Yellowing and physiological spots in wheat and barley crops

Summary

Cold weather during vegetative growth stages in recent years across New South Wales and southern Queensland has resulted in cereal crops turning a bit yellow with some physiological brown spots also common in barley.

These symptoms are often confused with disease but because they are purely physiological and related to environmental conditions, application of fungicides is not warranted.

The yellowing is believed to relate to transient nutrient deficiency associated with a reduction in the supply rate (uptake and mineralisation) under colder temperatures and may also be related to waterlogging in some seasons.