Current commercial sprayers apply herbicides uniformly across the entire field, even though there is extensive documentation that weeds are patchy in distribution and found on less than 40% of the area. There is a commercially available weed-sensing sprayer (WSS) that can discretely detect and treat weeds, but cannot differentiate between weed and crop plants. Therefore, the WSS sprayer can currently be used for weed control only in the area between crop rows. The objectives were to evaluate site-specific postemergence weed control and find temporal and spatial relationships with summer and winter weed vegetation within and across years, modify a decision support system and develop and disseminate weed biology and management information to producer, extension personnel, and consultants.