A bioherbicide trial in the Kimberley is showing how pastoralists can eradicate invasive weeds and still be certified organic.

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Bioherbicides are biologically-based control agents for weeds, which usually have fewer, or much milder, effects on the environment than chemical herbicides.

Researchers at the University of Queensland have developed a fungi based bioherbicide which kills Parkinsonia — an invasive weed that occupies vast tracts of pastoral land in northern Australia.

The work is being trialled at cattle stations near Fitzroy Crossing by Bioherbicides Australia, which is due to soon bring a licensed product to market in Australia.

John Szymanski, from the West Kimberley Rubbervine Eradication Project, has checked on the infected plants and the results were encouraging.

"One particular plot, in six months, all of the Parkinsonia was just decimated," he said.

"There was a thicket of about 40 plants. We only inoculated about 10 of those plants with this fungus.

"It's killed those trees but it's also spread to the others and decimated the whole lot.

"That's the beauty of this approach; you don't have to treat every tree.

"It'll kill the tree, but invade other tress and knock off seedlings and juveniles.

"It's a much lower intense treatment with the potential of 100 per cent success."

Inoculating Parkinsonia is a simple process: A single gelatine capsule is inserted into a hole drilled into the trunk of the weed and the fungi is left to do the rest.

A healthy Parkinsonia thicket. The woody weed has spread across northern Australia, occupying vast tracts of pastoral land. ( John Szymanski. )

Mr Szymanski said the bioherbicide might not be as fast acting as chemicals, but there were other advantages.

"The problem with that (chemical herbicides) is you may have to come back and retreat because it may not have killed the plant in one dose," he said.

"This can take between six and 18 months to two years for a plant to die, but we've seen large numbers of trees die after six months.

"There's no need to do a chemicals course or have licences to apply chemicals. The occupational health and safety issues are just far less."

Parkinsonia has spread across Queensland, the Northern Territory and the north of Western Australia.

According to the University of Queensland, it costs the Australian agriculture industry $60 million a year in chemicals to control.

But it is not one of the 10 species being targeted by new weed eradication funding announced by Acting Prime Minister Barnaby Joyce yesterday.

The Federal Government is giving a $6.2 million grant to the Rural Industries Research and Development Corporation to develop new biocontrol solutions for invasive weeds such as giant rat's tail grass, prickly acacia, mother-of-millions.

Mr Szymanski said bioherbicides would allow pastoralists to move away from using chemical herbicides and be certified organic.

"With chemicals we're just not going to get there. There's too much work," he said.

"But if we can provide a method that is a lot easier, less work and gets a total solution then I think pastoralists will use it."