Cucurbits – Downy Mildew

Crop(s): Cucurbits

Pest(s): Downy Mildew

Resistance Management Strategy for:

Group 4             (Phenylamide);

Group 11            (Quinone outside Inhibitor); and

Group 28 + 43    (Carbamate plus Benzamide); and

Group 40            (Carboxylic acid amide) fungicides

Group 49         OSBP (Oxysterol binding protein inhibitor)

  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, 28+43, 40 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, 28+43 or 49 products, at the interval recommended on the label, or a single spray of a Group 11 fungicide. Then resume the program of sprays using products from a different group to the Group 4, 11, 28+43 or 49 products just applied.
  3. DO NOT apply more than four sprays of a Group 4 or of a Group 40 product per season.
  4. DO NOT apply more than three sprays of a Group 49 product. Group 49 containing sprays should not consist of more than 33% of the total number of fungicide sprays per crop.
  5. DO NOT apply more than two sprays of Group 11 or 28+43 fungicide per crop.
  6. Apply Group 11 fungicides preventively.
  7. Apply Group 4 and 49 fungicides preventatively and only in mixtures with an effective protectant fungicide from a different mode of action group.
  8. 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 22, 2018

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 22 June 2018. All previous versions of this strategy are now invalid.