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A rare anobiid species in Japan, Priobium cylindricum, was found by chance in the restoration work of the Sambutsu-do of Rinnohji temple in 2008.Severe damage was found in some structural wooden pieces of the temple. The damage was very severe in hard (heart)wood, showing a powdery state and many holes of various sizes. Such severe damage of heart wood is commonly observed in timbers infested by termites, which are known to digest cellulose and hemicellulose effectively with enzymes such as cellulases. From observations of significant damage of heart wood of woodenhistoric buildings by Priobium cylindricum,we suspected that the anobiid might also utilize enzymes to damage cellulose of wood.Larvae of Priobium cylindricum were collected from infested wooden parts of the Sambutsu-do, and enzymatic activity of crude extract of the insect larvae was measured in comparison with that of a termite species, Hodotermopsis sjostedti, and other common insect species that affect cultural objects,such as Lasioderma serricorne, Attagenus japonicas and Anthrenus verbasci. As a result, crude extracts of the active larvae of Priobium cylindricum showed enzymatic activity of CMCase,xylanase and cellobiosidase.Comparative activity values of CMCase and xylanase were lower than those of a termite of Hodotermopsis sjostedti, but that of cellobiosidase which represents cellulase activity of crystalline cellulose was almost the same as that of Hodotermopsis sjostedti. However,larvae of Priobium cylindricum just before pupation did not show significant activity of such enzymes. This suggests that at least the active larvae of Priobium cylindricum that are infesting wood have detectable enzymatic activity. Larvae and adults of Lasioderma serricorne, larvae of Attagenus japonicas and adults of Anthrenus verbasci did not show significant cellulase activity. Crystalline cellulose content of the powdery parts infested by Priobium cylindricum was measured and compared with the healthy parts of the same timber.The result showed a decrease of crystalline cellulose content in the infested powdery parts, and this seemed to be consistent with the detection of cellulase activities from the active larvae of Priobium cylindricum.

A large scale fumigation process to control insect attack was conducted from July 17 to August 2, 2013 in the main hall of Rin-noh-ji temple in Nikko, Japan. It was revealed in the previous survey that the main structural members of the hall such as posts and beamshad been severely attacked by Priobium cylindricum. Fumigation was conducted for the main hall (11,450㎥)firstly and secondly for the disassembled wooden parts (2,672㎥). For fumigation, sulfuryl fluoride gas was used. Based on the results of laboratory tests, the concentration of the fumigation gas was kept at 50 to 70g/㎥ with temperature higher than 20℃ for 48 hours or more. To conduct the fumigation safely,special tools,equipment and plans were introduced, such as using an apparatus to supply fresh air to operators, procuring evacuation routes, and covering the hall and the stacked wooden members with special sheets.

Permeability of insecticides by infusion treatment was tested with wooden pieces filled with insect feces or frass of Priobium cylindricum. Six types of insecticides (one water soluble, and five water insoluble［oil solution and emulsion］) commercially produced by two companies were selected. Treatments were conducted in three ways. 1)Perforation hole with a 3 mm diameter and approximately 11 cm depth was prepared, and insecticides were injected into the hole with a high pressure injector. 2)Perforation hole with a 13 mm diameter and approximately 15 cm depth was prepared, and insecticides were directly poured into the hole. 3) Insecticides were applied to the surface of the radial section with a brush. Permeability of the insecticides was checked by cutting the treated wooden pieces with a horizontal plane and visually observing the area where insecticides had permeated. When the insecticides were directly poured into the hole,oil solutions permeated faster than emulsions. Compared with emulsions, permeation of oil solutions was 2 to 3 times more in volume. Emulsions remained in the bottom of the hole after 2 to 3 hours. When a cross section was observed,it was found that the insecticides had spread approximately 2-3 mm around the hole. Even at places filled with insect feces or frass, the insecticides had also spread. When the insecticides were injected with a high pressure injector,the speed of permeability was faster than when the insecticides were directly poured. However, the insecticides overflowed from the insect holes. When a cross section was observed, it was found that the insecticides spread approximately 2-3 mm around the hole just as when insecticides were directly poured. Even at places filled with insect feces or frass, the insecticides had also spread. When the insecticides were applied to the surface with a brush, the insecticides permeated approximately 4-5 mm from the surface of the radial section. Permeability of the insecticides seems to be dependent on their chemical characteristics. Further research is necessary to develop effective treatments using insecticides for conserving wooden historical buildings.

