The feature photograph, taken in 1973, shows my grandmother, uncle and a visitor inspecting a prickly pear tree on my grandmother’s property at Rannes, 100 kilometres southwest of Rockhampton, Central Queensland.

This huge pear tree is an ominous reminder of the “green plague” that took over large tracts of agricultural and pastoral land in central and southern Queensland and northern New South Wales between 1900 and 1930.


A story in the making

My husband Tony and I recently took a road trip between Brisbane and outback Queensland, passing through many districts that were densely infested by prickly pear over 100 years ago. Knowing a little of the story of the prickly pear invasion and keen to see examples of the plant up-close, we looked out for it as we travelled. We were not disappointed. We found many plants – large and small – growing along the roadside.


To our surprise, we discovered that there are many species of prickly pear. While Tony learnt the hard way that some plants contain myriads of minute prickles, I photographed the plants, noting their tough skin, torturous spines and beautiful flowers. But more about that later.


This post is the result of what we learnt about prickly pear. But more importantly it’s the story of my grandfather’s battle to eradicate this weed pest, the impact on landowners of the plant’s unprecedented spread throughout central and southern Queensland between 1900 and 1930 and how this invasive plant was eventually brought under control.

NOTE: A list of the references I used in preparing this story is found at the end of this post. References are numbered and displayed throughout the text in brackets [X].

●   ●   ●

What we learnt about prickly pear

Prickly pear is a general term for the numerous species of genus Opuntia, members of the Cactaceae family. The plants are drought-resistant perennial succulents that form low-growing shrubs or tree pears. They flourish in semi-arid warm sub-tropical and temperate climates. The stems are spiny, flattened, leafless and divided into segments called pads. Although the green pads may look like leaves, they are not. The flowers are large, striking and colourful (we saw two types – bright yellow and orange). [1]



During our road trip, we came across several different species of Opuntia. We identified three of the plants we found: Opuntia tomentosa, Opuntia stricta and Opuntia megacantha. There were other species, but we were unable to identify them.


You wouldn’t want to run into or fall onto a prickly pear plant! The pads of some plants have long spines (up to 4 cm in length); the pads of others have clusters of small spines (about 1 cm long).



Fruit are pear-shaped, prickly and (according to those we saw) red to purple. Tony picked the fruit of one of the plants, only to discover they were full of tiny bristles. Ouch! I lost count of the number of prickles I later removed from his fingertips.



Surprisingly, all parts of Opuntia spp. are edible. They may be consumed raw or cooked and are a good source of water. In fact, I’ve found numerous reports of people who have survived in the Australian bush for days, even weeks, eating only prickly pear. Here is one account, but a sorry tale. It dates from January 1923, around the height of Central Queensland’s “green plague” [2]:

Details are now to hand regarding the man Neilsen who was lost for nine days in the Dawson Valley and who subsisted on prickly pear. Neilsen, who is 49 years of age and of Danish nationality, went to Wowan in search of work and decided to make Baralaba or the Castle Creek construction camp. In going across country he became hopelessly lost in the worst patch of prickly pear in the Dawson Valley.

He lost his trousers owing to contact with the pear spines. No matter which way he turned he was confronted with huge masses of pear. He suffered tortures from the spines and his body became one mass of festering wounds. Neilsen’s mind became unhinged and a gash on his throat shows where he tried unavailingly to end his troubles.

Day succeeded day, and night succeeded night, and still he remained imprisoned. He subsisted on pears, which so inflamed his mouth that he was unable to eat anything. He almost lost the power of speech, until finally, on the ninth day the sadly bruised and bleeding mass of humanity staggered into Rannes, where Superintendent Achilles, of the Wowan Ambulance Brigade, gave first aid and conveyed him to the Mount Morgan Hospital. How Neilsen managed to escape, he himself does not know.

The prickly pear invasion

Prickly pear is not native to Australia. The plant is indigenous to North and South America. Captain Arthur Phillip brought plants from the Americas to Australia in 1788, intending to establish a cochineal dye industry in the new colony. Cochineal is a natural crimson red dye (carmine) obtained from the cochineal scale insect (Dactylopius coccus) that feeds on certain species of prickly pear. [3]

Commencing in the 1840s cultivation of prickly pear for the production of cochineal and its use as a hedging plant by some of Queensland’s early European settlers set off arguably one of the most extensive and devastating biological invasions of modern times.


