Canola Allies: Recruiting Insects For Natural Pest Control
18 August 2026, AU: The national Canola Allies project aims to attract and retain beneficial insects in canola crops early in the season so they can build resident populations that naturally suppress pest insects.
Early findings from the national Canola Allies project show that beneficial insects – those that attack pest insects and mites – are generally present in paddocks year-round.
But they’re often present in low numbers, or just “visiting”, says CSIRO’s Dr Sarina Macfadyen, who leads the 5-year Canola Allies project as part of GRDC’s investment in pest management.
The project includes several research streams in collaboration with the Western Australian Department of Primary Industries and Regional Development (WA DPIRD), NSW Department of Primary Industries and Regional Development (NSW DPIRD), South Australian Research and Development Institute (SARDI) and Murdoch University.
Identifying communities of beneficial insects across different parts of the country and quantifying the economic value they provide to growers through pest control are both part of the project.
Identifying beneficial communities
“This is the first project to monitor beneficials across Australia’s grain-growing regions in a consistent way,” Dr Macfadyen says.
We’re using a range of monitoring tools, such as pitfall traps, sweep nets, sticky traps and funnel traps, to build a clear picture of what the beneficial insect community in a canola field looks like.
There are 5 sentinel monitoring sites: 2 in New South Wales, 1 in South Australia and 2 in Western Australia.
“One key finding is that there are lots of beneficials out there. They are always around in your field. It’s just sometimes they’re in low numbers and they’re hard to see. We’ve been surprised by how many beneficials we find, even very early in the season,” Dr Macfadyen says.
Early-season chemical impacts
Field trials in 2024 and 2025 tested the impacts of seed dressings and early-season insecticide use on populations of beneficial and pest insects compared with untreated crops. Dr Macfadyen says the treatments had less impact on insect populations (both pests and beneficials) than expected.
She speculates this could be because newer generations of chemistry are less harmful to non-target species. However, it could also indicate emerging resistance issues in pest species. Further trials over the next 2 years are expected to help clarify these findings.
“What we have seen in trials are subtle differences. In the sprayed areas, for instance, there was slightly lower recruitment of juvenile beneficials than in untreated parts of the field.
Ideally, we want beneficials coming into the field, laying eggs or larvae or parasitising aphids, and then staying within that field for multiple generations.
“They stay in the paddock over winter in low numbers and then in spring, they’re ready to go when the weather warms and pest populations begin to take off. Many species of beneficials are already present in the paddock or surrounding landscape early in the season, but sometimes their population growth is delayed; numbers don’t increase as quickly as we expect. We’re still trying to understand the environmental and regional factors, such as a dry start to the season, that influence this.”
Financial impacts
In South Australia, Maryam Ehsangar at SARDI is leading trials to assess the economic value of beneficial insects that are already present in paddocks. As more growers consider purchasing beneficial insects from breeders to release into their crops, understanding the services already being provided by naturally occurring beneficial populations will help them weigh up the costs and benefits of doing so.
Large gazebo-like cages are established within canola crops to either exclude or allow access to naturally occurring beneficial insects, including parasitoid wasps. By comparing pest population development between exclusion cages and open-access cages, researchers can assess the extent to which these beneficial species contribute to natural pest suppression under field conditions.
The cage studies focus on early-season pests such as green peach aphid, with controlled aphid infestations introduced into the cages at crop establishment to create consistent pest pressure.
Regular monitoring of aphid abundance, parasitism levels, beneficial insect activity and crop condition is then conducted throughout the season.
Measurements are taken to determine how quickly beneficial insects respond to pest outbreaks, how effectively they suppress pest populations, and whether their activity varies between regions, seasons and crop growth stages.
Data generated from the trials will be used to develop a biocontrol indicator, which aims to quantify the contribution and economic value of beneficial insect activity in canola systems.
The indicator combines measurements of pest suppression, parasitism and crop protection outcomes into a framework that can help estimate the contribution of natural biological control within paddocks.
In the longer term, this work aims to support more informed pest management decisions and help identify situations where beneficial insects may reduce the need for insecticide applications.
