Last year, there were a number of wheat acres that should have been sprayed for leaf rust and were not. Some farmers didn't know about the leaf rust or they found out about it to late to do anything. This year, we are going to more aggressively publicize what is being seen in wheat fields around the state concerning wheat diseases, especially leaf rust.

Currently, leaf rust has been found at low levels at the Hays Agricultural Research Center. However, reports from the south-central part of Kansas and Oklahoma are seeing leaf rust increasing significantly, especially with the moist conditions they are experiencing. It is critical that you scout your fields routinely a minimum of twice a week until the crop has fully headed.

Leaf rust favors warmer weather (65 to 80 degrees) with some humidity. Currently, I feel that the weather conditions in Ellis County and the area are very favorable for a possibly huge outbreak of leaf rust within the next week or so. However, no one knows that for sure -- that is only my gut feeling. The most effective fungicide sprays are applied between flag leaf emergence through heading.¬ By now in Ellis County, our wheat has the flag leaf emerged, and I have seen a field of Jagger that was starting to head out earlier this week. Most fungicides must be applied before flowering; this means the treatments must be applied in the next seven to 10 days.

The yield response for foliar fungicides in Kansas will typically fall between 4 percent and 13 percent with the yield average response of 10 percent.¬ Yield responses can be greater than 20 percent in fields where leaf rust arrives prior to flowering.¬ 

The cost of a fungicide and application ranges between $21 and $27 per acre.¬ The price of wheat is still strong (above $8). Fields of Jagalene, Overley, Jagger and other susceptible varieties with a yield potential of greater than 30 bu./acre might be excellent candidates for a fungicide application.¬ 

Eric DeWolf, our K-State wheat disease specialist, even has observed some leaf rust forming on Post Rock, which has a high resistance rating for leaf rust, so all wheat varieties and fields should be scouted often for the detection of leaf rust.

For further information on leaf rust with some good color pictures of the disease and the different fungicide products and efficacy ratings go to our Web site at www.ellis.ksu.edu or stop by your local Extension Office.

* Contributing Author: Erick De Wolf, dewolf1@ksu.edu.

Stacy Campbell is Ellis County agricultural agent with K-State Research & Extension.