How many fungicide sprays will be needed in a season to control ASR?
Based on current research, if ASR arrives in Virginia during the reproductive stages (R1-R6), soybean producers will most likely need to apply from one to three fungicide applications to obtain optimal disease control. The number of fungicide applications, if any, depends on when ASR arrives, expected weather conditions, and the cost effectiveness of disease control (i.e. yield potential of the field, the expected price per bushel, cost of fungicide application, etc.). In Brazil during the 2003/2004 season, it was estimated that 95 percent of the acreage was treated with either one or two sprays. The number of sprays increased to an average of two to three sprays in the 2004/2005 season. Short-season cultivars had less exposure to the disease and, therefore, only required one spray, whereas long-season cultivars needed two to three applications to achieve adequate protection. In Georgia and Alabama, the first spray was deemed most important in controlling the disease in 2005. Therefore
