Wild oats is na important weed in wheat in the southwestern Pampas of Argentina representig a high percentage of the soil seed bank. Even though specific herbicice are use, a high number of panicles and seeds survive. The aim of this study was to evaluate the effect of post emergence selective graminides upon the development of the wild oats seed bank in a wheat crop. The experiment was conducted in a randomized block with four replications. The treatments were: a) control (no herbicides), b) tralkoxydim (150 and 200 g/ha), c) fenoxaprop-p-etil (69 and 83 g/ha), d) pirifenop-n-butil (50 and 55 g/ha), and e) diclofop metil (510 and 570 g/ha). All herbicides were used at the recommended rates. In the first year, with a low infestation level (153 plants/ m2), all herbicides had a good effect. No differences between treatments were observed. In the second year, with a high level (285 plants/m2), the production of wild oats seeds was reduced to between 60% and 95% compared with the control and there were differences between treatments. Despite the effectiveness of the treatments, the seed produced were enough to keep the seed bank constant.
Avena fatua control; tralkoxydim; fenoxaprop-p-etil; diclofop-metil; pirifenop-N-butil