Net form net blotch (NFNB), spot form net blotch (SFNB) and powdery mildew are important diseases of barley that have exhibited fungicide resistance in Australia. All fungal diseases of barley have the potential to develop resistance to any single-site fungicide that is used repetitively. Adopting good integrated disease management and fungicide usage practices now will help preserve the effectiveness of these useful chemicals.

Key points

• Fungicide resistance is the loss of fungicide effectiveness against a specific pathogen.
• Net form net blotch (NFNB), spot form net blotch (SFNB) and barley powdery mildew have all exhibited fungicide resistance in Australia.
• Rotate crops, plant resistant cultivars and manage stubble loads to minimise disease pressure.
• Avoid using a fungicide or fungicide Mode of Action (MoA) group in consecutive applications or more than twice in the same season.