We would like to assure Paul Gleave (Letters, 14 August) and Roger Brake (Letters, 15 August) that their concerns regarding Himalayan balsam are being addressed. Over the past decade, thanks to funding from the Department for Environment, Food and Rural Affairs and the Environment Agency, we have been investigating the natural enemies of this plant in its homeland in the valleys of the western Himalayas. An Indian fungus – a Puccinia rust species – has undergone intensive research during the past five years in our UK quarantine facility and has proved to be highly specific and damaging to its co-evolved host. The resultant pest risk assessment has been approved by both the UK and EU parliaments and the rust will be released in experimental trials later this year – a first for Britain and Europe. It is expected that the fungus will have a significant impact on the competitiveness of this invasive alien weed and thus reduce its highly deleterious effect on the British countryside.
Dr Harry Evans and Dr Rob Tanner
CAB International, Egham, Surrey
