The scale and parasitoid community on native hemlocks in japan

Publication date: Available online 9 May 2016 Source:Biological Control Author(s): Kristopher J. Abell, Rodger Gwiazdowski, Benjamin B. Normark, Naoto Kamata, Roy G. Van Driesche Elongate hemlock scale (EHS), Fiorinia externa (Hemiptera: Diaspididae), is an invasive species in the United States of Japanese origin that was first detected in New York in 1908. In the United States, EHS attacks eastern hemlock (Tsuga canadensis) and Carolina hemlock (Tsuga caroliniana), and has established in most states where these trees occur. Elongate hemlock scale density can be several orders of magnitude higher in the United States than in its native Japan despite the presence of the parasitoid Encarsia citrina (Hymenoptera: Aphelinidae) in both locations. We postulated three possible reasons for this: (1) cryptic diversity of E. citrina attacking EHS exists in Japan, but not in the United States, (2) additional parasitoid species attack EHS in Japan at significant rates, or (3) alternate armored scale hosts on hemlock in Japan enhance rates of parasitism of EHS by E. citrina or other parasitoid species. We surveyed 88 sites (or subsites) throughout Japan for all armored scales on hemlock to explore the scale community and the genetic diversity of the associated parasitoids, as well as the relationship between scale community species richness and percent parasitism of EHS. Six armored scale species were found on hemlock in Japan. Using two gene loci (28S -D2 and COI), 18 ident...
Source: Biological Control - Category: Biology Source Type: research