Japanese Knotweed

Thursday 24th June 2010 Lords Chamber

Question

11:28

Asked By

[Baroness Sharples]

To ask Her Majesty’s Government what plans they have for preventing the spread of Japanese knotweed.

[The Parliamentary Under-Secretary of State, Department for Environment, Food and Rural Affairs (Lord Henley)]

A controlled release of the highly specialist psyllid—Aphalara itadori—is currently under way to help control Japanese knotweed. If successful, this should restrict its growth, slow its capacity to spread as vigorously and enhance the effectiveness of management effort. It would not eradicate it altogether.

[Baroness Sharples]

I thank my noble friend for that reply but is he aware that it is more than 20 years since I first asked about knotweed and nothing seems to have happened since then? Should psyllid be released and the genie is then out of the bottle, how can we ensure that it is safe? Is there not a problem for people trying to get mortgages? When it is proved that they have knotweed in their gardens or on their land they cannot get a mortgage.

[Lord Henley]

My Lords, we are all aware that my noble friend has been pursuing this matter for about 20 years. This is an experiment worth doing. We have put a great deal of research into the safety of the psyllid that is being introduced to ensure that it will not eat anything other than Japanese knotweed. So far, as far as we know, it does not. If we find any evidence that the psyllid moves off, we will quickly eradicate it to ensure that it does not cause the damage that uncontrolled releases of biological agents can cause.

[Lord Campbell of Alloway]

What has been done about it over the past eight years?

[Lord Henley]

My Lords, a great deal has been done about it. I notice that the noble Lord, Lord Hunt of Kings Heath, is laughing, because he has had to address these questions before. I am grateful for the work that the previous Administration did in this area in introducing research into the said psyllid, the—let us get the name right again—Aphalara itadori. We hope that it will do the appropriate job in due course.

[Lord Davies of Oldham]

My Lords, we on this side wish the Minister well in the attempt to control Japanese knotweed. Will he emphasise that it is not just gardeners and people who own cultivated land who are concerned about it, but our public services? Knotweed represents a heavy cost on our railway system because of the threat that it represents.

[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.

[Baroness Gardner of Parkes]

Can the Minister tell us exactly what this mysteriously named thing is? Is it an insect, is it like the Hawaiian cane toad in Australia, or is it bacterial?

[Lord Henley]

My Lords, the psyllid known as Aphalara whatever it was, is a very small bug, of the order of two to three millimetres long. It is difficult to see with the naked eye, and a magnifying glass may be used better to see it. I have some pictures, which I could show to my noble friend after this Question if she wants to see whether she can identify that bug.

[Baroness Quin]

My Lords, I, too, pay tribute to the noble Baroness for her persistence in raising the issue. Is it not potentially a good news story that after so long, given the problems and great expense which this has caused to people in both urban areas and the countryside, that some of the cost incurred by this plant may be limited in future? I know that the Labour Government had also commissioned research into another method of control of Japanese knotweed, a leaf fungus, which also did not appear to attack other plants. Can the Minister confirm that that research is continuing and what progress is being made?

[Lord Henley]

My Lords, the noble Baroness is quite right to say that it is a good news story. That is why I was trying to offer some praise to the party opposite for the work done, particularly by the noble Lord, Lord Hunt of Kings Heath. We will continue our research on the fungus that the noble Baroness mentioned and, in due course, I hope that I will be able to tell her how that is getting on. I have nothing further to add to what I have said today, but we will continue with both avenues as appropriate.

[Lord Skelmersdale]

My Lords, would it not be quite a good thing if this bug, the name of which I cannot pronounce either, were to mutate and attack the oilseed rape seedlings that are desecrating our waterways and creating quite a large eyesore around the country?

[Lord Henley]

My Lords, my noble friend has a point, but we would be rather worried if the highly specialist psyllid mutated because that could cause considerable damage in areas that we would not be aware of. If we saw any signs of it mutating, we would have to stop these experiments.