Beetle threat to gardens

Adult vine weevils are very robust and mobile

Two species of beetle are threatening to wreak havoc in the UK's gardens.

The beetles are types of vine weevil, believed to have been accidentally imported from the Mediterranean and regarded as among the most serious garden pests in Europe.

Experts are alarmed by their growing numbers this year, with heavy infestations in London and other sightings in Cardiff and Edinburgh.

They have already been blamed for destroying entire plant foliages in these areas. Particularly prone are garden favourites such as cherry laurel, ivy and Viburnum.

People may have to resign themselves to the fact they may lose a few trunks

Max Barclay
Natural History Museum

Vine weevils attack plants with tough waxy leaves.

The adults eat notches out of the sides of the leaves, while the soil-living larvae can kill pot plants by biting the roots off below the surface.

The two new types of weevil are called Otiorhynchus armadillo and the less aggressive Otiorhynchus salicicola.

Max Barclay, curator of beetles at the National History Museum where he cares for 14 million specimens was first to discover the new weevils on the window of a Chelsea shop in 1998.

Serious pest

It was initially thought of as a freak, but more findings since then have confirmed the armadillo is the most common weevil in south-west London.

The armadillo (top) is more destructive than salicicola (bottom)

Mr Barclay told BBC News Online: "This has the potential to be a more serious pest than what we already have.

"It's caused a lot of damage, but I don't know what can be done.

"People may have to resign themselves to the fact they may lose a few trunks."

He suspects a common origin in Italy, where Britons import many ornamental plants.

Chemical treatments

But there is difficulty in tracing the source because of the subtle differences between species.

Cherry laurel is under threat

There are 22 existing species of weevil, but only one or two are regarded as pests.

Adults can be physically removed by shaking plants, or chemically treated.

Birds may help to control them when they realise there is a new food source, he added.

"This looks like it's here to stay. Many foreign pests don't last here, but not this one," Mr Barclay said.

It was previously thought they could not survive a British winter, but their increasing numbers may now be used to monitor climate change.