Current status of ecological researches on forest insect pests in Korea Forest Research Institute, Korea

Ecological research on forest insect pests in Forest Research Institute, Korea Forest Service, consisted of long-term monitoring, population dynamics and biology, impacts of climate change, community studies on pests, and surveys on natural enemies. Pests for long-term monitoring include invasive pine needle gall midge, Thecodiplosis japonensis; black pine bast scale, Matsucoccus thunbergianae; fall webworm, Hyphantria cunea; Sycamore lacebug, Corythucha ciliate; and native pine moth, Dendrolimus spectabilis; Japanese alder leaf beetle, Agelastica coerulea; Korean pine webworm, Acantholyda parki. Occasional pests Lycorma delicatula, Lymantria mathura, Ips acuminatus were monitored. Accumulated long-term data through national monitoring were analyzed for forecasting changes in density and seasonal occurrence of forest insect pests. To identify geographical variations in population dynamics of T. japonensis, pest of Pinus densiflora, data for density fluctuations and parasitism by natural enemies at 67 fixed survey sites from 1986 to 2005 were analyzed. Five patterns of T. japonensis population dynamics were presumed associated with invasive history and microclimate. Research is identifying relationships between seasonal occurrence of the insect vector of oak wilt, Platypus koryoensis adults and temperatures, and spatial distribution. Recently invasive L. delicatula injured broadleaf trees Ailanthus altissima and Vitis vinifera. Investigating overwintering L. delicatula eggs at three sites, we found mortality increased as minimum winter temperature decreased. Results of community studies using Malaise traps at nine sites in Japanese red pine forests revealed seasonal changes of coleopteran functional groups reflect changes in available food. Surveys on natural enemies of forest insect pests found Anastatus sp. and Platygaster robiniae parasitoids of invasive L. delicatula and Obolodiplosis robiniae respectively.