This YouTube interview ("Tools for tackling blackleg of canola") features Angela Vanderweil (Research Fellow, University of Melbourne) and Alec McCallum (PhD student, Melbourne Uni) discussing blackleg disease management. They emphasize fungicides as a key control tool but note the risk of fungicide resistance; the team conducts national stubble-based surveillance to detect resistance frequencies and advise growers. Findings reported include moderate-to-high resistance to Group 3 (DMI) fungicides across surveyed paddocks, while Group 7 (SDHI) fungicides remain effective. Management advice stresses three strategies: genetic resistance (grow resistant varieties), cultural practices (rotation, stubble management), and careful fungicide use (rotate/mix groups; spray only when needed). The project is based in Horsham with industry partner Mike Ross Graves Pathology and has GRDC funding for over 20 years.
Questions this video answers
Around 200 paddocks.
Historically up to 95% yield losses; typically around 5–30% when managed properly.
Moderate-to-high resistance detected to Group 3 (DMI) fungicides; Group 7 (SDHI) fungicides remain effective.
Chapters
Fungicides have become an integral part of controlling blackleg disease of canola. And so with that comes the risk of fungicide resistance. So it's really important that we keep on top of that and really know what's going on out there in the field so we can give growers advice.
Blackleg disease is probably the most important disease of canola and can cause significant yield losses. And the use of fungicides is a really important way of minimising those yield losses and controlling disease.
My name is Angela Vanderweil. I'm a research fellow at the University of Melbourne. I lead the project that we do on fungicide resistance and we have a team of people here in Horsham with our industry partner, Mike Ross Graves Pathology.
My name is Alec McCallum. I'm a current PhD student through Melbourne Uni, based here in Horsham. Blackleg disease in the past has caused up to 95% yield losses, but typically it's only around 5 to 30% when managed properly. And, yeah, fungicides are really important in managing that disease. So if we did lose the fungicides to resistance, then there would be significant yield losses.
At GRDC have been funding blackleg research for over 20 years, and we've been very fortunate to keep that work going since then. Blackleg is always going to be an issue for growers. They always are going to have to manage it. It's not a disease we can eradicate, and it's always present at the start of every growing season. And so it's really important for growers to understand the tools that they have to be able to control it. And they do have many tools now. So part of the work we're doing is surveilling for fungicide resistance. So we get stubble sent in from across the country, from agronomists. We can put them through these systems, collect the spores, and we can look at the frequency of fungicide resistance in each of those paddocks and then hopefully give advice to growers to say, hey, you've got a potential problem you might need to which do a different chemistry.
Already I've surveyed around 200 paddocks, the stubble from those paddocks, for fungicide resistance. And we found quite widespread resistance, sort of moderate to high levels, for the Group 3 DMI fungicides. But we're also testing the Group 7 SDHIs, and they've been found to be really effective still.
So for minimising blackleg of canola, there really are three strategies. There's genetic resistance, fungicides and cultural practices. The AFRIN thrive principles are avoid susceptible crop varieties, and that's extremely important for Blackleg. If you grow a resistant variety, going to have a lot less issues. With Blackleg, you want to rotate your crops to reduce your disease carryover. Avoiding last year's stubble is a primary way of controlling Blackleg disease. Non chemical control methods to reduce disease pressure, again minimising the impact of the stubble and only spray when it's necessary. And then if you are spraying, make sure you're rotating and mixing fungicide groups so that you're reducing the impact and potential risk of fungicide resistance. The difference between the DMIS and the SDHIS is generating a lot of disease in there, isn't there? The goal of our research is to be able to give growers confidence to use their fungicides without the risk of fungicide resistance evolving. And if it does evolve, have the ability to then manage that.
