Ornamentals – Myrtle rust

Crop(s):          Ornamentals

Disease(s):     Grey mould (Botrytis)

Resistance Management Strategy for:

Group 3        Demethylation inhibitors (DMI);
Group 7        Succinate Dehydrogenase inhibitors (SDHI);;
Group 3+11  DMI + Quinone outside inhibitors (QoI); and
Group 11        QoI.


  1. Fungicide groups that are classified as medium to high risk for fungicide resistance development, Group 3, 7 and 11 should be rotated as a key feature to reduce the development of resistance.
  2. Do not apply more than two (2) consecutive sprays of fungicides from Group 3, 7 or 11, unless mixed with a registered fungicide from a different more of action group with no known resistance or low resistance risk.
  3. If consecutive sprays of a Group 7 or 11, are applied, they must be followed by at least two applications of fungicide from a different group(s) before the same high-risk fungicide is used again.
  4. No specific resistance management strategy has been developed for low-risk fungicides, including those in Group M and BM. These products should be included in a management strategy as per label recommendations.

URL: https://croplife.org.au/resources/programs/resistance-management/ornamentals-myrtle-rust/
Content last updated: July 14, 2023

CropLife Australia’s Resistance Management Strategies provide a guide for crop protection product rotation through product groups. The strategies are a useful tool that supports farmers’ adoption of resistance management. All crop protection products must be handled and applied strictly as specified on the product label or APVMA permits.

These Resistance Management Strategies do not replace product labels. They are a guide only and do not endorse particular products, groups of products or cultural methods in terms of their performance. It is important to check with the Australian regulator’s (APVMA) product database for contemporary information on products and active constituents. The database can be sourced through www.apvma.gov.au

The information given in this strategy is provided in good faith and without any liability for loss or damage suffered as a result of its application and use. Advice given in this strategy is valid as at 14 July 2023. All previous versions of this strategy are now invalid.