New beetle for Britain is pear tree pest

25 September 2017

Images of the male and female Anthonomus spilotus beetle

Male (left) and female (right) versions of the Anthonomus spilotus beetle, found on pear trees in Kent

An invasive species of European beetle has been found preying on pear trees in Kent orchards.

The beetle, Anthonomus spilotus, has not been seen in Britain before. It attacks the leaf buds of pear trees early in the spring, reducing the number of fruit produced per tree.

Museum beetle curator Max Barclay, one of the team that identified the insect, speculates that the species crossed the Channel on individual pear trees imported by garden centres.

'The beetles have then flown off and found an orchard of pear trees and thought it was their lucky day,' he says.

Identification and control

The insect was found at two orchards in Kent, who alerted their local horticultural research centre, NIAB EMR. Staff at the centre then asked the Museum, with its vast collection and staff expertisefor help in identifying the beetle.

'It's very important that you identify a pest correctly to apply the right control regimes,' says Barclay.

Rows of short pears tree growing in an orchard

A pear orchard in Kent. The county has a long tradition of fruit growing, including pears and apples. © Acabashi licensed under CC BY-SA 4.0 via Wikimedia Commons
 

Now that the pest has been identified, the correct controls for the beetle can be put in place. The species may show up at other pear orchards in the south of Britain, says Barclay, but is unlikely to wreak havoc.

He says, 'It's not completely out of its natural range as it is from Europe, so it will have some competitors and predators.'

A continuing story of immigration

There are about 4,000 native beetle species in Britain. Every year they are joined by between 10 and 15 species from neighbouring European countries.

Most of these insects are not pests, so very few of them come to our attention. But given that the plants we tend to import are those useful to humans (such as fruit-producing trees), we are more likely to be importing their accompanying pests as well.

With climate change, we will have to brace ourselves for more pests arriving from warmer climates, says Barclay.

'You need to think of the British Isles with a long-term perspective, in that it was covered in glaciers until about 10,000 years ago. As those glaciers retreated it was effectively filled up with species from the south. And that's a process that is still ongoing.

'So you have a continuous migration of insects moving from the south as the climate becomes milder. And if that climate warming is currently speeding up then we are likely to see more species moving northwards.'

black-vine-weevil-news-two-column

The black vine weevil Otiorhynchus sulcatus is a major pest for fruit growers in the UK, causing estimated annual losses of £30 million. Photo by Denny Bruck/ARS.

The importance of global collections

For Barclay, pest identification cases like this show the importance of the Museum's collections, which total over 80 million specimens, including 10 million beetles.

'The collections are globally unique. They are so comprehensive that they enable us to identify things that no one else could. It's important to have so many species represented in one place so we can solve problems like this.

'The Natural History Museum is a global centre of excellence for the identification and discovery of the natural world.

Our experts and collections lead the way in accurately naming existing species and discovering new ones, in Britain and throughout the world.'

  • By James McNish

Related information

Max Barclay

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