Wheat Rusts in North Carolina
Low to medium levels of wheat stripe rust have been observed over the past week in a handful of fields in Raleigh, Plymouth, and near Goldsboro in the central Coastal Plain. In the Goldsboro area, the infection had clearly been present for some time.
Current weather in North Carolina is ideal for stripe rust development. This disease can spread very fast.
Unfortunately, we do not have good comprehensive stripe rust ratings for North Carolina commercial varieties because this disease is fairly rare here. Varieties that are widely planted and susceptible to stripe rust include DG Shirley and SS 8404, but many other varieties are susceptible too.
Unusually early and heavy levels of leaf rust have been observed broadly across the Coastal Plain. The early severity is due to the warm winter. We have leaf rust ratings for many, but not all, wheat varieties grown in North Carolina (http://www.smallgrains.ncsu.edu/_Misc/No38VarietySelection2015.pdf).
Please see the attached photos to distinguish leaf and stripe rust. Scout fields for rust. If significant infection is found and, *if* the field has good yield potential, treat immediately with fungicide. It is more important to catch stripe rust early than to catch leaf rust early. As you can see from the attached fungicide table, numerous products are highly effective on stripe and/or leaf rust.
The closer the crop is getting to flag leaf or beyond, the more you should avoid a strobilurin or strobi-containing product due to the risk of increasing DON if there is a scab epidemic at flowering.