Net blotch resistance in the South of the WA grainbelt is now less of a mystery – thanks to 330 samples sent in by 173 farmers during the 2019 season, CCDM researchers were able to carry out genetic and phenotypic tests (2256 lab tests in total!) that really showed us what was going on out there.
In a Crop Disease Podcast, CCDM Director Mark Gibberd joins Megan Jones as they discuss the results from the Barley Disease Cohort Project, where about 15 per cent of samples carried the mutation associated with fungicide resistance – CYP51A F489L – which were widespread throughout the grainbelt. 173 WA farmers sent in 330 barley samples for testing by the CCDM research team.
“On top of this result, in the phenotypic test, which looks at fungal growth in response to different concentrations of some DMI fungicides, we found only 21 of the samples were sensitive to the fungicides,” Mark said.
“A very large 161 were categorised as reduced sensitivity and 28 of the samples were categorised as fungicide resistant, so the dominant situation was either reduced sensitivity or fungicide resistant. This is a major concern for us as it shows that the reduced efficacy of some DMIs is now widespread.”
“As part of this project we want to be able to provide advice based on solid empirical evidence on how to approach fungicide resistance in the field and if you, as a farmer, are going to make adjustments to your program then what’s the economic value in doing that?”
Grass Patch farmer Dan Sanderson sent in a few barley leaves in September last year, and received a negative result for the mutation. In the podcast he talks about how he plans to manage disease going forward.
“It’s going to be a fairly low input year as we lost a lot of money last year. We won’t be proactive on disease control, we’ll be using cost effective measures,” Dan said.
“We’ve already had some summer rains, we’ve already got some subsoil moisture, and if it is looking like a good season we will monitor the crops and control the fungal diseases in the crops as we get them.
“I think over the last four or five years, growers in my region have become more aware of the problem, and that it is something we need to manage in the future.”
Chris Robinson, a Farmanco agronomist based in Kojonup, also joins the show with his take on the results and what his clients will do differently this season, including the application of an SDHI fungicide to the program if needed.
“I thought we would have had more mutations picked up, but it was good to see how much of the area where the mutation gene is and it has given us a better understanding to help us make better management decisions for this season coming,” Chris said.
“With barley becoming a strong part of the rotation and we push the boundaries on how often we are growing it year in year out, as well as our consistent use of the cheap triazole chemicals, I thought there would be a bit more of the mutation around as we haven’t really extended into the use of the other chemical groups.”
According to Mark Gibberd the results of this project have proven invaluable for dissecting further the genetic basis of what we’re seeing in terms of reduced sensitivity or fungicide resistance.
“This is not only a project where we are working to help growers and agronomists in WA’s south but the information we are collecting is such a valuable resource for our researchers that is helping them to truly understand the dynamics, complexity, size and scope with this particular problem.”
You can find out a lot more detail about this cohort project by listening to the podcast, including recommendations on what growers should do if they receive a fungicide resistant result, and some great tips from our CCDM Director.