Fungicide Evaluation in Winter Wheat

Objective:       

To evaluate application timings and rates of Headline for the control of stripe rust in winter wheat. 

Results:          

Headline was applied to Decade winter wheat at two rates (6 and 9 fl oz/A) and two growth stages (two tiller and flag leaf), either as single or sequential applications on May 1 and May 20, respectively (Table 2). The application of Headline resulted in significant differences for percent stripe rust infection, yield, and test weight. Stripe rust infection averaged 25.2%, and ranged from 7.7% to 61.7 percent. Most treatments afforded commercially acceptable control. However, the 6 oz/A rate applied at the two tiller stage of growth produced infection levels comparable to the non-treated check.  In turn, yields were statistically equivalent between these two treatments. 

            An analysis was performed to evaluate the economic feasibility of sequential fungicide applications. The highest adjusted gross return ($497.20) was obtained with 9 oz/A applied as a single application at flag leaf (Table 3). Conversely, the least profitable fungicide treatment ($413.50) was 9 oz/A applied sequentially.   This occurred despite having the highest level of stripe rust control.  In short, there was not a direct relationship between stripe rust control and profitability. 

Further, there was not a direct relationship between yield and profitability. Although the sequential application at 6 fl oz/A afforded the highest yield at 109.9 bu/A, the adjusted gross return was $495.60 per acre.  The benefit of making two applications at the 6 fl oz/A rate compared to a single application at flag leaf was $4.70. In comparison the financial loss of sequential applications at the 9 fl oz/A compared to the single application at flag leaf was $83.70/A.

Summary:       

Headline was effective at controlling stripe rust and the most economical application timing was at flag leaf at 9 fl oz/A.