Potatoes

Potato Early blight resistance management changes
potato_crop_in_flower

Syngenta introduced MIRAVIS® fungicide (200 SC) to the New Zealand potato market in 2018 and it was the first and only Group 7 (SDHI) fungicide to be registered in potatoes for Early blight (Alternaria solani) control. 

Recently, this changed with the registration of Emesto® Prime, another Group 7 SDHI, for use as an in-furrow (IF) treatment at planting to control Rhizoctonia solani. Other SDHI-based fungicide registrations for use as seed, IF or foliar treatments may well follow in time.

To comply with the MIRAVIS® label, a maximum of 3 SDHI’s per crop, per season are permitted. This includes IF applications or seed treatments.  

To prevent Early blight resistance to SDHI fungicides in areas where Alternaria solani remains sensitive, Syngenta NZ and Potatoes NZ recommend the following:

When managing SDHI fungicide applications, it is important to account for all uses of SDHI’s, including seed treatments, IF and foliar applications. 

If a SDHI fungicide has been applied as an IF and/or seed treatment, the following should apply:

  1. The first foliar fungicide application should NOT be an SDHI active ingredient
  2. A maximum of 2 MIRAVIS® foliar applications can be made during the season

“This is a robust programme that Syngenta Australia have formulated and are now recommending to potato growers. It focuses on disease prevention and the long-term, sustainable use of SDHIs, so it makes sense to adopt this programme in NZ,” said Paul Hassan, Technical Services Lead for Syngenta. 

“It is always in the industry’s best interests to follow up-to-date resistance management strategies, that aim to preserve important tools for the control of Early blight, among other critical diseases.

“Prevention is the key with Early blight. Apply MIRAVIS® at 375 mL/ha and in-tank mixture with a protectant fungicide prior to canopy closure.  This helps to prevent primary disease infection and premature defoliation that reduces crop yields” Paul said.  

When applying MIRAVIS® as a foliar application in growing areas where Alternaria solani populations are still sensitive to SDHI fungicides, please follow the recommendations outlined in the Resistance Management section of our MIRAVIS® Potato Technote which you can download here. 

To find out more about the Syngenta range of potato products, download the brochure or for more information, contact your local Syngenta Territory Sales Manager.