CropLife Australia recently unveiled updated target spot resistance management guidelines covering fungicide use at all stages of potato production.
Syngenta technical manager Matt Sherriff says this is a robust program focused on disease prevention.
“It is in the industry’s best interests as it maintains important tools for the management of target spot, among other critical diseases,” Matt said.
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 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 says it is critical 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 says 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 says.
This resistance management strategy does not replace product labels.
However, such strategies help avoid selection pressure on pathogens whichthat 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 go to croplife.org.au/resources/programs/resistance-management/potato-target-spot-early-blight/ or syngenta.com.au/crops/potatoes or speak with your local Syngenta representative.
