Mite used to take on wetland pest

A microscopic, sap-sucking mite has been introduced in Wales in a bid to help control an invasive Australian wetland plant that chokes up bodies of water and out-competes native plants.

In a first for Wales, a new biological control agent that feeds exclusively on Australian swamp stonecrop (Crassula helmsii) is on trial at WWT Llanelli Wetland Centre.

Brought to the UK in the early 1900s as a domestic plant, swamp stonecrop found its way into the wild and is now a serious problem. Its carpets smother native plants and reduce oxygen levels in water, threatening wetland wildlife. It has spread across the Llanelli reserve, which is an important haven for vulnerable species, including the water vole and otter.

The mite, whose secretions attack stonecrop shoots, was introduced in June and already there are signs that the trial is working.

Samantha Herbert