• Journal of Conservation Science
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• v.36 no.5
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• pp.333-338
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• 2020

Dye markers are used in the study of subterranean termites to determine colony territories and population sizes. Dyes not only allow the study of termite biology, but can also be used for control purposes. Although Reticulitermes speratus kyushuensis causes damage to wooden historical properties in Korea, the dye markers have not been applied. Therefore, we evaluated the applicability of Nile Blue A dye for R. s. kyushuensis. Filter papers dyed with concentrations of 0.05%, 0.10%, and 0.25% (w/w) were each fed to termite populations through a no-choice feeding test for 1, 3, or 7 days. After 4 weeks, the survival rate, dyeing rate, and maintenance of dyeing were recorded. The results showed high survival rates with lower dye concentrations and shorter feeding periods. Among the combinations of concentrations and days, high survival rates, dyeing rates, and dyeing maintenance periods were found at concentrations of 0.05% and 0.10% for 3 days of feeding. These maximized the survivorship and visibility. The results from the current study can be applied to investigate the ecology and control of R. s. kyushuensis in both the laboratory and field.

• Journal of the Korean Wood Science and Technology
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• v.51 no.3
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• pp.157-172
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• 2023

Azadirachta excelsa, is a plant belonging to the same genus as Indian neem (Azadirachta indica), and its use as a pesticide is reported by few studies. Despite being a different species, it is expected to have the same biopesticide potential as A. indica. Therefore, this study aims to investigate the anti-termite activity of n-hexane and methanol extracts of A. excelsa seed kernel at various concentrations against Coptotermes curvignathus. The methanol extract demonstrated greater termicidal activity than n-hexane at doses test of 2%, 4%, and 8%. It also showed 100% termite mortality on the third day of administering the 8% dose. According to the gas chromatography with mass spectrometry data, the putative main components of the n-hexane extract were hexadecanoic acid, ethyl ester (18.99%), 9,12-octadecadienoic acid (Z,Z)- (16.31%), and 9-octadecenal (16.23%). In contrast, the principal constituents of methanol extract were patchouli alcohol (28.1%), delta-guaiene (15.15%), and alpha-guaiene (11.93%). Furthermore, limonoids profiling of A. excelsa methanol extract was determined using Ultrahigh-performance liquid chromatography coupled with quadrupole-Orbitrap high-resolution mass spectrometry. The number of limonoids identified tentatively was fifteen, such as 6-deacetylnimbin, nimbolidin C, nimbolide, 6-acetylnimbandiol, 6-deacetyl-nimbinene, salannol, 28-deoxonimbolide, gedunin, nimbandiol, epoxyazadiradione, azadirone, 2',3'-dihydrosalannin, marrangin, nimbocinol, and azadirachtin. They were the same as those reported in the seed and leaves of A. indica, but its largest component in A. excelsa was 6-deacetylnimbin. As a result, the presence of these compounds may be responsible for the anti-termite activity of A. excelsa seed kernel extract. Additionally, column chromatography of methanol extract yielded 6-deacetylnimbin, which was found to be antifeedant and termiticide against C. curvignathus.

• Korean journal of applied entomology
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• v.62 no.3
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• pp.171-182
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• 2023

In the Republic of Korea, many of the wooden architectural heritage are located in forests and, therefore, are vulnerable to termite damage. In Korea, the predominant approach to termite control involves chemical control methods using termiticides. The rapid attraction of termites to termiticides is essential to shorten the control period. The current study investigated the attraction of Korean termites to carbon dioxide and the appropriate concentration of carbon dioxide required for effective attraction by conducting a basic experiment on the attracting effect in the underground environment. The results showed that carbon dioxide is effective for attracting termites, and an effective concentration range of 10% or less was selected. Additionally, this study established the potential and applicability of carbon dioxide as an attractant in the control of subterranean termites. Future studies should aim at conducting field studies on the application of carbon dioxide to improve the termite control effect, particularly in preserving wooden architectural heritage.

• Journal of the Korean Wood Science and Technology
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• v.34 no.2
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• pp.1-9
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• 2006

The structural wooden members of the ancient building are deteriorated by fungi and termite over time. The deteriorate of the members causes the decrease of the specific gravity and the strength of it, so the stability of the building is threatened. Therefore, in this study, the evaluation of the specific gravity, which is correlated with the strength of the wood, was conducted in the post member using Nondestructive Evaluation (NDE) - Drilling Resistance Test (DRT). For the purpose of it, the specific gravity and drilling resistance of small specimens was measured to obtain the correlation between the specific gravity and the drilling resistance. And then, the drilling resistance test of the post members, which were expected to have the deteriorated parts, was performed. Consequently, the correlation between the specific gravity and the drilling resistance was very high ($R^2=0.89$) and the distributions of the specific gravity were evaluated for the each member. Also, the results were verified by the visual inspection of the cross section of it. Especially, the various variations of the wood member such as the deteriorated parts with termite or fungi and the crack could be detected exactly but the knot couldn't because the drill could pass by or could not penetrate the knot.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.1
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• pp.83-88
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• 2013

This paper proposes a recommending system of the similar blogs gathered with similarities between blogs according to the similarity, dividing words, for each frequency, that individual blogs have. It improved the algorithm of k-means, using the model of the habits of white ants for better performance of clustering, and showed better performance of clustering as a result of evaluating and comparing with the existing algorithm of k-means as the improved algorithm. The recommending system of similar blog was designed and embodied, using the improved algorithm. TCA can reduce clustering time and the number of moving time for clustering compare with K-means algorithm.

