Not many towns have a monument to a caterpillar and its egg laying moth(er). This modest cairn in Dalby pays tribute to the exemplary efforts of the Cactoblastis Cactorum, responsible for the eradication of Opuntia Stricta, more commonly known as prickly pear. Myall Creek foreshore is undergoing some restoration work, so the monument is somewhat obscured by fencing.
Other friends of the little cactus suckers include the people of Boonarga near Chinchilla (an hour’s drive north-west of Dalby) who in 1936 erected the Cactoblastis Memorial Hall. Image via The Mail (Adelaide) – 26 December 1936.
In the 1970s, the people of The Ascension Islands in the middle of the Atlantic Ocean were well pleased with the insect too and honoured it on a postage stamp.
Image via Lepidoptera Larvae of Australia.
This post by Simon Miller from the John Oxley Library describes the contribution of Dr Jean Haney-White towards the eradication of the cactus.
And here’s the inscription on the Dalby monument.
In 1925 Prickly Pear, the greatest example known to man of any noxious plant invasion, infested fifty million acres of land in Queensland, of which thirty million represented a complete coverage. The Dalby region was then heavily infested. The biological control investigation was undertaken by the Commonwealth Prickly Pear Board, the joint project of the Commonwealth, Queensland and New South Wales governments.
Early in 1925, a small number of Cactoblastic Cactorum insects was introduced from the Argentine by Alan Parkhurst Dodd, OBE, who was officer-in-charge of this scientific undertaking. They were bred in very large numbers and liberated throughout the prickly pear territory. Within ten years, the insects had destroyed all the dense masses of prickly pear.
This plaque, affixed by the Queensland Women’s Historical Association on Thursday 27th May 1965, records the indebtedness of the people of Queensland, and Dalby in particular,to the Cactoblastic Cactorum, and their gratitude for deliverance from that scourge.
In other parts of the world, the moth isn’t so revered. Texans, for example, are fond of the prickly pear. It’s the state’s official plant symbol and a valued food source rich in Vitamin C. The moth, so loved in western Queensland, is listed there as an invasive pest.