Submitted to: Entomological News
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/27/2001
Publication Date: 4/20/2002
Citation: Lee, J., Lee, H., Schaefer, P.W., Fuester, R.W., Park, J.D., Shin, C.H. 2002. Gypsy moth parasite complex, mt. halla national park, cheju island, korea. Entomological News. 113(2): 103-112. Interpretive Summary: The gypsy moth is the most important forest and shade tree pest in the northeastern U.S. USDA and Korean scientists conducted studies on gypsy moth natural enemies on Cheju Island, a small island of volcanic origin about 56 miles south of the Korean Peninsula, to see if there were any natural enemies new to science occurring there that could have potential for biological control of gypsy moth in the U.S. Only four species of larval parasites, natural enemies that attack the caterpillar stage, were found on Cheju, whereas 12 species have been reported from mainland Korea. Likewise, only one species of pupal parasite was found on Cheju compared with at least four species on the mainland. Not only was the number of parasite species low, but rates of parasitism were low compared to the mainland. We suspect that Cheju Island has only been recently invaded by the gypsy moth, and that many of the pest's habitual natural enemies have lagged behind. Cheju Island does not appear to be a promisin source of natural enemies for biological control of gypsy moth, however it might benefit by the importation and release of natural enemy species from mainland Korea.
Technical Abstract: Parasitoids of gypsy moth were studied in an outbreak population at Mt. Halla on Cheju island, Korea. The larvae and pupae of this polyphagous insect were collected weekly from three sites on the mountain in 1998, and reared for parasite emergence. Components of the gypsy moth parasite complex and their impact on gypsy moth population were evaluated in terms of percentage parasitism rates, and compared to the previous report from mainland Korea. Nine natural enemies of the gypsy moth were recorded: 1 egg parasitoid, 4 larval parasitoids, 1 pupal parasitoid, 1 parasitic nematode and two diseases. Glyptapanteles liparidis (Bouche) dominated the insect parasitoid complex with a mean parasitism rate of 3.7%. The tachinid Parasetigena silvestris (Robineau-Desvoidy) was the second most important insect parasitoid, exerting a mean parasitism rate of 2.2%. In contrast to the low insect parasitism, the pathogens were recorded as main mortality factors; NPV contributed 43.7% to the gypsy moth mortality, and Beauveria prob. bassiana. caused that of 22.3%. The species richness of the parasitoid complexes recovered from the island accounted for 17.6-42.9% of those reported from sites on the mainland, with the total number of parasitoid species recorded from the island being 22.7% of that from the mainland. Cotesia melanoscelus (Ratzeburg) (Braconidae) and Phobocampe species (Ichneumonidae), important parasitoids affecting early-intermediate instars of L. dispar on the mainland, were not recorded on this island.