1. Management of blueberry rust HAL BB13002
Rosalie Daniel
Elizabeth Macarthur Agricultural Institute, NSW DPI

2. Blueberry rust (Thekopsora minima)
Prefers warm (20oC), humid seasons, moist leaves
Spread primarily by wind
Damages leaves and fruit
Where does it survive?
Where do spores come from?
When does it infect?
Biosecurity Tasmania

3. Disease cycle Sexual cycle Asexual cycle
NSW
Sexual cycle
Asexual cycle
Hemlock
From Eddie McGriff, University of Georgia Extension Agent, Coffee County, Georgia, on June 22nd, 2012 BLUEBERRY RUST - See more at:
Uredinia form on the lower leaf
Urediniospores reinfect blueberry in a repeating secondary cycle
Secondary infection leads to rapid build up of pathogen and spread of disease
In regions with mild winters where hemlock is absent, it is suspected that uredinia may overwinter on green leaves of blueberry and other Ericaceous hosts
Where hemlock is present, telia form in leaves at the end of the season, leaves fall to the ground. Basidia arise from germinating teliospores and basidiosopres infect young hemlock needles in the spring. Aecia are formed, releasing aseciospores to infect blueberry leaves
Many fungicides applied for other leaf spots will also have rust activity; this is particularly true of the strobilurin (Abound, Pristine, etc.) and DMI fungicides (Quash, Tilt, Orbit, Indar, Bumper, etc.). - See more at:
Caruso & Ramsdell 1995

4. Seasonal occurrence of rust

5. Chemical and biological fungicides and plant defence activators
Field trial (cv. C99-42):
Applied every 2 weeks from February – July 2014
Chemical/activator
FRAC
Mancozeb M3 P
Pristine (boscalid & pyraclostrobin )
7 & 11
P & S
Dithianon M9
Metiram
Tebuconazole 3 S
Copper M1
Silica
N/A NC

6. Development of rust symptoms* *
Proportion of leaf area covered with rust pustules two months after last spray (September 2014).

7. Other chemical and biological treatments
Lab and glasshouse trials:
Chemical/biological/activator
FRAC
Cyprodinil (Chorus) 9
Cyprodinil & Fludioxinil (Switch)
9 & 12
Fenhexamid (Teldor) 17
Fludioxonil ( Scholar) 12
Pyraclostrobin & Boscalid (Pristine)
7 & 11
Azoxystrobin & Difenoconazole (Amistar)
11 & 3
Pyraclostrobin (Cabrio) 11
Procloraz (Octave) 3
Cyproconazole (Alto)
Bacillus subtilis (Serenade) 44
Chitosan NC

8. What works?
Spores are present all year, particularly when there is moisture
No symptoms in trial until September (this year)
Mancozeb, metiram, copper and pristine inhibited symptoms
Dithianon and tebuconazole also inhibit symptoms, but residue problems
Are the spores dormant over cooler months or do they infect and not develop?
How does the fungus infect the fruit?

9. Options for management of rust
Sanitation
Source clean planting material
Prune/remove infected and dead plant material
Spray after pruning, at leaf flushes, particularly if conditions are warm and moist
Identification and development of resistant varieties

10. Acknowledgements Maurizio Rocchetti, Costa Berry Exchange
David Robertson, NSW DPI
Damian Collins, NSW DPI
Australian Blueberry Growers Association
Horticulture Innovation Australia Limited
Contact:
(02)