Improved Method to Characterize Leaf Surfaces, Guide Adjuvant Selection, and Improve Glyphosate Efficacy

Abstract

Glyphosate, one of the most widely used herbicides, plays an important role in controlling weeds and ensuring crop production. While using glyphosate, adjuvants are commonly added to improve its deposition on weeds and control efficacy. However, changes in weed leaf surface characteristics may reduce glyphosate penetration and contribute to evolved glyphosate resistance. Therefore, it is significant to introduce an improved method for regularizing leaf surface characterization and guide adjuvant selection to improve glyphosate efficacy. In this work, surface characteristics of typical weed leaves have been systematically investigated by 3D surface analysis and scanning electron microscopy, finally quantified by apparent surface free energy (ASFE) due to its comprehensive and quantitative evaluation of leaf surfaces. Moreover, the relationship between the weed leaf surface characteristics and the retention of glyphosate on weeds was established, further related to the control efficacy against weeds. To maximize the utilization rate of glyphosate, the types and concentrations of adjuvants should be regulated according to the ASFE of weeds. Our findings not only regularize the surface properties of weed leaves but also reveal their influencing mechanism on the deposition and biological activity of glyphosate, which provide effective guidance for the use of glyphosate.

Efficient delivery of the herbicide quinclorac by nanosuspension for enhancing deposition, uptake and herbicidal activity

“…The surface of barnyardgrass is covered with a relatively thick wax film, and the wax platelets result in increased roughness. 5 In addition, the trichomes distributed on the abaxial and adaxial surface cause reduced wetting and spreading of droplets. 4 All of the above properties lead to the hydrophobicity of the barnyardgrass surface.…”

“…However, the hydrophobic nature of barnyardgrass surfaces hinders the proper deposition of sprayed herbicides onto their target surface. 4,5 Furthermore, limited water solubility, dispersity issues and extreme lipophilicity of herbicides restrict the efficient uptake of active ingredients by weeds. [6][7][8] Quinclorac (3,7-dichloroquinoline-8-carboxylic acid) is an auxin-type herbicide with hormone-like properties, which is widely used to control barnyardgrass in paddy fields because of high selectivity.…”

Post-Emergence Water-Dispersal Application Provides Equal Herbicidal Activity against Echinochloa crus-galli and Rice Safety as Foliar Spraying of Penoxsulam

“…The leaf absorption of herbicide after spraying requires the active ingredient to be retained in the leaf and remain there for a sufficient time until it is absorbed. This process was influenced by factors such as the spray equipment [12], spray drops characteristics [13,14], and plant leaf surface characteristics [15][16][17]. When the herbicide is applied using post-emergence water-dispersal formulations, the absorption of the herbicide may occur through the stem after being dissolved in the water, and the active ingredient can then be translocated to the apical meristem.…”