Revista Brasileira De Herbicidas 2001; 2(1-2): 23-30
Purple nutsedge (Cyperus rotundus L.) control in sugar-cane crop with imazapic herbicide, isolated or in mixture whith pendimethalin
The major problem with the sugar cane crop is weed competition, especially purple nutsedge which is a very agressive plant. The trial was carried out at Usina São Carlos (a sugar mill), Jaboticabal-Sl’, during the summer period (1999/2000) aiming to study the effect of imazapic herbicide on purple nutsedge control, sprayed at pre and postemergence, alone or in mixture with pendimethalin. The experimental design was randomized blocks with thirteen treatments and four replications. The treatments were: controls (with and without weeds), imazapic herbicide (13.5,98.0, 122.5 and 147.0 g/ha), imazapic + pendimethalin (50+ I000, 60+ 1200, 70+ 1400 g/ha), in preemergence application. Postemergence treatments were imazapic, at the same doses, with surfactant 0.15% v/v. The herbicide was applied with a manual sprayer, with a constant pressure of 2,8 kg/cm- and jet nozzles with descontinuous deposition (XR II 002), using the equivalent of 250 Ilha of the herbicide solution. The sugar cane variety used was RB 855536. The best pre-emergence weed control (96%) was observed with 147 g/ha of ~mazapic at 27 days afte~ appl~cation .. The P?stemergence applications cannot be used because they caused high toxicity 111 the culture. The herbicide mixture (imazapic+pendimethalin) showed low efficacy for ali tested treatments.
534