Herbicides to weed control and in pre-budded seedlings (MBPs) of different varieties of sugarcane

Mudas pré-brotadas (MPB) de cana-de-açúcar chegam ao campo com a parte aérea e raízes desenvolvidas podendo apresentar sensibilidade a herbicidas e mudar o manejo de controle de plantas daninhas. Portanto, os objetivos deste trabalho foram: determinar o controle químico das plantas daninhas Cynodon dactylon, Chloris polydactyla e Merremia aegyptia; e determinar o efeito dos herbicidas em mudas de pré-brotadas de diferentes variedades de cana-de-açúcar. O delineamento experimental foi inteiramente casualizado com onze tratamentos e quatro repetições. Os herbicidas saflufenacil, clomazone, metribuzim, tebuthiuron, indaziflam, saflufenacil + clomazone, saflufenacil + metribuzim, saflufenacil + tebuthiuron, indaziflam + metribuzin, indaziflam + tebuthiuron, além de testemunha, foram aplicados para o controle de Cynodon dactylon, Chloris polydactyla e Merremia aegyptia e sobre as MPBs das variedades RB 867515, RB 966928 e CTC 9001. Avaliações de controle foram realizadas aos 15, 30 e 45 dias após aplicação (DAA) e de fitotoxicidade na cultura aos 15, 30, 45 e 60 DAA, além da biomassa seca da parte aérea. Para o C. polydactyla todos os tratamentos foram eficazes, para M. aegyptia os melhores tratamentos foram saflufenacil, metribuzin e saflufenacil + tebuthiuron e saflufenacil + tebuthiuron. No controle de C. dactylon destacaram-se clomazone, metribuzin, saflufenacil + clomazone e tebuthiuron. Os tratamentos indaziflam e indaziflam + metribuzin prejudicaram o crescimento inicial das MPBs das três variedades de cana-de-açúcar estudadas, portanto, apresentam limitação no uso em MPBs.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