Broccoli/Cauliflower – Downy Mildew

Crop(s):          Broccoli/Cauliflower

Disease(s):     Downy Mildew

Resistance Management Strategy for:
Group 4      Phenylamide;
Group 11     Quinone outside inhibitors (QoI);
Group 21     Quinone inside inhibitors; and
Group 49    Oxysterol binding protein inhibitor (OSBP).

  1. Applications made within the nursery count towards the total number of applications allowed per crop. It is recommended that disease control is started early and maintain a regular program using a fungicide from groups other than Group 4, 11, 21 or 49.
  2. When conditions favour disease development, DO NOT wait for disease to appear, but apply two consecutive sprays of a Group 4, 11, 21 or 49 product at the interval recommended on the label. Then resume the program of sprays using products from a different group to the Group 4, 11, 21 or 49 products just applied.
  3. DO NOT apply more than three sprays of a Group 4, 11, 21 or 49 product or 33% of the total number of fungicide sprays per season, whichever is more restrictive
  4. Apply Group 4 and 49 fungicides preventatively and only in mixtures with effective protectant fungicides from a different group
  5. DO NOT use a Group 49 product if it will be the last fungicide applied to the crop.
  6. Continue alternation of fungicides between successive crops. DO NOT make more than (6) six total applications of a Group 49 product per year on the same area targeting the same disease.

Content last updated: June 10, 2020

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 10 June 2020. All previous versions of this strategy are now invalid.