Wasps vs moths: Blickling gears up for insect battle royale

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. 

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. 

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.

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.