• Journal of the Korean Wood Science and Technology
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• v.43 no.6
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• pp.818-825
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• 2015

This study is conducted to develop new termite colony elimination system that can control termite colony much faster, and to eco-environmentally prevent termite damage occurred in wooden cultural heritage. As a result of laboratory test, we developed a component system, of which fipronil 0.001% (w/w) treated bait was used as a suitable termite colony eliminator. This system can be monitored without taking off underground, and it makes regular monitoring much more efficient. The result of field test showed that 36 termite baiting devices among 367 installed devices were damaged by foraging termites. After baiting, all of termite colonies attracted to devices were eliminated or their activity clearly decreased.

• 보존과학연구
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• s.32
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• pp.123-136
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• 2011

There are more than 2,800 different species of termites in the world, but just there is one species (Reticulitermes speratus kyushuensis Morimoto) in Korea. Once wooden structures are damaged by termites, we are applying chemical control methods such as fumigation, treatment of insecticidal and antiseptic chemicals, soil termiticide treatment, and termite colony elimination system to pest control. But in Korea, the termite infestation is gradually increasing, so it is essential to study on the present situation of termite control in US or Japan. Accordingly, in this part we have studied focusing on the case of US. In the US, there are three groups of termites : Subterranean, Drywood, Dampwood termites, and they caused more severe infestation compared with Korea. When a structure has become infested with termites, it is important that appropriate action must be taken: the chemical pest control (soil treatment, termite baiting, termite colony elimination), the modification and maintenance of buildings and the regular inspection for follow-up. And with consideration for different characteristics of termites, the process of pest control is made according to each species of termites. Most of the subterranean termite control is done by applying either termiticide to the soil or termite monitoring and baiting system around the structure. On the other hand, drywood termite control methods can be categorized as either the treatment for the whole structure or the treatment for localized area. Applications to the whole structure are done by fumigants or heat and the localized treatments are carried out with chemicals as well as heat, freezing, microwave and electricity.

• Korean Journal of Heritage: History & Science
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• v.54 no.2
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• pp.194-215
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• 2021

Termites are important decomposers in the ecosystem. They are also economically significant structural pests. In this study, we reviewed the developments of termite control and recent research on termite management to provide information on the prevention and control of termites. In Korea, most of the damage to wooden historical buildings is caused by subterranean termites. Reticulitermes speratus kyushuensis is the main species, which is widely found throughout the country. In the early 1900s, inorganic insecticides, such as arsenic dust, were used for termite control. After the synthesis of chlorinated hydrocarbon pesticide in the 1940s, it was widely utilized and demonstrated high termite control efficacy. However, chlorinated hydrocarbon insecticides were later banned, disappearing from markets after reports emerged concerning environmental contamination and toxicity to humans. Therefore, the termite control industry sought a new termiticide; hence many pesticides were utilized for termite control. Organophosphate (1960s), carbamate (1970s), pyrethroid, and insect growth inhibitor (1980s) were newly synthesized and adopted. In the 1990s, the first commercial baits using chitin synthesis inhibitors (CSI) were developed, providing a means to eliminate an entire colony of subterranean termites around a structure. Many studies have been carried out on soil termiticides (liquid termiticides) and CSI baits to increase their efficacy, and different baits such as aboveground bait stations, fluid bait, and high-durability bait were also developed in the 2000s. In addition, the paradigm of termite control has shifted from localized treatments using soil termiticides to area-wide pest management using CSI baits to create termite-free zones and protect buildings over time. Termite infestations in wooden historical buildings in Korea have been reported since 1980, and considerable attention was drawn in the 1990s when several UNESCO world heritages such as the Jongmyo Shrine and the Janggyeong Panjeon Depositories of Haeinsa Temple were infested by subterranean termites. Since then, a survey of termite infestation in wooden architectural heritage has been conducted, and the National Research Institute of Cultural Heritage and Heritage Care Program regularly monitors those properties. Finally, we suggest termite management using primarily CSI baits, selective application of various soil treatments applied to the object, foundation soil treatment, research and development of durable termite baits, application of area-wide programs for wooden-building complexes, application of integrated termite management (ITM), and regular education for owners and managers to prevent and reduce termite damage.

• Korean Journal of Ecology and Environment
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• v.33 no.4 s.92
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• pp.358-365
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• 2000

