An Australian first woody weed bioherbicide developed at UQ

A natural weed control that will help manage one of Australia’s most invasive introduced species became the first woody weed bioherbicide to be granted federal regulatory approval.

Australia’s farmers spend $1.76 billion every year on chemical herbicides to kill weeds on their properties. Unfortunately, this has also helped to drive Australia’s herbicide resistance problem and worse, the chemicals themselves often fail to destroy the seeds of invasive introduced species. Alternative weed management often involves the invasive mechanical clearing of land. There has never been a greater need for natural, ecologically sustainable alternatives to chemical herbicides.

A natural solution

The Di-Bak Parkinsonia fungal bioherbicide was developed at The University of Queensland by plant pathologist Professor Victor Galea and Dr Naomi Diplock. The co-developers used naturally occuring fungi that causes plants to die back to develop the bioherbicide.

Professor Galea and Dr Diplock were exploring the natural causes of dieback in introduced weed species, with a view to harnessing these fungi as a natural management method. Their research led them to a new and effective biological agent that is safe to use, causes minimal harm to the environment and allows sustainable and ethical weed control.

UQ’s commercialisation company UniQuest founded BioHerbicides Australia (BHA) in 2010 and immediately commenced work to develop a registration submission with the Australian Pesticides and Veterinary Medicines Authority (APVMA) to bring the technology to market.

That approval was finally granted in December, 2018 due to the challenges of gaining registration for a product type that had previously not existed, paving the way for its safe use nationwide and an Australian first.

BHA branded the bioherbicide as Di-Bak Parkinsonia after its target species, the invasive introduced parkinsonia prickle bush, which is rife across northern Australia.

Parkinsonia is one of Australia’s most invasive weeds, threatening rangelands, wetlands and natural waterways, as well as plant and animal species, Di-Bak Parkinsonia, which is made into capsules and safely injected into parkinsonia tree trunks, is anticipated to change the way farmers, governments and custodians manage weeds in the landscape.

The path to commercialisation and trial sites

UniQuest filed the initial patent applications in 2009 in Australia and 2010 in the United States.  Shortly after, UniQuest founded start-up company Bioherbicides Australia and licensed the UQ technology developed by Professor Galea and Dr Diplock to BHA. The company then sought regulatory approval to market Di-Bak Parkinsonia from the APVMA, which was finally granted in December 2018.

This delay was due to the innovative nature of the bioherbicide, which uses the targeted application of native Australian fungi and soil pathogens to destroy weeds, rather than complex chemical formulas.

Regulatory approval followed extensive trials of the Australian-first woody weedy bioherbicide, including at the country’s third-largest grazing property, Alexandria Station, in the Northern Territory.  The trial commenced by targeting an isolated infestation of Parkinsonia on two sites at Corporal Dam on the property in 2016.

Almost a quarter of the parkinsonia trees were treated with Di-Bak Parkinsonia with the aid of a prototype mechanical delivery device. The trial was evaluated on four occasions and supported by drone imagery and satellite data analysis.

By October 2019, significant dieback of parkinsonia had been achieved across both sites, with some evidence of tree-to-tree spread.

Di-Bak Parkinsonia was ultimately developed over 15 years and trialled with cattle producers, government departments and natural resource management groups with support from Meat and Livestock Australia.

In 2019, BHA officially launched its “killer capsule” application method of distributing Di-Bak Parkinsonia into woody weeds. The hand-held applicator drills a hole into the tree trunk, inserts the bioherbicide capsule and seals the hole with a plug in a matter of seconds.