Is fungicide resistance for real? Lets start by checking out this graph:
It’s real alright. But will it come to The Great Wave off Kanagawa falling on our sprayers? Thankfully, we’re more positive than that. As we detect more cases of fungicide resistance across Australia, we’re getting more insight into how to turn a tsunami into manageable rough seas ahead.
Our latest Annual Report by our Fungicide Resistance Group reported on three major cases of fungicide resistance in 2016 – these were:
- VIC and TAS: Wheat powdery mildew resistance to strobilurin fungicides from Group 11
- WA: Barley net-form of net blotch resistance to triazole fungicides from Group 3
- NSW, VIC and TAS: Barley powdery mildew resistance to triazole fungicides from Group 3
Straight from the report: Fungicide resistance cases identified within the Australian grains industry from 2012 to 2016
And here’s a map of where each were found from 2012 – 2016:
More about 2016’s three resistance cases
Last year, agronomists in Tasmania phoned CCDM’s Fungicide Resistance Group, reporting strobilurins were not working as well as they should in controlling wheat powdery mildew. The Foundation for Arable Research (FAR) also noticed a similar pattern in Victoria.
It wasn’t long until we discovered the mutation – G143A – a mutation well known in wheat powdery mildew across other parts of the world but until now was previously undetected in Australia.
FRG leader Fran Lopez-Ruiz said of the three cases highlighted in the 2016 report, this finding was probably the most concerning, as it will impact all areas affected by wheat powdery mildew.
“But because we detected it early, this finding acts as an early warning to implement anti-resistance strategies against this disease, particularly as there are only two modes of action currently available to treat wheat powdery mildew.
These are DMIs – group 3 (such as tebuconazole and epoxiconazole) and the strobilurins – group 11 (such as azoxystrobin and pyraclostrobin).
So far our researchers have detected resistant net form of net blotch (NFNB) in five widely spread locations across WA’s wheatbelt.
Fran said this finding was particularly interesting in a couple of ways.
“First, straight tebuconazole is not registered for the control of NFNB, however growers should be mindful that NFNB may be present when applying tebuconazole to control other barley diseases, which may contribute to NFNB issues in subsequent seasons,” he said.
“And second, if I had to put money on one of the net blotches developing resistance, I would have bet on spot form of net blotch (SFNB) given its higher incidence and how widespread it is when compared to NFNB. Perhaps SFNB will be next.”
Barley powdery mildew resistance is a bit of an old story for WA, having been discovered back in 2009, but now we are seeing it appear in NSW, Victoria and Tasmania, as this pathogen gets the better of triazole fungicides from group 3.
Fran said Tebuconazole was accessible and cheap and as such its popularity was understandable.
“However using this active ingredient repeatedly, without rotating fungicides between different modes of action, or using fungicide mixtures of different modes of action, will promote fungicide breakdown,” he said.
“Planting susceptible wheat and barley varieties will also create an environment for the pathogen to thrive.”
Get your crop diagnosed for fungicide resistance
Already test your weeds for herbicide resistance?
We’re inviting growers and advisors to do the same for their diseased crop. If you would like to test your crop for fungicide resistance – even before the resistance signs are evident – feel free to contact us for a sample kit, and drop a diseased leaf in the post. Email firstname.lastname@example.org for a kit.
“If growers detect resistance early, it is much easier for them to control a smaller resistant population, rather than a full blown resistant population, and I’m sure their neighbours will also be thankful for it,” Fran said.
The Fungicide Resistance Group’s Sampling Report Annual Review 2016
For the full report, click here.
About the Fungicide Resistance Group
With cutting edge methodologies and tools, their expertise can be applied to any Australian fungal pathogen, and often find themselves looking at many different pathogens across different crops and even across different industries. To find out more about them, visit www.ccdm.com.au/frg