It has been likened to a "fire front" that spreads five to 10 kilometres every year. But now there have been reports harrisia cactus has been found as far south as Narrabri and farmers want to the NSW Government to step up to control the weed that has a barb-like spear.
NSW Farmers' have called on the State Government to fund a concerted effort to control harrisia cactus in NSW, including biological options, and work with the Queensland Government to stop cross border re infestation.
Richard Clark, a NSW Farmers' Croppa Creek/North Star branch delegate and the director of North West Local Land Services (LLS), said North West LLS had made harrisia control a high priority but it did not have enough funds to control the infestation or even keep up with re-infestation coming over the border.
He said harrisia was now reported in Northern Tablelands LLS, Central West LLS and in Western LLS.
Mr Clark said the only biological control was the mealy-bug that required wet summers and was not persisting south of central Queensland. Mealy-bugs are soft-bodied, wingless insects that bury into the fruit segments to feed on the cactus to kill it. "This is a biosecurity issue which, while not being ignored, is being neglected because the problem is so big no one land manager can be effective," he said.
Matt and Lucy Godlee from Urawilkie on the NSW side of Goondiwindi have spent $440,000 in 15 years using chemicals such Grazon Extra to control the weed. In the last financial year alone they spent $21,000.
"We have tried to slash it and put sheep on it, which holds it back for a while but it doesn't kill it, it's like a fire front. It has reduced our carrying capacity by 15 per cent and every year we lose two or three livestock who get injured by the barbs," Mr Godlee said. Mr Godlee said each fruit contains around 800 seeds with an average plant producing 40,000 seeds a year, which were spread by birds, kangaroos and vehicles.
North West Local Land Services regional weed coordinator Pete Dawson, who heads up the harrisia cactus task-force, said it was working land owners and other organisations across NSW and southern Queensland to look at management strategies. Mr Dawson said these included coordinated chemical control works and focusing on identifying what's happening with mealy-bug populations.
"This bug is biological control agent, which has been around for about 20 years, proving in-effective on harrisia cactus in southern Queensland and north west NSW," he said.
"We are looking at research to determine what impact is being made by the mealy-bug and whether there is a need to fund additional research on new biological agents into the future."