A national property trade association has published a standardised policy to control Japanese knotweed.
The Property Care Association (PCA), which represents specialists who resolve structural issues, outlines a thorough guide to management of the herbaceous perennial, which can grow up to 1m a month and push through concrete, preventing mortgage approvals.
PCA chief executive officer Steve Hodgson said: "Japanese knotweed has been the subject of controversy in the UK property sector. This new code sets a robust measure of competence and will help address associated issues."
Ground Control national group training manager and BALI technical director Neil Huck added: "It's good that property people are taking notice of it. There need to be standards. We're trying to develop a system of people who are qualified to tackle it - there are a lot of cowboys out there making exorbitant claims they can't back up."
He said the weed's spread is often worsened by lack of knowledge among builders. "It is better if we are brought in as early as possible before development. It is worth a lot of money and we have a range of solutions. But we see it as part of the package for our clients." These include Tesco, Sainsbury's and Thames Water.
Dow AgroSciences has launched ICADE, which is a new herbicide containing triclopyr and aminopyralid. The product is odourless, has a low active ingredient salt formulation and no volatility issues. ICADE can also be used from March through to October.
Japanese knotweed Suggested solutions
Ground Control's methods:
Early Excavate deep and bury 6m down in a plastic membrane.
Late Excavate deep and then dump on a landfill site for contaminated soil.
Near water Individually inject weeds to preserve water quality.
CABI's jumping plant lice:
Not-for-profit organisation CABI worked with Defra and the Welsh Government to release the plant lice psyllid Aphalara itadori into Britain. The 2mm insects only eat Japanese knotweed and have so far survived here.