The death-watch beetle - accommodated in all the best places

Abstract

Preservation of historical buildings is a hot topic, and g e t t i n g hotter if predictions about global warming and climate change impact upon the built environment in the way we think they will. Invasions of exotic insect species and extre m e population fluctuations of indigenous species are widely re p o rted around the world. Timber pests are no exception, and we have already seen termites establish themselves in Southwest England and observed an increase in the p revalence of the house longhorn beetle, H y l o t rupes bajulus. This may be partly due to climate change, but it is also p robably related to changes in lifestyle. Central heating systems are now present in most historical buildings. And coupled with reduced ventilation, it can lead to condensation and warm e r, more humid environments inside buildings, c reating a more conducive environment for timber pests. It is also feared that another European timber pest, the death-watch beetle (Xestobium rufovillosum), is on the increase, which is a particular worry for architectural conservationists as the beetle has a preference for ancient oak timber found in cathedrals, palaces and stately homes (Belmain et al., 1998). Historically, beginning with attempts to treat the roof timbers of Westminster Hall at the beginning of the 20th century, surface treatment with chemicals has been employed as the treatment method of choice. Surf a c e t reatment has proved, however, of very limited effect in controlling the death-watch beetle in such historic buildings. As a result, between 1993 and 1997 the European Commission funded the international collaborative research project Woodcare, led by English Heritage, to understand the interaction between beetle behaviour, timber and fungus with a view to understand why surface treatments so often fail, and to evolve alternative environmentally acceptable treatment methods (Ridout, 1999). This short article outlines the problems involved in the effective control of death-watch beetle and some of the research which has been carried out to discover why it is so problematical and to develop better methods of control.