Jimmy Deenihan (Kerry North-West Limerick, Fine Gael) | Oireachtas source

I thank Senator Mooney for raising the matter this evening.

The species referred to by the Senator was first introduced to Ireland over 100 years ago. It forms dense thickets along roadsides, waste grounds and waterways, reproduces by vegetative means and is difficult to kill off once it becomes established. This plant is included in the list of the 100 most invasive alien species of the world. It forms dense cover causing native plant species to die off. It also grows to heights of 2 m to 3 m and reduces visibility along roadsides while also making access to sites difficult for walkers and anglers. In some instances its roots can damage paths and walls.

The National Parks and Wildlife Service of my Department has been working with the Northern Ireland Environment Agency to fund and manage the Invasive Species Ireland project since 2006. This initiative provides advice and guidance on the management of a range of invasive species, including the species referred to, which can negatively impact on the environment and on property on the island of Ireland. Best practice management guidelines for the species in question have been published and can be accessed on the project website. These guidelines provide practical advice to persons and organisations, including local authorities, on the removal and disposal of Japanese knotweed. A central requirement when dealing with Japanese Knotweed is to ensure that any viable rhizomes, the main means by which the plant spreads, are not given the chance to escape into the wider environment. It is recommended to spray the plant with a systemic herbicide prior to transport, to ensure no material is lost en route, and finally that the material is deeply buried in a properly managed landfill with an effective pest control management system which can deal with any regrowth.

I should also point out that the National Roads Authority has produced guidelines which can assist local authorities on the management of noxious weeds and non-native invasive plant species on national roads, which includes a section on the treatment of Japanese knotweed. The European Communities (Birds and Natural Habitats) Regulations 2011 includes provisions relating to controlling the possession and dispersal of ecologically harmful and invasive species of animals and plants, including Japanese knotweed. Regulation 50 of these regulations, which include provisions relating to the banning for sale of invasive species listed in the schedule to the regulations, is not yet in effect. It is necessary for my Department to carry out risk assessments on those invasive species subject to trade before I can bring this element of the regulations into force.

My Department is keeping abreast of initiatives currently under way in Britain using a specific insect to control Japanese knotweed. It is possible that such controls could be applied to Irish conditions without risk to native or economically important plants here.