Emerging from Lockdown: Pest Management
Understandably at this time of global uncertainty the worlds focus has been on one key news story, the coronavirus (Covid-19) pandemic and the countless lives that have been touched by it. Whilst people have been sheltering in their homes, many institutions in the UK have closed their doors to the public, for a prolonged period, for the first time since the second world war. The now dark and undisturbed exhibition and collection spaces that had so recently been used to welcoming throngs of visitors through their doors now have the potential to provide the ideal environment to another kind of visitor.
With the absence of people, both through the lack of visitors and staff being placed on the “Job Retention Scheme”, and with the lights turned off, many spaces will now have the ideal environment to harbor biological threats that feed on and ultimately damage and destroy collection items, creating the perfect storm of risk for important collection items.
Case Bearing Clothes Moth Larvae (Tinea Pellionella) - The larvae feed on natural fibers, fur, feathers and hair (Image Credit - https://butterfly-conservation.org/moths/case-bearing-clothes-moth)
Museum Pests and High Risk Collections
Insects commonly found in museums and galleries will feed on biological material, with different species preferentially grazing on a range of materials. Webbing clothes moths, case bearing clothes moths (above) and carpet beetle larvae (woolly bear) all feed on and potentially devastate collection items containing wool, fur, feathers, silk and skins; whilst silverfish and book lice consume the surface of damp paper. They can be brought into a building by other pests, such as birds nesting in roofs and rodents scurrying in and around cavities in walls, as well as on items being brought into the space without having gone through a quarantining procedure.
High risk collections include natural history and ethnographic; usually consisting of materials that often contain high levels of the previously identified high risk materials. Costume and textile collections also pose a significant risk, insects feeding preferentially on areas that may have been stained by bodily fluids or food stuffs. Items in storage can be held in close proximity, allowing an infestation to progress undisturbed without the execution of robust Integrated Pest Monitoring (IPM).
With the closure of public spaces; previously robust IPM procedures may have fallen by the way side for any number of reasons, primarily the lack of people power due to mandatory closures. A reduction in housekeeping routines will also leave a layer of dust, containing biological material, that will act as an additional food source. This also provides increased moisture due to its hydrophilic nature, creating condensation points for moisture in the air, allowing pests to thrive.
Silverfish grazing the surface of a 18th C engraving causing the loss of elements of the design layer.
The same image with a melinex overlay highlighting the extent of the biological damage in red.
Integrated Pest Management
Integrated Pest Management, refers to the processes carried out by collections, galleries and museums, originally developed for the food industry, to preventatively protect collection items from pest infestation, whilst reducing the use of pesticides. One element of this is maintaining high levels of hygiene; removing the food source, a process which has been noted, may have reduced during lockdown; another being pest monitoring.
By monitoring spaces where collection items are stored and displayed, as well as adjacent areas, the early stages of an infestation can be identified through the trapping of pests. This is done with 2 main types of inexpensive adhesive traps; blunder, where they catch what happens to walk over them and pheromone, which preferentially attracts a certain species before trapping them. Recording the pest activity on these traps over a defined period of time will enable the identification of outbreaks as well as map the extent of infestations within your space. Regular checking of these traps will allow the early identification of any issues.
A Blunder Trap - Placed in dark isolated places, where insects thrive, it traps whatever “blunders” across it with an adhesive pad on the interior.
The Adhesive Pad of a Used Blunder Trap - This used trap indicates an infestation of spider beetles as well as the presence of non pest insects (Spider, fly).
Emerging from Lockdown:
Now that a date has been given for Museums and other public spaces to reopen in England (4th July 2020), there are questions that will need to be asked as they prepare to welcome back visitors for the first time in over 3 months. Firstly an assessment of change over the period of lockdown will need to be carried out; this will include identification of any active infestations through a survey of items on display and in storage. Spotting droppings, signs of grazing, frass, webbing and casings are tell tale signs of pest activity within a collection. Documentation will be key during this process; firstly, to maintain an accurate condition record of all collection items and secondly, to have evidence if an insurance claim is to be pursued at a later date.
With the financial constraints that many arts organisations find themselves under, there will be pressure to deal with these outbreaks in a cost effective manner. The quarantining of affected objects, isolating them from the bulk of the collection to slow down any spread and to limit the damage, is one method. The application of an appropriate hot or cold treatment to kill all stages of pest life, whilst avoiding the use of pesticides on collection items, is a cost effective method if you have access to suitable equipment.
Depending on the size and quantity of items, it is possible that a household freezer, capable of maintaining -29oC and lowering the object to this point within 4 hours, will be suitable. If however larger items are in need of treatment (upholstered furniture, taxidermy), mobile trucks or offsite facilities may need to be sourced. Before treating, objects must be fully sealed in their own micro climate, using polythene with a full tape seal and once removed from the freezer the item must be left for 24 hours to acclimatise before unpacking. (Not all museum items are able to be frozen, please consult an expert before deciding to subject an object to a hot or cold treatment).
The recommencement of previously held house keeping routines, is another easy win in terms of disrupting the environment that may have become ideal for pests. Gallery cleaning as well as cleaning of museum and exhibitions items can be carried out as needed, serving the purpose of preparing the gallery for visitors and removing dust and any eggs that may have been laid on that surface.
Understandably, whilst issues will be similar for many collections, factors including size and type of collection, the size and type of the building itself as well as availability and expertise of staff will impact how reopening and assessing the collection will look. Financial pressures may be the most significant factor that many feel, but no matter what returning to the museum and gallery environment looks like, it is clear that there will be multiple challenges ahead to ensure that both the collections and people remain safe for years to come.
If you are experiencing an infestation in your collection; want to discuss your pest management procedures or have an item that has been adversely impacted by pest infestation, then please get in touch using the Contact Us link at the top of the page or email us directly.
Further Reading and Information:
https://icon.org.uk/system/files/public/waking_up_collections_final.pdf
https://www.english-heritage.org.uk/siteassets/home/learn/conservation/science/serpentine/insect-pests-historic-houses-poster.pdf
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4553500/
https://museumpests.net/solutions-low-temperature-treatment/
http://publications.gc.ca/collections/collection_2015/pc-ch/CH57-3-1-29-2009-eng.pdf