Stripe rust (Figure 1) was observed at a very low incidence in wheat research plots at the University of Kentucky Research and Education Center in Princeton (Caldwell County) late last week. Also last week, stripe rust was detected in Gallatin County, Illinois (next to Union County, KY), so it is likely that stripe rust has made its way into several counties in western Kentucky.
The cool, wet weather that we have been experiencing recently is favorable for infection and spread of the stripe rust pathogen.
Fortunately, many wheat varieties are resistant to stripe rust. For resistant varieties, no additional management will be needed. In addition to checking with the seed company about how resistant a specific wheat variety may be, this information may also be obtained by looking at the results of the 2016 University of Kentucky Wheat Variety Performance Trials.
If a variety is susceptible to stripe rust, a foliar fungicide application may be needed. Most fungicide products available for wheat will provide a satisfactory level of control of stripe rust as long as they are applied before stripe rust gets to damaging levels.
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An application of a foliar fungicide when flag leaves have emerged will help protect the most important leaf on a wheat plant and protect against yield losses.
Keep in mind that an application of a fungicide at the flag leaf emergence stage will not provide protection against Fusarium head blight (scab), and that an additional fungicide application may be needed later in the season (during the wheat flowering stage) to help protect against scab.
If stripe rust is detected in your field, please contact your local county Extension agent so that we can continue to track the spread of this disease across Kentucky and the U.S.