By the end of the nineteenth century, prickly pear infestation had become a huge problem for landowners in central and southern Queensland and parts of northern New South Wales. In fact, by 1900, four million hectares of land was pear-infested. [4]

In 1912 my grandfather, Donald William Beaumont (1884-1958), took up a “prickly pear selection” at Rannes in Central Queensland’s fertile Brigalow Belt. The land was undeveloped and prickly pear was taking hold. Up until this time my grandfather, his father and four of his brothers, based at Westwood (near Rockhampton), ran teams of horses, transporting goods from Rockhampton to stations in the Banana and Clermont areas. Taking up a landholding was a new venture, and a risky one, given that the land was known to be pear-infested. Under his lease agreement my grandfather was obliged to clear the land of the weed pest. [5]


Like his contemporaries, my grandfather tried to eradicate the prickly pear by digging it up, crushing and burning it. These methods, unfortunately, didn’t stop the plant’s spread. The seeds were spread by birds eating the fruit and via cattle manure. Cattle readily ate some species of Opuntia and my grandfather (like so many other graziers) used the moisture-laden pads as cattle fodder during periods of drought.

Biological control of prickly pear (pre-World War I)

In 1912 (the same year my grandfather procured his property) the Queensland Government established the Prickly Pear Travelling Commission. Between 1912 and 1914, it conducted a world survey of the plant’s natural insect enemies. As well, in 1912, the Queensland Government built a research station at Dulacca, on the Darling Downs in southern Queensland. [6] Dr Jean White was appointed as its director. [7]


Early trials (commencing in 1914) focussed on various introduced species of cochineal scale insect (or mealybug) – voracious feeders of prickly pear – and a number of chemical controls (such as chlorine gas and arsenic). Unfortunately the onset of World War I put an end to this work. [8]

Prickly pear continued to spread unabated throughout central and southern Queensland and northern New South Wales. Its impact was heartbreaking for the many landowners affected by the pear’s unrelenting takeover of their land. In 1919, the following report appeared in a Queensland newspaper [9]:

A station inspector who has just returned from a tour through the Upper Burnett and Dawson country, when asked “What about prickly pear?” threw up his hands and said, “Good Lord, don’t speak of it. It makes me ill to think of it.” It has got to be something pretty bad to call for such a remark from a hard-headed inspector. “Look here,” he remarked, “in one place a goanna was on the road, and it had to run about 30 yards [approximately 30 metres] before it could get an opening in the pear to get off the track. You can imagine how thick that pear was. It has spread wholesale, and every time I go out it is worse and worse.”

By 1920, 24 million hectares of land in Queensland and New South Wales was pear-infested. [10]


It’s hard to imagine how distressing it was for landowners (like my grandfather) who battled to keep the weed pest at bay. The struggle must have been so costly in terms of time, money and resources. And the prickly pear problem didn’t go away. It lasted for years, decades.


Biological control of prickly pear (from 1920)

In 1920, the Governments of the Commonwealth, New South Wales and Queensland agreed to work together to find a solution to the prickly pear problem and together they set up the Commonwealth Prickly Pear Board. [11]

In mid-1922 the Commonwealth Prickly Pear Board opened a biological experiment station at Westwood, near Rockhampton, in Central Queensland. Westwood was selected because the district had a plentiful supply of several species of pear and a congenial climate. At Westwood, scientists conducted experiments with moth-borers, bugs and cochineal insects. [12]

The four species of prickly pear most common in Central Queensland were Opuntia ernermis (“cabbage pear”), Opuntia stricta (velvety tree pear, the main pest of the Rockhampton and Burnett districts, also known as “Gayndah pear”), Opuntia tomentosa (velvety tree pear eaten readily by cattle) and Opuntia megacantha (known as “Gracemere pear” or “Westwood pear”, which cattle would not eat). [13]

From the Westwood station, cochineal insects were distributed throughout Central Queensland. My grandfather’s property would have been one of those to benefit from the program, which was conducted between 1924 and 1928, with promising results. [14]

RANNES, Sunday. During the past month the distributor of insects for the Prickly Pear Commission (Mr H Sara) has been, with the distributing plant, busily engaged in the vicinity of this town distributing cochineal insects along the many miles of roads leading to different parts that are infested with prickly pear. Over 50 miles of roads, as well as some private property, have been treated. Over 1000 cases of insect infected leaf have been cut from near the local railway station, where a few leaves of insect infected leaves were planted about two years ago. Several truckloads of cochineal infected leaves were obtained from other parts. … Mr Sara has now gone on to Baralaba where it is expected that a similar heavy programme will have to be worked out to treat all the prickly pear of that centre. [15]



In 1923, the Queensland Government established a Royal Commission to investigate the prickly pear problem. [16] The Commonwealth Prickly Pear Board set up a second experimental field station, at Chinchilla on the Darling Downs. It complemented the main research and quarantine laboratory at Sherwood, on Brisbane’s outskirts. A third field station was set up at Biniguy, near Moree, in New South Wales. [17]


The Cactoblastis moth solution

In 1924, Mr Alan Dodd, entomologist and director of the field station at Chinchilla, travelled to Uruguay and Argentina, where he studied Cactoblastis cactorum, a rather plain-looking grey-brown moth native to South America. The moth’s larvae bore into the stems of the prickly pear and consume the plant tissue, leaving nothing but a rotting outer husk. [18]

