Bugs to control invasive canal weed

Published: Thursday, 08 August 2019

THE Wey & Arun Canal Trust is enlisting the help of 1,000 tiny bugs to help control an invasive water fern which can clog the waterway and threaten other plants, fish and invertebrae.

An army of weevils has been released into the canal at Dunsfold on the Surrey/Sussex border to eat its way through the fast-growing and non-native Azolla weed, which can form a dense cover on the water and deprive other species of light and oxygen.

Weed weevilUsually die out

The weevils can feed and reproduce only on the Azolla, and usually die out naturally once they have eaten their way through the fern, helping to control the weed without the need for chemicals.  The recent hot weather has provided ideal conditions for the Azolla to thrive, and it can rapidly double in size in warm weather, forming a thick blanket and posing a serious threat to water wildlife
Wey & Arun Canal Trust’s Conservation and Ecology Director John Reynolds explained:

“We have invested in buying in the weevils as a safe and environmentally friendly way to control this problematic fern. Our aim in restoring the canal is to increase biodiversity, and keeping on top of the water fern will help to ensure the ecology of the waterway remains healthy.”