Grape – Downy mildew

Crop(s):          Grape

Disease(s):     Downy mildew

Resistance Management Strategy for:

Group 4            Phenylamides (PA);
Group 11          Quinone outside inhibitors (QoI);
Group 11+3     QoI + Demetylation inhibitors (DMI);
Group 21          Quinone inside inhibitors (QiI);
Group 40          Carboxylic acid amides (CAA); 
Group 45          Quinone outside inhibitor, stigmatellin binding type (QoSI);
Group 45+40  QoSI + CAA; and
Group 49          Oxysterol binding protein homologue inhibitors (OSBPI).

1. Apply all these fungicides preventatively. Group 4 fungicides should be applied before the first sign of oilspots or as soon as possible after an infection period.
2. Group 49 fungicides should be applied prior to infection and only in mixtures with effective fungicides applied at an effective rate from a different cross resistance group. The mixing partner should give effective control of downy mildew at the rate and interval selected. Only apply Group 49 for a maximum of one in every three sprays of the total number of downy mildew sprays, and no more than two applications per season.
3. Mixtures are defined as co-formulations or tank mixes at label rate of alternative mode of action.
4. Apply a maximum of two consecutive applications of any one group.
5. Start preventative disease control sprays using non-Group 4 protectant fungicides, typically when shoots are 10-20cm long. Continue spraying at intervals of 7-21 days depending on disease pressure, label directions and rate of vine growth.
6. Limit the use of Group 4 fungicides to periods when conditions favour disease development. Always apply Group 4 fungicides in mixtures.
7. Do not apply Group 11 (including Group 11+3) consecutively when applying alone.
8. Apply a maximum of 2 sprays per season of Group 11 (including mixtures), Group 45+40 and Group 49.
9. Do not apply a spray containing Group 40 as the last spray of the season.
10. Only apply a spray containing Group 40 a maximum of 50% of the total number of downy mildew sprays.

* Refer to points 8 & 10