In early 1925, 2750 eggs of C. cactorum were imported from Argentina. Within a year the 2750 eggs had multiplied to more than 2.5 million, an increase of 900 fold! The first batches of the moth eggs were released on prickly pear in the Chinchilla district in February and March 1926. The trial was a great success. [19]

The Chinchilla “Bug Farm” (as the locals called it) became the breeding place for the moths and from here the moth eggs were distributed throughout Queensland. [20]


Remarkably, by 1931, five years after release of the first C. cactorum eggs, Queensland’s “green plague” was under control. In 1936, the Queensland Government closed the field station at Chinchilla. Its job was done. [21]



By 1936, my grandparents’ property, like so many others in rural Queensland, was clear of the weed pest.

The district of Kokotungo is situated in the Dawson Valley, 12 miles from Rannes and 16 miles from Baralaba, and it extends as far north as Gainsford. This district embraces some of the most fertile land in Queensland. A few years ago it was not possible to grow anything in this district owing to the enormous growth of prickly pear. The pear has since been almost completely exterminated by the Cactoblastis. So complete has been the eradication that the pear has been turned into fertile soil through the work of the Cactoblastis combined with the innate healing powers of the earth. … [22]

By the mid-1930s my grandparents had a small dairy herd on their property and ran a successful family dairy. The cream was transported by rail to the Wowan butter factory. My grandfather planted grain crops or cotton on some of the land but kept most of it as pasture for raising beef cattle.


A grateful community’s novel tribute

During our recent roadtrip, at Boonarga, about 12 kilometres southeast of Chinchilla beside the Warrego Highway, Tony and I stopped to see what this grateful community built as a tribute to Cactoblastis cactorum.

It’s a general social and meeting hall!

The Cactoblastis Memorial Hall was built for the Boonarga community in 1936 by Mr Jack Schloss. The building commemorates the triumph of the Cactoblastis moth over the prickly pear, which had previously devastated properties in the district. It’s surely the world’s largest public monument to an insect! The Cactoblastis Memorial Hall was added to Queensland’s Heritage Register on 21 September 1993. [23] It is still used today.



A success story worth telling

In Queensland today, all species of Opuntia are prohibited invasive plants except for O. microdasys, O. elata, O. stricta, O. aurantiaca, O. monacantha, O. tomentosa and O. streptacantha species, which are restricted invasive plants. Currently there are eight insects and one mite keeping Queensland’s prickly pear population under control. [24]

Although prickly pear can still be seen along roadsides and on properties in parts of Queensland and New South Wales, nearly 100 years after the height of Queensland’s prickly pear plague, these plants are no longer a serious environmental threat.

The conquest of prickly pear by the moth Cactoblastis cactorum is acknowledged in scientific circles worldwide as an outstanding example of biological control of a weed pest. Indeed, according to Mr Alan Dodd, Director of the Biological Section, Department of Public Lands, Queensland, it was nothing short of a miracle. He summed it up this way: “Cactoblastis has enacted the role of a beneficent Providence and has handed us back a great territory that we or our parents lost through neglect and lack of effort and vision.” [25]

As Mr Dodd told his audience in 1941, this success story is worth telling and re-telling.



Click here for details of references used in preparing this story.


