• Journal of Korean Society of Forest Science
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• v.97 no.6
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• pp.570-575
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• 2008

This study was carried out to provide basic information on physiological changes of 4-year-old seedlings of Pinus thunbergii inoculated with pine wood nematodes by analyzing changes of symptom development, stem and needle water content and nematode populations in stem. Twenty days after inoculation, needles were discolored as an external symptom, and xylem drying and pith browning occurred at the above and below of the inoculation sites as an internal symptom. However, xylem drying began to occur 10 days after inoculation, which was determined by the difference in drying status of xylem and cortex between control and inoculated seedlings. Although population of pine wood nematode increased from 5 to 10 days after inoculation, it has increased dramatically from 10 to 20 days after inoculation when both internal and external symptoms appeared. As the time passed by after inoculation with pine wood nematodes, water content of stem and relative water content in current needles and branch gradually decreased. As the number of nematodes increases, water content of stem and relative water content of current needles and branches decreased significantly. There was a positive relationship between the number of nematodes and xylem drying and/or disease development, but the number of nematodes rapidly decreased as seedlings become severely diseased.

• Journal of Korean Society of Forest Science
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• v.100 no.3
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• pp.374-381
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• 2011

The purpose of this study is to examine the possibility of early detection of Pine Wilt Disease (PWD) using NDVI (Normalized Difference Vegetation Index) from ADC (Agricultural Digital Camera) imageries. The PWD induces the different patterns of reduction of NDVI between healthy trees and infected trees, due to the withered leaves on the infected trees. Based on these phenomena, the DI showing the NDVI variations of trees by time series was employed to detect the infected trees. To find out the differences of DI level between normal and infected trees, DIs of trees from May to August in 2007 were calculated and these were analyzed with GLM (General Linear Models) in SAS 9.2. As a result, the difference of DI between in June and August shows the most significant level (0.0001). The discriminant analysis was performed between normal and infected trees, using the DI of June and August. As the result, hit ratio of trees and the accuracy of grouping with Jack-knife method were shown 71.9% and 73.5%, respectively. These results showed that the DI is effective to detect the trees infected by the PWD and it is useful to prevent the PWD.

• The Korean Journal of Pesticide Science
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• v.13 no.4
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• pp.267-274
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• 2009

This study was carried out to select effective preventive pesticides against pine wilt disease caused by pinewood nematode (PWN), Bursaphelenchus xylophilus on trunk injection. 1,000 fold aquatic solution of abamectin 1.8% EC and emamectin benzoate 2.15% EC were lower mortality (7.3% and 8.3% respectively) against PWN on 1 day after treatment. However effects of abamectin 1.8% EC, emamectin benzoate 2.15% EC, fosthiazate 30% SL and fenitrothion 30% SL were inhibited the reproduction of PWN over 99.6% in Botrytis cineria media. Effect of trunk injection of abamectin 1.8% EC and emamectin benzoate 2.15% EC at the rate of $10\;m{\ell}$ per 10 cm in diameter of breast height (DBH) on mortality of Japanese black pine, Pinus thungergii by inoculated PWN was 0% and 3.3%, respectively at the applied year however when injection of fosthiazate 30% SL were treated with the rate of $5\;m{\ell}$ per 10 cm tree DBH, mortality of tree was 63.3%. Abamectin 1.8% EC and emamectin benzoate 2.15% EC was showed high preventive efficacy representing >90% against PWN at the following year. PWN preventing efficacy of trunk injection was lower in naturally occurred area (mortality of pine tree in control was 11.7% at the first year) of PWN than artificially infected site (mortality of pine tree in control was >76.7% at the first year), PWN preventing efficacy of trunk injection of abamectin 1.8% EC and emamectin benzoate 2.15% EC at the rate of $10\;m{\ell}$ per 10 cm in DBH was 91.5% and 82.9%, respectively, at the applied year and 89.5% and 82.6% respectively at the following year in PWN naturally occurred site. Control efficacy by trunk injection of abamectin 1.8% EC and emamectin benzoate 2.15% EC was more higher in 10 fold dilution with 10 fold high amount of aquatic solution than no dilution with 10 fold less amount of aquatic solution. The preventive effect of trunk injection of abamectin 1.8% EC and emamectin benzoate 2.15% EC at the rate of $5\;m{\ell}$ per 10 cm in DBH was showed 100% at the applied year in PWN inoculated tree.

• Journal of the Korean Wood Science and Technology
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• v.35 no.6
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• pp.50-56
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• 2007

FAO standard for heat sterilization of wood, International standards for phytosanitary measures (ISPM) No.15, must meet heat-treated wood core temperature to be higher than $56^{\circ}C$ and keep the temperature for more than 30 minutes. This study was carried out to analyze the heat treatment characteristics of domestic pinewood sterilized with the FAO standard. To enhance the effectiveness of heat treatment process in mountainous district energy consumption and time required to reach target temperature were evaluated at various temperature and relative humidity conditions and moisture contents of wood. Heat-treatment of high temperature and high humidity reduced the required heating time. Lower humidity levels at same temperature reduced energy consumption per unit time. However, lower humidity levels could not reduce total energy consumption greatly because longer treatment time was required at that condition. It is necessary to estimate energy consumption and predict treatment time in dynamic heating and cooling situations, because it frequently happens not to meet optimum treatment condition due to poor surrounding climates and operation performance of heat treatment facility in real field.

• 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.

