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Prickly Pear and Ecology

The prickly pears, or the whole Opuntia botanical genus, are cacti (Famiglia Cactaceae) originating in Mexico.

The prickly pears multiply propagating in the surrounding soil to form large colonies of a clonal nature. This biological characteristic is the main reason why, in some places, prickly pear is considered a real weed. In others, this cactus has played the role of real natural disaster.

The prickly pears (especially the Stricta species) were imported to Australia in the 18th century AD. The first use that was made of it was for ornamental purposes but, at a later time, the population began to use them as a real natural agricultural fence or as a growth substrate for the development of dye cochineal.

Shortly thereafter, the Indian figs quickly became an invasive species, occupying 260, 000 square kilometers of agricultural land with a real dense jungle up to 6.1 meters high.

Dozens of farmers abandoned their land because of what was said: "the green hell". The dwellings were suppressed by the growth of cacti that advanced at a rate of 1, 000, 000 hectares per year.

In 1919, the Australian federal government established the "Commonwealth Prickly Pear Board" to coordinate the eradication of the Pest Species. The first attempts at mechanical and chemical removal failed; therefore, ultimately, biological control was attempted.

The Cactoblastis cactorum moth was introduced from South America in 1925, whose larvae feed on the prickly pear; in this way, the population of the weed was quickly reduced.

The son of the well-known entomologist Frederick Parkhurst Dodd, Alan Dodd, played the role of elite officer in the battle against the prickly pear cactus.

A memorial hall in Chinchilla, in the state of Queensland, commemorates the moth that saved the Australian lands from the cactus.