The latest recruits for the fight against moths will be the smallest pest control team in town.
Rentokil plans to release entocyte parasitic wasps into the nooks and crannies of museums, heritage sites and homes to stop moth infestations.
The tiny wasps are less than 0.5 mm in size, and they prevent moths from reproducing by parasitizing their eggs and laying their own eggs inside the moth eggs, preventing the larvae from hatching.
Instead of spraying the areas with toxic insecticides, the pest control company says using the wasps is a sustainable way to get rid of the moths. It is also safer for the material, as particularly delicate and valuable items can be damaged by fumigation or heat treatments used to get rid of moths; using wasps to get around this problem.
This is why the new treatment is particularly useful in museums, historical venues and theater collections, which often have precious textile works that cannot risk damage due to harsh removal methods.
Paul Blackhurst, Head of Technical Academy at Rentokil, said: “Entosite is a revolutionary non-toxic solution that sensitively and effectively eliminates clothes moth infestations from delicate, fabric and textile items of sentimental or historical value.”
The wasps provide ongoing protection against the infestations as their life cycle continues after their eggs hatch, meaning wasps emerge that will seek out and destroy any new moth eggs. They eventually die out once there are no more eggs to eat.
They are released from specially designed pouches to place in cupboards, drawers or anywhere else moths can hide, which have a slow, timed release, meaning there is a steady supply of wasps over a few weeks.
The wasps commonly seen at picnics are social wasps, but their parasatoid cousins are rarely seen because they are so small and tend to be host specific (a species will latch on to caterpillar larvae, for example).
They are understudied and include the smallest insect in the world, the fairy wasp Dicopomorpha echmepterygiswhich is wingless and blind and measures about 0.127 mm in length.
Prof Charles Godfray, who teaches population biology at the University of Oxford and has studied parasitic wasps throughout his career, said these wasps are very important as “natural pest control” or “biological control”.
When there was an outbreak of whiteflies in Africa that destroyed cassava, a critical crop, scientists researched the parasitic wasp that targeted the bugs. “It was brought into Africa and it was extremely successful and the problem was reversed. This has had tremendous economic and social benefits.”
Godfray said scientists are working to find the specific parasitic wasps that can attack certain pest species, and that this is happening in the UK: “In tomato greenhouses in the UK 15 or 20 years ago it was discovered that one could increase the yield of tomatoes by bringing in bumblebees, but the problem when you do that is that you can no longer use any insecticides in the greenhouse because it will kill the bees.
“Then you get a problem with whitefly. But now there are a number of commercial companies that produce the parasitic wasp that is specific to the whitefly, and that controls the issue without insecticide.”
And it’s also for sale to the general public: “There are companies that sell parasitoids that will attack aphids, that will attack leaf miners as well as the whiteflies,” he said.
