Recent rain in Queensland has created ideal conditions for the devastating parthenium weed to germinate, but there is some confusion over who is responsible for its management, what is being done to control it, and what it looks like.
After Queensland Country Life contacted multiple councils, agriculture departments, landcare groups, spray contractors, farmers and concerned residents, it became clear there was some confusion surrounding the weed, which costs Australia's beef industry $16.5 million per year and cropping industries several million dollars per year.
In Queensland, parthenium management is the responsibility of the landholder until it reaches roadsides and other public land, which then makes it a council issue.
However, several councils couldn't provide timely information on recent sightings or programs to control the specific weed.
Parthenium weed (parthenium hysterophorus) originates from parts of North and South America and was first discovered in Queensland in 1955 - thought to be introduced via contaminated machinery during World War Two.
It has since spread through central and southern Queensland and NSW where it is now well established.
This month, QCL received unconfirmed reports of the weed around Oakey, Glengallan and Freestone.
Parthenium can be confused with annual ragweed, perennial ragweed, burr ragweed and lacy ragweed when in the vegetative stage. However, parthenium can be distinguished from all these species by its ribbed stems and white flower-heads.
The fleabanes are also reasonably similar, but do not have highly dissected leaves or ribbed stems.
Also, it is not to be confused with tanacetum parthenium, known as feverfew, which is grown as an ornamental or for medicinal purposes. While some consider it a weed, there are several nurseries and florists in Queensland advertising the plant for sale.
Southern Queensland Landscapes knowledge and information support officer Holly Hosie said parthenium weed could often be confused with bishop's weed or hemlock.
Nevertheless, Ms Hosie said landholders should be diligent and report anything they're not sure about to either the local council or Biosecurity Queensland.
"Parthenium is a category three restricted invasive plant under the Biosecurity Act 2014 and everyone has a general biosecurity obligation to take all reasonable and practical measures to minimise the biosecurity risk associated with dealing with parthenium," she said.
"Following on from good rainfall and favourable conditions we are seeing an impact to primary producers right throughout the region from weeds; including increased time and investment in spraying, slashing and or mechanical control methods."
Brad and Kerryn Piggott at Christmas Creek Cattle Company, south of Rolleston, know all about parthenium.
They say they've battled it since the late 1970s when oil and gas companies may have spread it while exploring the region.
While they've had it under control in the past, the recent rain has led to an infestation.
"Because we have been so dry for so long, and now we've had a wet winter, the parthenium has really taken off again," Ms Piggott said.
"Where we've had buffelgrass dieback and the ground is bare and we haven't had a chance to plant legumes, it has just exploded."
The pair have been working with DAF biosecurity experts and Central Highlands Regional Council rangers on integrated pest management, using the parthenium beetle, stem galling insects and a rust pathogen.
But since the drought reduced population numbers, they resorted to herbicides this year, spraying about 1000ha with metsulfuron-methyl.
"It's a poisonous, expensive habit. We're not organic, but we like to use pest management and biological controls," Ms Piggott said.
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IN THE NEWS:
Brandon Long
Brandon Long is a Queensland Country Life journalist based in Toowoomba.
Brandon Long is a Queensland Country Life journalist based in Toowoomba.
