Be on the Lookout for Wheat Rust Diseases

Carl A. Bradley, Extension Plant Pathologist, University of Kentucky

Stripe rust (Fig. 1) was diagnosed by the Plant Disease Diagnostic Laboratory at the UKREC this week in a wheat sample that came from Lyon County.  In addition, leaf rust (Fig. 2) of wheat has been observed in states south of Kentucky (Arkansas and Mississippi), and appears to be moving northward.  Some wheat varieties have high levels of resistance to these diseases; therefore, it is important to know the susceptibility of the varieties planted. Resistant varieties likely will not require any additional management for rust disease control; however, a foliar fungicide application may need to be considered for susceptible varieties. The 2016 multi-state university foliar fungicide efficacy table for wheat diseases can be found here:

Stripe Rust found in west Kentucky

Stripe rust has been found at low levels in southern Christian County in west Kentucky. I am sure it is in other counties in the west as well. Levels do not appear to be high, meaning that scattered plants with symnptoms were found, but bonified hot spots were not seen. In any event, it would be prudent to check your fields for the presence of stripe rust. If you find hot spots (not just single plants) you probably should  not wait to spray until early flowering, the typical time of application targeting head scab. However, if you just see a few scattered leaves here and there, I believe you could wait until flowering to spray with little risk that stripe rust will get ahead of you.

The greatest risk is in varieties that are known to be highly susceptible to stripe rust, such as "R35". However, if you find a hot spot in any variety, that would be cause for alarm since the fungus can overcome know resistance.

Scout for Stripe Rust in Wheat

Don Hershman, Extension Plant Pathologist, University of Kentucky


Be on alert for stripe rust. The disease may have overwintered in your area and there may be some hot spots that could serve as fuel for a rapidly developing problem on a field by field basis. I wrote a KY Pest News article on this a couple of issues ago. It may not be a problem, but it is easy to miss things this time of year unless active crop scouting is taking place. The disease level in this particular field really increased over the past two weeks. Phil Needham said he has seen stripe rust in other fields too, but this one in Oak Grove is the worst so far. Still, there may be fields with a similar level of disease.


For information on management of stripe rust go to Chapter 7 of the Wheat Management Guide.

Figure 1. Stripe rust in wheat.

 Figure 2. Stripe rust in wheat.