Since pine wilt disease was first reported in Busan in 1988, this disease has become a serious threat to pine forests in Korea. A general survey for Bursaphelenchus xylophilus group (B. xylophilus, B. mucronatus) nematodes were carried out to determine their geographic range, host tree species and insect vectors, Monochamus species. Based on the survey results, B. xylophilus were found over 57 cities or district and a similar nematode, B. mucronatus also has been isolated over 30 cities or district including Jeju and Pocheon. The Asian type of B. mucronatus was founded from Pinus thunbergii and P. densiflora, generally associated with M. alternatus as its insect vector. The European type of B. mucronatus which was limited distribution to the central areas, such as Yeongwol, Bonghwa, Yeongdeok, was also found on P. koraiensis and P. desiflora associated with M. saltuarius. Both Monochamus species transmitted both Bursaphelenchus species and co-existed in Muju and Yeongdeok predicted as their range margin. Their range margins shifted northwards compared to 2006, seemingly as a result of climate change. Recently, the European type of B. mucronatus has been identified in other several areas since it was first reported in Pocheon in 2008. Several reports indicate the potential pathogenicity of European type of B. mucronatus and other species, B. sexdentati and B. lenoni in Europe. Therefore, sustainable survey and the study for the newly invading Bursaphelenchus species as well as the member of B. xylophilus group should be performed to protect Korean forests.

Monochamus alternatus and M. saltuarius were reported as the vectors of Bursaphelenchus xylophilus, pine wood nematode in Korea. According to Kwon et al. (2006), each of 2 species has occupied their own regional distribution : M. saltuarius in southern part including Jeju island and M. alternatus in mid-northern part of Korean peninsula. We measured the supercooling point (SCP) of 2 species (laboratory-reared populations) by each of developmental stages. The SCPs of 2nd, 3rd and 5th instar larvae of M. saltuarius were -7.68±0.19℃, -7.02±0.69℃, -4.93±1.34℃ each of stages. On the other hand, the SCPs of 3rd, 4th, 5th instar larvae and pupae of M. alternatus. were -4.46±1.12℃, -5.94±1.33℃, -7.83±1.44℃, -9.53±1.78℃ each of stages. The SCPs of M. saltuarius larvae generally was lower than that of M. alternatus. The pupae of M. alternatus and 2nd instar larvae of M. saltuarius had the lowest SCP among measured samples. On the other hand, the highest SCP were recorded in 2nd and 5th instar larvae, each. This result shows that regional distribution of 2 beetles may be associated with the adaptation capacity to low temperature represented by the SCP as well as the developmental temperature. However, beetles experimented were not collected from pine forest fields. In further study, we are planning experiments with field populations and all developmental stages.

This study was performed to investigate the emergence timing and daily emergence from the different tree species logs (Korean white pine, Pine, and Japanese larch) at Cheongwon, Chungcheongbuk-do from 2006 to 2008. Pine sawyer adults began to emerge on early May (2~10th day) and finished on mid-June (4~20th day) in the Korean white pine and pine logs. However, pine sawyer adults began to emerge on mid-May (13th day) and finished late May (27th day) in Japanese larch logs. Japanese larch logs shows shorter emergence timing of pine sawyer adult compare to those of other two tree species. Emergence timing shows no difference between males and females. Sex ratios of emerged adult in 2007 were 0.55 from Korean white pine, 0.46 from Pine, and 0.59 from Japanese larch, it shows no difference among tree species. Female and male adults emerged throughout 24 hrs, 22.8% of the total adults emerged from 12~14:00 (22.8%) and adults emerged lowest from 06~08:00. Of the adults emerged from the logs, 98.9% was univoltine and the rest was biennial which emerged next year.

To investigate the ecological emergence of pine sawyer beetle adult, it was examined the escape time and period and daily escape according to the tree species at Cheongwon, Chungbuk from 2006 to 2008. In the emergence chamber with non-shading treatment, the adults began to escape on May 6 in Pine and Korean white pine, May 13 in Japanese larch, and the last day of emergence was examined the beginning to Middle of June in Pine tree, middle to last of June in Korean white pine, last of May in Japanese larch, it showed the difference among tree species. In the emergence chamber with shade treatment, the first day of emergence of adult was delayed the eleven to sixteen days and showed lower 2.22℃ in temperature compare to the emergence chamber with non-shading treatment. Escape period did not show the difference between males and females. Daily emergence was escaped throughout 24 hrs. Number of emergence adult in daily hours was highest emerged with 22.8% in 12-14:00 and lowest in 06-08:00. Among escaped adults from shaded chamber in 2007, ratio of the adults of one generation per year was showed 98.8% and ratio of one generation in two year was observed 1.1 % in 2008. From 2006 to 2008, sex ratio of emerged adult from Korean white pine was showed 0.53-0.58 and its average was 0.54.

