Seletividade de saflufenacil aplicado em isolado ou associado a outros herbicidas em milho

Abstract

Among the methods of control of weeds infesting corn, the chemical stands out as the most used, due to its efficiency, practicality and lower cost when compared to other available tools. Therefore, the objective of this work was to evaluate the selectivity of saflufenacil applied alone or associated with pre- and post-emergent herbicides in the corn hybrid SYN 488 VIP. For this, two trials were installed, one in the 2019/20 agricultural year and the other in 2020/21, in an experimental design of randomized blocks with 4 replications. The treatments applied in pre- and post-emergence were; atrazine (3000 g ha-1 ), atrazine + simazine (1500 + 1500 g ha-1 ), atrazine + oil (2400 g ha-1 ), S-metolachlor (1680 g ha-1 ), atrazine + S-metolachlor (1665 +1305 g ha-1 ), mesotrione + atrazine (100 +1000 g ha-1 ), pyroxasulfone + flumioxazin (120 + 80 g ha-1 ). These same treatments applied in preemergence were used in post-emergence with or without saflufenacil; plus a weeded control. The variables evaluated were phytotoxicity to corn at 7, 14, 21, 28 and 35 days after application of treatments (DAT). At 21 DAT, the physiological variables of maize were measured. At the time of maize harvest, grain yield components such as; (ear length, number of rows per ear, number of grains per row, thousand weight and grain yield) were determined. The herbicides that showed the highest phytotoxicity to Syngenta 488 VIP3 maize hybrid were S-metolachlor + saflufenacil (T12), atrazine + oil + saflufenacil (T11), atrazine + Smetolachlor + saflufenacil (T14) and pyroxasulfone + flumioxazin + saflufenacil (T16). The use of pyroxasulfone + flumioxazin + saflufenacil (T16) negatively affected the physiological characteristics of the maize hybrid Syngenta 488 VIP3. The herbicides S-metolachlor + saflufenacil (T5) and atrazine + saflufenacil (T10) showed the best performance for all maize grain yield components. The application on maize of the herbicides, atrazine + saflufenacil (T2 and T10), atrazine + oil + saflufenacil (T4), S-metolachlor + saflufenacil (T5), mesotrione + atrazine + saflufenacil (T7), atrazine + simazine + saflufenacil (T13) and atrazine + Smetolachlor + saflufenacil (T14) showed the highest grain yields.