A 2-yr field study was conducted to measure the growth and development of Russian thistle (Salsola iberica Sennen and Pau # SASKR) in the growing crops of winter and spring wheat (Triticum aestivum L.) and after harvest of these crops. In herbicide-free conditions, few Russian thistle seedlings emerged in winter wheat. Only 50% of these plants survived compared to 92 and 95% survival in spring wheat and crop-free treatments, respectively. Compared to growth in the crop-free treatment, both wheat types suppressed oven-dry weight, height, and width of Russian thistle plants during the crop-growing season and after crop harvest. During the crop-growing season, winter wheat suppressed Russian thistle height and width more than spring wheat. After crop harvest, oven-dry weight of Russian thistle plants grown in winter wheat stubble was suppressed 75% compared to plants grown in spring wheat stubble. Russian thistle plants grown in crop-free, spring wheat, and winter wheat treatments produced 152 100, 17 400, and 4 600 seeds/plant, respectively.
