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Japanese Knotweed

Volume 802: debated on Thursday 12 March 2020


Asked by

To ask Her Majesty’s Government what progress they have made towards the eradication of Japanese Knotweed.

My Lords, Japanese knotweed is a tenacious species which is currently difficult to control on a large scale. Biocontrol agents have shown the potential to reduce the invasive capacity of Japanese knotweed and provide a cost-effective and time-effective way of managing this problem. We have been trialling biocontrol methods to control Japanese knotweed and are working to establish two highly specific biocontrol agents: the Aphalara itadori psyllid and a Mycosphaerella leaf spot fungus.

My Lords, it is 10 years since we first talked about the jumping plant louse, the psyllid, in this House. Another six months have gone by and there is another Question on Japanese knotweed. Can the Minister give us more information about the two biological agents, particularly the psyllid, which we have been talking about for so long? Secondly, can he tell us about updated government advice on property transactions when Japanese knotweed is on the property, particularly for people seeking mortgages, following last May’s Select Committee report?

My Lords, we accepted the recommendation in the Science and Technology Committee report to commission a study of international approaches in the context of property sales, and we expect to receive the final report at the end of March. I shall make sure that the noble Lord receives it. On the psyllid, there are problems with climatic issues, so more recently we have been seeking psyllids from the north and west of Japan, where we think the climatic conditions could be more similar to our climate.

As for the work that CABI, the Centre for Agriculture and Biosciences International, is doing with the leaf spot fungus, this is a single-mating type of specialist pathogen developed into a product for direct application, but which would not persist and spread in the wild or threaten any native species. I emphasise that because the last thing we want is any unintended consequences. This is going to take some years to reach the shelves if it is successful, but it is all part of our endeavour to control this very invasive plant.

My Lords, I refer to my entry regarding Rothamsted in the register of interests. It seems that the much-maligned Japanese knotweed does have some uses after all: it has been found to contain a unique compound which can outperform traditional antibiotics in tackling Lyme disease. Does the Minister agree that this underlines why we need more research into using nature-based solutions to tackle animal and human diseases?

The noble Baroness has hit upon something concerning nature and many of the plants around the world. This is why we need to look after our planet—because many of these plants will provide the solutions to many diseases. As for Japanese knotweed, I am aware of what she says: it is successful in Japan because it has these biocontrols. The problem in this country—this is the distinction—is that it is so invasive that it is causing significant issues. Therefore, its source, where there are biocontrols, would be a better place for such things than encouraging it here. In fact, under the Wildlife and Countryside Act 1981, we should not be doing that anyway.

My Lords, are not the professionals dealing with this in this country using Roundup? Is that not the most effective thing available at the moment? Does the EU not have plans to ban this and, if so, will we follow suit?

My Lords, the UK experts participated in the European Food Safety Authority’s recent assessment of glyphosate and supported its conclusions. The Government therefore agree with the continuing approval of glyphosate. Of course, we always base our considerations on the best available advice and that is what we will continue to do.

My Lords, are the experiments using derivatives of Japanese knotweed to tackle the growing problem of Lyme disease pertinent to this country? If they are, will the noble Lord put the details in the Library?

I certainly shall. As I said to the noble Baroness, obviously, we want to use nature- based solutions to many of the diseases and problems that humans, and indeed animals, have. I shall certainly put a copy of any information that I have in the Library and send a note to the noble Lord.

May I congratulate the noble Lord, Lord Greaves, on taking up the mantle of my noble friend Lady Sharples so ably.

Both my noble friend Lady Sharples and the noble Lord are tenacious in seeking to deal with this very difficult plant.

My Lords, I spend rather more time than I would like on the west coast railway service, which sometimes goes very slowly, and when looking out of the window you see along the tracks an awful lot of Japanese knotweed, which I gather was planted in Victorian times. What are the Government doing to try to get Network Rail to sort this problem out?

My Lords, the Government provided a very substantial settlement for operations and management, including vegetation management, to Network Rail for England and Wales. Last year, Network Rail met with the Property Care Association to discuss knotweed; the meeting was an opportunity to discuss current management, and to explore how Network Rail can give trackside neighbours the assurance they need, particularly to satisfy mortgage lenders, for instance.

My Lords, does the Minister think that if Lady Sharples were in her place, she would have been impressed by the progress that is being made?

My Lords, my noble friend is very understanding that sometimes psyllids do not work as well as we would like. I am pleased to have this opportunity to say there is continuing research, because this plant is very successful in this country, but is an invasive species. We should be very watchful and raise awareness about the issues of invasive species.

My Lords, 263 years ago this week, we shot an Admiral to encourage the others. Does the Minister think maybe we should do something not quite as serious, but quite serious, to move this forward? Lady Sharples must be looking on from her home with amazement.

It is my privilege to occasionally see my noble friend, and she is always extremely encouraging. As for shooting admirals, I am not sure—shooting Ministers, perhaps, but certainly not admirals.

My Lords, I inform the House that before she retired, Lady Sharples extracted a promise from me that I would ask this Question at least every six months.

If it is my privilege to answer this Question again, I look forward to that. With research, we are always impatient and want the results now. I can promise your Lordships that through CABI, Defra is recognising that we need to find ways of doing this. For instance, the Environment Agency is experimenting with electro weeding, and on the Severn it has reduced Japanese knotweed by 50%. We are endeavouring to make progress.