One of Norfolk's most popular visitor attractions is about to embark on a rare form of crowd control - enlisting an army of tiny wasps to tackle an ever-growing colony of cloth-eating moths.

Blickling Hall is launching a pioneering trial to control common clothes moths, which can cause serious damage to carpets, furniture, clothing and other wool and silk objects.

The team at the National Trust site will use a two-pronged attack - deploying both microscopic parasitoid wasps and moth hormones to target the winged inspects' whole lifecycle.

%image(14396591, type="article-full", alt="An adult clothes moth, the target of the new trial at Blickling Hall.")

Hilary Jarvis, assistant national conservator, said: “We are really hoping this pioneering approach will provide a practical and sustainable method that any of our properties can use to deal with serious infestations.

“Although these are rare, they can sometimes prove immune to our usual, more gentle approaches, with potentially serious results.”

The tiny wasps are only half-a-millimetre long and are considered the clothes moths' natural enemy. They lay their own eggs inside moth eggs so it is a wasp, rather than a moth larva, that hatches.

%image(14450075, type="article-full", alt="A frosty morning at Blickling Estate, Norfolk.")

The pheromones used are designed emulate the natural chemicals female moths give off, confusing the males when it comes to mating time.

David Loughlin, owner of Historyonics, the company supplying the wasps and pheromones, said: “There has been a global move to adopt biological techniques to manage pests of food crops, so this is a natural development to adopt similar tools to manage the pests threatening our valuable national heritage.”

Ms Jarvis said the lockdowns of the past year have suited the bugs that can be found in National Trust properties.

%image(14517820, type="article-full", alt="A moth hole in Blickling's Brown Drawing Room carpet, plus signs of moth webbing and 'frass' - faeces.")

%image(14517822, type="article-full", alt="Moth damage to Blickling's State Bedroom carpet.")

She said: "The relative quiet, darkness and absence of disruption from visitors and staff provided perfect conditions for larvae and adults alike from March onwards.

“When we closed all of our houses, we knew insects would likely thrive, so pest monitoring was high on our list of essential tasks in 2020. Staff did monthly checks, which meant we could take swift action before outbreaks could take hold.”

Among the treasured items at Blickling which could be threatened by the moths include the ‘Peter the Great’ tapestry - gifted by Catherine the Great to Blickling’s then owner in the 1760s - and a state bed whose ambassadorial canopy and headcloth are the most complete 18th-century examples of their kind.

%image(14396593, type="article-full", alt="Blickling Estate houses many treasures.")

%image(14517824, type="article-full", alt="Moth damage to a pair of green tweed knickerbockers. owned by the National Trust.")

%image(14396594, type="article-full", alt="One of the microscopic wasps (Trichogramma evanescens) that will be used to fight the moths.")

%image(14517826, type="article-full", alt="Insects and moths can cause irrevocable damage to the National Trust's treasures. This shows the results of an insect infestation in a cushion at Tyntesfield, Somerset.")

%image(14517827, type="article-full", alt="A holder with pheromone 'tabs' that disrupt adult moth breeding.")

%image(14517829, type="article-full", alt="A card dispenser containing about 2,400 parasitoid wasps in an oak drawer.")

%image(14517831, type="article-full", alt="A card dispenser containing about 2,400 parasitoid wasps.")

%image(14517832, type="article-full", alt="The "Peter the Great" Room at Blickling Hall, with the tapestry of Peter the Great triumphing over the Swedes in 1709. The tapestry and Axminster carpet are among the treasures that could be targeted if the moths were allowed to go unchecked.")

%image(14396600, type="article-full", alt="The State Bedroom at Blickling showing bed with red hangings and carpet. The room was designed in 1780 with the bed placed behind the pillars of the alcove in an archaic arrangement.")