• Journal of Korean Society of Forest Science
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• v.95 no.5
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• pp.543-550
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• 2006

Distribution patterns of two pine sawyer species (Monochamus alternatus which is the main vector insect and M. saltuarius which is the potential insect vector of the pine wood nematode) were investigated in Korea. The data were collected at 89 study sites which were chosen to cover the whole region of South Korea. The selected pine trees were killed in early April and left for I year in the pine stands to be egg-laid by the pine sawyers. Emergence of the beetles from the dead pine trees was checked from early April to late July. M. saltuarius was the most abundant in the mid to northern areas of South Korea, whereas M. alternatus in Jeju-do, southernmost island of Korea. Considering temperature distribution patterns in areas where the two species occur, their thermal distribution boundary may be formed around $13.2^{\circ}C$ of annual mean temperature. The hypothesized distribution map of the two Monochamus species under the invasion of pine wilt disease is suggested on the base of thermal distribution of Korean peninsula.

• Korean Journal of Remote Sensing
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• v.35 no.3
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• pp.359-373
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• 2019

Bursaphelenchus xylophilus(Pine wilt disease) is a serious threat to the pine forest in Korea. However, dead wood observation by Pine wilt disease is based on field survey. Therefore, it is difficult to observe large-scale forests due to physical and economic problems. In this paper, high resolution images were obtained using the unmanned aerial vehicle (UAV) in the area where the pine wilt disease recurred. The damaged tree due to pine wilt disease was detected using Artificial Neural Network (ANN), Support Vector Machine (SVM) supervision classification technique. Also, the accuracy of supervised classification results was calculated. After conducting supervised classification on accessible forests, the reliability of the accuracy was verified by comparing the results of field surveys.

• Korean journal of applied entomology
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• v.48 no.4
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• pp.527-533
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• 2009

This study was performed to investigate the escape of pine wood nematode (PWN), Bursaphelenchus xylophilus, from two vector species (Monochamus alternatus and M. saltuarius) through oviposition and feeding behavior. First, we checked number of PWNs escaped from M. alternatus emerged from three different cases of pine logs. In case A, healthy pine trees were cut into logs and left in pine forest infected with PWN. In case B, healthy pine trees were cut into logs, left in large screen cage, and let them oviposited by M. alternatus emerged from pine trees infested with PWN. In case C, pine trees which were harboring M. alternatus were cut into logs, and PWN was inoculated artificially. The M. alternatus adults emerged from the above three cases of pine logs were checked in the next year to know how many PWN they were harboring in their bodies. The percentages of M. alternatus harboring PWN (18.3 and 15.6%, respectively) and number of nematodes per vector ($5,713.1{\pm}9,248.3$ and $2,034.1{\pm}4,746.8$ PWNs, respectively) in case A and B logs are similar to each other. However, the percentage and the number in case C (38.3% and $20,083.1{\pm}32,188.3$ PWNs) were higher than those of case A and B. Among 52 M. alternatus adults harboring PWN from all the three cases, 20 adults (38.5%) were harboring more than 5,000 PWNs per beetle. And these 20 adults were harboring 97.9% of the total PWNs in 52 adults. Second, we checked the daily escape of PWNs from M. alternatus and M. saltuarius collected at pine forest infested with PWN. The PWN escaped from their vector body for $34.9{\pm}12.4$ days for M. alternatus, and for $23.9{\pm}16.2$ days for M. saltuarius, reaching at peak escape during the 2nd week of emergence of the two vector species. A 44.5 and 47.2% to the total PWNs escaped from vector body within 2 weeks of vector emergence for M. alternatus and M. saltuarius, respectively. The number of PWNs escaped from each vector was $3,570.6{\pm}5,189.2$ and $1,556.2{\pm}1,710.3$ for M. alternatus and M. saltuarius, respectively.

