Macadamia – Husk spot

Crop(s):          Macadamia

Disease(s):     Husk spot

Resistance Management Strategy for:

Group 1               Methyl benzimidazole carbamates (MBC);
Group 3               Demethylation inhibitors (DMI);
Group 7               Succinate dehydrogenase inhibitors (SDHI);
Group 11             Quinone outside inhibitors (QoI); and
Group 7 + 11      SDHI + QoI.

Maximum recommended number of sprays which can contain Group:



Total number of husk spot targeting sprays

1 3 7 7+11 11 (Incl. 7+11)
1 1 1 1 1 1
2 2 2 1 1 1
3 2 2 1 1 1
4 2 2 1 2 2
5 2 2 1 2 2
6 3 3 2 3 3
6+ 3 3 2 3 3
  1. Do not apply consecutive sprays of products containing Group 7 or 11. Consecutive sprays include mixtures containing Group 7 or 11.
  2. If applying Group 1 or 3 fungicides, do not apply more than two consecutive sprays (including from one season to the next) of fungicides from the same group before changing to another group. This applies for fungicides sprayed alone or in tank mix with another mode of action.
  3. When mixtures are used for Group 7 resistance management, applied as tank mix or as a co-formulated mixture, the mixture partner should provide satisfactory disease control when used alone on the target disease and must have a different mode of action.
  4. When using a Group 7 fungicide alone, the number of applications should be no more than one in every three sprays of the total number of fungicide applications per season.
  5. If used alone, apply Group 7 fungicides in strict alternation with fungicides from a different cross-resistance group.
  6. For programs in which tank mixes or pre-mixes of Group 7 fungicides are used, the number of SDHI-containing applications should be no more than ½ (50%) of the total number of fungicide application per season.
  7. If used in mixtures, apply Group 7 fungicides in a maximum of 2 consecutive applications.
  8. In programs where  Group 7 fungicides are made with both solo products and mixtures, the number of SDHI containing applications should be no more that ½ (50%) of the total number of fungicides applied per season.
  9. The spray program should be considered and the strategy applied on a whole-orchard basis.


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

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.