Rangelands NRM Blog, News & Resources

Early action needed to prevent spiny cactus spread

Rangelands NRM is advising that early identification and control of weedy cactus species are essential if they are to be prevented from spreading further in WA’s outback areas.

Rangelands NRM’s Geraldton-based Regional Landcare Facilitator, Paul Erkelenz, said the group of spiny weeds has already established some strongholds in parts of the Northern Goldfields and pose a threat to agriculture and the natural environment.

“Weedy species of cactus can out-compete native plants and injure both livestock and native animals with their spines,” Mr Erkelenz said.

“They are most likely to spread and proliferate along the edges of water courses and in flood out areas which, unsurprisingly, are often also the most important areas for biodiversity and pastoral grazing enterprise productivity.”

Mr Erkelenz warned there are large parts of our southern rangelands that could be seriously impacted by cactus but where early action by pastoral land managers and other community members can halt its spread.

Various species of cactus have been introduced to Australia since the days of the First Fleet, mostly as garden plants but, curiously, also in the hope of establishing a dye industry, using the cochineal insects which infested the plants.

Common species of weedy cactus in WA’s rangelands include coral cactus, Hudson’s pear and prickly pear. There are no species of cactus that are native to Australia.

“Because of their ability to survive in harsh, arid environments, they were a popular ornamental to grown in gardens in many outback settlements, particularly mining towns and station homesteads”, Mr. Erkelenz said.

“It’s from these old plantings, often after the town or homestead has been abandoned, where most of the problem infestations have spread”.

Mr. Erkelenz said the early identification and control of small outbreaks of weedy cactus should prevent it becoming an issue in areas where it is not already well established.

“Firstly, it is important that all land managers are very aware of where outbreaks of weedy species of cactus are present on their properties”, he said.

“Make sure you mark down the locations on your property map, and/or log it into your GPS device. As much as it is possible, try also to find out what’s present on adjoining parcels of land, particularly if you’re down stream of an old town or homestead”.

“Secondly, make an effort to treat small outbreaks of weedy cactus, using mechanical means such as digging out and burning, or a herbicide registered for that purpose”, Mr. Erkelenz said.

“Again, give priority to controlling outbreaks on or near watercourses and floodplains. Be prepared to retreat some outbreaks one to two times; the plants can be quite hard to kill.”

Further information on weedy species of cactus and their control can be found on the Australian Invasive Cacti Network website or the DAFWA website.

Image: Prickly Pear (Opunia stricta) one of the spiny cactus species (©DAFWA)