Biochar-Enhanced Sulfur: Mechanistic Insights into a Novel and Effective Bactericide

The development of green, efficient, and stable pesticides for controlling agricultural pathogens remains a critical research focus. Elemental sulfur, although widely used for its bactericidal and insecticidal properties, suffers from aggregation, poor dispersibility, and limited contact with target organisms, restricting its effectiveness. In this study, we synthesized a novel biochar-sulfur composite by combining sustainable biochar with sulfur at low temperatures. The resulting material exhibited enhanced dispersibility and a five-fold increase in bactericidal efficacy compared to sulfur alone, as demonstrated in tests against <i>R. solanacearum</i> and <i>E. coli</i>. Additionally, the composite maintained 80% efficacy after five cycles of use, highlighting its favorable cyclic performance. Mechanistic studies revealed that biochar accelerates sulfur's redox reaction, generating free radicals that drive efficient bactericidal action. This work provides a simple and sustainable approach for developing sulfur-based antimicrobial pesticides, offering new opportunities for sulfur utilization in agriculture.