Biological Control: Non-target Impacts

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Steps in a Weed Biological Control Program | Choosing Target Weed | Native-range Surveying | Choosing Best Potential Agent | Host-specificity Testing | Mass-rearing, Release and Evaluation | Non-target Impacts

• The introduction of exotic natural enemies for the biological control of weeds is an irreversible process. Consequently the primary concern with the release of biological control agents into a new country is the potential for unforeseen or unintended effects on native or beneficial non-target plant species. This is why exotic biological control agents are carefully scrutinised during host-specificity testing to prevent the importation, release and possible establishment of natural enemies that pose a risk to non-target organisms. The risks associated with an introduction are measured against the benefits and risks associated with other control tactics (e.g. herbicide) or against what can be expected by doing nothing against the weed.

• Based on results from host-specificity testing, 17 species of agents that have been released for biological control of nine weed species in Australia were identified as having the potential to attack at least 30 native species. Since their release the circumstantial evidence gathered indicates that these agents do not seem to have a major impact on the non-target species in the field. However more post-release evaluations are required to properly document the extent (if any) of non-target effect after agent introductions.

• For more details see: Willis, A.J., Kilby, M.J., McMaster, K., Cullen, J.M. and Grove, R.H. (2003). Predictability and acceptability: Potential for damage to non-target native plant species by biological control agents for weeds. In: Improving the selection, testing and evaluation of weed biological control agents, (eds H. Spafford Jacob & D.T. Briese), pp. 35-49. CRC for Australian Weed Management, Technical Series 7.
  

Biological Control Home | Key Resources

Steps in a Weed Biological Control Program | Choosing Target Weed | Native-range Surveying | Choosing Best Potential Agent | Host-specificity Testing | Mass-rearing, Release and Evaluation | Non-target Impacts