The warmer southern counties of England are most at risk from the common clothes moths, English Heritage warned today (Sunday 22 April) as it revealed the results of its year-long, country-wide Operation Clothes Moth which called on the public to monitor clothes moths in their own homes and so help the conservation charity better protect its collection of historic wool carpets, fine tapestries and period clothes. Operation Clothes Moth also uncovered an alarmingly high number of a new species, the pale-backed clothes moth – a useful early warning signal for English Heritage to guard against the appearance of that particular pest at the historic houses in its care.

And as Operation Clothes Moth revealed that flats and pre-1950 homes are more susceptible to clothes moths, English Heritage is this week publishing a new guide – Pests in Houses Great & Small – to help the public not only treat but prevent clothes moth infestations in their own homes (see below for English Heritage’s top tips for combatting clothes moths).

Operation Clothes Moth was launched in April 2017 after English Heritage’s expert conservators saw over a period of five years, the numbers of common or webbing clothes moth (Tineola bissellella) double and observed the appearance of the pale-backed clothes moth (Monopis crocicapitella). The charity called on the public to help it decide where and how to concentrate its conservation efforts – visitors to English Heritage sites were given a free clothes moth trap and asked to record the presence and type of the pest in their own homes and then post their results to the English Heritage website.

Five thousand traps were collected from English Heritage sites across the country with data received from an impressive 42 counties (in comparison, English Heritage only monitors cloths moths in 11 counties). Now a year later, our conservation scientists have crunched the numbers and can reveal that the reported catch of the common clothes moth was significantly higher in London and South East than anywhere else in the country.
The results are:

1. London and South East (average of 23 clothes moths per trap)
2. South West (average of 17 clothes moths per trap)
3. West Midlands (average of 16 clothes moths per trap)
4. East of England (average of 12 clothes moths per trap)
5. North East (average of 6 clothes moths per trap)
6. North West (average of 5 clothes moths per trap)
7. East Midlands (average of 3 clothes moths per trap)

As for the pale-backed clothes moth, 460 were registered – a number far higher than expected when compared to English Heritage’s sites where only 15 were caught. This surprise result gives English Heritage further warning to look out for this moth on our traps and in our properties and thereby prevent damage to our historic collections.

Amber Xavier-Rowe, English Heritage’s Head of Collections Conservation, said: “The response from the public has been brilliant and the data we’ve gathered has been invaluable in informing our understanding of the clothes moth threat. Now that we know where the clothes moth concentration is the highest, we can put in place extra measures to ensure that our historic houses in these areas are fully protected and preserved for future generations. We wouldn’t have been able to do that without the public’s help.”

“Operation Clothes Moth has really resonated with a lot of people who yes, want to help us protect our collections but also to protect their favourite woolly jumpers!”

According to the Operation Clothes Moth results, flats or apartments are more susceptible to clothes moths as they have shared walls. Clothes moths numbers were higher in older, pre-1950 properties as they have more voids, fireplaces and attics than modern houses.

To help the public deal with (or better still prevent) infestations of clothes moths, English Heritage’s experts have now captured in a single guide their 20 years of practical experience of protecting historic collections from insect pests. Published on Tuesday 24 April, Pests in Houses Great & Small: An English Heritage Guide (RRP £14.99) will help home owners – no matter what the size of their house – to spot pests and provides solutions for both dealing with them and preventing their return.

From Pests in Houses Great & Small: An English Heritage Guide:
Top Tips for preventing clothes moth infestations

• Check for moths in the crevices, creases and folds of clothing as well as behind labels.
• Make sure clothes are clean before storing them.
• Keep items in vacuum bags or boxes with sealed tight lids.
• Take out items hanging up inside your wardrobe and shake them at least once a month – clothes moths hate being disturbed.
• Regularly vacuum around the bottom of wardrobes and any shelves.
• Check underneath seats for signs of webbing or 'cases'. Also check around piping, in deep buttons and in the seat or arm crevices.
• Have open chimneys checked and cleaned once a year by a professional chimney sweep. Check lofts and attics for bird nests. Remove and destroy any nest material found.
• Once a month, move large items of furniture sitting on carpets and vacuum the areas underneath.
• After using your vacuum cleaner, empty the contents into a black plastic bag. Seal it up and dispose of in an outside bin.

Top Tips for treating clothes moth infestations

• Many of the old moth ball formulations which were used to repel and kill adult moths are now banned or not recommended. There are safer alternatives; lavender has been found to be effective (e.g. dried bunches hung up, in sachets or gel products), but these must be replaced regularly and are not effective on larvae inside clothes or carpets.
• Similarly, adult clothes moth can be killed by spray aerosols, but it is larvae that do the most damage and targeting these are far more difficult.
• Many insecticide sprays and dusts will kill larvae, but only if they come into contact with them, so repeated treatment may be necessary. At English Heritage we use Constrain, a water based insecticide tested for use on historic fabrics.
• The best way of killing adults, eggs and larvae of clothes moths in clothing and small textiles is to deep freeze items. Seal them in plastic ‘freezer’ bags at -18°C for at least two weeks to be certain of killing everything. After treatment, do not remove items from the bag for at least 24 hours to prevent condensation problems.
• It is recommended that larger items, such as rugs, carpets and upholstery, are treated in a commercial freezer or by a controlled heat process carried out by reputable companies.
• Finally, moth control will not be achieved rapidly. Good housekeeping, safe storage of items and regular checking is essential. Using a certified and experienced clothes moth pest controller is recommended for dealing with large scale problems.

Pests in Houses Great & Small: An English Heritage Guide (RRP £14.99) is published on 24 April and is available for purchase from the English Heritage Online Shop and all good bookshops.