Plan to use jumping lice in battle against Japanese knotweed

Jumping plant lice from Japan could be released in Britain to control Japanese knotweed, under plans from the Department for Environment, Food and Rural Affairs (Defra).

The non-native sap-sucking insect would be released under licence to tackle the weed, notorious for causing terrible damage to buildings, roads and railway lines; driving out other plants; and eroding river banks.

The ornamental plant was introduced in the early 19th century and escaped into the countryside, where it enjoys an unfettered existence, with no natural enemies.

A national eradication plan through conventional means was estimated in 2003 to cost £1.56bn. These attempts to cleanse the countryside of Japanese knotweed have required herbicides, physical weeding of plants and treating the soil.

In its native habitat, the plant is associated with 186 species of plant-feeding insects and mites, none of which is found here. Five years of research by scientists at CABI has shown that a species of psyllid, Aphalara itadori, is the best candidate to control the knotweed. The scientists believe the introduction of the psyllid would not adversely affect native wildlife and could significantly reduce the costs of tackling Japanese knotweed.

Defra and the Welsh Assembly government are considering licences to release the insect and ministers are seeking views from the public on whether the scheme should go ahead. A consultation was launched yesterday and closes on 19 October.