Caring for carriages: pests

Pests such as the clothes moth can do unlimited damage if left unchecked © National Trust

Pests such as the clothes moth can do unlimited damage if left unchecked

At this time of year you'll see us peering into the many nooks and crannies of all the carriages, armed with a good torch and beady eyes. As the weather slowly improves and spring finally arrives, the insects are waking up from their winter of dormancy, which means it’s a critical time for us to be on the look out for any insect pests hiding in, and eating, our collections.

The insect pests that can feed on, and destroy, our collections tend to be very small. For example, the book louse is just a fraction of a millimetre long. Although we don’t have any books or many paper items in our displays, the carriages do have lots of components made from organic materials, such as textiles, leather and wood. Sadly, there are insect pests which enjoy a taste of all of these too.

Pest control

If we do find any evidence of insect pests we do several things. In order to find out how extensive the problem is we firstly do a full inspection of the carriage in question. We pay particular attention to the area the problem was first spotted and other areas of a similar nature. What we do next depends on what we find, but usually we would very carefully remove the insect pests and any frass using tweezers and a small vacuum cleaner, making sure we don’t cause any further damage to the collection material in the process.

Keeping data

In order to keep an accurate record of what we find, we cover the vacuum nozzle with muslin and count what we catch. Good housekeeping (keeping the carriages and the rooms they’re in clean) and being vigilant usually prevents pest infestations escalating. If we ever find a serious problem, we would consider localised chemical treatments.

As already mentioned, one important part of the process is to keep a comprehensive record of any pest activity - this enables us to identify areas at risk, monitor if a problem is getting worse and, if so, how quickly, and see if any treatment is working or not.

In recent years the National Trust has started to collate its insect pest data with that from other museums around the country in order to create a comprehensive overview of the correlations and anomalies in different types of collection, geographical areas and environments.

Common pests

Some of the pests we come across at the Carriage Museum are described below.

Clothes moths and house moths

  • Tineola bisselliella - common (webbing) clothes moth
  • Tinea pellionella - case-bearing clothes moth
  • Hofmannophila pseudospretella - brown house moth
  • Endrosis sarcitrella - white-shouldered house moth

The adults of these four moth species are small, vary in colour and themselves are harmless to collections, but their larvae can cause a lot of damage and would happily munch their way through textile collections all over the world if given the chance.

Carpet and museum beetles

  • Anthrenus verbascii (the varied carpet beetle) and other Anthrenus species including the museum beetle
  • Attagenus pellio - two-spot carpet beetle and other Attagenus species such as the fur beetle and 'vodka' beetle

Adult carpet beetles look very different depending on the species. Of the two common ones in the UK one is black with a white spot on each wing and the other is patterned with bright orange and white patches. Once again, it’s not the adult beetles that harm collections but their young larvae offspring, which are really small when they hatch but greedily eat their way through silk, wool, feathers, fur and skins until they get large enough to pupate and change into adults.

Wood-borers

  • Anobium punctatum - common furniture beetle (‘woodworm’)

It is unusual to see adult furniture beetles and even less common to see their larvae as they live in internal tunnels in wooden objects that are created as they eat through the wood. What you’re more likely to see is neat circular holes and a small pile of frass, which looks like pale sawdust, where the adult beetles have bitten their way out of the wood. The larvae can survive hidden for several years, all the time causing catastrophic internal damage. The danger here is that an externally strong-looking object can actually be structurally weak and even collapse before there is any visible sign of the problem.