Fungicide itself as a trigger to facilely construct Hymexazol-Encapsulated polysaccharide supramolecular hydrogels with controllable rheological properties and reduced environmental risks

•Fungicide itself can trigger the formation of self-delivery polysaccharide supramolecular hydrogels.•The polysaccharides are biodegradable alginate and carboxymethyl chitosan.•The as-prepared hydrogels have controllable rheological properties and tunable multifunctionality.•The hydrogels possess shear-thinning, pH and ionic strength-responsive swelling properties.•This bioactive molecule itself-triggered self-delivery system can reduce the environmental risks of current-using pesticide.