Stubble Olympics: the cereal pathogen 10cm sprint – growth patterns of fungi causing crown rot, common root rot and yellow leaf spot in post-harvest cereal stubble

Abstract

Take home messages
• Wetter is better (for cereal pathogens): moist conditions promoted growth of pathogenic fungi (Fusarium pseudograminearum, Bipolaris 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.