A natural weed control that claims it will change the way Australia manages woody weeds in the landscape is now on the market after being granted federal regulatory approval following an eight-year wait.
The Di Bak Parkinsonia fungal herbicide, developed by University of Queensland plant pathologist Professor Victor Galea and Dr Naomi Diplock, is the first woody weed bioherbicide in Australia to be granted such approval.
In addition, the applicator developed to deliver the biocontrol agent is being trialled for chemical applications and is vastly reducing current labour costs.
According to Peter Riikonen, the managing director of Bioherbidices Australia, formed by UQ’s Uniquest commercialisation company in 2010, the product received Australian Pesticides and Veterinary Medicines Authority approval last month, which paved the way for the product to be used safely nationwide.
He said current attempts to contain the tropical American plant, which is so problematic that it’s been listed as a Weed of National Significance in Australia, included invasive mechanical clearing of land or potentially harmful chemical sprays, which gave the fungal bioherbicide much potential.
The agent can be injected into the trunk of the parkinsonia tree and cause it to die without damaging the surrounding environment.
Vic Galea said it had taken 10 years of research, development and approval to get to the stage where Di Bak Parkinsonia was commercially available, largely because the APVMA had never regulated a bioherbicide before.
“It was a challenge – they worked hand-in-hand with us to adapt their processes. They had to create hurdles for us to jump over,” he said.
While the registration is for parkinsonia control, UQ is working on biocontrol agents for a range of woody weeds, prickly acacia, mesquite, Chinee apple, and bellyache bush among them, using the same principles.
“We have an extensive range of fungi, which we screen, and adjust the blend,” Mr Galea said. “The idea is to have a range of products available eventually.”
For those battling prickly acacia, he said more trials on a possible agent would have to be conducted, which meant it was still four to five years off commercial release.
He expected APVMA approvals to be quicker in future, thanks to having jumped through the initial hoops, but said they would still have to prove each worked well.
The company, which is based at the UQ Gatton campus where manufacturing and dispatch takes place, has also invented a device that injects the capsules into the tree trunks, which it sells.
It drills a hole and pushes the capsule in, sealing it with a wooden plug in a five second process.
The fungi then uses the tree’s moisture to germinate.
“You could use a cordless drill with an 8mm bit and a hammer – you can be high tech or low tech,” Mr Galea said.
He added that chemical herbicides still had a place in weed control but that bioherbicides gave more options, especially in high density stands of trees where basal bark spraying was impossible.
“We innoculate some trees, starting at the periphery, and it works its way inward. It’s like throwing the match in,” he said.
In the way of scientific experimentation, they have also used the process with chemical herbicides in the capsules to target species they haven’t developed a bioagent for yet, and have recorded “interesting” results.
“Glyphosate works well – we can kill a tree with less than a tenth of a conventional dose, there’s no carrier backpack, no mixing of anything, and it’s very convenient.
“It doesn’t leak out of the plant onto the ground; there’s no overspray either.
“The forestry industry is looking at using it for thinning in plantations and in trials so far we think it can halve labour costs.”
Parkinsonia is one of Australia’s most invasive weeds, threatening rangelands, wetlands and natural waterways as well as native plants and animal species, but Mr Galea said the bioherbicide would change the way woody weeds were managed in our landscape.
Related: Graziers gunning for parkinsonia