Performance of herbicides for weed control in sorghum

Abstract

Chemical weed control in sorghum crop is limited by the low quantity of herbicides registered for the crop. Studies on the effects and effectiveness of herbicides in sorghum crop are essential to increase alternatives for the control of weeds. In this context, the present study was to evaluate the effect of intoxication caused by herbicides in sorghum, as well as the effectiveness of these for weed control. The experiment was conducted the field in a randomized block design, evaluating eight treatments with four replications. The treatments consisted of three herbicides applied preemergence (g ha^-1): trifluralin (1200), S-metolachlor (768) and clomazone (1000); four treatments with postemergence herbicides applied: bentazon (720), bentazon + atrazine (480 + 880), atrazine (2200) and bentazon + pendimethalin (720 + 1000); and a check without herbicide (control in weed). Herbicides applied preemergence (clomazone, trifluralin and S-metolachlor), caused high toxicity in the sorghum plants. No injuries were observed in sorghum plants by the use of herbicides in postemergence. The clomazone and trifluralin herbicides had control for all evaluated monocotyledonous weeds, though the S-metolachlor only did not get to control C. echinatus. The use of atrazine or mixture with bentazon showed promising to control dicotyledonous weeds.