Australia
July 24, 2025
Steve Michelmore in his crop of potatoes, after trialing MIRAVIS(R) Duo fungicide for target spot control via both boom and chemigation application.
CropLife Australia recently unveiled updated target spot resistance management guidelines that covers fungicide use at all stages of potato production.
“This is a robust program that focuses on disease prevention,” said Syngenta Technical Manager, Matt Sherriff. “It is in the industry’s best interests as it maintains important tools for the management of target spot, among other critical diseases.”
While agronomists are well versed in rotating Mode of Action groups, it is important everyone is familiar with the updated CropLife guidelines and employ a suitable, preventative program in situations that are conducive to disease development.
There are an increasing number of Group 7 (SDHI) products registered as a fungicide or nematicide for use in Australian potatoes as seed or in-furrow treatments at planting. These include Syngenta’s VIBRANCE® Premium seed treatment registered for control of several key pathogens (active ingredients fludioxonil + sedaxane, Groups 7 + 12), Sumitomo’s Excalia*, registered for soil borne Rhizoctonia solani control (active ingredient inpyrfluxam, Group 7) and Bayer’s Velum* Prime Nematicide registered for control of root knot nematode (active ingredient fluopyram, Group 7).
The revised CropLife target spot strategy addresses the risk of seed or in-furrow applications preceding foliar applications of SDHI fungicides. If a Group 7 seed or in-furrow treatment has been used, the first foliar fungicide application should not contain a Group 7.
Matt said, it is critical that the first foliar fungicide application should not be a product belonging to Group 7. In this case, growers should utilise an alternative fungicide group before using a MIRAVIS®, MIRAVIS® Duo, or MIRAVIS® Prime fungicide, which also contain an SDHI (Group 7) active ingredient.
There are also restrictions in the CropLife strategy around the use of solo Group 7 fungicides, such that, MIRAVIS® fungicide should not be used back-to-back, being a solo SDHI formulation. However, depending on the disease scenario, Matt said MIRAVIS® Duo or MIRAVIS® Prime may be used consecutively as they are co-formulations with a second mode of action.
MIRAVIS® Duo (Groups 3 + 7) is registered for target spot and powdery mildew control throughout all critical stages of the growing season. It also has the benefit of being able to be applied through chemigation.
Where Sclerotinia or Botrytis are of concern, applications of MIRAVIS® Prime (Groups 7 + 12) provides preventative control of these diseases, as well as target spot (see the label for application rates and restrictions).
“Prevention is the key with target spot, with the application of a MIRAVIS® formulation prior to canopy closure, helping to prevent disease onset and premature defoliation that reduces crop yields,” Matt said.
This resistance management strategy does not replace product labels. However, such strategies help avoid selection pressure on pathogens that can infer natural resistance on subsequent generations that can ultimately lead to ‘failure’ of products.
For details on the potato target spot resistance management strategy visit: www.croplife.org.au/resources/programs/resistance-management/potato-target-spot-early-blight/ and for more information about the Syngenta range of potato products click here or speak with your local Syngenta representative.
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