Larvae of Monochamus saltuarius showed normal growth and development on conifers of Pinus koraiensis, P. densiflora, Abies holophylla, Larix leptolepsis, P. bungeana, and P. rigida, respectively, but the conifers influenced significantly the body weight and the survival rate of larvae. Though the larval body weights were in a wide spectrum among treatments, growth curves of them were very similar from each other, showing continuous increase from the early larval stage to about 3 months old. The body weight was decreased slightly after the feeding period of the early 3 months. The size of larvae and adults became the largest from P. bungeana fed larvae. The mid-sized ones were from P. koraiensis, P. densiflora and A. holophylla. Small ones came from L. leptolepsis and P. rigida. The larval growth was retarded without water supply. Overall survival rates from the early stage of a larva to a fertile adult were 53.6% from P. koraiensis, 51.8%, P. densiflora, 34.7%, A. holophylla, 17.8%, P. bungeana, 16.7%, L. leptolepsis, and 12.3%, P. rigida. Adults from larvae fed the 6 species of conifers, respectively, were grown into the reproductively potent adults, which laid viable eggs. A few of overwintered larvae did not pupate and remained still as a larva until the late October of the year. Data from the field survey, the head width emerged from P. koraiensis was larger than that of L. leptolepsis. The adult emergence hole in P. koraiensis was larger also. While, the size of the emergence hole was larger in the artificially innoculated log of P. koraiensis, which was kept for a larva to be with a minimized food competition and sufficient water supply, than that of the field.

본 연구는 2006년과 2007년에 경남 진주의 소나무재선충병 피해임지 내에 있는 고사목을 대상으로 소나무재선충(Bursaphelenchus xylophilus)의 매개충인 솔수염하늘소(Monochamus alternatus)의 기초 생태를 연구한 결과이다. 솔수염하늘소(Monochamus alternatus) 유충의 소나무 내 분포와 소나무의 직경에 따른 솔수염하늘소 유충의 침입공수, 우화수, 우화율, 자연치사율을 조사하였다. 소나무 직경별에 따른 솔수염하늘소 유충의 분포를 조사한 결과 최소직경은 2.0 ㎝이었으며 최대 직경은 31.5 ㎝였다. 5~10 ㎝ 사이의 직경에서 가장 많은 수의 침입공이 분포하였고, 가장 적은 수가 분포하는 직경은 30 ㎝ 이상이었으며, 솔수염하늘소가 가장 많이 우화한 직경도 5~10이었다. 각 직경별 솔수염하늘소 우화율은 직경 5~10 ㎝에서 13.5%로 가장 높았다. 조류에 의해 유충이 포식 된 수가 가장 많은 소나무의 직경은 10~15 ㎝로 14.4%의 유충이 소실되었고, 조류에 의해 피해를 입지도 않고 우화하지도 않은 자연 치사된 비율은 71.3%였다. 소나무 수고에 따른 솔수염하늘소 유충의 침입공 분포는 6~7m에 가장 많이 분포하였고, 직경에 따라 수고와 상관없이 소나무전체에 분포하기도 하였다.

This study was performed to investigate the toxicity of 39 registered insecticides to the susceptibility, systemic effect, and residual effect and control effect against Pine sawyer beetle, Monochamus saltuarius. Eleven kinds of chemicals such as fenitrothion, fenthion, phenthoate, phosphamidon, dinotefuran, actamiprid, clothianidin, thiacloprid, thiamethoxam, esfenvalerate + fenitrothion, and fipronil were showed 100% insecticidal activity both in body spray and twig dipping bioassay. Among these chemicals, fenitrothion and fenthion were showed 100 % insecticidal activity when sprayed at 4000 times diluted solutions, and phenthoate, thiacloprid, thiamethoxam and fipronil were showed 100% insecticidal activity when sprayed at 2000 times diluted solution. Root systemic effect was showed 100% mortality in phosphamidon, clothianidin, thiamethoxam, and 77.7% in thiacloprid. In residual effect, fenitrothion and thiamethoxam were showed 80% mortality fifteen days after treatment (DAT), and fenthion, phosphamidon, clothianidin were showed 80% mortality ten DAT, fenitrothion, thiamethoxam, fipronil showed 100% mortality in seven DAT, thiacloprid was showed 100% mortality in three DAT. Fenthion and phenthoate were showed 100% mortality one DAT. In the control effect, 6 kinds of chemicals were showed 100% mortality one DAT and all chemicals showed 100% mortality three DAT.

