Woolly Adelgid

While the hemlock woolly adelgid (Adelges tsugae) was introduced to the western U.S. in the 1920s, DNA evidence indicates that the population in the eastern U.S. came from eastern Asia.  The western hemlock (Tsuga heterophylla) are resistant to their population of adelgid due to the trees similarities to native asian hemlock, but the eastern (Tsuga canadensis) and Carolina (Tsuga caroliniana) hemlocks are more susceptible and can be killed by the infestation.

hemlock woolly adelgid (Adelges tsugae) by Lorraine Graney, Bartlett Tree Experts,
Researchers found flies native to the western U.S. which are attacking and eating the adelgid.  After ten years of research, the silver flies (Leucopis piniperda and L. argenticollis) were gathered from Washington and released on May 12 in Tennessee and on June 5 in New York under a permit from the USDA Animal Plant Health Inspection Service.  Most of the flies are confined to infested branches covered by bags, but there are open releases.  While the flies are unlikely to eradicate the adelgids, they may reduce the overall population.

Source Article: Flies released to attack hemlock-killing pest
Hemlock woolly adelgid images: Adelges tsugae Images
Hemlock woolly adelgid Wiki article: Adelges tsugae Wiki
Hemlock woolly adelgid map: Adelges tsugae map
Don't Move Firewood: Adelges tsugae