Tiny wasps are being used in a new pest control strategy to control moths | Insects

The newest recruits in the fight against moths will form the city's smallest pest control team.

Rentokil plans to release Entosit-type parasitoid wasps into the nooks and crannies of museums, cultural monuments and houses to prevent moth infestation.

The tiny wasps are less than 0.5 mm in size and prevent the 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 wasps is a sustainable way to get rid of the moths. It is also safer for the textiles, as particularly delicate and valuable items can be damaged by fumigation or heat treatments to control moths. Using wasps avoids this problem.

This makes the new treatment particularly useful for museums, historic venues and theater collections, as they often contain valuable textile works that cannot be damaged by aggressive removal methods.

Paul Blackhurst, Head of Technical Academy at Rentokil, said: “Entosite is a revolutionary, non-toxic solution that gently and effectively eliminates clothes moth infestations from delicate fabric and textile items with sentimental or historical value.”

The wasps provide continuous protection from the infestation because their life cycle continues after their eggs hatch. This means that wasps emerge, seeking out and destroying new moth eggs. They eventually die out when there are no more eggs to eat.

They are released from specially designed bags that are placed in wardrobes, drawers or other places where moths can hide. They are released slowly and on a timed basis, ensuring a steady supply of wasps over several weeks.

The wasps often seen at picnics are social wasps, but their parasitoid relatives are rarely seen because they are so small and mostly host-specific (one species, for example, clings to caterpillar larvae).

They are little researched and include the smallest insect in the world, the fairy wasp Dicopomorpha echmepterygiswhich is wingless and blind and is about 0.127 mm long.

Prof. Charles Godfray, who teaches population biology at Oxford University and has researched parasitic wasps throughout his career, said these wasps are very important as “natural pest control” or “biological pest control”.

When a mealybug infestation occurred in Africa, decimating cassava, a major crop, scientists studied the parasitic wasp that controlled the aphids. “These were introduced into Africa and were extremely successful, and the problem was solved. That had enormous economic and social benefits.”

Godfray said scientists are working to find special parasitic wasps that can control certain types of pests, and this is currently happening in the UK: “Fifteen or 20 years ago, in British tomato greenhouses, it was discovered that you could increase tomato yields by introducing bumblebees. The problem is that you can no longer use insecticides in the greenhouses because they kill the bees.

“Then you get a problem with whiteflies. But there are now a number of commercial companies that produce the parasitic wasp that is specific to whiteflies and can control the problem without insecticides.”

And these are also commercially available to the general public: “There are companies that sell parasitoids that attack aphids, leaf miners and whiteflies,” he said.