Barley – Powdery mildew

Crop(s):         Barley

Disease(s):    Powdery mildew

Resistance Management Strategy for:

Group 3                Demethylation inhibitors (DMI);
Group 5                Amines (morpholines);
Group 7                Succinate dehydrogenase inhibitors (SDHI);
Group 7 + 3        SDHI + DMI;
Group 11 + 3      Quinone outside inhibitors (QoI) + DMI;
Group 11 + 4      QoI + phenylamide (PA); 
Group 13             Aza-napthalenes; and
Group 11+7+3    QoI + SDHI + DMI.

1. Fungicides should be used preventatively (as protectants) or at the very first sign of disease. If disease is established within the canopy, fungicides may not produce optimal results and there is high chance of selection for fungicide resistance. In high disease pressure situations, integrated management approaches should be considered to reduce fungicide resistance including:
   • The removal of stubble,
   • Crop rotation (avoid barley on barley)
   • Control of green bridge volunteers
   • Use of tolerant or resistant varieties
   • Strategic use (timing and application technique) of fungicides
2. Do not apply more than two applications per growing season of products containing any of the above listed Groups containing products. This includes in-furrow or seed treatments that have activity on powdery mildew. Combinations of in-furrow and seed treatment are counted as one application.
3. Do not apply consecutive applications of Group 11 containing products. This includes in-furrow i.e. If a Group 11+4 fungicide has been used in-furrow at planting, the first foliar fungicide spray must not contain a Group 11 fungicide.
4. If a Group 7 and Group 13 seed treatment has been used with foliar activity (as determined by label claims), the first foliar fungicide applied must not contain a Group 7 fungicide.
5. Group 7 foliar fungicides must always be in a co-formulation or in mixture with a registered mixing partner with a different mode of action, with no known resistance.
6. Minimise use of Group 3 fungicides which are known to have compromised efficacy due to resistance.