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

Abstract

Key findings •The pathogens that cause cereal diseases such as crown rot (CR), common root rot (CRR) and yellow spot (YLS) can grow within cereal stubble after harvest under high humidity. Inoculum levels in cereal stubble can increase above harvest levels in wet weather. •The levels of disease resistance to CR, CRR or YLS in the varieties and crops tested do not appear to slow or limit pathogen growth after harvest, and therefore did not influence post harvest inoculum accumulation. However, variety and crop selection for disease resistance in-crop is still a useful disease management strategy. •In stubble with 100% relative humidity (wet/rainy/foggy/dewy weather), the CR fungus progressed fastest (1 cm/day) with the YLS pathogen the slowest (0.4 cm/day). This is likely to influence which pathogen dominates in following seasons if there are mixed infections in the same crop. •A reduction in cereal stubble biomass might limit CR, CRR and YLS growth after harvest in stubble and reduce the amount of inoculum carried forward. Options could include selecting low-biomass varieties, low harvest heights or cutting for hay, but field validation is required.