by Don Hershman, Kentucky Pest News No 1072

The 70 bushels per acre state yield average for wheat in Kentucky in 2005 confirms the overall lack of disease we saw in most wheat fields in Kentucky this spring. One disease that was a considerable concern in some fields this spring, is stripe rust, caused by the fungus Puccinia striiformis.

Historically, stripe rust has primarily affected wheat in cooler climate areas, like the Pacific Northwest. However, beginning in the 1990's we began to see an upturn in stripe rust in states like Louisiana and Arkansas that cannot be described as "cool". Last year we had some fields in Kentucky that would have been seriously hurt by the disease if a foliar fungicide had not been deployed. Other soft red winter wheat states also reported a significant increase in stripe rust in recent years, especially during 2005.

This movement of stripe rust into new areas is apparently the result of the development of a new race (s) that has blown into the U.S. from Mexico. All evidence at this time suggests that we will now be dealing with stripe rust on a more regular basis, much the same as we do with leaf rust (caused by P. recondita). My experience, thus far, is that the modern foliar fungicides we have available for wheat disease control all do a pretty good job in managing stripe rust. However, a more efficient and economical way to manage stripe rust is by the use of resistant varieties.

Many currently available soft red winter wheat varieties have good to excellent resistance against stripe rust. Stripe rust ratings were made in Kentucky this year and this information can be gleaned from the 2005 Kentucky Small Grain Variety Performance Test publication, available through your local county Extension office, or on-line at www.uky.edu/ag/WheatVarietyTest.