Stubble Olympics: the Cereal Pathogen 10cm Sprint

GRDC - Author: Toni Petronaitis (NSW DPI, University of New England), Clayton Forknall (DAF QLD), Steven Simpfendorfer (NSW DPI) and David Backhouse (University of New England)

Type: Research Paper
Knowledge level: Advanced

Farm Table says:

The authors of this paper note in the conclusion: “Right now, we are still trying to understand if and how saprophytic growth of cereal pathogens during fallow and non-host rotation may affect disease risk in subsequent seasons. It is possible that the recent higher rainfall experienced in many areas may have spiked pathogen levels right before sowing, placing new crops at a higher risk than in previous (drier) years. Furthermore, the extended dry conditions (2017-19 seasons) have allowed inoculum to persist at damaging levels for much longer than normal (2-4 seasons). So, be vigilant about checking this years’ cereal crops for disease symptoms and consider appropriate in-crop management strategies if necessary.”. Please access the full paper via the link below if this research interests you.

The take home messages from this GRDC  funded research are below. Please access the full paper via the link below for methodology, references, acknowledgements and discussion.

  • Wetter is better (for cereal pathogens): moist conditions promoted growth of pathogenic fungi (Fusarium pseudograminearumBipolaris sorokiniana and Pyrenophora tritici-repentis) within post-harvest cereal stubble, meaning inoculum levels of crown rot, common root rot and yellow spot may increase if wet weather is experienced after harvest
  • Not all cereal stubble is created equally: some pathogens progressed further in oat than bread wheat stubble. Additionally, there are indications that the resistance ratings of varieties and crops do not reflect the extent of saprophytic growth post-harvest
  • Each cereal pathogen had a unique stubble-colonisation pattern: the crown rot fungus was the quickest to progress within all stubble types and the yellow spot pathogen was the slowest. This is likely to influence which pathogen dominates in following seasons if mixed infections have occurred in the same crop
  • Reducing cereal stubble biomass may limit the post-harvest progression of pathogenic fungi in stubble, thereby reducing the amount of inoculum carried forward. Options could include selection of low-biomass varieties, low harvest heights or cutting for hay, however field validation is required.

Figure 3. Inoculum production as a percentage (%) of different types of cereal stubble colonised by three pathogens subject to moisture conditions of 90% RH, 92.5% RH, 95% RH, 97.5% RH or 100% RH for seven days. Error bars represent approximate standard error of the mean.

2020 - Australia - GRDC - Author: Toni Petronaitis (NSW DPI, University of New England), Clayton Forknall (DAF QLD), Steven Simpfendorfer (NSW DPI) and David Backhouse (University of New England)
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