First Ever Use In Europe Of An Insect To Fight Invasive Plant Species

University of Leicester biologists established that the Japanese Knotweed in Britain was one the biggest females in the world- a clone of cuttings brought into Britain in the 1850s. Costs of controlling it in Britain have been put at £1.5 billion.

Defra's Food and Environment Research Agency (Fera) has now launched a public consultation exercise into plans to control the Japanese Knotweed using a highly specialist sap-sucking insect –or psyllid- called Aphalara itadori.

This follows a rigorous testing regime undertaken by the not-for-profit research organisation CABI at their quarantine laboratories, the purpose of which is to be as sure as possible that potential biocontrol organisms are restricted to Japanese Knotweed and cannot be tempted to stray onto related British plants or economically important species.

Lead scientist Dick Shaw said: “Using information compiled by scientists at the University of Leicester, Biocontrol experts at CABI were able to focus their collecting efforts on the precise region of Japan where the European clone of Japanese Knotweed originated. 

“A number of Japanese invertebrates and micro organisms have been subjected to a rigorous testing regime. The aim of biological control is not to eradicate the target organism, but to weaken it so as to restrict spread and increase the effectiveness of other control measures (i.e less herbicide use).”

The psyllid doesn’t actually eat the plant, but sucks the sap like an aphid, and also produces vast numbers of offspring on Japanese Knotweed plants, which severely affect the morphology and vigour of the plant. 

Dr Shaw added: “Since there has never been a release of a biocontrol agent for a plant species in Europe, extreme caution is being exercised by all concerned”.  The proposed organism has now satisfied the scientific community that the proposed release under licence would be both safe and beneficial to the environment. On July 23 2009 the government inaugurated a public consultation on the release, subject to the satisfactory conclusion of this process, approval should be granted for the first releases in April 2010.

“Early releases would be made only under licence, and would be closely monitored, with appropriate contingency plans in place.  At the point that the organism is declared to be ordinarily resident, anybody may move it between knotweed sites. Given the fact that our Japanese knotweed is a single clone I feel we have excellent prospects for the specific and effective control of Japanese Knotweed in Britain. “