Initial growth of sugarcane pre-sprouted seedlings in two types of application of herbicides

Abstract

The specie Cyperus rotundus is among the weeds most difficult to control and can cause high losses in the sugarcane crop. The practices adopted in the culture guarantee the values of yield, among them, is the weed management. The objective of this work was to evaluate the initial growth of sugarcane pre-sprouted seedlings submitted to herbicide application before or after planting. Two experiments (pre and post-planting) were conducted in greenhouse, in a completely randomized design, with four replications. The treatments corresponded to the herbicides applied in three pre-planting doses: sulfentrazone (400, 800 and 1,600 g a.i. ha-1), diclosulam (96.6, 193.17 and 386.34 g a.i. ha-1), imazapic (66.5, 133 and 266 g a.i. ha-1) and imazapyr (250, 500 and 1,000 g e.a. ha-1) and post-planting: halosulfuron (56.25, 112.5 and 225 g a.i. ha-1), ethoxysulfuron (67.5, 135 and 270 g a.i. ha-1), 2,4-D (670, 1,340 and 2,680 g a.e. ha-1) and MSMA (987.5, 1,975 and 3,950 g a.i. ha-1). In addition to two controls without herbicide application. The crop injury, height, diameter, number of leaves, number of tillers, chlorophyll content, leaf area, dry mass of shoot and root were evaluated. Post-planting treatments were considered selective, since the crop injury were low, and the other parameters evaluated were not different from the control. For pre-planting applications, crop injury were observed up to 60 days after application (DAA) for sulfentrazone.