Views sought on knotweed predator in the UK

BBC News 22 Jul 09;

The public's views are being sought on the introduction of a plant-eating predator from Asia into Britain to help control Japanese knotweed.

Scientists have identified an insect that keeps the superweed under control in its native home of Japan and think it could do the same in Britain.

The consultation is being carried out by Defra and the Welsh Assembly before a final decision is made.

If the plan gets the go-ahead, the insect could be released next summer.

This would be the first time that biocontrol - the use of a natural enemy to control another pest - has been used in Europe to fight a weed.

The release would initially take place at a small number of sites before a wider introduction in England and Wales.

The superweed research has been carried out by Cabi, a not-for-profit agricultural research organisation, and the study has been peer reviewed by the Advisory Committee on Releases to the Environment.

The team has spent several years trying to find potential candidates to control the spread of Japanese knotweed, looking for predators that feed only on knotweed and not on any of Britain's native plants.

Their chosen insect is a small psyllid called Aphalara itadori that feeds on the sap of the superweed, stunting its growth.

Dick Shaw, the lead researcher on the project, said: "This psyllid is a true knotweed specialist and our research shows that it could be a safe and effective control agent for one of our worst weeds.

"We are really pleased that the programme has reached the public consultation phase and look forward to hearing the outcome."

Japanese knotweed was first introduced to the UK as an ornamental plant in the 19th Century, but it has since spread rapidly, damaging plant biodiversity as well as hard structures, such as buildings, paving stones and flood defences.

But getting rid of it using current methods - weed killers and physical removal - is expensive - in 2003 the cost of national eradication was estimated at £1.56 billion.

The researchers claim that biological control will be a cheaper and more environmentally friendly option for controlling the superweed.