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Plan to introduce Japanese Knotweed predator

Japanese knotweed, one of the most damagingly invasive plant in the UK, Europe and across the US, may soon be tackled with one of its few natural `predators`.

An application to release tiny sap-sucking non-native insects has been made the Department for Environment, Food and Rural Affairs (Defra) and the Welsh Assembly Government.

Research by scientists at CABI has shown that a species of “jumping plant lice” - the psyllid Aphalara itadori - is the best candidate to control the scourge.

The fast-growing weed has causes major problems through rapid invasion of habitats to the exclusion of other plants, as well as eroding river banks and damaging buildings and other structures.

Eradication through conventional means - herbicides and physical removal of plants - is estimated to have cost £1.56bn in 2003, according to Defra.

The plant escaped into the countryside after being introduced as an ornamental plant in the 19th century. The government now is consulting the public about whether to use another non-native species to control it. The results are due in October.

Readers' comments (3)

  • I would refer those proposing this idea to the second half of the late Michael Crichton's seminal lecture entitled "Complexity Theory and Environmental Management", where he discusses the management of Yellowstone National Park. http://www.michaelcrichton.com/speech-complexity.html

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  • I forwarded the article to Cornwall Council's vegetation advisor and his response was....'Eradication through conventional means - herbicides and physical removal of plants - is estimated to have cost £1.56bn in 2003, according to Defra'

    No. This is estimation of cost of eradication not 1 years cost. I said I would let you know. He can be contacted jmacfarlane@cornwall.gov.uk

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  • The introduction of an alien species from Japan to combat an existing problem is a potentially dangerous solution albeit a cheaper solution than existing herbicide controls for Japanese Knotweed. The possible impact this alien insect will have upon the native flora and fauna is as yet unknown and may not become apparent for several years after its introduction.
    There is well documented evidence to suggest that irreparable and uncontrollable damage can be done to our native species on the introduction of alien species both in animal and plant life.
    I strongly urge the government not to take this route but to further explore additional herbicide controls.
    I am extremely concerned that this insect will displace existing native insects which may in turn have disastrous consequences along the food chain. or it may turn it's attention to other road/river side plants thereby upsetting an entire and often fragile ecological system.

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