A new weapon could help British honeybees fight off one of their biggest foes, scientists hope.

Bee numbers are dwindling globally and honeybees have their own set of issues, chief among which is the parasitic pest the varroa mite.

This insect causes devastation in beehives because it attacks bee larvae at a young age and sucks their blood for the rest of their life.

It arrived in the UK in the early 1990s and is now a widespread issue damaging hives. Its presence costs the domestic beekeeping industry around £27million a year and the Government considers it a "major threat for apiculture".

Current pesticides have proven ineffective at controlling the mite because they cannot target the pest without also damaging the bees themselves.

But scientists in the United States have created a new generation of pesticides which target only specific genes and are able to combat the mite without harming the beehive.

The RNA pesticide can be applied as a spray, much like conventional chemical pesticides, or can be put into bee food and is only biologically active when it comes into contact with certain genes.

One of the early iterations of RNA pesticides targets a varroa mite gene but no bee genes, acting as the "perfect pesticide", according to the journal Science.

"This pesticide has the potential to be the most specific pesticide we know," Dr Juan Luis Jurat-Fuentes, from the University of Tennessee, said at the AAAS Annual Conference in Boston.

The first RNA pesticide has been approved by the US Environmental Protection Agency to combat the Colorado potato beetle.

Early data is promising and could soon give beekeepers a new weapon with which to combat the varroa mite.

RNA is a form of genetic material, similar to DNA, that acts as a messenger in cells and helps convert genetic code into proteins

The pesticides work by interrupting this protein-making process with their own RNA to neuter the mite. It doesn't kill the parasite but makes it ineffective.

"There's a very urgent need to find new pesticides," said Dr Jurat-Fuentes.

"There are going to be two billion more people by 2050. That rapid increase in global population is going to bring a lot of issues and challenges. One of the biggest challenges is going to be the ability to produce enough food."

The bee-saving pesticide, being developed by GreenLight Biosciences, is now also being considered for approval. The process is more complex than for the potato beetle due to the complex relationship between the mite and the bees.

As a result, the pesticide is administered to the bees in sugary food pouches instead of as a spray. The ingested RNA pesticide then goes into their body and begins acting on the mites who are sucking their blood.

There are concerns around how quickly the pests will develop resistance to the RNA approach, with some early evidence indicating that the highly specific mechanism could lead to rapid resistance.

Dr Jurat-Feuentes said: "It's not a matter of will they. It's a matter of when will they?"