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Proposed release of the non-native biological control agent Listronotus elongatus for the control of Hydroctyle ranunculoides (floating pennywort) in England


Defra are seeking views on whether the non-native weevil Listronotus elongatus should be released into England to reduce the impact of the invasive weed Hydrocotyle ranunculoides.

Hydrocotyle ranunculoides was first recorded as being naturalised in the UK in Essex in 1990, and has since been found across England, Wales and Northern Ireland. The weed clogs up slow-moving water bodies, hampering access for recreational activities, such as fishing, and reduces the aesthetic appeal of landscapes, with knock on effects to tourism. It also negatively impacts on water flow, sedimentation, and light and oxygen levels, and endangers communities of native plant species and associated fauna.

The weevil Listronotus elongatus has shown promise as a biological control agent of H. ranunculoides, and CABI has produced an assessment of the weevil’s safety for release in England.

For further information on how to comment on the proposed release of the weevil, please see the attached letter.

The deadline for responses is 7th May 2021.