For oats and barley, the greatest yield response from leaf disease control is when the fungicides are applied at the flag leaf emerged stage. This stage is when the last leaf emerges from the stem before the head emerges (Fig 1).
Application of a fungicide at the flag leaf can have a significant improvement on grain yield, lodging and test weight. This is largely due to the increase in plant health. (See Fig 2,3)
Fusarium is a big issue in both winter wheat and spring wheat. This disease reduces yield and lowers grain quality and this may lead to price reductions. For optimum suppression of fusarium, apply when 80% of the heads have emerged and when 50% of the heads are in flower. See Fig 4