Recovery of Sasajiscymnus tsugae (Coleoptera: Coccinellidae) and Laricobius nigrinus (Coleoptera: Derodontidae) released against hemlock woolly adelgid, Adelges tsugae, in the Great Smoky Mountains National Park

As part of a biological control program against hemlock woolly adelgid (HWA), Adelges tsugae Annand (Hemiptera: Adelgidae), two predator species, Sasajiscymnus tsugae (St) (Sasaji and McClure) (Coleoptera: Coccinellidae) native to Japan and Laricobius nigrinus (Ln) Fender (Coleoptera: Derodontidae) native to western North America, have been released in the Great Smoky Mountains National Park (GRSM). Since 2002, ca. 390,000 St and ca. 6,600 Ln beetles have been released in 166 and 26 sites in GSRM, respectively. To evaluate establishment of these released predators, an extensive survey was initiated in 2008. In each release site examined, beat-sheet sampling was conducted for four man-hours on accessible hemlock trees. St adults (n=78) and St larvae (n=145) were recovered from seven of the 44 St release sites surveyed in 2008 and 2009. Of the 10 Ln release sites surveyed in 2009, adult Ln (n=18) were recovered from three sites. Additionally, adults of the native L. rubidus LeConte were recovered from two of the 10 Ln release sites (n=18) and three of the 44 St release sites (n=9). This study provides documentation of St and Ln recovery in the Appalachian Mountains of the eastern United States. Surveys are scheduled to continue through 2010.