한라산 구상나무 군락지에서 구과 해충의 발생 현황을 파악하기 위하여 2019년 8-10월에 3개 지역의 4개 조사구에서 구과 117개를 수집하여 생육상에서 우화시킨 후 출현종과 개체수를 확인하였다. 지역별 구과 해충의 피해율 조사를 위해 4개 조사구에서 93그루 1,235개 구과의 구과 해충 피해를 확인하였다. 조사 결과, 채집된 117개 구과에서 솔알락명나방 233개체, 구상애기잎말이나방 101개체, 똥파리 4개체가 확인되었다. 구과 당 평균 개체수는 솔알락명나방 1.99, 구상애기잎말이나방은 0.86개체로 솔알락명나방이 2배 이상 많은 것으로 나타났다. 그리고 한라산 4개 조사구 전체 구상나무 구과의 평균 피해율은 49.7에서 80.1%로 조사구별 차이를 보였다. 또한, 구과 피해율은 수목 당 구과 수가 많을수록, 피해 구과에서 우화하는 구과해충 수는 구과의 크기가 클수록 증가하는 것으로 나타나 본 연구에서 확인된 구과 해충은 수목 당 구과 수가 많으면서 상대적으로 큰 구과를 갖는 구상나무를 선호할 것으로 예상되었다.

본 보고는 2020년 산림 지역에서 대발생하여 큰 피해를 준 매미나방과 대벌레에 의한 피해면적과 피해수종에 대해 기술하였다. 매미나방에 의한 식엽 피해는 강원(1,638 ha), 경기(1,134 ha), 충북(726 ha), 서울(476 ha) 등 중부지방을 중심으로 심각하였다. 대벌레는 서울시 은평구와 고양시 덕양구 사이에 위치한 봉산(약 19 ha)에서 대발생하였다.

본 연구는 북방수염하늘소 성충이 집합-성 페로몬 트랩에 유인되는 시기를 명확하게 규명하기 위해 수행하였다. 또한 집합-성 페로몬에 유 인된 개체의 난황 성숙도를 조사하여 집합-성 페로몬 트랩에 유인되지 않은 개체와 비교하였다. 이를 위해 홍릉시험림 내 망실 안에 유인제인 집합-성 페로몬을 매단 다중깔때기트랩과 집합-성 페로몬을 매달지 않은 다중깔때기 트랩을 각각 1개씩 배치하고, 우화망실에서 채집한 북방수염하 늘소 성충을 우화시기별(우화 직후, 후식 1일차, 후식 7일차, 후식 10일 경과 후 교미)로 그룹화한 후 트랩이 배치된 망실 안에 방사하여 트랩에 포획 여부를 조사하였다. 각각의 시기별로 80개체(20개체씩 4반복)를 대상으로 실험하여 총 320개체를 망실 내에 방사하였다. 조사 결과, 우화 후 7일 동안 섭식한 개체들의 유인 포획률이 가장 높았으며, 교미 후에는 유인 포획률이 급격히 낮아지는 경향이었다. 또한 집합-성 페로몬이 있는 경 우에만 후식 7일차 그룹의 유인 포획률만 통계적으로 유의미한 차이를 보였다. 성별에 따른 유인 포획률의 경우, 암컷이 수컷에 비해 많이 포획되긴 하였으나, 암컷과 수컷 간의 유인 포획률 차이는 없는 것으로 확인되었다. 우화 직후와 후식 1일차에는 모든 개체에서 난황이 미성숙한 상태였으나, 후식 7일차와 교미 후에는 모든 개체에서 성숙한 난황을 확인할 수 있었다. 따라서 페로몬트랩은 우화 후 초기에 후식을 통한 소나무재선충 전파가 가능하므로 소나무재선충병의 확산 억제를 막기에는 제한적일 가능성이 있다. 반면, 성적으로 성숙한 성충을 포획하고, 야외 발생을 조사 하는 등으로는 활용 가능성이 있을 것이다.

To develop a empirical model for predicting the spring flight period of overwintering Ips acuminatus adult, their density were monitored in Korean pine (Pinus koraiensis) forests at Chuncheon in 2015. The monitoring data of the beetles and temperature in the forests were used to develop the empirical predictive model based on degree-day model, and it was validated using the data from Korean pine forest at Wonju in 2018. The lower threshold temperature for flight (LTF) and a thermal requirement for the onset of flight activity of the beetles in spring were estimated. As the result, the LTF was estimated as 1.3 ℃ and 269.96 DD was required for the spring flight. The median flight date estimated by the empirical model was one day earlier than the observed flight date. Therefore, the model is suitable for predicting the spring flight of overwintering I. acuminatus.

Wildfire, which may effect on the spatial distribution of many insects, is one of important disturbances in forests. Because Monochamus beetles are known as vector insects of pine wood nematodes in Korea and burned pine trees can be used as oviposition habitats for Monochamus beetles, we investigated the changes in spatial and temporal distributions of M. alternatus and M. saltuarius across fire severity classes. We also studied other saproxylic beetles, such as cerambycid, scolytid, and bark beetles, which are potential insect pests for pine trees. Study area was classified by fire severity, such as unburned, light (<25% burned), moderate (25~75%), and severe (>75%). Spatial distribution of saproxylic beetles were significantly related to the fire severity.

