Managing glyphosate-resistant weeds with cover crop associated with herbicide rotation and mixture

Abstract

Herbicide resistance has become a major concern for agricultural systems, and integrating weed management practices seem to be the most promise way for its mitigation. The effects of cropping systems including ruzigrass (Urochloa ruziziensis) associated with herbicide rotation programs were evaluated for the management of glyphosate resistant conyza (Conyza sumatrensis) and sourgrass (Digitaria insularis) in soybean and corn production systems. A 3x3 factorial was evaluated in four consecutive soybean (spring-summer) and corn (fall-winter) double cropping seasons. Factor A consisted of three combinations of cropping systems in the fall-winter: corn, corn plus ruzigrass, and ruzigrass alone. Factor B was based on increasing levels of diversity in herbicide mode of action over the four-year period (5, 8, and 11 MoAs). The results indicate that using ruzigrass significantly increased soil coverage by cover crop residues. In general, the cover crop was more efficient for conyza than for sourgrass control, whereas herbicide programs provided greater control on sourgrass than on conyza. Besides the weed suppression effect, the accumulation of ruzigrass biomass on the soil surface during the fall-winter also improved yield of soybean in the spring-summer. The integration of ruzigrass as a cover crop and the use of herbicide programs with multiple modes of action can provide efficient control of glyphosate-resistant conyza and sourgrass. The use of only one of these strategies was not effective in most cases, especially for the long term.

ACCase-inhibiting herbicides: mechanism of action, resistance evolution and stewardship

“…The harvest weed seed control is a promising tool to destroy weed seeds at crop harvest, lowering the soil seed bank and adding one additional diversity level in weed control . Likewise, the integration of herbicide rotation and mixture with cover crops such as Brachiaria ruziziensis is a successful example of integrated weed management to mitigate herbicide resistance (Marochi et al, 2018).…”

Sensitivity of Digitaria insularis to herbicides in agricultural areas, in the Brazilian Cerrado biome

“…However, all populations were susceptible to clethodim, confirming the importance of this herbicide for the management of D. insularis. Moreover, good agricultural practices should be used to avoid the evolution of new cases of resistance and multiple resistance, including the use of soil cover plants, crop rotation, mixture of herbicides, and the association of chemical and mechanical weed control methods (Marochi et al, 2018;Raimondi et al, 2020).…”

“…According to Adegas et al (2018), the cost of weed management in soybean crop areas with glyphosate-resistant D. insularis may increase from 165 to 290%. Resistant D. insularis plants are difficult to control due to the reduced chemical control options available (Carpejani & Oliveira, 2013;Gazola et al, 2016;Zobiole et al, 2016), which not only requires changes of herbicides, but also of the weed management in agricultural areas, from the medium to long term, considering rotations and mixtures of herbicide, and the use of soil cover crops to mitigate the weed resistance and prevent the selection of biotypes with multiple resistance (Marochi et al, 2018).…”

Multiple resistance to glyphosate and imazethapyr in Bidens subalternans

“…Herbicide rotation with different MoAs is essential to prevent and manage multiple resistance evolution. More importantly, additional non-chemicals practices should also be included in weed management strategies, such as crop rotation, cover crops, mechanical and cultural control (Marochi et al, 2018). Thus, machinery cleaning is another important measure to prevent the spread of this problem (Takano et al, 2018).…”