The Prickly Pear’s history in Australia
In the 19th century there was a decision to introduce the spiked, hardy, and now-very-on-trend cactus, the Prickly Pear (mostly the species Opuntia stricta for those who like their fancy latin names)to Australia to use as natural agricultural fencing (with additional industry benefits we will discuss in a bit). Unfortunately this prickly little fella was pretty darn happy living in Australia and rather than hanging out as a fence line it took over farmlands (40,000 km2) and became an environmental pest. While these guys look awesome out there in the Aussie landscape, they aren’t supposed to be there and were making agricultural land unusable and changing native habitats and ecosystems. Deciding that the whole thing was a bit of a mistake, in 1925 a prickly pear hungry moth was imported from South America and successfully ate it’s way through the population. People were so impressed by this moths efforts they erected a shrine to it in Dalby, Queensland. This cacti species is pretty in Vogue, so if you choose to keep one here in Australia make sure it’s an indoor plant or covered from seed dispersal by birds. The last thing you want is for your pet spikey to be contributing to environmental weed issues.
You may eat and wear bugs.
One of the main reasons why the prickly pear was introduced into Australia was for the prospect of being able to start a dye industry. Cochineal is a prickly pear associated product that is made from the bugs that feed on Opuntia cacti. Until the advent of synthetic dyes in the mid nineteenth century cochineal was the primary source of red (and pink shades) dye . This red dye is created by harvesting the cacti munching bugs, drying them out, and extracting their carminic acid defense system which is utilised to colour textiles and food. It can still be found in both industries but synthetic dyes are preferred for textiles as they are cheaper and easier than harvesting and drying out bugs. However, as it is a natural colourant (and many people prefer natural in their food) it is still used in the food industry even though some folks have allergies to it. The prickly pear also provides nutritional fruit for people to eat and were/are sometimes used for cattle food during droughts in Australia.
Prickly Pear for other dye-stuff uses.
While doing some book related research I was surprised to find that this versatile cacti has other dye industry applications. According to an article in the ‘Journal of the Taiwan Institute of Chemical Engineers’ (which is…of course…. everyone’s fave go-to Sunday read) prickly pear can be used as a cheap and eco friendly biosorption option for man made dyestuffs (Methylene Blue, Eriochrome Black T, and Alizarin S were the ones tested). Investigation, experiments, and lots of mathematical equations show that dried prickly pear absorbs these dyes rapid, specifically for more acidic dyes, and it’s capacity to absorb is temperature dependant (cooler is better than warmer). The researchers suggest that prickly pear can be used as an effective natural biosorbent for the economic treatment of wastewater containing synthetic dyes. A result that is interesting for fashion industry folk who are trying to green their game and reduce water pollution from dye processes.