Question to the Department for Environment, Food and Rural Affairs:

To ask Her Majesty’s Government what progress is being made with the pilot schemes for control of Japanese Knotweed (Fallopia japonica) using the psyllid Aphalara itadora; and what assessment they have made of schemes and proposals for the control of Japanese Knotweed (Fallopia japonica) in other parts of Europe, and North America.

Following rigorous laboratory testing which identified the psyllid Aphalara itadori as a suitable biocontrol agent for Japanese knotweed, it was released under licence to two sites in spring 2010, subject to a programme of close monitoring. After reviewing the data collected, the Food and Environment Research Agency, as the licensing authority, approved releases in spring 2011 to seven sites in England and one site in Wales.

The psyllid has successfully overwintered since then, but numbers have remained low so additional releases were made at the sites in spring of 2012, 2013 and 2014 to boost numbers with the aim of achieving establishment. This rate of progress is not unexpected. The sites continue to be closely monitored.

This was the first intentional release of a non-native organism to control an invasive plant in Europe. Other classical biocontrol programmes from around the world have taken five to ten years from release to achieve successful biological control.