Sooty moulds and milling quality of cereals

Sooty moulds affect all cereals. Due to their potential impact on milling quality, it is important to recognise higher-risk crops and manage them accordingly.

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How sooty moulds affect milling quality

  • Several pathogen species* cause sooty moulds in cereals
  • Infection rarely has any effect on grain yield
  • However, the disease causes discolouration of ears and grain
  • This visible presence of sooty moulds affects marketability – particularly in milling wheat

*Two key sooty mould species – Alternaria spp. and Cladosporium spp. – have also been linked to black-point disease, which also affects milling quality.

Black-point disease in cereals

Life cycle and symptoms of sooty moulds

Life cycle

The fungi are not host-specific, so they can affect all cereals.

These pathogens overwinter on crop debris and vegetation.

They can survive adverse conditions as spores or mycelium on many types of material.

They do not require living host material to survive, as they derive nutrients from dead or decaying tissues (i.e. saprophytic).

Airborne conidia, released during grain development, are responsible for the most significant infections.

They most commonly colonise ears after growth stage 75, especially ears that are prematurely ripe or affected by aphid honeydew.


The usual symptom of sooty moulds is a darkening of the ears before harvest.

This is most commonly seen in wet weather, where delays in harvesting result in severe blackening of ears and discolouration of the grain.

The most severe symptoms are often associated with root or stem-base diseases, which cause premature ripening of the crop.

White heads often become severely affected by sooty moulds.