The Cactoblastis cactorum insect was introduced in 1923 .
Insect 's defeat of the prickly pear enabled the Queensland dairy industry to rebuild and expand during the late 1920s , leading to the 1930s dairy boom .
The Cactoblastis cactorum insect was introduced in 1923 , and its defeat of the prickly pear enabled the Queensland dairy industry to rebuild and expand during the late 1920s , leading to the 1930s dairy boom .