Australia combats invasive rabbits and prickly pear cactus with biological control

Australia has spent more than a century battling invasive species that threaten its agriculture and native ecosystems. European rabbits were released in 1859 by Thomas Austin, quickly proliferating to an estimated 600 million by the 1920s and causing severe soil erosion, loss of native flora, and billions of dollars in damage. Control methods evolved from extensive rabbit-proof fences to the introduction of the Myxoma virus in the 1950s, which initially reduced rabbit numbers by 90 %, and later the Rabbit Haemorrhagic Disease Virus in the 1990s as rabbits developed immunity.

A similar large‑scale biological program began in 1926 when the Cactoblastis cactorum moth was released to curb the spread of invasive prickly pear cactus. Together with cochineal insects, the moth devastated the cactus, reclaiming roughly 7 million hectares of farmland within a decade. The success is hailed as a landmark in pest‑management, though officials caution that biocontrol is not universally reliable, citing the later introduction of cane toads that became a new invasive threat.