NATURAL ENEMIES OF THE ASIAN GYPSY-MOTH (LEPIDOPTERA, LYMANTRIDAE) INSOUTH-KOREA

Thirteen season-long collections of larvae and pupae of gypsy moth, Ly mantria dispar L., were made at seven forest sites near Seoul, South K orea, from 1984 to 1989 to detect the natural enemies and to determine their importance. Thirty natural enemy species were identified, inclu ding twenty that parasitized 12,388 of the 52,351 larvae and pupae rea red during the study. Tachinid, braconid, and ichneumonid species acco unted for >99% of this parasitism, with tachinids being more abundant than braconids, which were more abundant than ichneumonids. The bracon id Cotesia melanoscelus (Ratzeburg), which parasitized 24.4% of first and second instars, was the most important parasitoid. Parasitigena si lvestris Robineau-Desvoidy (Tachinidae), which parasitized 27.6% of fi fth and sixth instars and 36.3% of the prepupae, was second in importa nce. Blepharipa schineri Mesnil, a larval-pupal tachinid parasitoid, w hich killed 37.5% of the pupae, is considered to be the best candidate for establishment against the moth in the United States. The nuclear polyhedrosis virus (NPV) caused the greatest mortality observed in the study, at times killing all larvae. No relationship was observed betw een levels of parasitism and gypsy moth population densities except fo r C. melanoscelus, which caused more parasitism in larger populations. Artificially created populations experienced levels of parasitism sim ilar to those of natural populations, except for a greater abundance o f C. melanoscelus in the artificial populations. Season-long parasitis m rates ranged from 13.3 to 33.4% and averaged 23.7% overall versus 12 % recorded in comparable studies in the United States. The great contr ast in the abundance and pest status of the gypsy moth in Korea and in the United States probably relates to the large differences in parasi tism.