Synedrellopsis grisebachii is a weed of great importance for pastures in Brazil, presenting outstanding aggressiveness, with its control being thus desirable for successful forage production. The aim of this work was to evaluate the chemical control of S. grisebachii at their reproductive phase and their effects on the germination characteristics of the weed's achenes. The treatments consisted of applying the herbicides glyphosate (100, 200, 900, and 1.800 g ha-1), paraquat (34, 68, 300, and 600 g ha-1) and triclopyr (75, 150, 667, and 1.334 g ha-1) and the control without application. Achenes were collected at 15 days after application and were submitted to germination tests to determine germination percentage and speed. After 29 days of germination, the viability of non-germinated achenes was verified by the tetrazolium test. The effectiveness of the herbicides was evaluated by visual scores of the control at 7, 14, 21, and 28 DAA. It was concluded that the control of S. grisebachii at the reproductive stage requires application of1.334 g triclopyr ha-1. At this stage, the plant was highly tolerant to glyphosate and to paraquat, as well. For the germination characteristics ofthe progeny, triclopyr at doses of 150 and 667 g ha-1promoted a reduction in the germination rate and viability, while glyphosate and paraquat had no effect.
Synedrellopsis grisebachii; chemical control; germination power
