Joint action of common herbicides on the control of Alhagi pseudalhagi (Bieb.) Desv.: A comparison study.

Alhagi pseudalhagi (Bieb.) Desv. is a highly invasive plant species that causes significant ecological and economic damage in many regions. Herbicides combination is a valuable tool in modern weed management, offering benefits such as broader weed control, reduced resistance development, minimised environmental impact and improved cost‐effectiveness. Six greenhouse studies investigated the joint action of glyphosate, 2,4‐D, paraquat and glufosinate‐ammonium on camelthorn control using the additive dose model (ADM) as a reference model. A randomised complete block design with four replications and seven doses of each mixture was used for the experiments. The values of ED50 (effective dose causing 50% response reduction) and ED90 were calculated from the three‐parameter log‐logistic models for each herbicide applied alone or in mixtures of fixed ratios. Two different statistical software used to test the data revealed similar results. A strong synergistic effect was observed in the mixture of paraquat with 2,4‐D on camelthorn with a high λ‐value equal to 1.64, while the mix of glufosinate ammonium with glyphosate or paraquat‐induced a moderate synergism with λ‐value of 1.29 and 1.16 respectively. Despite a slight synergistic tendency, 2,4‐D binary mixtures with glyphosate or glufosinate‐ammonium followed ADM (additive effects). In contrast, reduced translocation in the paraquat + glyphosate combination, means that the herbicides did not move effectively within the plant, resulting in a significant antagonistic effect with the lowest λ‐value equal to 0.02. The mixtures with additive effects are generally suggested to be combined by increasing the rate of one of the herbicide components or an adjuvant to result in sufficient combination absorption and translocation to affect camelthorn control. [ABSTRACT FROM AUTHOR]