Box caterpillar is Britain's biggest garden pest

A destructive species of caterpillar which decimates the hedgerows of Britain’s upper classes has spread to all UK countries and tops the pest ‘most wanted’ list.

The Chinese caterpillar decimates box hedges and has been spotted in the gardens of various stately homes.

They decimate the ornamental trees by devouring all the leaves.

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A destructive species of caterpillar which decimates the box hedgerows of Britain’s upper classes has now spread to all UK countries and tops the pest ‘most wanted’ list (stock)

‘We have 4.5 million members, who are allowed to ask us questions,’ Stephanie Bird, the RHS’s entomologist, told The Times.

‘Based on the questions we work out the number one inquiry. Historically slugs and snails are always top. This year it is set to be the box caterpillar.’ 

The pest arrived on British shores a decade ago and has spread at a prolific rate but started mainly in London and the South East .  

It is difficult to police the pest and homeowners are encouraged to remove them by hand. 

There is little guidance available and few effective ways of eradicating the pest. 

Experts believe the moth originated in China and either flew across the English Channel or stowed away in containers of imported plants. 

Invasions of slugs and other garden villains can be controlled through a variety of means but the Chinese box tree caterpillar is currently freely running riot. 

The caterpillar, a native of East Asia first discovered in the UK in 2011, feeds vociferously on box plants – stripping them bare.

While feeding, it covers itself under a blanket of pale fine webbing that can cover infected plants.

China, the native home for the caterpillars, sees them limited by hornets which feast on them. 

Experts believe the moth originated in China and either flew across the English Channel or stowed away in containers of imported plants. Invasions of slugs and other garden villains can be controlled through a variety of means but the Chinese box tree caterpillar is currently freely running riot (stock)

But in Europe they have decimated vast swathes of wild box trees and plagues of moths pester entire villages.

Pesticides are available for large areas and professional gardens but the average person is unable to obtain these.

There are also deepening concerns the pest will reach beyond the current confines of domestic and stately homes. 

If it spreads to wild box trees in the UK it may destroy all semblance of the plant.  

Measures are being taken to try and counter the pest, as the RHS and various researchers investigate ways of effective control. 

The faeces of the caterpillar itself may offer the best solution. 

New invasions avoid areas that are already infested and spreading the scent of the caterpillar throughout may dissuade them from settling in a new box. 

They are constantly being monitored by the European Boxwood and Topiary Association as any signs of invasion are recorded.