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Managing fungicide resistance keeps future options open

Scott Mathew, Syngenta Viticulture & Fruit Portfolio Lead

Growers are being urged to carefully consider the use and rotation of different fungicides to preserve the choices available to them, well into the future.  Certain fungi can become resistant to different fungicide groups over time thus reducing their effectiveness in controlling the disease.

In any fungal population, there are likely to be some individuals that have a degree of natural resistance, making them less susceptible to fungicides. The continual use of a fungicide, or fungicides from the same mode of action (MoA) group, can lead to an increase in the number of resistant individuals and can make the fungicide ineffective against the target disease. For this reason, CropLife Australia have put in place fungicide resistance management strategies for medium-high risk crops. 



Growers who utilise all of the available management strategies and follow the CropLife fungicide resistance management strategies, will reduce the risk of resistant pathogens surviving and multiplying, helping to delay the onset of fungicide resistance development. 

Fungicides are classified according to the chemical activity group, or MoA, which refers to the specific stage of the disease cycle they target. Different fungicide group numbers allow growers to know which fungicide MoA group they have used and makes it easier to follow resistance management strategies for that crop and disease.

Some fungicide MoA groups have a higher risk of resistance than others. As such CropLife Australia has a recommended resistance management strategy for the control of powdery mildew in strawberries that encompasses fungicides from Groups 3, 7, 7 + 12, and 11; a similar resistance management strategy exists for the control of grey mould (Botrytis cinerea) in strawberries with fungicides from Groups 2, 7, 7 + 12, 9, 9 + 12 and 17.

Syngenta has MIRAVIS® Prime, which is a combination of Group 7 and 12, available for lettuce and leafy vegetables, berry crops, potatoes and table grapes. “MIRAVIS® Prime combines two modes of action for powerful, long-lasting control of disease, and as a management tool to help delay the onset of resistance.”

MIRAVIS® Prime will become a key product to help growers achieve quality produce with excellent control of sclerotinia, powdery mildew and botrytis, but should not be relied upon as the sole option. 

By following the fungicide resistance management recommendations of CropLife, growers can help ensure the range of products that are currently available, are here for the long-term.

If growers don’t rotate fungicides from different mode of action groups throughout the season, and from one season to the next, it will hasten fungicide resistance development.

There are many instances throughout the world where the overuse of products has seen fungal pathogens rapidly become resistant to some mode of action groups.  

By rotating chemistry, following guidelines and label directions, growers can take care of the products currently available and ensure they are viable well into the future.

Contact your local Syngenta representantive for more information.



About Syngenta Australia
Syngenta is a leading agriculture company helping to improve global food security by enabling millions of farmers to make better use of available resources. Through world class science and innovative crop solutions, our 28,000 people in over 90 countries are working to transform how crops are grown. We are committed to rescuing land from degradation, enhancing biodiversity and revitalizing rural communities. To learn more visit and