Foliar fungicides have proven to be an effective tool to manage foliar diseases in this region. They are very effective against leaf rust, stripe rust, and glume blotch. Following is a discussion of our local applied research over almost thirty years.

Foliar fungicides do not enhance yields—they can only protect potential yields from loss to the rusts or glume blotch. Consequently, they are not profitable in the absence of disease.

Our early work was focused on evaluating the performance of foliar fungicides on varieties that were highly susceptible to leaf rust and stripe rust. As would be expected, a fungicide application on susceptible varieties was almost always profitable when disease was present. Our most recent work concentrated on evaluating the performance of foliar fungicides on commercially planted varieties – wheat varieties with at least some level of resistance to the rusts. The results were quite different than our early work with susceptible varieties.

Over the past four years, we conducted a study on the profitability of an inexpensive foliar fungicide (tebuconazole) on four commercially planted varieties with good resistance to both leaf and stripe rust. The varieties included Syngenta Magnolia, Syngenta Coker 9553, Pioneer 25R47, and Terral LA 841.

We selected tebuconazole because it was as effective as any wheat fungicide on the market, at a fraction of the cost of the others.

The tables below compare the yield response of these four locally adapted varieties to a single application of tebuconazole. The numbers represent the bushel per acre change we observed by applying a foliar fungicide. Most of the values we observed by applying a foliar fungicide were not statistically different from the untreated checks (statistical differences are denoted by an asterisk*). The negative numbers do not indicate that we produced less grain by spraying the fungicide, but are just a reflection of random variation in the experiment. But they clearly show there was no advantage to the fungicide application in that instance.