Japanese Knotweed

Lord Greaves Excerpts

Thursday 12th March 2020 Lords Chamber

Asked by

[Lord Greaves]

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

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

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.

[Lord Greaves (LD)]

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?

[Lord Gardiner of Kimble]

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.

--- Later in debate ---

[Lord Gardiner of Kimble]

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.

[Lord Greaves]

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.

[Lord Gardiner of Kimble]

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.