Oak wilt disease caused by Raffaelea quercus-mongolicae is one of the serious diseases in Korea. Infected trees showed wilting and discolourations on the cambium when the bark of a tree is peeled, since it deters moisture migration. Raffaelea quercus-mongolicae is vectored by Platypus koryoensis. In this regard, it was assumed that there might be a positive correlation between the number of gallery generated by P. koryoensis and the level of damage on the infected tree by the oak wilt disease. In order to link the occurrence of dead oak trees with the number of galleries produced by P. koryoensis, five regions (Incheon, Anyang, Gwangmyeong, Icheon and Gimhae) were selected in Korea. The number of galleries on Mongolian oaks produced by attack of P. koryoensis was counted in four directions between 50cm and 100cm from the ground level. Furthermore, Vegetation was investigated from the area where the oak wilt disease occurred, and a data logger was set up to collect data including temperature and relative humidity in each region at the elevation between 100~200m. A significant difference was observed in the number of galleries made by the insect vector between dead trees and trees infected with oak wilt disease, while no difference was observed from the vegetation on the area investigated. We will further investigate as to whether climate factors might contribute to the density and the successful invasions of the insect vector to the oak trees.

Pine wilt disease caused by Bursaphelechus xylophilus has continued to expanding in Korea since its first occurrence identified from Busan in 1988. The direction of spread and density of two vector insects, Monochamus saltuarius and M. alternatus, are closely associated with the expansion and occurrence of pine wilt disease being observed in Korea. In 2016, a pheromone trap was installed to investigate the density of each vector. A correlation between the density of two insect vectors and the number of trees infected by pine wilt disease was further investigated in Gyeongnam, Gyeongbuk, Ulsan, and Jeju. To perform a correlation analysis, the number of infected trees was counted within a radius of 50m from which the pheromone traps were installed. In addition, factors that might have an effect on the density of vectors were investigated. This includes the altitude, temperature and forest type from the site where the pheromone traps were installed.

Forest insect pests monitoring provides essential information for forest management against their outbreaks. Long-term monitoring data for forest insect pests have been collected by National Institute of Forest Science at national level since 1968. Forest insect pests for long-term monitoring include pine needle gall midge, black pine bast scale, fall webworm, pine moth, spotted lanternfly, etc. The monitoring data were analyzed effect of meteorological factors on the outbreaks of sporadic forest insect pests. Our results showed that meteorological factors can influenced on outbreak of forest insects. The species including Lepidoptera has more occurred when fall and winter temperature were relatively high during the period, suggesting that their outbreaks depends on mortality rate during winter diapause. In Diptera, species abundance was positively related with amount of precipitation in spring but negatively related with summer temperature. The species belong to Hymenoptera was also more abundant when spring temperature was relatively warm. These results can provide useful information for predict potential forest insect pests from climate change.

Korean oak wilt (KOW) caused by Raffaelea quercus-mongolicae and its vector, Platypus koryoensis is one of the most severe forest pests in Korea. In spite of its importance, information about dispersal of P. koryeonsis is very limited. In here, a hypothesis related to long distance dispersal (LDD) of KOW reflecting behavior of P. koryoensis is proposed. When attack density of P. koryoensis increased, location of entry holes in the trunk moved to upward. The individuals which escaped from entry holes in upper trunk had potential to fly upper part of trees and they flew longer distance probably by aid of winds. We suggested that this density dependent dispersal of the beetle explain the spatial dynamics of KOW in large scale.

Korean Oak Wilt (KOW), was first recorded in Gyeonggi Province in 2004, and since then has increased steadily in its occurrence and ecological and economic impacts. Platypus koryoensis vectors the symbiotic fungus Raffaelea quercus-mongolicae, which is the causative agent of KOW. KOW may be closely related to recent climate changes, which have allowed P. koryoensis to extend its distribution range in Korea. And it results in greater overlap with the susceptible host tree, Quercus mongolica throughout Korea. In this regard, changes in the climate suitability of P. koryoensis and Q. mongolica were predicted using CLIMEX model and the influences of other environmental factors such as elevation and the number of days with heat wave were also identified in this study.

Pine wilt disease (PWD) is one of the hazardous pine tree diseases in whole world. In Korea, PWD has been spreading since it was first observed in Busan in 1988. Dispersion of PWD is mainly mediated by its vectors such as Japanese pine sawyer. In this study, we characterized environmental condition including meteorological factors, geographical factors, and land use factors influencing on the occurrence of PWD. The occurrence data of PWD were collected at 153 sites where were the initial occurrence sites of PWD in local government regions such as city, Gun, or Gu scale. We used Akaike Information Criterion (AIC) to evaluate the relative importance of environmental variables on the discrimination of occurrence or absence of PWD. The results showed that altitude, slope, and distance to road were the most influential factors on the occurrence of PWD, followed by distance to building. Finally, our study presented that human activities highly influenced on the long term dispersal of PWD.

Wildfire is one of important disturbances in forests, which may effect on insects distribution. In Sangju, about 13 haof pine forests was burned in March, 2017. We investigated the response of insects to fire severity in burned pine forests,Sangju. Study area was classified by fire severity as 5 classes, such as unburned, light, light-moderate, moderate-severe,and severe. We placed 4 multi-funnel traps in each fire severity class. A total of 729 insects belonging to 42 specieswere collected during May 24 to October 12, 2017. Spondylis buprestoides (447 individuals), Sipalinus gigas (50 individuals),and Acanthocinus carinulatus (43 individuals) were dominant species accounted for 74.1% of total. According to fire severity,abundance and species richness were increased with fire severity, especially in high-medium area. Interestingly, two Monochamusspecies, vector insects of pine wood nematodes, were more caught in more severed area than in other classes.