The prickly pear cactus was a scourge in outback regions of Australia until the Cactoblastus moth was introduced in 1926 as a biological method to eradicate this introduced plant pest.
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A consignment of 3,000 Cactoblastus moth eggs reproduced and the next generation numbered in excess of two and a half million eggs. These were distributed to selected areas from which eggs were gathered and scattered over an increasing area until about 300 million moth eggs had been successfully translocated. By 1932 most of the infested country had been reduced to soggy masses of decaying yellow pulp and by 1934 the cactus had been brought under control.
This cactus was first introduced into Australia in the early colonial days by the English West India Company who wanted to set up a dye manufacturing industry. Captain Arthur Phillip on his voyage to Australia in 1788, called in at Rio de Janeiro and took aboard prickly pear cactus plants containing colonies of the Cochineal beetles for this purpose. Sadly, the beetles died out before an industry could get off the ground. But, unfortunately the prickly pear cactus went on to become a devastating environmental weed.
The Cochineal beetles, which produce a deep maroon pigment stored in their body fluids and tissues, make the prickly pear cactus their home where they feed off the plant’s moisture and nutrients with their beak-like mouthparts.
The source of this much prized dye had been known from ancient times and was used and revered by the Aztecs before the Spanish Conquest not only for its brilliant colour but also for the fact that it’s one of the few water-soluble colorants to resist fading.
The Spanish introduced the Cochineal beetle with its host to the Canary Islands where a dye industry flourished until the advent of synthetic pigments and dyes in the late nineteenth century which saw the downfall of commercial natural dye production.
Natural plant dyes are favoured today by artists and crafters because they contain many different pigments which create unique colours.
Natural dyes are found in garden plants and include daffodil and dahlia flowers to make red, yellow and orange. Carrots produce orange colourings, spinach turns green and celery a warm yellow. The fruit of blackberries and mulberries turn a deep purple-blue and dried portulaca flowers provide rich red, scarlet and orange tones.
Diary
September 24 & 25: The Central Coast Garden Club will hold its inaugural Daffodil & Flower Fair in the East Ulverstone Football Club rooms Parsons Street, Ulverstone 10-4 Saturday and 10–3 Sunday. Featuring cut flowers, floral art, children’s activities, garden stalls as well as morning and afternoon teas, soup and sandwich lunches. Admission $2, under 16s free.
October 8: The Australian Plant Society will have a spring plant sale 10-4 at the Max Fry Hall, Gorge Road Trevallyn, Launceston.
October 18: The Australian Plant Society meet at the Max Fry Hall on Gorge Rd, Trevallyn, Launceston at 7.30pm.
Guest speaker for the evening is Mark Wapstra who will speak on ‘Tasmania’s grassland orchids: in desperate need of help”.
October 19: The Launceston Horticultural Society meet at the Windmill Hill Hall, High Street, Launceston at 8pm. Visitors most welcome.
Daily: The Emu Valley Rhododendron Garden 55 Breffay Road, Romaine, Burnie is open from 9 to 5.
Enjoy the garden where the vireyas are bursting with colour as are the big leaf rhododendrons.