A harvesting vehicle includes a header having a cutter bar, a crop transport draper and a reel mounted above the cutter bar to sweep the crop to the draper. The operation of the header is autonomously monitored and controlled to reduce operator loads or to run autonomously by detecting: reel wrapping; differential rates of flow of crop on the header at different locations; where the crop to be cut is at least partly lodged so that stems of the crop are not vertical; the presence of a crop streak of uncut or poorly cut crop behind the cutter bar and/or a band of disturbed soil behind the cutter bar. The detector is arranged to control ground speed, header height, reel height and operation.