The wheat fields in the area that I have been visiting are now moving out of the jointing phase of growth and into the boot/heading phase.
This growth stage is critical because the flag leaf, which is largely responsible for development of the grain head, has emerged and unfurled and the developing head is now exposed. Growers should consider applying a fungicide to their crop at this stage in order to keep the newly emerged flag leaves and developing grain head disease free.
Here is an excerpt from the 2012-2013 UGA Wheat Production Guide regarding fungicide use:
The decision about whether or not to use a fungicide needs to be made carefully. Fungicides do not increase yield. They only help preserve yield and test weight. They should be applied at the correct rate and time according to the label. Fungicides should be applied with enough water to get good coverage: 5-7 gal/acre for aerial and 20-30 gal/acre for ground application. Use of a spreader-sticker will help improve leaf retention and fungicide performance. When applying fungicides always read the label and comply with the instructions and restrictions listed.
Generally, the most effective time to apply fungicides is from flag leaf emergence to completion of heading but be certain to follow any label restrictions concerning time of application, the number of applications, and total amount of fungicide that can be applied per season.
The following link is to page 484 from the 2014 Georgia Pest Management Handbook. It shows you the products are available in Georgia for foliar wheat disease management.
If you need assistance in determining which product is the best fit for your situation, contact your local extension agent.