The guardians of our national heritage have said they are winning the fight against a bug which would otherwise feast on some of the country’s finest historic treasures.
Clothes moth numbers have fallen 18 percent at the National Trust‘s stately homes, according to the charity’s annual insect pests report.
The fall follows a 39 percent drop the previous year, benefitting the Trust’s carpets, upholstery, taxidermy, woollen and silk artefacts and objects.
Report author, Alexandra Radford, Assistant National Conservator at the Trust, said: “The alarming increase we saw in 2021, driven by lockdown closures, is now a distant memory. This is excellent news for all our collections.
“The drop is likely because pest numbers are still falling from their lockdown highs, but it also reflects the decisive action and relentless efforts of house teams to manage moth numbers.
“We’ve put in place more training and resources to help property teams with integrated pest management, which is crucial to good collections care.”
Despite the apparent success tackling clothes moths – the larvae of which can damage tapestries, state bed silk hangings and more – silverfish numbers have risen by six percent, according to the Trust’s report.
Ms Radford said the “slight” rise coincided with Britain becoming wetter in the last few decades, with increased heavy rainfall creating the damp conditions silverfish thrive in.
The critters, which feed on books, paper and cotton, are at the top of the Trust’s pest leaderboard. Also on the rise are woolly bear (carpet beetle larvae) and booklice.
The Trust’s success in bringing down clothes moth numbers has been attributed in part to a trial of moth pheromones at Blickling Hall, Norfolk, where tabs of female pheremones, usually secreted to attract a mate, have been deployed throughout the house.
These tabs use electrostatic technology to transfer the female pheremone onto males, sewing confusion among male moths and reducing their chances of finding a female.
Overall, insect numbers have decreased 11 percent compared to the Trust’s 2022 Integrated Pest Management data. The charity put this down to another year of “turbulent” weather, with record temperatures, multiple storms and rainfall.
Ms Radford said: “Nature is reflecting back the impact of these extremes. Without a doubt, the ongoing unpredictability and extremes in temperatures and moisture are feeding through into insect breeding cycles and patterns.”
The report also found traditional spring and summer breeding periods continue to merge into one, possibly driven by earlier springs and more protracted, milder autumns.
Ms Radford said: “In the past, we saw a more distinct spike in breeding cycles, but these are becoming blurred. Optimum breeding conditions are starting earlier and carrying on for a longer period of time to create one long reproductive season.”
She concluded: “Knowing this will help house teams prepare for the peak times when nymphs and larvae begin to emerge and take action before they start causing problems for our collections.”
