GRDC Update 2026: Steve Marcroft on maintaining canola production without boosting disease-related losses

Maintaining canola production without increasing disease-related yield losses was the hot topic presentation from a visiting Victorian canola pathology researcher at WA’s biggest grain conference. The research, conducted by Australian Canola Pathology Program co-ordinator Steve Marcroft was presented to WA grain growers at the 2026 Grains Research and Development Corporation Update at Optus Stadium earlier this month. Speaking to a packed conference room, Mr Marcroft said data compiled from more than 50 paddocks in WA — and about 100 paddocks interstate — would contribute to the UCI BlacklegCM app that assists growers decisions for canola blackleg upper canopy infections. “The aim of this project is to try and bring the whole thing together — we’re looking at the genetics, we’re looking at how much disease is there,” he said. “We’re looking at the phrenology of the crop, the date of the first flower etcetera, and all the regional effects. “We’ve got weather stations everywhere, and we’ve got sprayed and unsprayed strips to look at what the yields are — and all of that data is going to be used to develop the UCI (BlacklegCM) app.” Blackleg is the most serious disease Australia canola crops face, typically causing 5 to 30 per cent yield loss for growers — previous epidemics of the it have caused up to 95 per cent yield losses. A stubble-borne disease, blackleg spores are released from stubble during rainfall events before landing on canola plants and causing lesions and crop sickness. “It survive on canola stubble and then each winter — when the weather conditions are correct it throws out blackleg spores . . . and we’re talking billions and trillions of spores,” Mr Marcroft said. “The first thing you want to know in blackleg stubble-borne disease . . . it’s not like an oblique disease like a rust when it needs to build up and then come in each season — it’s there in a high proportion every single year. “Every single one of these wind-blown spores are all genetically different, so the genetic or the evolution potential of the disease is really high.” Mr Marcroft said the collection and screening of canola samples from agronomists and growers would assist in the measuring of quantitative resistance of the crop disease. “When you put a fungicide on you can see you get pretty much complete control, but you get the same level of control by just delaying your flowering.” “There’s a real opportunity here to use good resistance and a reasonable flowering date, and we can pretty much control up a canopy without the need for fungicides.” Mr Marcroft said WA growers would be choosing cultivars based on disease management issues — not on high yield. “If we do this, maybe we’ll get away with it to some degree, maybe we won’t,” he said.