Herbicide efficacy in the fall management of Richardia brasiliensis, Commelina benghalensis, Conyza sumatrensis AND Digitaria insularis

Abstract

Other herbicides, alone or in combination with glyphosate, may be effective in controlling Richardia brasiliensis, Commelina benghalensis, Conyza sumatrensis e Digitaria insularis. Therefore, the aim of this study was to evaluate the efficacy of herbicides, alone or in combination, in the control of these weeds in the off-season. Three composite experiments were conducted by applying herbicides, alone or in combinations. Experiments 1 and 2 were conducted in Palotina, State of Paraná (PR), Brazil. Experiment 3 in Iporã, PR, Brazil. The three during fall 2017 in fallow areas after soybean harvest. The experiment was a randomized complete block design with 4 replications and weed control at 7, 14, 21, 28, 35, and 42 days after application (DAA). The control of R. brasiliensis and C. benghalensis was evaluated in the three experiments, the control of C. sumatrensis, in experiments 1 and 2, while the control of D. insularis was evaluated only in experiment 3. Data were subjected to analysis of variance and F-test (p < 0.05). The treatment means values of experiments 1 and 2 were compared by Tukey’s test (p < 0.05), and the treatment mean values of experiment 3 were grouped by the Scott and Knott test (p < 0.05). Some herbicide combinations were effective in controlling R. brasiliensis, C. benghalensis, in a single or sequential application. Herbicide combinations were effective in controlling C. sumatrensis with sequential application. Herbicide combinations in a single application did not provide satisfactory final control (≥ 80%) for D. insularis.

Incremento na eficácia de herbicidas no controle de plantas daninhas devido a aplicação sequencial de glufosinate + saflufenacil

“…The application of glyphosate, alone or in a combination, followed by the application of glufosinate, effectively controlled fleabane (Albrecht et al, 2020b). Similar effects were observed by Meyer and Norsworthy (2020) for the subsequent application of glufosinate in grass and broadleaf control as well as by Bottcher et al (2022) for the combined application of saflufenacil in fleabane and Benghal dayflower.…”

“…Sequential application of glufosinate was important in Benghal dayflower control, as it increased the efficacy of chlorimuron or s-metolachlor, alone or in combination with glyphosate; in contrast, carfentrazone alone or in mixture with glyphosate achieved 100% control even without subsequent application of glufosinate (Jerônimo et al, 2021). Furthermore, subsequent application of saflufenacil or other herbicides was effective after the initial application of glyphosate + Protox inhibitor + dicamba in controlling Benghal dayflower (Bottcher et al, 2022).…”