Pine sawyer beetle, Monochamus saltuarius preferred the feed on fresh twig of Korean white pine trees (Pinus koraiensis) than one-year old and two-year twig. It means that the current twig is appropriate to increase the lifespan and reproduction of this insect. In a bioassay after fractionated the hexane layer from the water layer, the hexane layer did not show feeding response; however, the water layer was preferred in the order of fresh twig>one-year twig>two-year old twig. By HPLC analysis, we identified three kinds of sugar, namely, fructose, sucrose, glucose. The quantity of fructose was the highest in fresh twig followed by one-year and two-year old twig. In the preference test using each standard sample, the order was fructose>sucrose>glucose at 10, 30 μg/filterpaper, and fructose>sucrose >glucose at 50μg/filterpaper. From the above result, fructose plays an important role as a feeding stimulant for pine sawyer adult.

Pine wilt is the most important disease of pine trees in Korea, Japan and China. The pathogen causing this disease, the pinewood nematode (Bursaphelenchus xylophylus), is transmitted vectored by adults of some cerambycid beetle species and the Japanese pine sawyer, Monochamus alternatus, is the major vector species in Korea. Although chemical insecticides have been used to kill vector insect and thus prevent transmission of the pathogen, the efficacy is not good. In Japan, to control this insect, an entomopathogenic fungus was studied and developed as an insecticide. This is thought to be the convenient and effective method to control M. alternatus. Recently, there are several reports about the pinewood nematode is vectored by also the pine sawyer, M. saltuarius, in Korea. The objective of this study, therefore, was to isolate and identify entomopathogenic fungi from M. saltuarius cadaver to control it. We collected the cadaver of M. saltuarius and then screened several fungi colonies. The pathogenicity of each fungus was tested using oak longicorn beetle, Moechotypa diphysis, as substitutive insect. M. diphysis is also serious pest to various trees in forest. As the result, only one of them showed high pathogenicity against M. diphysis. Selected fungus was identified by microscopic examination and DNA analysis. Pathogenicity was also evaluated to 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.

As a major component of cuticle wax, cuticular hydrocarbon plays key roles as a chemical cue among inter- and intra-species in some beetles like as pheromone and alleolochemicals in addition to the physical function. In this study, cuticular hydrocarbon was analyzed and compared with three species of beetles adult, Monochamus alternatus, M. saltuarius belong to the Monochamus sp., and belong to the same class, Moechophyta diphysis, a typical vector of pine wilt disease. The composition of cuticular hydrocarbon of three species of beetles adult did not show the difference between male and female in intra-species, however, showed the difference in inter-species. They also differed from carbon numbers in inter species as 25-32 in M. saltuarius, 25-35 in M. alternatus, and 23-31 in M. diphysis. Major constituent of M. saltuarius was analyzed as n-C25, 2 or 4 MeC26, 9-C25:1, n-C27, 4-MeC28, n-C29, (9,x)-,and/or (11,x)-diMeC29; those of M. alternatus were n-C25, n-C27, 4-MeC28, n-C29, (9,x)-, and/or (11,x)-diMeC29, 9-C29:1, n-C29, (9,x)-,and/or (11,x)-diMeC29; and those of M. diphysis were n-C25, n-C26, n-C27, 3-MeC27,9-C29:1, 11-MeC29. The contents of n-alkanes were as follows: M. saltuarius ≒ M. alternatus > M. diphysis. The contents of monomethylalkanes were as follows: M. diphysis > M. saltuarius ≒ M. alternatus. The contents of dimethylalkanes were as follows: M. saltuarius ≒ M. alternatus > M. diphysis. And the content of olefine in female were analyzed as follows: M. saltuarius > M. alternatus ≒ M. diphysis, and the male's contents were similar in three kinds of beetles.

