Biological control of weeds in Australia: the last 120 years

The development of the field of biological control of weeds in Australia is described, from the first attempts in 1903 to the present day. The interest sparked by the obvious success of prickly pear program, apparent from 1930 to 1935, resulted in several programs during the next 20 years, followed by a decline in activity until the 1970s when activity increased enormously following the success of the skeleton weed program and the effective use of a plant pathogen for the first time. This momentum was maintained until the beginning of the present century with several successes and was marked by several important advances in genetic profiling, host-specificity testing, economic evaluation, conflict of interest resolution and the ecology of insect/plant interactions, including evaluation of the effectiveness of individual introductions. Biological control has proved to be a valuable and effective approach to weed management in Australia with 39% of all programs considered to produce complete or near-complete control, 30.5% partial control and an average benefit–cost ratio of 23:1. Funding for research has been variable with a decline from the late 1990s but with a significant increase again since 2020.