Abstract

Weed infestations and the few post-emergent control alternatives available are some of the main problems in the management of ornamental and sports lawns. Given the exposed, the study aims to evaluate the selectivity of five herbicides to four grass varieties: Paspalum notatum (bahia grass), Cynodon dactylon (bahama grass- ITG6), Zoysia japonica (japanese lawn grass) and Zoysia japonica (imperial – ITG5), as well as the control efficiency of those upon nutsedge (Cyperus rotundus) and sudan grass (Urochloa decumbens). The following herbicides were applied in the recommended doses:  sulfentrazone + diuron, isoxaflutole, triclopyr, 2,4-D and halosulfuron. Visual phytotoxicity symptoms in turfgrass and weed control were performed at 7, 14, 21, 28, 35 and 42 days after herbicide application and, at the end of the evaluations, was quantified the dry weight. The herbicides sulfentrazone + diuron and isoxaflutole were not selective to any turfgrass, although sulfentrazone + diuron controlled C. rotundus and U. decumbens species and isoxaflutole controlled only U. decumbens.  However, halosulfuron and 2,4-D herbicides were selective to all of grasses and promoted weed species control. The herbicide triclopyr was selective to P. notatum, Z. japonica and Z. japonica– ITG5, and it can be used to control C. rotundus and U. decumbens.

Key words: Urochloa decumbens, Cynodon dactylon–ITG6, Cyperus rotundus, Paspalum notatum, Zoysia japonica.