Termites are wood destroying insects found across much of the world. It is no wonder that they can be of concern in historic sites around the world. This article looks at termite control in a few selected historic buildings including the Statue of Liberty in New York, The Christiansted National Historic site in St. Croix in the US Virgin Islands, and the Tzu–Su temple in Taiwan. Historic sites like these often use wood as the original key building material. Back then, treated wood like we have today wasn’t invented so these historic sites are left vulnerable to pests. Use of cedar wood which is repellent to most insects was as close as these historic sites could get to pretreatments. 

IPM uses threshholds of pests to determine when actions should be taken. These are easy to define for crops and agriculture, and less easy to determine for urban and structural pests since much of that is subjective. The presence of termite damage prompts immediate treatment without considering a particular economic injury threshold as you might for other commoditiy’s IPM. In historic buildings any damage is monumental and economic injury is immedate.  

Subterranean termite treatments can be preventative or remedial. In the case of historic buildings the ship has long since sailed on most preventative measures. In the process of restorations, treated materials can be used but that can only go so far. This leaves us with remedial.

There are a few different options for termite treatments, these include liquid termiticides in soil, in ground baiting stations, and above ground baiting stations. In each of the historic sites, the Statue of Liberty, Christiansted Historic site, and the Tzu Su temple, these options were explored. Liquid termiticides were less viable options in these historic sites as drilling into foundations was not feasible. The fragile nature of historic sites means that disruptions to the structure are to be avoided at all costs. Bait stations therefore became the main tool.  

In the late 90s, termites were found in each of the aforementioned historic sites. I won’t go through the details of the exact years and timing for each site but in each case, in ground and above ground monitoring stations were deployed to determine extent of infestation. You can access the full paper for more details if you are curious in the references section at the end of this article. They also used technology like acoustic emissions devices that monitors the sounds of termite activity.

They applied in ground bait stations and above ground bait stations around the sites discretely. In each case, the monitoring stations showed reduced numbers of termites over the course of months and years since bait installation. The Statue of liberty saw complete reduction in about a year after bait deployment, The most troublesome section of Christiansted took up to 39 months so around three years for complete elimination of termite activity, and the Tzu Su temple had elimination of formosan termites in some sections within 6 months and others closer to a year. 

The moral of the story here is that pest control in historic sites can be a tricky thing to handle and this paper gives a detailed overview of the success in some iconic sites where termite infestations were eliminated using only baits in a relatively short period of time.  

Article by Ellie Lane, BCE-Intern

References

Nan-Yao Su, Termite IPM in historic sites, Journal of Integrated Pest Management, Volume 15, Issue 1, 2024, 26, https://doi.org/10.1093/jipm/pmae013 

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