To evaluate the influences of stocking and removal of silver carp on plankton communities and physicochemical parameters, fish biomanipulation was conducted in six enclosures constructed on the coast of a hypertrophic lake during the summer of 1997. Of these, three enclosures were established for the fish-stocking experiment; one fishless enclosure used as a control and two enclosures with high and low densities of fish. The other three enclosures for the fish-removal experiment were prepared in an entirely converse process compared to that for fish stocking. The results of randomized intervention analysis (${\alpha}=0.05$) showed significant changes in several physicochemical parameters and plankton communities after fish stocking and removal. Fish stocking decreased water transparency, DO, pH and chi-a (> $40\;{\mu}m$), while increasing the concentration of nitrogen and chi-a (<$2\;{\mu}m$). However, water transparency did not increase by fish removal. Small plankton communities, such as picocyanobacteria, eukaryotic picoplankton and ciliates (<$2\;{\mu}m$) showed significant reciprocal changes after both fish treatments: increase by the presence of fish and decrease by the absence of fish. No count of large sized phytoplankton and zooplankton showed significant change in the presence of fish, while large zooplankton, Diaphanosoma, Cyclopida and nauplii were significantly increased by fish removal. Although the frequent heavy-winds and endless supply of phosphorus from the lake sediment strongly disturbed the fish behavior and enclosure management, the stocking and removal of silver carp showed an obvious reciprocal influences on plankton communities and its physico-chemical parameters in a shallow-hypertrophic lake.

• Journal of the Korean Wood Science and Technology
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• v.43 no.1
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• pp.104-111
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• 2015

The three-year inspection of 20 tree stumps in the fire prevention area around the wooden building confirmed that termite colonies had been rapidly spread. In particular, four buildings among thirty one wooden buildings of Songgwang-sa temple were infected by the termite, indicating that the habitate of termite has been spread across the fire prevention area over the temple area. However, a non-destructive microwave diagnosis showed that internal damages have been progressed until now, suggesting a high risk to the building. These results suggest that the fire prevention area should be properly maintained to have harmful element controlled. Therefore, effective methods are required to eliminate tree stumps or wood materials used to establish fire prevention area near wooden buildings.

• Journal of the Mineralogical Society of Korea
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• v.19 no.4 s.50
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• pp.277-289
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• 2006

This study was carried out to find a new material having high removal efficiency for the harmful red tide. C. polykrikoides grow very fast and accumulate into dense and visible patches near the surface of the seawater ('Water bloom'). Some mineral medicines and Hwangto (reddish soil consist of clay minerals and Fe-oxides) were used in this study to remove C. polykrikoides. The pre-determined sprinkling ratio of mineral vs. seawater which contains approximately 5,000 cells/mL of C. polykrikoides was 10 g/L. In order to quantify the removal efficiency, the density of living cells was measured by counting with the Intervals of 0, 10, 30, and 60 minutes after sprinkling. Five Hwangtos feom different localities were examined in this study. It is found that a material with a high concentration of Fe and Al was the most effective to remove C. polykrikoides. After the sprinkling of the Hwangto showing the best removal efficiency in the test, 99% of total algaes were found to be eliminated within 60 minutes. Jeokeokji showed the highest removal efficiency among clay mineral medicines(92% removal efficiency after 60 minutes), and the rests in decreasing order are as follows: Gamto (91%) > Baekseokji (89%) > Hydromica (81%). In addition, Fe-oxide mineral medicine similarly looking as fine-grained earthy Daejaseok showed 100% removal efficiencyafter 30 minutes, and Wooyoeryang, 95% after 60 minutes. It is noted that even little addition (1 g/L) of Daejaseok, 10% of Hwangto concentration into seawater showed the removal efficiency of 100% after 60 minutes. From the results, it could be concluded that the fine-grained earthy Daejaseok was the most effective natural mineral medicine to remove the C. polykrikoides from seawater. Under the microscope the removal mechanism was found to be activated in the following order: adsorption, swelling of chain colony, chain colony crisis and algaecide.

• 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.

• 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.

• Korean Journal of Heritage: History & Science
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• v.53 no.4
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• pp.188-197
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• 2020

Termites play an important role as decomposers of the forest ecosystem, while simultaneously causing enormous damage to wooden structures. Currently, two species of subterranean termites have been reported in Korea, and termite damage to historical wooden buildings is occurring nationwide due to climate change, forest fertility, and the locational characteristics of historical wooden buildings. Subterranean termites make their nests underground or inside timber. Termites move underground and access wooden structures through the lower parts of the buildings, adjacent to the ground. Once termites attack the wooden structures, it not only spoils the authenticity of cultural heritage structure, but also hampers structural stability due to the decrease in the strength of the material. Therefore, it is important to prevent termite damage before it occurs. Chemical treatments are mainly used in Korea to control and prevent the damage. In foreign countries, physical barriers are also used to prevent entry to wooden buildings, along with chemical treatments. Physical barriers involve installing nets or particles that termites cannot pass through in the lower part of the building, around the pipes, and between the edges of the building or exterior walls and interior materials. Advantages of a physical barrier are that it is an eco-friendly method, maintains long-term effect after installation, and does not require the use of chemical treatments. Prior to applying physical barriers, studies into the characteristics of termite species must be undertaken. In this study, we evaluated the minimum passage size that each caste of Reticulitermes speratus kyushuensis can move through. We found that workers, soldiers, and secondary reproductive termites were able to pass through diameters of 0.7mm, 0.9mm, and 1.1mm respectively. Head height of termites was an important factor in determining the minimum passing size. Results from the current study will be used as a basis to design the mesh size for physical barriers to prevent damage by termites in historical wooden buildings in Korea.