Uso de herbicidas no controle de plantas daninhas e em mudas pré-brotadas (MBPS) de diferentes variedades de cana-de-a?úcar

摘要

Pre-sprouting seedlings (MPB) of sugarcane arrive in the field with the aerial part and roots developed, being able to present sensitivity to herbicides and to change weed control management. Therefore, the objectives of this work were determine the chemical control of Cynodon dactylon, Chloris polydactyla and Merremia aegyptia ; and to determine the effect of the herbicides on pre-budded seedlings of different varieties of sugarcane. The experimental design was completely randomized with eleven treatments and four replicates. The herbicides saflufenacil, clomazone, metribuzim, tebuthiuron, indaziflam, saflufenacil + clomazone, saflufenacil + metribuzim, saflufenacil + tebuthiuron, indaziflam + metribuzin, indaziflam + tebuthiuron, and control were applied for the control of Cynodon dactylon, Chloris polydactyla and Merremia aegyptia and on MPBs varieties - RB 867515, RB 966928 and CTC 9001. Control evaluations were performed at 15, 30 and 45 days after application (DAA) and phytotoxicity in the culture at 15, 30, 45 and 60 DAA, in addition to biomass of the aerial part. For C. polydactyla all treatments were effective, for M. aegyptia the best treatments were saflufenacil, metribuzin and saflufenacil + tebuthiuron e saflufenacil + tebuthiuron. In the control of C. dactylon we could highlight clomazone, metribuzin, saflufenacil + clomazone e tebuthiuron. The indaziflam and indaziflam + metribuzin treatments impaired the initial growth of the MPBs of the three studied sugarcane varieties; therefore, they present limitations in the use of MPBs.