Enhanced herbicide efficacy using charcoal‐based nano formulations to control <scp> <i>A</i> </scp> <i>butilon theophrasti</i> and shattercane‐mimic <scp> <i>S</i> </scp> <i>orghum bicolor</i>

BACKGROUND: Advanced formulation and delivery systems are needed to maintain efficient adhesion, minimize runoff and reduce herbicide volume. Nanoparticle herbicide formulation is an exciting approach with the potential to reduce application rates, minimize soil residues, and precisely penetrate to the weed's cuticle. The objective of this study was to investigate the efficacy of commercial and nano-carrier-based formulations of glyphosate and glufosinate to control Abutilon theophrasti and shattercane-mimic Sorghum bicolor. RESULTS: Results suggest that the nano formulations (0.5× and 1×) of both herbicides showed two to four times greater leaf injury in A. theophrasti and S. bicolor over their commercial formulations. This may be attributed to two mechanisms: (a) reduced particle size and increased surface area created by ball milling resulted in better adhesion, and (b) active charcoal may assist in molecules adsorption, prolonging uptake through epidermal tissue. Ball-milled charcoal-herbicide formulations resulted in 60% greater leaf injury relative to non-milled formulations (5%). At 3 weeks after treatment, 0.5× nano-glyphosate showed 50-60% leaf injury in S. bicolor, representing a two-fold increase over commercial formulations. A. theophrasti exhibited greater tolerance across treatments, but injury increased notably with 1× nano-glufosinate and nano-glyphosate treatments. Scanning electron microscopy revealed enhanced epidermal disruption and cellular collapse in nano treatments compared to commercial formulations. CONCLUSION: Charcoal-based nano formulations enhanced the efficacy of glyphosate and glufosinate at reduced application rates through increased foliar adhesion and penetration. These results show the potential of nano-formulated herbicides as an environmentally sustainable approach for modern weed management. © 2026 Society of Chemical Industry.