Abstract

This study determined the efficacy of sulfentrazone, halosulfuron and imazapic applied in preemergence conditions for the control of purple nutsedge (Cyperus rotundus L.) in response to weed tuber density. The tubers were planted in 5 L pots at densities of 6, 18, 24, 30 and 36 tubers/pot (133.3, 399.9, 533.2, 665.5 and 799.8 tubers/m², respectively), and sulfentrazone (800.0 g a.i.ha^-1), halosulfuron (112.5 g a.i. ha^-1) or imazapic (147.0 g a.i.ha^-1) was applied 24 h after planting. The experimental design was the Completely Randomized Design (CRD) in a 5×4 factorial scheme with 4 replications. At the end of the experimental period (60 days after planting), the number of dead and viable tubers, dry biomass of viable tubers, and number and dry biomass of epigean manifestations were determined. The data were analyzed using the F test, and the means were compared using Tukey’s test at 5% probability. Independently of tuber density, sulfentrazone performed better than either imazapic or halosulfuron in controlling nutsedge epigean manifestations and tubers.

Key words: Purple nutsedge, chemical control, herbicides, preemergence.