At several trial sites in 2025, beneficial insect populations became active later than expected in canola crops, limiting the ability of the cage studies to fully capture early-season biological control effects. As a result, the trials are being repeated in 2026 to validate the approach under a wider range of seasonal conditions.
The right time for parasitoids
Trials in NSW are also evaluating the effectiveness of released beneficials, modelling the timing of releases to optimise biocontrol of pests. The modelling will be used to develop a decision-support tool for growers.
CSIRO researcher Dr Jessa Thurman coordinated trials in 2025 targeting green peach aphid. She says pesticide resistance is increasing among aphid species, particularly the green peach aphid, which directly damages canola plants and is also a vector for disease. Parasitoid wasps may help suppress aphid populations and reduce reliance on insecticides as part of an integrated pest management approach. Her trials involved 10 canola crops on farms across the Tamworth region, with paired parasitoid wasp release and no-release sites on each property.
Camera traps identified that wasps emerged from the commercially supplied parasitised aphids 6 to 9 days after they were distributed, rather than the 1 to 2 days previously thought. This new information will help to refine the timing of releases and when growers can expect to see impacts.
Refuge vegetation
Higher levels of non-crop habitat around paddocks significantly increased parasitism levels within crops, suggesting that refuge habitats support natural populations of parasitoid wasps. Fields with fewer refuge habitats showed a greater response to the release of commercially supplied parasitoids.
Dr Thurman says released parasitoids should be viewed as an inoculation strategy for crops. “They add to the existing wasp population but are not what controls aphids immediately. The wasp population must be built up over time.”
She notes that most of the 10 trial sites had significant refuge vegetation within 1 km of the crops. Further research is needed to test the impact of parasitoid releases in more intensive agricultural landscapes, where fewer wasps are moving in from refuge habitats.
Dr Macfadyen says NSW is also leading research to understand whether the number of flowering resources, particularly in autumn, influences the abundance of beneficials at a landscape scale and their recruitment into canola crops.
“There’s a huge range of species in ag landscapes. And detailed laboratory studies have shown that particular flowering types can increase the fecundity and longevity of certain beneficial species,” she says.
“We know that flowers can extend the length of time adults remain active within a crop, but we don’t have data on whether they lay eggs there or how long they stay overall. We also know that beneficials are present in pasture, native vegetation and roadside verges.
“Essentially, we want canola fields to become nurseries for beneficials. We want the canola field to be the most attractive place in the whole landscape, apart from perhaps another flowering crop. And then we need to make sure they are eating pest species.”
Attractants and prey preferences
These are 2 aspects being explored by Associate Professor Wei Xu and his team at Murdoch University. While the research is at an early stage, the longer-term vision is to develop attractants that will draw beneficial insects into crops and encourage them to remain longer, increasing the likelihood they will forage for pest species while pest numbers are still low.
Early exploratory work on attractants for beneficial insects has already identified several plant volatiles that will be trialled this year.
In parallel, other research is exploring whether beneficial insects can be “trained” to recognise canola crops as habitats containing preferred prey species.
Murdoch University PhD candidate Ali Zahid is investigating whether spotted ladybirds can be conditioned to more effectively target specific pests, including diamondback moth caterpillars, green peach aphid and cabbage aphid.
Mr Zahid says the diets of ladybirds raised for commercial release may influence how effective they are in the field. In his laboratory trial in 2025, ladybirds responded more quickly to prey they had previously been exposed to. He is continuing to research how long ladybirds need to ‘learn’ prey preferences, and whether this learning can be transferred through generations.
Preventive strategy
Dr Macfadyen says all these research streams contribute to a layered approach to biological pest control, encouraging beneficial insects to suppress pest populations and keep them low for as long as possible.
“You end up with a slower growth of pest populations because there’s something helping keep them in check. I think it also gives growers a bit of breathing room to understand really what is happening with the health of the crop, instead of having massive pest outbreaks that seem to appear overnight.
“That’s where we think beneficials can provide value – keeping pest populations low for as long as possible and hopefully getting to the end of the season, potentially without having to spray at all.
“Once you have a major pest outbreak and numbers are above threshold, beneficials probably won’t make much difference, and that’s where pesticides still have a role.”
The Canola Allies project will conduct trials for another 2 years, wrapping up in 2028.
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