2001년부터 2002년까지 소나무재선충의 매개체인 솔수염하늘소 성충의 생체중과 체장, 체폭, 두폭, 더듬이의 길이 및 색깔 등을 조사하였다. 소나무재선충에 감염되어 고사된 소나무를 일정한 길이로 잘라 우화망실 안에 두고 우화하는 솔수염하늘소 성충을 채집하여 조사하였다. 분산분석결과 생체중, 체장, 체폭의 측정치는 암컷이 수컷보다 높았고, 두폭은 암수간에 차이가 없었으며, 촉각의 길이는 수컷이 더 길었다. 암컷(n=563)과 수컷(n=601)의 평균 생체중은 각각 0.305g과 0.277g, 체장은 20.97mm와 19.93mm 체폭은 6.52mm 와 6.18mm, 두폭은 3.78 mm와 3.70mm, 촉각의 길이는 31.19mm와 45.49mm이었다. 촉각의 길이나 체장과 촉각 길이의 비율은 암수간에 중복되는 범위가 많아서 이것을 기준으로 암수를 구분할 수는 없었다. 그러나 성충(n=4,033) 촉각의 털 색깔을 조사한 결과, 예외 없이 암컷 촉각의 모든 편절 마디의 기부쪽 절반 정도가 회백색의 미모로 덮여 있으나, 수컷 촉각의 편절 마디는 전체적으로 흑갈색의 미모로 덮여 있었기 때문에, 이 특징으로 암수를 쉽게 구분할 수 있었다.

1999년부터 2002년까지 경남 진주의 소나무재선충에 의한 피해임지 내에서 고사목을 대상으로 솔수염하늘소 유충침입공과 성충탈출공 및 번데기방의 크기와 갱도길이 등을 측정하고, 소나무 내 분포를 분석하였다. 소나무 내 솔수염하늘소의 유충 침입공수는 1당 수관부가 56.2 개인데 비해 수간부는 27.7개로서 수관부가 훨씬 많았다. 직경이 8-l0 cm인 공시목에 침입공의 27.5%와 우화공의 22.4%가 분포하였고 이보다 굵거나 가는 공시목에는 적었다. 침입공의 형태는 타원형으로 입구의 표면적은 평균 65.8 이었다. 성충탈출공은 원형으로서 직경은 평균 7.0mm 이었다. 공시목의 표면에서 번데기방까지의 깊이는 평균 24.8 mm이었고 번데기 방의 부피는 200-2,000 ㎣이었다 성충의 탈출공은 수관부가 수간부보다 많았으며, 공시목의 직경이 8-10cm에서 22.4%로 가장 많이 분포하였다. 유충 침입공과 성충 탈출공까지의 목질부 표면에서 직선거리는 평균 3.3 cm이었으며, 침입공에서 탈출공까지의 갱도 길이는 평균 46.2 nm이었다.

부산, 경남, 경북, 전남, 전북 22개 지역 19수종 238본의 고사목에서 1989년 4월부터 9월까지 선충류와 곤충류를 조사한 결과, 소나무 재선충은 부산지역에서만 검출되었으며, 어리소나무 재선충은 진주와 진해에서 분포가 확인되었다. 고사목에서 분리.동정된 선충류는 9속 13종이었으며 6속은 미동정되었다. 동정된 선충 중 Diplogasteroides dimidius, Rhabdontolaimus adephagus, R.janae, Mikoletzkya diluta, M. ruminis, m. langcauda, Parasitorhabditis hylurgi, Panagrolaimus concolor, Panagrodontus dentatus, Prothallonema intermedium, Macrolaimus canadensis는 우리나라 미기록종이다. 한편, 고산목에서 채집된 곤충은 5목 9과 25속 27종이었는데 딱정벌레목이 3과 19속 22종으로 가장 많았다. 그중 나무종이 10속 12종으로 빈번히 채집되었으며, Hypothenemus eruditus가 꽃싸리, 싸리, 조록싸리, 만리화, 닥나무에서 채집되어 새 기주로 추가되었다. 소나무 재선충의 매개충인 솔수염하늘소는 복부에서의 선충 검출수가 가장 많았으며, 성충 한마리당 선충 보유수는 최대 127,535마리, 최소 2,616마리, 정균 42,817마리였다.