• Korean journal of applied entomology
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• v.56 no.2
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• pp.187-193
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• 2017

The Japanese pine sawyer, Monochamus alternatus Hope, is a representative vector of the pine wood nematode, Bursaphelenchus xylophilus, which causes wilting symptoms in pine trees. A control method using a net has been introduced, which is an alternative method to the fumigation for the control of dead pine trees by pine wilt disease. This study was carried out to investigate the factors that induce gnawing and escaping behaviors of M. alternatus. The behaviors were examined after M. alternatus adult was placed in a confined space at different temperatures. M. alternatus adults could escape through mesh net torn by gnawing when they were confined in a space of 30 mm or less in diameter. The success rate of escape was high at 20 to $30^{\circ}C$, and no adults escaped at $15^{\circ}C$. The enticement of M. alternatus adults by food didn't affect the success rate of escape. In the case of not being confined in a narrow space, the escaping hole could not be formed because the gnawing was not concentrated on one part. M. alternatus moved its body in a narrow space using the tarsus of middle and hind legs, and made an escape hole by concentrically gnawing the obstacle on the front side with mandible, and showed a behavior of getting out while supporting the body by supporting the front legs. The present results will be able to use as an important basic information for evaluating the performance of mesh net which confines M. alternatus adults and suggested by alternative method to fumigation technology.

• Journal of the Korean Wood Science and Technology
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• v.36 no.6
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• pp.41-48
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• 2008

The required energy for the heat treatment of pine log was evaluated in this study. A proper heat treatment of pine log infected by pinewood nematode (Bursaphelenchus xylophilus) can prevent spreading of the infection by pinewood nematode and make the infected pinewood valuable again. The FAO (Food and Agriculture Organization of the United Nations) heat treatment standard for various types of infected wood for which a heat treatment of the core part of the wood is necessary is 30 minutes at $56^{\circ}C$, taking into account the international standards for phytosanitary measures (ISPM No. 15). In this study, the energy consumption during the heat treatment was separated into two kinds of energy, initial energy for heating kiln drier and to reach set point temperature and relative humidity and the required energy supplementing heat loss. The initial required energy per unit time is greater than that during the treatment. The energy consumption per unit time varied little during the heat treatment. As a result, the set point relative humidity with set dry bulb temperature and density of wood dependent on moisture content are very important factors to change energy consumption in the experiment. The heat treatment at higher temperature and higher humidity levels requires more energy consumption but less treatment time. It is expected that a more effective energy program could be planed for the heat treatment of pine log through this study.

• Journal of Korean Society of Forest Science
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• v.102 no.4
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• pp.499-505
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• 2013

Pine wilt disease has known as a serious forest disease in East Asia such as Japan, Korea and China. Fumigation and burning are considered as best way to treat infected tree at early detection. For investigate spectral reflectance characteristics of infected trees, periodic measurement has been done in both infected and non-infected trees. Infected and non-infected trees' reflectance (400 nm~2,500 nm wavelength) are detected from June to October with GER3700 spectrometer. Noise of reflectance data was corrected using cubic spline interpolation method. Reflectance was changed in most of infected trees with ranges Red (600 nm~700 nm) and Middle Infrared (1,400 nm~1,500 nm) within two months after injected by Pine Wood nematode (PWN), but there was no differences in non-infected trees. Infected and non-infected trees were compared statistically in each period. As a result, we found that a statistically significant difference was occurred at Red and Middle Infrared (MIR) 2 months after injection (p<0.05), however, no significant difference in near infrared (p>0.05). Therefore, the early detection of infested pine trees by PWN may possible through detecting the change of spectral reflectance at red and MIR.

