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Improving lives by solving problems in agriculture and the environment

Testing the psyllid: first field studies for biological control of knotweed

Japanese knotweed (Fallopia japonica) is one of the most damaging invasive weeds in the UK. It spreads extremely quickly, preventing native vegetation from growing and is a problem to the construction industry. Current control methods rely mainly on expensive chemicals. But after years of research, we are now releasing and testing a natural control agent - a tiny sap-sucking psyllid at a few sites in the UK.

Project Overview

So, what's the problem

Japanese knotweed (Fallopia japonica) is one of the most damaging invasive weeds in the UK. It spreads extremely quickly, preventing native vegetation from growing, and is a problem to the construction industry as it is capable of exposing weaknesses in buildings, foundations, concrete and tarmac. Current control methods rely mainly on chemicals, and it has been estimated that the costs of control in the UK would be over £1.5 billion. CABI has been testing the potential for more sustainable, longer-term control using biological control methods.

What is this project doing?

CABI is carrying out the Government approved release of the specialist psyllid Aphalara itadori (Insecta: Hemiptera: Psylloidea) as a control agent for Japanese knotweed in the UK (see After 7 years of research in Japan and in specialist quarantine facilities in the UK, it has been established that this tiny, sap-sucking psyllid is a knotweed specialist and can only complete its development on Japanese knotweed. The risk of damage to native plant species has been shown to be very low indeed.

The research programme and release are supported by various organisations, including Cornwall County Council, the Welsh Assembly Government, Defra, the Environment Agency, British Waterways, South West Regional Development Agency and Network Rail. The releases take place as a field trial at a number of sites in England and Wales. Part of the release is a monitoring plan, which aims to record the impact of the insect on the knotweed, but also to detect any potential adverse effects on native plants and invertebrates.


First releases at a limited number of sites have been made, and preparations for a second release phase are underway. All results are reported to regulatory authorities.

The team

Project team

Staff image of Alex Brook

Alex Brook

Project Manager - Ecologist

Staff image of Corin Pratt

Corin Pratt

Invasive Species Management Researcher

Staff image of Suzy Wood

Suzy Wood

Scientific Support

Staff image of Kate Constantine

Kate Constantine

Project Scientist


  • United Kingdom


  • Start: 01/04/2010
  • End: 31/03/2014

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