Thierry Thomann, CSIRO European Laboratory, seeking natural enemies of gorse.

Scientist search for natural enemies throughout a weeds native range.

Biological control of Gorse

Scientists are searching for fungal pathogens as potential biocontrol agents for gorse in Australia.

  • 1 September 2009 | Updated 14 October 2011

Introduction

Gorse (Ulex europaeus L., Fabaceae) is a major environmental and pasture weed in many temperate climate areas throughout the world. Originally from Western Europe it was deliberately introduced into Australia in the early 1800s as an important hedge and ornamental plant.

Today, it has been declared in Australia as a Weed of National Significance (WONS) due to its:

  • invasiveness
  • impacts
  • potential for spread
  • effects on socioeconomic and environmental values.

Gorse occurs in all states except the Northern Territory, but the heaviest infestations occur in south-eastern Australia, primarily in Victoria and Tasmania.

Gorse is an invasive weed found in all Australian states and territories except the Northern Territory.

Gorse control methods include:

  • mechanical clearing
  • cultivation
  • herbicides
  • hand-pulling
  • fire
  • grazing
  • pasture management
  • re-vegetation.

Biological control is also used when access is difficult and the opportunity for other methods is limited.

Background for biocontrol

Biological control of gorse has been intensively studied following the classical approach, with insects as the control agents.

Several insects have been released in Australia including:

  • gorse seed weevil Exapion ulicis released in 1939
  • gorse thrips Sericothrips staphylinus released in 2001
  • gorse spider mite, Tetranychus lintearius released in 1998. 

No fungi have so far been used as biological control agents for gorse.

Healthy flowering stem of a gorse plant.

A healthy infestation of Gorse can produce millions of seeds every year.
Diseased stems of gorse plants.

A promising fungal agent has been identified from samples of diseased gorse.

Current research

A new project was initiated in 2006 in collaboration between the University of Tasmania and the CSIRO European laboratory (CSIRO-EL) to find fungal pathogens that may have potential for use as biological control agents against gorse in Australia.

Surveys, one in autumn 2006 and one in spring 2007, were conducted in its native range:

  • northern Portugal
  • north-west Spain
  • south-western France.

Isolation and culture of the most promising fungi were made from samples of diseased gorse.

The pathogenicity tests of these fungal pathogens will be performed on Australian accessions of gorse prior to selecting the highest potential candidates and to investigating them further by testing their host specificity.

In collaboration with the Landcare research New Zealand, during the autumn surveys, prospecting was also conducted for autumn active seed-feeders, but none were found.

Learn more about CSIRO's invasive plant Current research.