• Korean journal of applied entomology
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• v.59 no.4
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• pp.295-301
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• 2020

In this study, we aimed to investigate the changes in the catch rate of Monochamus saltuarius, based on sexual maturation by using aggregation-sex pheromone traps. Ovariole development of caught M. saltuarius females was compared to that of the ones not caught using traps. In a mesh cage set up at the Hongneung experimental forest, we placed a multi-funnel trap with or without an aggregation-sex pheromone lure. M. saltuarius adults, which emerged from pine logs, were grouped in four according to the emergence dates (0, 1, 7, and 10 days after emergence [DAE]). We released beetles into the mesh cage to investigate the catch rate using the traps. In each group, a total of 80 beetles (20 beetles × 4 replications) were tested, making it a total of 320 beetles. Among the four groups, M. saltuarius adults in the 7 DAE group were caught more frequently using the traps, especially with a pheromone lure; the other groups showed a low catch rate. A similar number of female and male beetles were caught using the traps. Regarding ovariole development, all the female adults in the 0 and 1 DAE groups were immature, while those in the other two groups were completely developed. Therefore, aggregation-sex pheromone traps might have a limitation in the prevention of pine wilt disease because of the transmission of pine wood nematode during maturation feeding of newly emerged M. saltuarius adults. However, aggregation-sex pheromone traps can be effective for collecting sexually mature M. saltuarius adults, for the investigation of seasonal occurrence of beetles in forests.

• Korean journal of applied entomology
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• v.62 no.1
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• pp.43-48
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• 2023

The efficacy of spinetoram sprayed from an unmanned helicopter to control two insect vectors of pine wood nematodes, Monochamus alternatus and M. saltuarius was assessed. By using a ULV (Ultra Low Volume) sprayer, the mortality rates of phenthoate, bifenthrin, etofenprox, and diflubenzuron, which are registered for use against coleopteran insects, indoxacarb and spinetoram, which are registered for use against lepidopteran insects, were evaluated for efficacy as aerial spraying agents. The ULV test, using 33- and 55-fold dilutions of phenthoate, bifenthrin, indoxacarb, and spinetoram demonstrated a 100% insect mortality rate upon contact and feeding mortality on the third day after treatment, while etofenprox and diflubenzuron exhibited a slightly lower mortality rate than the remaining compounds. Consequently, spinetoram was selected as a candidate pesticide for aerial spraying and its efficacy to control the insect vectors was assessed. The x 33 dilution of spinetoram resulted in a 98.6-100% control efficacy against two insect vectors. However, risk assessment for bees following aerial spraying will be necessary before applying the pesticide to control insect vectors.

• Korean journal of applied entomology
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• v.49 no.3
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• pp.211-218
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• 2010

Cuticular hydrocarbons (CHCs) of the pine sawyer (Monochamus saltuarius), Japanese pine sawyer (M. alternatus) and oak longicorn beetle (Moechotypa diphysis) were analyzed by GC, GC-MS and compared. Monochamus beetles are typical vectors of pine wilt disease but Moechotypa diphysis, which belongs to the same family, is not. They possess different CHCs in carbon number: 23-25 in M. saltuarius, 25-32 in M. alternatus, and 23-29 in M. diphysis. In comparison to inter-species, these three species of adult beetles have different numbers and chains of constituents of CHCs. In comparison between male and female in intra-species, the quantities of CHCs show the difference but constituents are not. Major constituent of M. saltuarius were analyzed as n-pentacosane > n-nonacosane > n-heptacosane; those of M. alternatus were n-nonacosene > n-pentacosane > n-nonacosane; and those of M. diphysis were n-heptacosane > 13-methylheptacosane > 3-methylheptacosane. From the body surface, most saturated carbohydrates of 3 species beetles are composed of n-alkane (40.2 - 65.7%) and followed by olefines > monomethylalkanes that one or two double bonds in M. saltuarius and M. alternatus. Otherwise, M. diphysis have the difference in order of monomethylalkanes > olefins.

• Korean journal of applied entomology
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• v.59 no.3
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• pp.209-215
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• 2020

Debates over the ecological and public health impacts of aerial pesticide sprays are increasing. This is particularly true for controlling Monochamus beetles, which are vector insects of pinewood nematodes. In 2017, adult female orb-web spiders, Trichonephila clavata, were sampled from pine forests in Yangsan-si, Gyeongsangnam-do, Korea, where the aerial pesticide spray, fenitrothion or thiacloprid, was used for several decades. The biological traits of the spiders (body weight, body length, carapace width, and total hind leg length) were compared among treatment sites (no-spray, sprayed three times, and sprayed five times), and differences were observed. The body length, carapace width, and total hind leg length of the spiders in the sprayed areas were significantly shorter than in the no-spray area, but there were no differences between the area sprayed three or five times. These results indicate that repeated exposures to an aerial pesticide spray can alter morphological parameters, which influences population-level fitness. Future studies should monitor the spider long-term responses to pesticides (a direct effect) and prey availability (an indirect effect).

• Journal of Korean Society of Forest Science
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• v.99 no.4
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• pp.528-533
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• 2010

Cage plots were established in 2008 to find the relationship between combination of tended Japanese red pine sapling and the habitation of Monochamus alternatus, a vector for pine wood nematode. Japanese red pine sapling tended at different times were successively put into the cage, and then the adult of Monochamus alternatus was put in June. Presence or absence of the larva was determined November. Sapling tendings were done at seven successive times in 2009, mid- and late February and March, mid-April, May and June. Some saplings were also tended in mid-October of 2008, the previous year of this experiment. The larva was found in all the saplings tended later than mid-March in 2009. No larva was found in the saplings tended in mid-October of 2008 and those in February of 2009. In case of the combination the by-products of mid-February and late March of 2009 and mid-October of 2008, the larva was found in the by-product of mid-February and late March of 2009, but those in mid-October of 2008 was not. When the saplings tended in mid-October of 2008 and mid- and late February of 2009 were put into the cage singly, the larva was found in all the saplings. Results indicated the mixture of the saplings tended at different times affected the habitation of Monochamus alternatus differently.