The dispersal distance and the flight behaviour of adult Platypus koryoensis were examined using mark-release-recapture experiment in central Korea in 2013. Sticky traps were attached to the trunks of oak trees toward release point and opposite direction up to 48.8m from the release point. For each direction, two traps were attached on upper (1.5m from ground) and lower (0.5m from ground) trunk. Platypus koryoensis which emerged within 24 hours were marked with fluorescent powder and released at 11:00 a.m. The number of recaptured beetles was counted after 30 and 90 minutes after release. The experiment was replicated three times on 20, 21, and 26 June. The numbers of beetles released were 299, 810, and 208, respectively. Recapture rates at 90 minutes after release on 20, 21, and 26 June were 0.09, 0.06, and 0.03, respectively. More than 85 percent of recaptured beetles were caught in 30m. The numbers of beetles caught by sticky traps in upper and lower trunk were not significantly different, indicating that P. koryoensis do not hover but just land and move to explore suitable for living site in trunk when they attack oak tree. The valley breeze which drive upward the valleys and mountain slopes in the daytime blew during experiment periods and maximum flight distance of P. koryoensis was 43m, even though the beetles flew against the wind.

The fall webworm, Hyphantria cunea (Drury) (Lepidoptera: Arctiidae), was originally distributed in North America and spread into central Europe and eastern Asia in the early 1940s. This species was first found in Seoul, Korea in 1958. In this study, the effect of temperatures on development in regional variation of the H. cunea was investigated. Local populations of fall webworm were collected in Goyang and Pusan, Korea and the larvae were reared on an artificial diet, incubated at seven constant temperatures of 17.5, 20.0, 22.5, 25.0, 27.5, 30.0 and 32.5℃ under the photoperiod 16L:8D. The average developmental periods decreased as the temperature increased at all stage in the Goyang population. The temperature dependent developmental rates in each stage were well described by linear and nonlinear Briere model in the Goyang population. The lower threshold temperature for development from egg to adult was 13.7℃ and all the eggs did not hatch at 32.5 ℃. Optimum temperatures for reproduction was 22.5℃, and average number of eggs laid by individual female at the temperature was 441.5±121.8. Developmental periods of larval and pupal stage in the Goyang population were not significantly different from those in the Pusan population at 25℃.

The diurnal flight pattern of Platypus koryoensis (Murayama) was examined using sticky traps attached to the trunks of oak trees in central Korea in 2011. The flight activities of the beetle were estimated on the basis of 2-h interval trap catches from 05:00 to 17:00, between June 9 and July 21 (the peak flight period of the beetle). Peak flight time of the beetle ranged from 09:00 to 13:00, with variations due to the day surveyed and the facing slope. The flights began when the air temperature reached 16.7 °C, and the flights peaked when the air temperature was 23.6 °C. Flights were not observed during rainfall, suggesting that rainfall is one of the factors that influence beetle flight. The time of sunrise was not significantly correlated with the flight initiation time. The direction of flight along with the slope was changed bidirectional to unidirectional (movement from upslope to downslope) between 9:00 and 13:00.

The wood-boring and bark beetle (Cerambycidae, Curculionidae, Scolytinae) community in Korean white pine, Pinus koraiensis Sieb. & Zucc., forests was surveyed using Malaise traps in 2007. A total of 1,669 wood-boring and bark beetles were collected, including 193 cerambycids from 16 species, 221 curculionids from 21 species, and 1,255 scolydid beetles from 6 species, of which the dominant species was the ambrosia beetle Xyleborus mutilatus Blandford. Ranked by order of population size, the wood-boring and bark beetle community in Korean white pine showed high dominance by one species of Scolytinae, suggesting the community was unstable and had low biological diversity. Thinning in Korean white pine forests influenced the abundance of bark and ambrosia beetles, whose populations in particular stands increased 1 year after thinning, and then decreased the following year.

