Tea tree oil Pickering emulsions stabilized by sodium lignosulfonate-zein covalent conjugate for fungicide delivery and enhanced control efficacy against peanut sclerotium blight

Peanut sclerotium blight is a globally widespread plant disease caused by Sclerotium rolfsii Sacc. , often leading to significant reductions in peanut crop yields. Due to its soil-borne transmission, effective control of this pathogen remains challenging. This study developed a tea tree oil (TTO) Pickering emulsion (Teb/TTO-PE 5 ) for delivering the fungicide tebuconazole (Teb) by using a covalent conjugate of sodium lignosulfonate (SLS) and deamidated zein (DA-zein) as stabilizers, with further stability enhanced by adding 0.3 wt% xanthan gum (XG), producing another TTO Pickering emulsion (Teb/XG/TTO-PE 5 ). The stability of Teb/XG/TTO-PE 5 was directly demonstrated by its ability to avoid phase separation after being stored at room temperature for 21 days. Additionally, it minimized droplet rebound and enhanced surface wetting, which facilitated efficient interfacial transfer during application. The dual active components in TTO Pickering emulsions exhibited controlled release behavior, enhancing both the targeting and control of the fungicide. Seed germination assays confirmed that the TTO Pickering emulsions did not significantly affect peanut seed germination. Pot experiments revealed that Teb/XG/TTO-PE 5 therapeutic intervention group maintained an average lesion rate of below 5 % in peanut plants infected with 21-day-old Sclerotium rolfsii Sacc. strains. The successful development of these Pickering emulsion fungicide delivery system offers an environmentally sustainable and crop-safe strategy for controlling peanut sclerotium blight.