In the extensive insect trapping surveys in 2009 and 2010,several wood-boring Anobiids were captured in historic buildings in Nikko World Heritage area. Among them,Priobium cylindricum was the major and the severest deteriogen of Sambutsu-do of Rinnohji temple,and Trichodesma japonicum was the major wood-boring insect affecting Nitenmon of the temple. Together with insect monitoring using adhesive tapes, this year (2011) effects of lightening and pyrethroid vapor were tested. Regarding Priobium cylindricum, the adult beetles were strongly attracted to the adhesive tapes lit up with LED lights or by sun light. Also, adult beetles of Trichodesma japonicum were captured or found around the area where slight beams of sunlight came infrom outside through gaps on doors. Therefore, adult beetles of these species are thought to be effectively captured by light attraction. Vaporized pyrethroid (profluthrin)was applied at Nitenmon and the circumstance was compared with the one at another building (Ro-mon of Takino-o-jinja of Futarasan-jinja) where no chemical was applied. In a laboratory observation, pyrethroid vapor was effective on an adult beetle of Trichodesma japonicum; the beetle was knocked down in a glass jar containing a small piece of pyrethroid-impregnated paper. But there were not very obvious knock-down effects on insects on site,probably because of the high ventilation rate of the wooden historic building.

Since life period of adult Anobiidae is short in general,it is difficult to find live adults during visual survey on site. However,holes and insect feces can sometimes give information of activity and probable species. Feces of major wood-boring insects were collected in the large-scale survey of historic buildings in Nikko conducted in 2010. Five species of Anobiidae were found in the survey: Priobium cylindricum, Trichodesma japonicum, Sculptotheca hilleri, Hadrobregmus pertinax and Oligomerus japonicus. Insect feces of 4 of these species were collected from damaged wood and observed. It was found that feces of Priobium cylindricum and those of Hadrobregmus pertinax are similar and they appear powdery to the naked eye but a closer look reveals them to be irregular in shape. Feces of Trichodesma japonicum are very similar to feces of Nicobium hirtum, but generally bigger in size. Feces of Sculptotheca hilleri also appear powdery to the naked eye, and when they were observed under a microscope it was found that many were globular shaped. As feces of Sculptotheca hilleri have characteristic shape and size when compared with those of other species of Anobiidae,it is likely to identify them from feces alone. Information other than those of feces, such as the sizes of holes and distribution of insects, need to be taken into consideration when making more precise identification although insect feces can provide good clues for insect identification.

A very rare anobiid species in Japan, Priobium cylindricum, was found by chance in the restoration work of the Sambutsu-do of Rinnohji temple in 2008. Severe damage was found in some structural wooden pieces of the temple. The damage seemed to have rare characteristics: very severe damage in hard (heart) wood, parts extensively damaged to a powdery state and many holes of various sizes. However, damage was not clear by observation from the outside of the structure, especially when seen from the red painted layer of urushi. To know the possibility of the same kind of infestation at a building close by and other structures, survey using adhesive tapes (fly catcher ribbons) were performed to see adult insect emergence in the warm season,from June to August. Since such surveys turned out to be useful for seeing a possibility of damage by such woodboring anobiids, a large-scale survey with an extensive number of adhesive tapes (about 27,000 of fly catcher ribbons) was conducted at about 70 historic buildings in Nikko World Heritage site, from the end of April to August, 2010. In this report, the actual strategy of the trapping is shown: The adhesive ribbons were set by experienced carpenters inside the buildings, on the lofts and under floors where the traps do not disturb tourists in the buildings and where, for insects, it is usually dark and undisturbed. Such methods turned out to be very effective in looking at possbile damage by wood-boring anobiids, about which quite little information exists. This survey also provides information on the rare wood boring anobiids which will be useful in considering countermeasures to the insects.

