Performance de diferentes herbicidas no controle de capim camalote (Rottboellia exaltata) em cana-de-açúcar)

Abstract

Brazil is the world's largest producer of sugarcane, and camalote grass (Rottboellia exaltata) causes losses in crop productivity due to the low efficacy of the herbicides recommended for controlling this weed. Therefore, the objective of this work was to analyze the efficacy of different herbicides alone or in combination in the pre-emergence control of ragweed, also evaluating the selectivity of the herbicides on sugarcane stubble. The experiment was conducted in the city of Bom Sucesso, Paraná, in an area of ratoon sugarcane, using a randomized block design with four repetitions. Twenty treatments were tested, including Tebuthiuron, Clomazone, Indaziflan, Isoxaflutole, Amicarbazone, Pyroxasulfone, Flumioxazine, Diuron, Hexazinone, Sulfometurom Methyl, used alone or as a mixture, and the control group, which did not use any chemical control. The aim of the study was to evaluate the selectivity and the percentage of control of the treatments, and the evaluations were made using a visual percentage scale (ALAM, 1974), from 0 to 100% of phytotoxicity and 0 to 100% of control. The phytotoxicity evaluations were done 7 and 15 days after the application, and those that evaluated the percentage of control at 30, 60, 90 and 120 days after the application. The results obtained were analyzed and submitted to the Scott-Knott test. The treatment amicarbazone + isoxaflutole + indaziflan was the only mixture that provided satisfactory control (>80%) over the camalote grass (Rottboellia exaltata) seed bank, with a control percentage of 92% over the seed bank, also showing good selectivity to sugarcane with a phytotoxity percentage of 45% at 14 DAA.