17th May 2022

At a free info session on 10th May, 21 attendees heard from Dr John Ireson of TasWeeds Biocontrol who gave an overview of what biological control for weeds is, what it can achieve, and how it is made safe to use. He concentrated on three major environmental and agricultural weeds: gorse, broom and ragwort. 

Image: Info session at Claude Rd Hall, (c) Jakob Sprickerhof

Three insects that feed on gorse have been released in the state, and significant die-back events have been recorded. A contributing factor to these events was likely that plants, weakened by the insects, were then attacked by native fungal pathogens. 

Image: Gorse with moth webbing, at Landcare Tasmania's release of gorse biocontrol agent last year. (c) Jakob Sprickerhof

Some 40 years ago, ragwort was still a major agricultural weed in Tasmania, and attendees at Claude Road Hall remembered seeing fields full of yellow flowering ragwort in the area back in the 70s and 80s. Biocontrol agents have been a major success in controlling ragwort. Attendees are seeing small patches coming back, and John Ireson said that the beetle that feeds on it was still around. There is a good chance that outbreaks will be contained.

One major concern for attendees was foxglove, which now covers large paddocks in the Kentish area, and flowers at almost any time of the year. There currently is no research into biological control for foxglove being done. Several attendees were interested in either joining an existing Landcare Tasmania community group or forming a new group to support each other in the fight against foxglove.

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This event is part of Landcare Tasmania’s Gorse Biological Control Project and has been made possible by generous funding from the JM Roberts Charitable Trust