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O controle de plantas daninhas na cultura do cafeeiro é dificultado pela escassez de herbicidas seletivos para a cultura em fase de implantação. Uma alternativa para contornar os danos causados pelos herbicidas é o uso de protetores químicos com capacidade de minimizar a intoxicação dos herbicidas. Objetivou-se avaliar a seletividade de herbicidas aplicados isoladamente ou em mistura no tanque com o Fertiactyl Sweet® para plantas de café recém-transplantadas. O experimento foi realizado em vasos em delineamento inteiramente casualizado, em esquema fatorial 10x2, com quatro repetições. O primeiro fator correspondeu a nove herbicidas: (oxyfluorfen; sulfentrazone; flumioxazin; [isoxaflutole + indaziflam]; isoxaflutole; indaziflam; [metribuzin + indaziflam]; chlorimuron-etílico; e metsulfuron-metílico) e o controle sem aplicação de herbicida; o segundo fator constou da presença ou ausência do Fertiactyl Sweet. Os tratamentos foram aplicados em “over the top” aos 30 dias após o transplantio. De 7 aos 172 dias após a aplicação (DAA), avaliou-se a porcentagem de intoxicação. E aos 172 DAA, mensurou-se as variáveis morfológicas das plantas. A adição do Fertiactyl Sweet junto à calda dos herbicidas não modificou a tolerância das plantas de café aos herbicidas. Os herbicidas mais tolerantes para o café foram o oxyfluorfen e o sulfentrazone. A mistura comercial indaziflam + metribuzin causou a morte das mudas de café. O Fertiactyl Sweet® não reduziu a intoxicação das mudas de café arábica (Catuaí vermelho - linhagem 44) causada pelos herbicidas estudados. Os herbicidas metsulfuron-metílico e oxyfluorfen foram os mais tolerados pelas plantas de café recém-transplantadas.

The no-tillage system is considered an important tool for sustainable production. In this system, the burndown of brachiaria is usually performed with the application of systemic herbicides, such as glyphosate. As a result of environmental conditions (temperature, relative humidity and winds), the timing of spraying can directly interfere in the control efficiency. Therefore, the objective was to study different times of application of glyphosate in the control efficiency of Urochloa brizantha cv. Marandu. The glyphosate was applied in the morning, afternoon and evening, at doses of 0; 360; 720; 1080; 1440 and 2160 g a.e. ha-1. To analyse the efficiency of U. brizantha burndown, the phytotoxicity was evaluated at 21 days after application. At 42 after application a mowing was done and 90 days after mowing, the dry matter accumulation and the Leaf Area Index of regrowth were determined. The best control results of Urochloa brizantha cv. Marandu were obtained in the applications of glyphosate during the morning and afternoon. Evening applications of glyphosate should be avoided.

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Knowledge of the minimum rate of glyphosate required to eradicate sugarcane ratoons can reduce the amount of herbicide used. To confirm this hypothesis, this study aimed to investigate the tolerance of different sugarcane cultivars to chemical eradication, at different glyphosate rates. The experiment was conducted in a randomized block design in a split-plot scheme, with four replications. The sugarcane cultivars (IACSP94-2094, IACSP94-2101, IACSP93-3046, IACSP94‑4004, IAC86-2480, and RB72454) were allocated in plots and the glyphosate rates (0, 1,440, 2,160, 2,880, 3,600, and 4,320 g ha-1), in the sub plots. The traits evaluated were signs of poisoning symptoms; total chlorophyll content, plant height, percentage of dead tillers, and dry weight of the plants. At 45 days after application (DAA), the glyphosate rate of 1,440 g a.e. ha-1 eradicated the cultivars IACSP94-2094 and IACSP94-2101, as well as RB72454 with application of 2,160 g a.e. ha‑1. Application of glyphosate 2,880 g a.e. ha-1 eradicated both IACSP93-3046 and IAC86-2480 and glyphosate 3,600 g a.e. ha-1 eradicated IACSP94-4004. The most tolerant cultivar was IACSP94‑4004, eradicated at the rate of 3,600 g. a.e. ha-1. This confirms the hypothesis that knowing the cultivar's tolerance leads, in practice, to a smaller amount of herbicide applied to the environment, which also reduces production costs.