Victorian researchers have contributed to a worldwide project aiming to improve Australian weed management by engaging new biological control agents.
The second phase of an seven-year AgriFutures Australia project which focused on identifying and releasing biological control agents for weeds has recently closed, with 11 weeds targeted for biological control.
Six of the weed targets now have a biological agent undergoing mass or trial release programs.
Agents include rust fungus agents African boxthorn and flaxleaf fleabane, the weevils cambomba and sagittaria, with the latter mass-reared for releases throughout infested waterways and irrigation channels in Victoria and New South Wales.
Agriculture Victoria research scientist Jacki Steel said local research scientists focused on new biological agents for the weed silverleaf nightshade.
She said they also worked on improving the science around the risk assessment process that biocontrol agents have to go through before being released.
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"There's one particular biological agent that is looking very promising for silverleaf nightshade from the research overseas and there's another one in the back pocket," she said.
"We'd like to make sure before we bring an agent in that it's worth doing some research in Australia, and we do that in our quarantine labs, of course, but some preliminary research with silverleaf nightshade where we checked whether lace bugs would attack or cause damage to potatoes and in eggplants.
"So this research that we did overseas found that it was quite specific in damaging the silverleaf nightshade and we'll now continue testing it in our labs in Australia against a whole range of other plants."
Ms Steel said researchers will consult with industry to make sure they are testing potato cultivars that are "economically valuable".
"They need to be on board with our testing and trust that we have their interest at heart, and that is to control these weeds."
Researchers from CSIRO along with other state agricultural bodies undertook work with colleagues from Iran, Ethiopia, Paraguay and many other countries to identify potential biocontrol agents for importation into Australian quarantine.
Ms Steel said international collaborators were crucial to her research at a local level.
"We use these researchers overseas to help us find populations of weeds and do research to see which insects are being used there as a host," she said.
"Once we've decided which organisms or insects we want to focus on, they'll do some preliminary work to try and bring it up in a lab condition because not all insects can be bred in captivity.
"Then for testing on things like potatoes and eggplants, we can actually provide them with cultivars that are important in Australia, just so they're not testing something that's just important overseas but we make sure that we test things that are important to us."
She also said weed control was important for agricultural production and there have been benefits based on past biological control agent releases.
"For example, skeleton weed has been reduced as a consequence of the release of a biological control agent, and cropping industries have seen a value in not just reduced impacts, but also in reduced control costs," she said.
"Once the research is done, we don't need to spray these things, the insects can be doing the work for us."
AgriFutures Australia project coordinator Alex Ball, said the outcomes of this project will also benefit farmers in livestock sectors.
"Once established, biological control agents will begin to reduce weed impact on sheep and cattle grazing properties, cropping, public lands and irrigation channels improving the productivity, profitability and sustainability of Australian agriculture," Dr Ball said.
"In turn, all Australians will benefit from a more productive agricultural industry, shoring up Australian's international competitive position".
Establishing a biocontrol agent in Australia is lengthy process, with the time from identifying a potential biocontrol agent to its mass-release taking 5-10 years on average after testing and regulatory compliance.
Significant progress has also been made in identifying biological control agents for damaging weeds including Koster's curse, navua sedge, African lovegrass, giant rat's tail grass, and saffron thistle.
