Weevils To Tackle Invasive Water Fern In Cwmbran
A colony of North American weevils is being introduced into a section of canal in Cwmbran to tackle an invasive species of water fern responsible for killing a number of fish.
The water fern (Azolla filiculoides) was found at the Ty Coch section of the Monmouthshire and Brecon Canal and grows rapidly, covering the whole water surface and reducing oxygen levels in the water.
It was introduced into the UK in the 1800s as an ornamental plant for garden ponds but spread into the natural environment and is now regarded as one of the UK’s most invasive plants.
The weevils are small insects, just 2mm in size, and supplied by specialist company AzollaControl which has used them effectively to treat problem areas in waterways across the UK. They feed exclusively on the water fern so don’t cause any damage to humans, other animals or plants..
Volunteers from the Waterworks Ty Coch Restoration Project and Waterway Recovery Group will work with Torfaen council to remove most of the existing fern from the surface of the canal, and the weevils will be introduced to keep it from re-growing in significant quantities.
The leader of Torfaen council, Bob Wellington CBE, said: “This year has been a particularly bad one for Azolla spread due to the previous mild winter, and as such illustrates the practical problems that climate change can bring. Our officers have devised a safe and effective plan of action that works with nature, and means we can avoid using artificial chemicals in the canal.
“We are very lucky to have an enthusiastic group of volunteers from the Waterworks Restoration Project and Waterway Recovery Group to remove the bulk of the weed, and using the weevils I am confident that we can prevent it from re-growing and doing more damage in the future.”
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