Thousands of tiny weevils are to be released into a river near Boston, Lincolnshire, to reduce the volume of azolla, also known as the fairy or water fern, growing there. Azolla is an ultra-fast growing plant which can double in size every four to five days and can quickly form dense mats up to 30cm thick.The weevils will be released near Cow Bridge on the Maud Foster Drain today, 28 June.
Debbie Sylvester, Operations Delivery Team Leader, said:
“Azolla grows extremely quickly and can completely cover the water’s surface. These weevils eat only this plant and should help to control its spread.”
Azolla is extremely invasive and difficult to control because of its fast growth rate and ability to re-grow from the tiniest fragment. Beetles were used last year to control the weed on the River Till and River Witham, near Lincoln.
Like many other invasive plants, azolla was first introduced to the UK as an ornamental exotic from the Americas in the 1800s. Invasive species cost the UK economy an estimated £1.7-billion every year: they cause damage to riverbanks and buildings, increase flood risk, crowd out and can kill off native wildlife. They can also become so prolific on waterways that anglers and boaters are unable to use them.
The EA advise that homeowners can do their bit to help prevent the spread of invasive species like azolla by not dumping aquatic plants in the wild and always disposing of old plants and pond material responsibly, by composting or using a green waste bin.