• The Korean Journal of Pesticide Science
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• v.19 no.2
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• pp.141-150
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• 2015

Thirty-two actinomycetes isolates from Korean forest soil were screened for their nematicidal and reproduction suppression activity against pine wood nematode (PWN) which is widely spread in Korea. Culture filterates of 21 isolates showed more than 90% mortality at 2-fold concentration. Among them, AM210, SG16, YD116 and YD315 were more effective than others on reproduction of PWN. The YD116 isolate was identified as Streptomyces atratus by morphological and 16S rDNA analyses. Hydrazine hydrate, similar to hydrazidomycin which has cytotoxicity among substances from S. atratus against PWN, was tested for its nematicidal activity. Ten ppm of the hydrate showed 60.8% mortality. Additional studies are needed for practical use of the S. atratus YD116 isolate.

• Korean journal of applied entomology
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• v.42 no.4
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• pp.315-321
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• 2003

Larval entrance and adult emergence holes of Japanese pine sawyer (Monochamus alternatus), primary vector of pinewood nematode (Bursaphelenchus xylophilus), were measured in dead pine logs from 1999 to 2002. Their distributions within pine log were also analyzed. More numbers of entrance and emergence holes were distributed on crown than trunk part as 56.2 and 27.7 holes/m$^2$, respectively Higher proportions of entrance (27.5％) and emergence holes (22.4%) were distributed on the log with 8 to 10 cm diameter; the larger or the smaller logs had fewer holes. Surface area of entrance hole was 65.8 $\textrm{mm}^2$ and diameter of emergence holes was 7.0 mm in average. Average depth of pupal chamber was 24.8 mm from surface to the bottom of the chamber, and its volume ranged from 200 to 2.000 ㎣ Average distance between entrance and emergence holes on bark surface was 3.3 cm. Gallery length from the beginning of entrance hole to the end of emergence hole was 46.2 mm.

• Journal of the Korean Wood Science and Technology
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• v.39 no.1
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• pp.15-20
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• 2011

The pine wilt disease is one of the most serious forest diseases that kill the pine trees, and the study on the invasion and movement of the pine wood nematode within the tree is very important for understanding the inhabitation of pine wood nematode. In this relation, the microscopic observation was carried out to study the place of inhabitation and movement of pine wood nematode within the infested wood. In result, the rays were mainly infested by pine wood nematode and showed dark discoloration due to their necrosis in cross, radial and tangential surface. Also, the intensive damage was found in the resin canals. On the other hand, some traumatic resin canals in tangential band were identified in the sapwood near the cambium. In the ray, the pine wood nematode occurred more commonly in the ray parenchyma cell and fusiform ray with horizontal resin canal than in the ray tracheid and uniseriate ray without horizontal resin canal, respectively. The pine wood nematode was thought to move from ray to tracheid through the large natural opening, window-like pit, in the cross-field, neither through the small natural opening, bordered pit, in the tracheid nor through the tracheid wall by creating a bore hole.

• Journal of Ecology and Environment
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• v.38 no.1
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• pp.85-93
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• 2015

In 2013, the epidemics of pine wilt disease caused by the pine wood nematodes (Bursaphelenchus xylophilus) resulted in damages to the forests of black pine (Pinus thunbergii Parl.) trees in Jeju Island, Korea. Among the affected trees, an old black pine tree at Cave Temple on Mt. Sanbangsan was included and died due to the prevalence of pine wilt disease. The tree was on Mt. Sanbangsan, which was designated as a National Scenic Place with the Number 77 and was believed to be more than 400 years old in age. By examining the disc of the tree stem obtained from the height of 2 m, we counted the tree rings from 4 different directions and cross-dated the readings by comparing the records of drought simulated from the BROOK Model. Our analysis indicates that the tree seems to have grown since late 1860s. Contrary to the belief of the general public, we can conclude that the age of the tree was estimated to be at maximum 150 years, which means that it was not the same old tree as was shown in the painting of the Tam-Ra-Sun-Ryeok-Do (an old painting book for the Inspection Tour of Jeju Island) published in 1702. Discussion was extended to the life history of the tree in growth and leaning and the measures to protect the tree species from the damages of the pine wilt disease caused by pine wood nematodes.