• 보존과학연구
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• s.37
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• pp.5-15
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• 2016

We isolated microorganisms from soil arounding the stump and surface of stump in Bubjusa temple in Boeun, Heungguksa temple in Yeosu and Leeyongwoo house in Boseong. As a result, a distribution percentage of bacteria was high and there was a region-specific difference in bacteria colony. There was greater microbial diversity and population in the Leeyongwoo house in Boseong.

• Korean Journal of Heritage: History & Science
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• v.54 no.1
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• pp.206-219
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• 2021

The warming of the climate is increasing the damage caused by termites to wooden buildings, cultural properties and houses. A group removal system can be installed around the building to detect and remove termite damage; however, if the site is not visited regularly, every one to two months, you cannot observe whether termites have spread within, and it is difficult to take prompt effective action. In addition, since the system is installed and operated in an exposed state for a long period of time, it may be ineffective or damaged, resulting in a loss of function. Furthermore if the system is installed near a cultural site, it may affect the aesthetic environment of the site. In this study, we created a detection system that uses wood, cellulose, magnets, and magnetic sensors to determine whether termites have entered the area. The data was then transferred to a low power LoRa Network which displayed the results without the necessity of visiting the site. The wood was made in the shape of a pile, and holes were made from the top to the bottom to make it easier for termites to enter and produce a cellulose sample. The cellulose sample was made in a cylindrical shape with a magnet wrapped in cellulose and inserted into the top of a hole in the wood. Then, the upper part of the wood pile was covered with a stopper to prevent foreign matter from entering. It also served to block external factors such as light and rainfall, and to create an environment where termites could add cellulose samples. When the cellulose was added by the termites, a space was created around the magnet, causing the magnet to either fall or tilt. The magnetic sensor inside the stopper was fixed on the top of the cellulose sample and measured the change in the distance between the magnet and the sensor according to the movement of the magnet. In outdoor experiments, 11 cellulose samples were inserted into the wood detection system and the termite inflow was confirmed through the movement of the magnet without visiting the site within 5 to 17 days. When making further improvements to the function and operation of the system it in the future, it is possible to confirm that termites have invaded without visiting the site. Then it is also possible to reduce damage and fruiting due to product exposure, and which would improve the condition and appearance of cultural properties.

• Journal of the Korean Wood Science and Technology
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• v.45 no.5
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• pp.544-558
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• 2017

The objective of this research is to investigate preservative efficacy for refractory species in field tests. The field tests were set up to evaluate the preservative performance of western hemlock and white spruce preservative-treated to the residential products group C and D of Canadian standard (CSA O80 Series-08) that have been developed for residential use in above-ground and ground-contact conditions, respectively. They were incised and pressure-treated with alkaline copper quaternary (ACQ) or copper azole (CA). Treated samples for the ground contact stake test and ground proximity test were installed in Jinju, Korea on November 2010 according to AWPA E7-09 and AWPA E18-06, respectively. Each sample has been annually assigned ratings for decay and termite attack, based on AWPA E7 grading system. After six years and five months of exposure, the untreated samples showed decay and particularly severe damage by termite attack but all the preservative-treated samples showed no decay. The results showed that the 5-mm penetration depths may be applicable for the treatment of refractory species. This paper discusses what to consider for the use of refractory species in Korean wood preservation industry from the penetration and retention points of view.

• Korean Journal of Soil Science and Fertilizer
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• v.30 no.2
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• pp.168-177
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• 1997

This study was carried out to find the physico-chemical properties of soils and the rice growth at the pilot project rice farm of Buchanan city, Liberia. The results were as follows. Soils were classified as Plinthic Ferralsols. Real tropical soils had an oxic B horizon of 30cm thick with diffused horizon boundaries. The surface soils have Ochric A horizon with low organic matter. Plinthite was distributed throughout the whole soil profile unevenly. Exposed to sun light, Plinthite was dried out, hardened, and developed irreversibly into ironstone. There were 286 termite hills in 20ha in the project area. The pH value of the termite hills was higher than that of the ordinary soil two units. Soils of the termite hills had higher contents of carbon, nitrogen, available phosphate and exchangeable bases, especially calcium(2,000mg/kg). Available Fe contents was 230~330mg/kg in the surface soil, and 2,200mg/kg in the subsoil. This caused bronzing of rice in a few days after transplanting. The tolerance of Fe toxicity was lower in Korean cultivars than in Liberian cultivars. The tolerant cultivar was Hangang among Korean cultivars and Nizersail and Suakoko 8 among Liberian cultivars. Area weighted average percolation rate was 8.3mm/day and infiltration rate was 2~2.5mm/hr.

• Journal of the Korean Wood Science and Technology
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• v.43 no.6
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• pp.804-809
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• 2015

Since Korea is home to Reticulitermes speratus, a kind of subterranean termites that prefer dark and humid conditions, there have been increasing damages to wooden structures by termites. One noticeable attribute of Korean subterranean termites is that they prefer than Pinus densiflora, the major construction material for Korean traditional houses. And because wide varieties of termites are distributed all over the world, it is not so easy to choose appropriate control methods depending on specific areas. This necessitates careful applications of the following control methods depending on the kinds of termites: fumigation treatment, soil termiticide, preservatives and insect treatment, termite colony elimination system, chemical treatment, and other physical and biological treatment methods. The purpose of this study is to investigate the control effects of environmentally-friendly Alkaline copper quaternary (ACQ), Copper Azole (CuAZ) and Micronized copper quarter (MCQ) on the termites contributing to the damage of wooden structures. It was found in this study that wood with preservative treatment produced a significantly higher termicidal efficacy than untreated wood.