Pre-sowing application of combinations of burndown and pre-emergent herbicides for Conyza spp. control in soybean

Abstract

Together, Conyza bonariensis, C. canadensis and C. sumatrensis show 105 reported cases of biotypes resistant to herbicides like glyphosate, paraquat, and acetolactate synthase (ALS) inhibitors. The application of pre-emergent herbicides combined with burndown herbicides is believed to be effective in controlling Conyza spp. during soybean pre-sowing management. The objective of this study was to evaluate the efficacy of sulfentrazone/diuron, imazethapyr/flumioxazin, and diclosulam in mixtures with diquat, paraquat, or glufosinate on the control of Conyza spp. Two field experiments were conducted in a randomized block design with four replicates. Treatments consisted of the application of pre-emergent plus burndown herbicides, besides the weedy control treatment (without application), for a total of 10 treatments. The control of Conyza spp. was evaluated at 7, 14, 21, 28, and 35 d after herbicide application, and symptoms of injury in soybean plants were evaluated at 14, 21, 28, and 35 d after herbicide application. The herbicides sulfentrazone/diuron, imazethapyr/flumioxazin, and diclosulam in combination with burndown herbicides diquat, paraquat, or glufosinate were effective in controlling Conyza spp. in the pre-sowing management of soybean, highlighting good options for pre- and post-emergent herbicide rotations. Mixtures with diclosulam showed a higher potential for injury to soybean plants than sulfentrazone/diuron and imazethapyr/flumioxazin.

Sumatran fleabane (Conyza sumatrensis [Retz.] E. Walker) control in soybean with combinations of burndown and preemergence herbicides applied in the off-season

“…Studies highlight the effectiveness of herbicides with preemergence action in controlling Conyza spp. in soybean, for example, flumioxazin (PITTMAN et al, 2019), diclosulam (KRENCHINSKI et al, 2019), diuron (SANTOS et al, 2015), sulfentrazone (ALBRECHT et al, 2021), imazethapyr (ALBRECHT et al, 2020c) among others.…”

Alternativas ao paraquat para o controle químico de azevém, aveia e buva

“…A proibição do uso do paraquat apenas reforça a necessidade da caracterização e delineamento de novos manejos. Neste sentido, pode ser ressaltado o glufosinate (Tahmasebi et al, 2018;Albrecht et al, 2020c;Cantu et al, 2021;Albrecht et al, 2021), o que foi observado neste estudo, principalmente, por exemplo, nas associações com saflufenacil. A aplicação de glufosinate + saflufenacil também é destacada em outros trabalhos como eficaz no controle da buva (Waggoner et al, 2011;Zobiole et al, 2018).…”