DCQ pest management co-ordinator Brett Carlsson said: "While all of the Cylindropuntia species treated in the project had a rapid rate of spread, major success in the fight against the Class-2 pests has occurred.

"We have made major in-roads to some large infestations in the region, and we've also picked up several previously unknown infestations, as well as some unknown species," he said.

"We've increased awareness of cactus species across the region and have reduced the potential for spread by containing and controlling outbreaks."

Another success for the project has been the treatment of the weed on the Longreach town common by Longreach Regional Council officers.

Local laws team leader Matt Werner said the weed had made most of the land unusable.

"The cactus has been so thick along the creek lines and floodplains that drovers have had to use alternative stock routes, which puts pressure on grazing land," he said.

"We've cut tracks through a 3.5km² area with dozers, which has not only granted accessibility for drovers and their stock, but has segregated areas so we can treat them one at a time.

"We do this by foot or on motorbikes with triclopyr (the chemical) and diesel. The diesel is a binding agent and gives the chemical a chance to poison the cactus," Mr Werner said.

"Overall we have treated 90 per cent of the town common, 100 per cent of the floodplains have been treated, and because of the resilient nature of this weed, we will continue to do this every couple of months."

Mr Werner said he'd seen cactus growing 1m high in tall trees and had heard of cactus growing on a meat hook outside a shed.

"I've even known a segment to be placed into a plastic bottle and to have grown without water inside the bottle for over 12 months," he said.

Mr Carlsson said while the project offered financial assistance to land holders to further work in controlling infestations, it had also implemented an awareness campaign on the emerging threat of these weeds.

"The project contributes to the long-term control of these species - they can be stopped but it will take a long-term effort from all stakeholders to beat it," he said.

The cactus eradication effort is a component of the DCQ Eradication and Prevention project, a project which received funding of more than $410,000 under Biosecurity Queensland's Reclaim the Bush: A Pest Offensive, a program under the Blueprint for the Bush initiative.

HISTORY NOTE

An earlier, successful eradication of a cactus invasion stands out in our history books - and several memorials have even been built to the event.

There's a display at the Powerhouse Museum in Sydney, which gives the history:

"The prickly pear, an attractive flowering cactus with a delicious pear shaped fruit, was brought to Australian gardens from South America in the 1830s.

"It grew quickly and farmers used it to form very effective hedges to fence farmland. Unfortunately it also resisted drought and had no predators, so it spread very quickly.

"By 1900 the prickly pear covered most of Queensland's best grazing land.

"In 1920 the Commonwealth Prickly Pear Board was formed to get rid of the cactus pest.

"Scientists were sent to the USA, Mexico and Argentina to find an insect that ate it in its native environment.

"They chose a moth called Cactoblastis cactorum, whose caterpillar eats prickly pears, and released it in Australia in 1926.

"Within 10 years, the caterpillars had cleared 11 million hectares of prickly pear." (See picture).