CABI releases rust fungus to control invasive Himalayan balsam

Himalayan Balsam (image courtesy of CABI)

Himalayan Balsam Rust fungus released

Himalayan Balsam is the bane of many a river managers life, with often the only effective treatment being hand pulling over a number of years.  Now a new agent is possibly coming to the rescue of reducing the impact of this pernicious non-native in the form of a fungus that is host specific.

On the 23 July 2014, the Himalayan balsam rust was approved for release by Defra Ministers making this the first fungal biological control agent to be released against a weed in the European Union.  The release was co-ordinated by CABI under licence from Natural England

The initial 2014 release was focused around three release sites in Berkshire and Cornwall.  These sites were carefully selected to have (1) discrete populations where we could carefully monitor the progression of the rust throughout the course of the season and (2) stable populations where the rust would not be washed away by river flows or suchlike. Natural England granted a licence under the Wildlife and Countryside Act 1981 which allowed CABI to plant eight pre-infected Himalayan balsam plants within each site.

The sites have been monitored since the initial planting out of infected plants and secondary infection has been observed on neighbouring plants close to the source inoculum at both sites in Berkshire. Plans are now being made to increase the number of sites for the 2015 release.

For more information please visit the CABI website: http://himalayanbalsam.cabi.org/release-update/

www.cabi.org