Japanese Knotweed

Lord Greaves Excerpts

Thursday 24th June 2010 Lords Chamber

[Lord Henley]

My Lords, the noble Lord is right to emphasise the costs, as did my noble friend in her supplementary question. It can cause major structural damage. We estimate that the costs of managing it are about £150 million a year but, as the noble Lord will remember from when he had to deal with the matter, back in 2003 the cost of total eradication was estimated at £1.5 billion. Now, obviously, it would be a great deal more. We should wait to see what this psyllid can do and whether it leads to a much better control of Japanese knotweed.

[Lord Greaves]

My Lords, first, I congratulate the noble Baroness, Lady Sharples, on her persistence in pursuing this matter over many years—even before I was here. It is now coming to some fruition. If the present small-scale release tests in the real world prove successful, what is the next step?

[Lord Henley]

My Lords, if those tests are successful, obviously we would want to take it on, on advice from the appropriate scientists, to lead to greater control of Japanese knotweed. I have to say that it will take a considerable time before we know whether it will be effective; it is thought that it could be five to 10 years before we see any evidence of greater control.