L. G. H. Bridi

The research proposal was part of the evaluation of the application technology, control efficiency and selectivity of the chia crop (Salvia hispanica L.) subjected to sequential applications of herbicides inhibiting the enzyme ACCase. The experiment was conducted under field and in the laboratory conditions at the State University of the Midwestern Paraná State University (UNICENTRO), CEDETEG Campus, Guarapuava, Paraná, Brazil. The treatments consisted of the sequential application of clethodim (108 and 216 g ha-1), sethoxydim (184 and 368 g ha-1), tepraloxydim (200, 100 and 200 g ha-1), haloxyfop (48 and 96 g ha-1), fenoxaprop (110 and 220 g ha-1), quizalofop (120 and 240 g ha-1), fluazifop (250 and 500 g ha-1), weeded control and unweeded control. All herbicides were associated with the adjuvant mineral oil Assist™ (0.25 L ha-1) and sprayed with an application rate of 200 L ha-1. No significant differences were found between the treatments for the spray deposition of herbicides applied to crabgrass (Digitaria horizontalis). In chia, the average deposition of the treatments clethodim (216 g ha-1), sethoxydim (368 g ha-1), tepraloxydim, haloxyfop and fenoxaprop was 16.5% higher than the group of other herbicides. All herbicides were efficient for crabgrass, especially in sequential application, although they caused height reduction and more evident phytotoxicity symptoms in the crop in the second application (≤18%). However, only haloxyfop (48 and 96 g ha-1) and quizalofop (240 g ha-1) were not considered selective for sequential application in chia because they reduced grain yield by around 15.3% and 26.7%, respectively.

This study aimed to evaluate the efficacy of the herbicide pyraflufen-ethyl, with and without the adjuvant, for the control of Raphanus raphanistrum (wild radish) in wheat pre-sowing, as well as the spray deposition dynamics and physicochemical properties of the spray solutions. Two experiments were conducted under field and laboratory conditions, comprising 12 treatments: pyraflufen-ethyl (7.5, 8.75, 10.0, 11.25, and 12.5 g ha-1), applied with and without the adjuvant (Lanzar® 0.2% v/v), iodosulfuron-methyl (10.0 g ha-1), and an untreated control, in a completely randomized design. Results indicated that the tank mixture of pyraflufen-ethyl with the adjuvant reduced pH, increased electrical conductivity, and had little effect on the static surface tension of the solutions. The combination of pyraflufen-ethyl with the adjuvant Lanzar® (0.2% v/v) decreases pH, increases electrical conductivity, and has minimal effect on the surface tension of the solutions. Pyraflufen-ethyl, from a dose of 7.5 g ha−1 combined with the adjuvant Lanzar® (0.2% v/v), significantly enhanced spray deposition and the speed of control of Raphanus raphanistrum, while also demonstrating selectivity for use in pre-sowing applications in wheat cultivation.