A pH-responsive double network hydrogel for control of tomato bacterial wilt

Ralstonia solanacearum is a major plant pathogen causing bacterial wilt, whose unpredictable onset hinders timely detection and effective control. Here, we report the design, preparation and field use of a dual pH-responsive multifunctional double network (DN) hydrogel for the efficient and sustainable control of bacterial wilt. The primary network of carboxylated agarose chelates Zn²⁺ and loosens under acidic conditions (pH ≤ 5) to release a pesticide (zhongshengmycin) and Zn²⁺, while the secondary L-phenylalanine (Phe)/ Zn²⁺ network disassembles to provide additional bioactive components (Phe and Zn²⁺). This dual-triggered release achieves a combined antibacterial effect, enhances plant growth, and activates plant disease resistance pathways. A simple root application protects plants for up to 14 days, and field experiments demonstrate disease control for up to 30 days, significantly preserving tomato yield. Here, we present a sustainable, effective system for managing bacterial wilt and highlight the potential of smart hydrogels in crop protection.