An ambrosia beetle, Platypus koryoensis, is a vector of Raffaelea quercimongolicae that is known to cause Korean Oak Wilt (KOW), one of the serious threats to forest healthy in Korea. To manage P. koryoensis properly, it is necessary to clarify flight period of the adult. This experiment was conducted to elucidate the relationship between temperature and the flight period based on field observation in three forests consisted of Quercus mongolica from 2007 to 2009 except winter season. Date of flight period for 50% (FP50) was estimated by the cumulative Weibull distribution model based on cumulative proportion of the adult density and air temperature. Relationship between site temperature and the date of FP50 of P. koryoensis was the most significant when temperatures below 6.5℃ were excluded, suggesting lower threshold temperature for the flight period based on the site temperature. The pooling cumulative proportion of flight period against degree days was well described by the degree-day model, which has explanatory power for the 89% of year and site variation in the flight period and predicted accurately the flight pattern in 2011.

Spatio-temporal distribution pattern of an ambrosia beetle, Platypus koryoensis (Murayama) which is vector of Raffaeleaquerci-mongolicae K.H. Kim et al, a causative agent for Korean oak wilt (KOW) was examined in the stand level. Spatial distribution of P. koryoensiswas influenced by their density. Relationship between degree of aggregation and density was positively correlated when the density was extremely low or high whereas the relationship was reverse when the density was intermediate. Patch of P. koryoensis formed around or near dead trees or partial dead trees, suggesting these trees indicated epicenter of P. koryoensis. Fraction of trees attacked by less than 100 individual of P. koryoensis in the stand per year increased abruptly whereas fraction of trees attacked over 1,000 individuals of P. koryoensis increased gradually. Our results showed that the dead trees would be an epicenter of P. koryoensis and the number of trees killed by the ambrosia beetle would be reduced by lowering total population of the ambrosia beetle around the epicenter.

The developmental time and survival of overwintering larvae of Monochamus saltuarius were studied at 7 constant temperatures (16, 20, 23, 25, 27, 30, 34℃), and a photoperiod of 16 : 8 (L : D) h. The total mortality of overwintering M. saltuarius was lowest at 27℃ (7%) and highest at 34℃ (93%). The total developmental time decreased with increasing temperature between 16℃ (49.48 days) and 34℃ (13.00 days). The relationship between the developmental rate and temperature was fitted by five nonlinear developmental rate models (Logan 6, Lactin 1, 2 and Briere 1, 2). The nonlinear shape of temperature development was best described by the Briere 1 model (r2=0.99). The developmental variation of overwintering larvae was well described by the three-parameter Weibull distribution model (r2=0.98). The temperature-dependent developmental models of M. saltuarius developed in this study could be used to predict emergence period of the adult, or to develop a population dynamics model of M. saltuarius.

Pine wilt disease (PWD) is one of the most serious forest tree diseases and now the damaged area covers 7,877 ha and more than 60 cities in Korea. The causal agent of PWD, Bursaphelenchus xylophilus is transmitted by the insect vectors, pine sawyers (Monochamus spp.). Spread of PWD damage and control effect for PWD are directly related to dispersal potential of Monochamus spp. vectors. Recently, harmonic radar technology has been applied as a means for tracking individual dispersal of tagged insects. Tracking insects with harmonic radar system is similar to a mark-and-recapture technique, in which an organism is tagged, released, and recaptured. Our objective is to develop a harmonic radar tracking system by using lightweight tags to investigate dispersal of Monochamus spp., insect vectors. The harmonic radar system consists of two parts: a commercially available, light-weight (1.6 kg), handheld transceiver (RECCO Rescue System) and a small tag that reflects the transceiver signal (917 ㎒) at harmonic frequencies (1,834 ㎒). A tag consists of a miniature diode (Toshiba ISS350) with wires (36-gauge tinned copper) soldered using conductive epoxy on each side to produce a dipole antenna. These tags were evaluated in an open field to assess their maximum detection range, and at tag length of 13 ㎝, the tag was detected at >100 m.