A very rare anobiid species in Japan, Priobium cylindricum, was found by chance in the restoration work of the Sambutsu-do of Rinnohji temple in 2008. Severe damage was found in some structural wooden pieces of the temple. The damage was very severe in hard (heart) wood: a powdery state and many holes of various sizes were seen. However, damage was not clear when seen from the red painted layer of urushi. At another structure, Daiyu-in Nitenmon, anobiids, Trichodesma japonicum and Sculptotheca hilleri, were trapped by adhesive ribbons in 2009. Since adhesive ribbons turned to be effective tools in investigating signs of infestation, extensive survey of insects with adhesive traps (about 27,000 ribbons) in about seventy historic buildings in the Nikko World Heritage site was performed from the end of April to August, 2010. Several species of anobiid were found on the adhesive traps. Some of them had caused infestation at certain buildings. At the Sambutsu-do of Rinnohji temple, extensive restoration is now planned for the next ten years. In the process, it is very important to completely eradicate all anobiid insects inside the wooden pieces which would be reused in the restoration. For the purpose, experiments on CO2 treatment and sulfuryl fluoride (Vikane®) fumigation were performed. Firstly, tests were performed on actual wooden blocks from the structure damaged by Priobium cylindricum. Effects of the treatments were examined by X-ray CT (computer tomography) scanning, and comparing the 3D images to detect activity of the larvae. Secondly, tests were performed on dense wooden blocks (30 x 30 x 30 cm, about 20kg) with thick urushi painted layer on the surface using test insects Sitophilus zeamais. As a result, it was shown that damaged wooden blocks were effectively treated by CO2 treatment and Vikane® fumigation, but they did not achieve 100% mortality of test insects inside the dense wooden blocks with thick urushi layer. From these results, it is supposed that eradication of insects in damaged wooden blocks with no urushi painted surfaces is effective, but large-scale fumigation of the whole building would not achieve 100% mortality of anobiid insects inside the wooden blocks covered with thick urushi layer, especially large pillars 15m in height and with diameter of about 70cm. It would also be important to use residual insecticide on the surface (or into some depth) of the wooden pieces, which will be used for the restoration of the building, to prevent further invasion and damage by the anobiids.

Extensive survey of beetles with sticky insect traps (about 27,000 traps) in about seventy historic buildings in Nikko World Heritage site was performed from the end of April to August 2010. Several species of Anobiid were found on the sticky traps: Priobium cylindricum, Trichodesma japonicum, Sculptotheca hilleri, Hadrobregmus pertinax, and Oligomerus japonicus. Some of them had caused severe infestation at certain buildings. There is little information about the anobiid species, but from the sporadic patterns of numbers of anobiids on sticky traps in many buildings over fairly vast areas, it is supposed that these anobiids may inhabit the natural places (forests) around the historic buildings. Nicobium hirtum is a well known anobiid which infests wooden objects and buildings in Japan. But surprisingly, we did not observe the species in the surveys in the Nikko area. Adult insects were most significantly caught on sticky traps from May to July. Since there is little information about these kinds of anobiids, this trapping survey provided important information about the characteristics of the insects and ideas for appropriate countermeasures to protect the buildings from the insects.

Damage by wood borer insects is often observed with wooden objects or wooden historic buildings. X-ray CT (computer tomography) is a non-destructive method used to look into inside conditions of cultural objects. We tried to observe the change over time of damaged objects using X-ray CT and to detect the activity of some insects. By measuring damaged objects repeatedly, it was found that the activity of some insects was detectable as changes in their position inside the objects. Usually, it is not easy to appraise the effect of pest controlling treatment on wood borerinsects in actual damaged wooden pieces. Thus, we tried an application of X-ray CT to learn the effect of treatment in these cases. We divided a wooden block which was infected by Priobium cylindricum into two pieces. Only one piece was treated with approximately 60% CO2 for two weeks to eradicate insects. Then the activity of insects in both wooden pieces was observed over time by X-ray CT. Changes in the position of insect larvae were clearly shown in the non-treated wooden piece. On the other hand, no change was observed in the treated wooden piece. It was possible to estimate the effect of treatment of insect eradication by comparing the activities of insects over time by X-ray CT.