  1. Pricky Pear. Queensland Government. Business Queensland. (Website). Online: Retrieved on October 6, 2019.
  2. Lost in Prickly Pear. (1923, January 16). Warwick Daily News (Qld. : 1919 -1954), p. 2. Retrieved November 2, 2019, from
  3. The Prickly Pear Story (PDF). Queensland Government. Department of Agriculture and Fisheries. (Website). Online: Retrieved on November 1,
  4. Prickly Pear. Queensland Historical Atlas. (Website). Online: Retrieved on October 6, 2019.
  5. Ibid.
  6. Prickly Pear Experimental Station. (1912, July 10). The Brisbane Courier (Qld. : 1864 – 1933), p. 4. Retrieved November 1, 2019, from
  7. Prickly Pear (1912, March 23). Queensland Times (Ipswich, Qld. : 1909 – 1954), p. 3 (DAILY). Retrieved November 1, 2019, from
  8. Prickly Pear. Queensland Historical Atlas. (Website). Online: Retrieved on October 6, 2019.
  9. PRICKLY PEAR SPREADING. (1919, March 15). The Queenslander (Brisbane, Qld. : 1866 – 1939), p. 35. Retrieved November 1, 2019, from
  10. The Prickly Pear Story (PDF). Queensland Government. Department of Agriculture and Fisheries. (Website). Online: Retrieved on November 1,
  11. Dodd, A.P. (1941). The Conquest of Prickly Pear. A Paper read at a meeting of the Historical Society of Queensland, Inc., at Newstead House, on Thursday, February 25th, 1941. Available online as a PDF file at
  12. PRICKLY PEAR. (1922, October 14). Morning Bulletin (Rockhampton, Qld. : 1878 – 1954), p. 11. Retrieved November 1, 2019, from
  13. Ibid.
  14. Dodd, A.P. (1941). The Conquest of Prickly Pear. A Paper read at a meeting of the Historical Society of Queensland, Inc., at Newstead House, on Thursday, February 25th, 1941. Available online as a PDF file at
  15. PRICKLY-PEAR WAR (1926, August 30). The Daily Mail (Brisbane, Qld. : 1903 – 1926), p. 4. Retrieved October 6, 2019, from
  16. PRICKLY PEAR. (1923, March 14). Toowoomba Chronicle and Darling Downs Gazette (Qld. : 1922 – 1933), p. 5. Retrieved November 1, 2019, from
  17. PRICKLY PEAR. (1924, May 24). The Capricornian (Rockhampton, Qld. : 1875 – 1929), p. 56. Retrieved November 1, 2019, from
  18. PEAR PESTS (1924, April 16). The Daily Mail (Brisbane, Qld. : 1903 – 1926), p. 6. Retrieved November 1, 2019, from
  19. Dodd, A.P. (1941). The Conquest of Prickly Pear. A Paper read at a meeting of the Historical Society of Queensland, Inc., at Newstead House, on Thursday, February 25th, 1941. Available online as a PDF file at
  20. Cactoblastis Moth and Prickly Pear. Australian Plants Online. (Website). Online: Retrieved on November 1, 2019.
  21. THE JOB DONE, PRICKLY PEAR FIELD STATION AT CHINCHILLA TO BE CLOSED (1936, November 21). The Telegraph (Brisbane, Qld. : 1872 – 1947), p. 26 (LATE WEEK END FINAL ALL THE NEWS). Retrieved November 1, 2019, from
  22. KOKOTUNGO (1936, September 24). Morning Bulletin (Rockhampton, Qld. : 1878 – 1954), p. 2. Retrieved October 6, 2019, from
  23. Cactoblastis Memorial Hall. Queensland Government. Queensland Heritage Register. (Website). Online: Retrieved on November 1, 2019.
  24. Pricky Pear. Queensland Government. Business Queensland. (Website). Online: Retrieved on October 6, 2019.
  25. Dodd, A.P. (1941). The Conquest of Prickly Pear. A Paper read at a meeting of the Historical Society of Queensland, Inc., at Newstead House, on Thursday, February 25th, 1941. Available online as a PDF file at


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Prickly pear and its nemesis: A plain grey-brown moth via @jsalecich
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8 Comments on Prickly pear and its nemesis: A plain grey-brown moth

  1. I remember one year when I enthusiastically and successfully collected some ripe cactus fruit and made jam out of the fruit. It was a slow process to get into the fruit and scoop out the flesh using heavy gloves. I have never had the urge to repeat the process.

    Growing up on my parents’ farm, I remember my dad talking about the cactus blaster moth as we also had parts of the property infested with the plant but was brought under control with the moth.

    Great research, Judy, loved reading about the history of it all.

    • Dear Sylvia. Thanks for sharing your experience of the prickly pear – its fruit and its presence on your family’s property. Yes, I’ve heard about folk using the fruit to make jam – I’m most impressed. Good on you for trying! Thanks for your encouraging feedback. I certainly learnt a lot as I researched this weed pest. Best wishes, Judy. xx

  2. Judith (Beaumont) I would like to keep in touch. My mother was a Turner in Wowan and I am doing my Geneology and I am sure mum knew Beaumont’s in the 1930’s from what I have found. I am sure I shared messages with you previously.John Hooper.

    • Dear John. Yes, I recall we chatted via messenger and on Facebook about the Banana Shire Council. I recall that you were the Shire Mayor for many years, and are now retired. I also recall that your parents married at the little Anglican Church at Wowan, which I have photographed and researched. I would be most happy to keep in touch. You can contact me via email ( if you like. Kind regards, Judy.

    • Thanks, Chris. I’m glad you enjoyed my version of the prickly pear story – the triumph of a very plain-looking grey-brown moth over the weed pest. Yes, the hall is a great tribute. Best wishes, Judy.

  3. I enjoyed your Prickly Pear blog. The moth was a savior. Also they have found an insect for Harrison cactus but it is a slower Performer. This cactus is now spreading through the Goovigen, Don River flood Plains into the Dixalea area. It grows low in the grass and horses can’t see it.

    • John, I’m so pleased you enjoyed reading my story about the prickly pear. Yes, the moth was the graziers’ saviour. It is not good to hear that the prickly pear is spreading again in parts of the Banana Shire. Kind regards, Judy.

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