Black-point disease in cereals and its impact on milling quality

Black-point infected plants produce chemicals in the bran and the germ area, resulting in brown-to-black specks in flour. Due to its impact on quality, it is important to recognise higher-risk cereal crops and manage them accordingly.

The disease is associated with several airborne fungi and affects all cereals, although wheat and barley are most commonly affected.

Although black-point pathogens are thought to include Alternaria spp. and Cladosporium spp, evidence linking these fungi with the disease is limited and mostly circumstantial.

These pathogens overwinter on crop debris and vegetation. The release of airborne conidia during grain development are responsible for the most significant infections.

In particular, high humidity or frequent rainfall from the milky-ripe to soft-dough stage and lodging promotes infection by these fungi.

Some varieties are more prone to black-point than others.

Black-point-infected plants produce chemicals in the bran and the germ area, resulting in brown-to-black specks in flour, poor bran colour and rejection.

Symptoms are only visible after harvest. Affected grain shows a darkening of the outer coat, particularly at the embryo end of the grain.

The disease is potentially more severe on larger grains. Such grains are associated with a more open floret, which potentially allows fungal spores greater access to the germ end of the grain.

Disease incidence is greater in grains with a higher specific weight.

Black-point has no significant effect on yield.