Revista Brasileira De Herbicidas 2015; 14(4): 263-270
Application rates and herbicide in weed control in pasture
Pastures formed with Cynodonn lemfuensis Vanderyst are excellent alternatives for feeding livestock. The competition from weeds can cause damage to pasture, and Vernonia polyanthes and Desmodium incanum are among the main competing species. The objective of this study was to evaluate the efficacy of different herbicides to control Vernonia polyanthes and Desmodium incanum, applied in high and low spray mix volumes. The experiment was established in an area formed for over 10 years by African stargrass (Cynodonn lemfuensis). The experimental design was a randomized block in a 2×7 factorial arrangement with two spray mix volumes of 50 and 200 L ha-1 and seven herbicides. Variables phytotoxicity on grass Cynodonn lemfuensis at 3, 7, 14, 21 and 28 days after application (DAA) and control of weed plants Vernonia polyanthes and Desmodium incanum at 7, 14, 21 and 28 DAA were evaluated. There were no high levels of phytotoxicity in the pasture. The treatments that provided the best controls of Vernonia polyanthes and Desmodium incanum were fluroxypyr-meptyl + triclopyr, 2,4 D + aminopyralid and 2,4 D + picloram. Spray mix volumes provided no significant differences in the evaluation of control after 28 DAA for herbicides, but were higher for some treatments at 7, 14 and 21 DAA. Thus, the lowest volume of spray mix (50 L ha-1) becomes a viable alternative in the control of these species in the pasture.
314