Written evidence submitted by Crop Protection Association (JKW0008)
Overview
The Crop Protection Association (CPA) welcomes this inquiry into the effects of Japanese Knotweed on the built environment and is grateful for the opportunity to respond.
We have set out in this submission our responses to the topics where we believe we can offer the most helpful view to the Committee, rather than commenting on each issue the inquiry seeks to address.
Summary
Japanese Knotweed is estimated to cost the UK economy £170 million a year, with around two per cent of UK properties currently affected by it.
Recently, a landmark court ruling gave two homeowners in Wales the right to claim damages against Network Rail, after it failed to protect their properties from knotweed. The case could see property owners across the UK able to claim damages if their homes are entangled by the plant.
Another recent ruling, this time in Bristol, allowed the City Council to use the provisions of the Anti-Social Behaviour Crime and Policing Act 2014 to address a Japanese Knotweed infestation and secure on order requiring a landowner to undertake removal works (as well as receiving an £18,000 fine).
These rulings demonstrate some of the issues faced by homeowners, businesses and local authorities in relation to Japanese Knotweed. That is why it is crucial that effective methods of control are available.
The herbicide glyphosate is the most effective tool for controlling Japanese Knotweed – an invasive species which causes serious issues for UK homeowners. Without glyphosate, knotweed could spread across parks, railways and streets, disrupting travel in the process.
About us
The CPA is the voice of the UK plant science industry, promoting the essential role of science and innovation in protecting food, parks, gardens roads and railways. The CPA advocates good stewardship, better regulation and best practice.
The Association represents companies in the UK involved in the development and manufacture of a wide range of plant science technologies including crop protection products, or pesticides. The CPA has 25 member companies, covering around 96% of the UK pesticide market. Details of membership can be viewed online: http://www.cropprotection.org.uk/who‐we‐are/.
What scientific evidence exists on the effects of Japanese Knotweed on the built environment?
Earlier this year, researchers from Swansea University released the results of the world’s largest study into eradicating Japanese Knotweed. They found that Knotweed can be controlled using glyphosate at the right time of year, however, this can usually take three to five years. The researchers from Swansea University provide some advice for homeowners concerned about knotweed:
- Knotweed cannot be controlled by one herbicide treatment in a single year. Any treatment strategy should be long-term and target both the aboveground and extensive belowground parts of the plant.
- The most effective treatment involves working with the biology of the plant and targeting the correct herbicide (glyphosate), when the plant is vulnerable to its effects, from summer into late autumn.
- Once knotweed has been effectively controlled using glyphosate, don’t disturb the land as it is likely to come back. Even if the aboveground parts of the plant are dead, the belowground rhizome system probably isn’t.
- Don’t try digging out the knotweed yourself, it is easy to miss parts of the root and spread it and you cannot dispose of the plant with your garden waste – indeed, it is illegal to do so.
The full Swansea University study can be accessed at: https://link.springer.com/article/10.1007%2Fs10530-018-1684-5
An accompanying press release can be found at: https://www.swansea.ac.uk/press-office/news-archive/2018/swanseauniversityscientistsleadthewayintacklingjapaneseknotweed.php
The herbicide glyphosate, identified by Swansea University as being the most effective treatment, has been subject to a great deal of debate over recent years. However, the EU’s own European Chemicals Agency (ECHA) and European Food Safety Authority (EFSA), along with regulators around the world, have all found glyphosate to be safe for human health and the environment.
Without glyphosate, control of Japanese Knotweed would become increasingly difficult and costly.
How does the presence of Japanese Knotweed affect mortgage lending decisions and property valuations?
Japanese Knotweed has led to serious issues for many homeowners trying to sell their properties and have even put some at risk of ASBO rulings. Without glyphosate, knotweed could spread across parks, railways and streets, possibly disrupting travel.
The presence of knotweed has caused many property deals to fall through and has devalued homes. Homeowners find it incredibly difficult to deal with knotweed on their own.
Research conducted by OnePoll in 2017 found that from a sample of 100 UK adults;
- The average cost after knotweed appeared was £1,880, while 10% lost more than £4000.
- One in seven (15%) saw a property deal fall through because of a knotweed infestation.
- One in five (20%) saw the value of their house drop because of the presence of the weed.
- One in ten (10%) had to compensate someone or pay insurance claims.
The research also reveals a poor understanding of the legal and financial risks around knotweed.
- Only one in five (23%) know you have to dispose of the plant – which is a controlled waste - at a licenced landfill site.
- Only one in ten (11%) know you could get an ASBO for failing to control the weed.
- One in five (23%) know that a neighbours’ insurance company can pursue you for damages if an infestation comes from your property.
Invasive species such as Japanese Knotweed create a serious risk to biodiversity by crowding out native species. It can lead to major damage of infrastructure and can clog up waterways, exacerbating flood risks.
The weed is now present all over the UK, and it’s important that experts have access to the most effective treatments available.
Glyphosate is recognised as being the most effective tool for controlling Japanese Knotweed, without it the problem would be far worse, and homeowners would have to resort to expensive and less effective methods of treatment such as excavation and disposal of the waste.
December 2018