SELECTIVITY OF HERBICIDES APPLIED ALONE AND IN TANK MIXTURES TO SWEET SORGHUM IN POST-EMERGENCE

Abstract

The small number of herbicides registered for sorghum (Sorghum bicolor (L.) Moench) restricts its cultivation. The aim of this study was to evaluate the selectivity of herbicides applied alone or in tank mixtures to sweet sorghum in post-emergence. Two experiments were conducted in greenhouse, the first with herbicides applied alone and the second with herbicide mixtures. Based on the results of greenhouse experiments, treatments were selected to evaluate selectivity in the field. In the field experiment, the herbicides applied alone and herbicide mixtures did not differentiate from the control without herbicide application regarding to phytotoxicity, fresh mass of the aerial part, percentage of dry mass of the aerial part and Brix of sweet sorghum at 28 days after application. The treatments considered selective were: atrazine (1000 to 2000), bentazon (360 to 720), S-metolachlor (576 to 864), mesotrione (48 to 150), carfentrazone (4 to 8), 2,4-D amine (335 to 670), besides mixtures with [atrazine + S-metolachlor] [601 + 471.2] and [901.5+ 706.8], atrazine + 2,4-D amine (1000 to 2000 + 100.5 to 268), atrazine + tembotrione (1000 + 42 to 63) and atrazine + mesotrione (1000 + 48 to 72) (doses in g a.i. ha^-1).