Page last updated at 07:16 GMT, Thursday, 25 March 2010

Insect to fight knotweed hotspots in Wales


The bug is being tested out in Swansea

An insect will be released to tackle to problem of Japanese knotweed in Wales after the environment minister gave the go-ahead.

In Japan the psyllid insect Aphalara itadori is a natural predator of the plant which in the UK costs over £150m a year to clear and control.

Jane Davidson said its release, as part of a trial, would be a "ground-breaking natural approach" to killing the plant.

It is the first time biocontrol has been used in the EU to fight a weed.

Japanese knotweed is extremely successful at spreading throughout the countryside and, as a highly invasive non-native species, poses a significant threat to biodiversity in Wales.

It is extremely difficult to remove and costs the development industry millions of pounds to control each year.

As a sustainable, natural approach this project is ground-breaking and will help to reduce the huge cost of treating and killing this devastating plant
Environment Minister Jane Davidson

The trial is expected to begin by July.

To maintain laboratory conditions, locations are not being made public but the Welsh trial is believed to be planned for the Swansea area.

Ms Davidson said: "Tackling the problem of Japanese knotweed, which was introduced to Britain in the 19th Century, will not only help protect our native plants and animals but also help businesses in Wales.

"As a sustainable, natural approach this project is ground-breaking and will help to reduce the huge cost of treating and killing this devastating plant for the local authorities and other industries."

The Welsh Assembly Government is working with the UK government's department for environment, food and rural affairs (Defra) to pilot the insect solution at various sites in Wales and England.

Aphalara itadori on the knotweed
The insects feed on the sap of the knotweed stunting its growth

Japanese knotweed is a particular problem in south Wales.

In Swansea, one of the worst affected parts of Britain, the total biomass of the plant is estimated to exceed 62,000 tonnes.

Research project

A long-running research project into the biological control of Japanese knotweed has been part funded by the assembly government.

It has been carried out by the Commonwealth Agricultural Bureaux International (Cabi), an organisation specialising in the use of natural enemies or means to control pests.

Cabi lead researcher Dr Dick Shaw said: "This is a great opportunity for the UK to benefit from a technique commonly used outside Europe."

The insects stunt knotweed growth by feeding on the plant's sap.

Cabi will manage the release of the insect under licence to ensure it doesn't attack other plants.

If the first phase is successful, the psyllid will be released at further sites where it will continue to be monitored.

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