CABI releases rust fungus to control invasive weed, Himalayan balsam

26 August 2014 – From today, not-for-profit research organization, CABI, will be releasing a rust fungus at locations in Berkshire, Cornwall and Middlesex as part of field trials to control the non-native, invasive weed Himalayan balsam (Impatiens glandulifera) using natural means.

Himalayan balsam has rapidly become one of the UK’s most widespread invasive weeds, colonizing river banks, waste land, damp woodlands, roadways and railways. The Environment Agency estimates that the weed occupies over 13% of river banks in England and Wales. It can reach over three metres in height and competes with native plants, reducing biodiversity. Large scale chemical and manual control is often not feasible and not economically viable.

Himalayan balsam infestation on the river Torridge, Devon, UK
Himalayan balsam infestation on the river Torridge, Devon, UK (Rob Tanner, CABI)

Using existing measures, the Environment Agency estimates it would cost up to £300 million to eradicate Himalayan balsam from the UK.

The release of the rust fungus comes after an eight-year research programme funded primarily by Defra and the Environment Agency, with contributions from Network Rail, the Scottish Government and Westcountry Rivers Trust. During the course of the research, testing in quarantine laboratories has established that the rust fungus causes significant damage to Himalayan balsam and does not impact on native species.

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