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Protecting the longevity of new fungicides

Fungicide resistance is real and is with us right now.  We need to recognise that it is going to continue to be a problem for decades to come. 

Fungicide resistance is something that cannot be stopped, unless we halt using these products. This is not a reality in our farming systems today. What we can do is look at management strategies that slow down fungicide resistance and development of reduced sensitivity. 


In using fungicides, the number of applications and the number of times we are exposing the pathogen to  products, increases resistance risks. This is especially true if we repeat using the same products or modes of actions. We can reduce the risk of developing fungicide resistance by: 

  1. Reducing the number of fungicide applications used in the growing season; and
  2. Making sure that we rotate the different modes of action and products used. 

Cost is a big determinant on what fungicides are used. However, now there is a fungicide armory which is reasonably accessible in price. Meaning we can use different modes of actions such as:

  • Group 3 demethylase inhibitors (DMIs – triazoles)
  • Group 11 quinone-outside inhibitors (QoIs)
  • Group 7 succinate dehydrogenase inhibitors (SDHIs)

These three modes of action are the three groups of fungicides growers are depending on, and if we mix these up within the season and make sure that we are not repeat using the same mode of action, this will slow down fungicide resistance development.

Further Information

GRDC Updates 2019 paper – Protecting The Longevity Of New Fungicides

GRDC Podcast – Take the slow train to fungicide resistance

GRDC COmmunities – Fungicide resistance – Back to basics


Fran Lopez-Ruiz, CCDM 

Luise Sigel, Agriculture Victoria 


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