A very rare anobiid species in Japan, Priobium cylindricum, was found by chance in the restoration work of the Sambutsu-do of Rinnohji temple in 2008. The insect caused very severe damage in hard (heart) wood. The inside of beams, pillars and smaller wooden pieces was extensively damaged to a powdery state. However, damage was not clear by observation from the outside of the structure, especially when seen from the red painted thick layer of urushi. Such damage was more obvious in the recycled older wooden pieces, which suggested a possibility of the survival of the insects in the recycled wood. Records of previous restoration were examined, especially with photos of the restoration made from 1954 to 1961. Extensive damage was seen at the restoration at that time. The damage seen in the records and photos seemed to have characteristics similar to the recent damage by Priobium cylindricum. From the comparison of the characteristics of damage, it was suggested that Priobium cylindricum might have been involved in the similar damage to the building at the time of restoration several decades ago.

Much is not known about the ecological characteristics of wood-boring anobiids that infest wooden cultural properties in Japan except for those of a very frequently seen species, Nicobium hirtum. A very rare anobiid species in Japan, Priobium cylindricum, was found by chance in the restoration work of the Sambutsu-do of Rinnohji temple in 2008. Severe damage was found in some structural wooden pieces of the temple. The damage seemed to have rare characteristics: very severe damage in hard (heart) wood, parts extensively damaged to a powdery state and many holes of various sizes. However, damage was not clear by observation from the outside of the structure, especially when seen from the red painted layer of urushi. To know the approximate number of insects in the structure, surveys with an extensive large number of adhesive tapes (fly catcher ribbons) were used to see adult insect emergence in the warm season, from June to August. As a result, a large number of adult insects of Priobium cylindricum was trapped with the adhesive ribbon in the loft and basement spaces of Sambutsudo. On the other hand, there was no sign of emergence of the insect in the loft of the adjacent structure, Goho- endo. At another structure, Daiyu-in Nitenmon, Priobium cylindricum was not found by the same method. But other anobiids, Trichodesma japonicum and Sculptotheca hilleri, were trapped by adhesive ribbons in the loft. There were signs of infestation in the logs in the loft space, and dead insects of these species were also found on the floor. A live adult insect, a live larvae and droppings of Trichodesma japonicum were found from one of the damaged wooden pieces. From these observations it is highly possible that this anobiid has been involved in the same kind of damage to wooden logs and panels in the loft. The survey measure adopted here was very effective in catching the insects which may be involved in the present damage. Countermeasures must be proposed based on the results of such surveys.

Restoration work of the Sanbutsu-do of Rinnohji temple in Nikko (World Heritage) was conducted in 2008. Severe damage was found in some structural wooden pieces of the temple. The damage seemed to have rare characteristics: very severe damage in hard (heart) wood, such parts were extensively damaged to powdery state and there were many holes of various sizes. However, damage was not clear by observation from outside of the structure, especially when seen from the red painted layer of Urushi. Such characteristics were very rare, though many examples of insect damage have been observed in historic structures in Japan. Thus, the severely infested wooden pieces were investigated to identify the insects involved. Insects found in one of the pieces were identified as Priobium cylindricum, a very rare anobiid species in Japan. This is thought to be the first record of damage by this species in a historic building of important cultural property in Japan. Sanbutsu-do was reconstructed in 1645 (Edo period). The damage was more severe in parts where old wooden pieces (Edo period) are used than in the partially added pieces dating to the 1950's restoration. Damage was observed at various parts of the structure. Countermeasures were proposed based on the results of the survey of the structure.