Peanut Rx: A Prescription Program to Better Manage Fungal Diseases.

To protect their crop from diseases, peanut growers in Georgia have historically initiated fungicide programs 30 days after planting and continued applications on a 14-day schedule for seven sprays. Growers have been unwilling to adopt weather-based spray advisories; however many growers sought means to reduce the cost of fungicide programs without losing yield or disease control.  “Peanut Rx” allows growers to estimate risk of disease in fields by assessing the impact of nine production factors and field history on diseases.  Once the grower has determined the risk of disease, Peanut Rx can be used to develop fungicide programs appropriate for the level of disease risk.  In this study “Peanut Rx” was the basis for assessment of reduced-input fungicide programs.  The reduced-input fungicide programs were compared to a full-season fungicide program for disease control, yield, and value to the grower. In 2008 three field studies were conducted in Georgia and two studies were conducted in Alabama.  A standard full-season program from Syngenta Crop Protection (Tilt/Bravo (1.5 pt/A) applications 1 and 2, Abound (18 fl oz/A) applications 3 and 5, and Bravo WeatherStik (1.5 pt/A) applications 4, 6, and 7) was compared to a moderate-risk 5-spray program and a low-risk 4-spray fungicide program.  Risks at each research site for leaf spot diseases, stem rot, and limb rot were typically assessed as “high” or “moderate” based primarily on short crop rotation and variety selection.  It was estimated that a grower could save $11.94/A and $31.07/A each season if able to spray five or four times, respectively, rather than seven times.  In these trials, low-risk, moderate-risk, and high-risk fungicide programs did not differ in control of leaf spot, rust, or soilborne diseases nor did they differ in yield.  Thus, specific reduced-input fungicide programs can be beneficial to growers when used in appropriate situations.