Submitted to: Government Publication/Report
Publication Type: Book / Chapter
Publication Acceptance Date: 6/20/2004
Publication Date: 9/20/2004
Citation: Fuester, R.W., Swan, K.S., Kenis, M., Herard, F. 2004. Determining the host range of aphantorhaphopsis samarensis, a specialized tachinid introduced against the gypsy moth, pp. 177-194. In R.G. Van Driesche and R. Reardon (eds.), Assessing host ranges for parasitoids and predators used for classical biological control: a guide to best practice. U.S. Dept. Agric. Forest Health Technology Enterprise Team, Morgantown, West Viginia FHTET-2004-03. Interpretive Summary: The gypsy moth, accidentally introduced from Europe in 1869, is the most destructive forest and shade tree pest in the northeastern U.S. and adjacent areas of Canada. Natural enemies that attack the pest in Europe and Asia have been imported and are being studied by USDA and cooperating scientists. Before an imported natural enemy species can be released into the environment, an environmental assessment must be made that addresses the potential risk that the candidate species would present to non-target species. A book chapter was prepared for a publication ASSESSING HOST RANGES FOR PARASITOIDS AND PREDATORS USED FOR CLASSICAL BIOLOGICAL CONTROL: A GUIDE FOR BEST PRACTICE. The chapter included background information on the gypsy moth problem and a case history of the research done on a parasitic tachinid fly released in North America for biological control of the gypsy moth. Field and laboratory tests conducted both in Europe and the U.S. indicated that this fly had a very narrow host range attacking only the caterpillars of moths in the tussock moth family Lymantriidae. Successful development was observed only in the genus Lymantria, having a single introduced species, dispar (gypsy moth) in North America, and in the genus Orgyia, which contains a number of pest species in North America: whitemarked tussock moth, Douglas fir tussock moth, rusty tussock moth, and western tussock moth. Laboratory tests also indicated that the fly would not attack caterpillars of the monarch butterfly, luna moth, or number of other moth species.
Technical Abstract: A book chapter was prepared for a publication ASSESSING HOST RANGES FOR PARASITOIDS AND PREDATORS USED FOR CLASSICAL BIOLOGICAL CONTROL: A GUIDE FOR BEST PRACTICE. The chapter detailed the case history of the host range studies on APHANTORHAPHOPSIS SAMARENSIS, a parasitic tachinid fly released in North America for classical biological control of the gypsy moth, LYMANTRIA DISPAR. The case history described the host-parasitoid system, non-target species occurring in North America, the testing plan, as well as the results and their interpretation. The gypsy moth, a destructive forest pest, became established in New England during the nineteenth century, and has spread as far west as Wisconsin and as far south as North Carolina. The natural enemy proposed for study, A. SAMARENSIS, is of European origin, where it has demonstrated an ability to find gypsy moth larvae at low density and is considered an important biotic mortality agent. Three approaches were used: (1) field collection and rearing of potential alternate or alternative hosts at European sites where A. SAMARENSIS was known to occur, (2) choice tests offering females of A. SAMARENSIS both gypsy moth and native North American species of Lepidoptera, and (3) host suitability tests in which we artificially inoculated European non-target species with mature eggs of A. SAMARENSIS dissected from gravid females. In the field studies, a total of 851 caterpillars, belonging to at least 54 species other than gypsy moth in 11 families, were collected over several years, but none yielded A. SAMARENSIS, with the possible exception of a single larva of the nun moth, LYMANTRIA MONACHA (L.), and the rusty tussock moth, ORGYIA ANTIQUA (L.), with yielded puparia resembling those of A. SAMARENSIS. In laboratory tests, we offered females of A. SAMARENSIS 11 native species of North American Lepidoptera in five families, but only the lymantriid ORGYIA LEUCOSTIGMA (J. E. Smith), was successfully parasitized. In host suitability studies, we inoculated 10 species of Lepidoptera in eight families with mature eggs of A. SAMARENSIS, but parasitism was successful only in L. DISPAR. Based on the results obtained, it was concluded that A. SAMARENSIS has a high degree of host specificity, is ecologically separated from threatened or endangered species, and does not represent a serious threat to a very short list of non-target species it might attack, because they are themselves eruptive species.