Prickly Pear makes a comeback

prickly-pear-comeback
Photo of Prickly Pear near Roma by Bob Wilson

You don’t have to travel far inland in Queensland to see that Prickly Pear, the invasive scourge of farmland in the early 1900s, is making a comeback. ‘The Pear’ as it is sometimes known by farmers, has started to re-appear, growing and spreading after the floods of 2011 and 2012.

The Opuntia species (a member of the Cactaceae family) was introduced to Australia (by white settlers) in the late 1880s to form hedges and provide fodder for times of drought.

Prickly Pear, a cactus plant from the Americas, thrived in the Australian outback. The combination of cacti and rabbits, another introduced species, took a heavy toll on Australian farmland at the turn of the century. By the 1920s, Prickly Pear was a major problem. After some years of experimentation, authorities introduced a biological control in the form of the Latin American Cactoblastis Moth. The moth lays eggs on the prickly pear and its larvae eat the cactus. This was hailed as one of the world’s most successful examples of biological control (the moth eggs were distributed manually). Within six years all varieties of the prickly pear cactus had disappeared.

Not so circa 2017, with varieties of Prickly Pear re-emerging along roadsides and in paddocks around western Queensland and the southern Downs. When we travel I notice things like this and habitually make notes (usually when I’m a passenger).

In some areas (Goondwindi to Inglewood is particularly bad); the cactus has spread into farmland back from the road. Some plants look unwell, though whether through poisoning or biological controls we don’t know.

At this point it should be noted that the variety known as Tree Pear (photos) has some resistance to Cactoblastis, though it can succumb to a cochineal insect. The Southern Downs Regional Council recommends the application of herbicides.

In the interests of moistening a dry subject, let me digress and mention two folk bands that enshrined the Prickly Pear legend into folklore.

Toowoomba musicians John and Sandy Whybird formed Cactoblastis Bush Band when John, then a high school teacher at Chinchilla, saw what Prickly Pear could do to the land. He taught students about the pest and the late 1920s solution to the invasive species.

The band, which recently recorded a CD, performed at the Chinchilla Museum last September to commemorate the 90th anniversary of the introduction of Cactoblastis to the area.

A Brisbane folk duo (Jan Davis and the late Tony Miles), adopted the clever stage name Prickly Pair. They played together for eight years in the late 1980s and early 1990s.

My research led me to the Urban Dictionary, which defines Prickly Pair as slang for the stubble growing back on a man’s testicles after shaving (for an operation or whatever).

Anyway, the Common Pest Pear is back and local farmers ought to know that notification of infestation is required under the Biosecurity Act 2014. No-one expects a problem of the scale which caused farmers to walk off their land after ‘The Pear’ and rabbits finished off what floods and drought had missed. There’s a plaque alongside the Moonie River at Nindigully that commemorates the success of the Cactoblastis moth, when the use of poisons and cochineal insects proved to be ineffective.

Early settlers, in their wisdom, decided to set up a cochineal industry to provide dye for clothing. The cochineal is a scale insect from which the natural dye is extracted. The insects are found on the pads of prickly pear cacti then brushed off and dried.

The Pear is commonly spread by birds and animals eating the fruit and excreting seeds. However, the new spread of Prickly Pear has been accelerated by floods moving broken cacti pads from one location to another.

The State Government’s Business Queensland website describes the Pear as “vigorous in hot, dry conditions, causing other plants to lose vigour or die. It competes and invades pastures and impedes stock movement and mustering.”

Authorities took the rampaging cacti seriously and began investigating biological control agents in 1912. More than 150 insect species were studied, with 18 insects and one mite released in Queensland.

Today, eight insects, including Cactoblastis cactorum remain established in Queensland. An article by Leonie Seabrook and Clive McAlpine in the Queensland Historical Atlas describes Prickly Pear in Queensland as a generic term for five different Opuntia cacti.  Three are low-growing shrubs up to 1.5 metres high and two are tree pears, growing up to three metres. The article observes that at the height of the infestation in 1925, prickly pear had spread across 24 million hectares in Queensland and New South Wales.

While the (imported) Cactoblastis Moth was hailed as a biological saviour, early settlers must shoulder the blame for importing invasive species and pests into Australia. Apart from prickly pear and many other weed species, settlers also introduced cane toads, rabbits and feral goats, pigs, cats, brumbies, foxes and camels.

Prickly Pear observations aside, we had four lovely days hiking in Carnarvon Gorge where the weather was balmy. It did rain on the last day but I went for a walk anyway. It’s only rain, as they say in NZ.

As you’ll have gathered, we just spent 10 days towing our little caravan out to Carnarvon Gorge via Rolleston and back via Injune, Roma, St George, Nindigully, Goondiwindi and Warwick. Today we headed home, via Toowoomba and Esk.

Other on-road observations included a lot of road kill, a feral cat, a lone kangaroo out in the middle of the day, a couple of pelicans in a dam, two emus foraging in the long grass, an abandoned car that had been pillaged for parts and a bloke on a recumbent bicycle (the rider lying down and pedalling in a reclining position). We saw two vans smaller than our 12-footer and a massive RV being towed by a 4×4 (with a small car being towed behind that).

We had the usual (and unusual) mishaps common to most caravan expeditions. Like trying to move the car when it was still shackled to the caravan by metal chains (good one, Bob). I bought one of those stainless steel coffee percolators you brew on the stove. First cup I poured tasted a little soapy. As I sipped further down the cup it transpired someone had left a spoonful of congealed dishwashing liquid in the bottom of the cup. (Guess who usually does the dishes? Ed.)

A highlight of the trip was the free camp at Nindigully, where about 50 caravanners were camped beside the Moonie River. A goodly number of them gathered in the pub to watch the State of Origin decider. Many people left at half-time (we assume they were NSW supporters or maybe they were just cold). The ones who remained were in good spirits, taking their crushing defeat like good sports. As we headed back to the van in the dark we heard a chorus of cheering and the war cry ‘Queenslander!’ from the pub.

How do you reckon NSW will go next year?” I asked She Who Spilt A Pot of Pepper In the Van But Didn’t Want It Mentioned.

“I reckon they’re cactus,” she said, chortling quietly under her maroon beanie.

Online subscribers might have noticed we did not file a FOMM last week. That’s because we were out bush and offline. I did post a 2014 column to email subscribers. You can read it here:

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