Fuente: WIPO "tomato" Pesticides useful in the treatment of plant disease are provided. A pesticide includes: a nanocellulose scaffold with a cellulose nanocrystal (CNC) that is modified to include a diamine or quaternary amine; and a metal nanoparticle conjugated to the nanocellulose scaffold via the diamine or quaternary amine. Conjugation of the metal nanoparticle to the nanocellulose scaffold can facilitate improved surface adhesion of the metal nanoparticle on a plant surface, thus rendering the metal nanoparticle less amenable to removal from the plant by environmental factors. The enhanced surface adhesion can extend the duration of the antibacterial, antifungal, and/or antiviral action of the metal nanoparticle and reduce the number and/or frequency of pesticide applications required for plant treatment. The pesticide can include a plurality of modified CNCs and metal nanoparticles conjugated to the modified CNCs. Methods for treating plant disease and methods for synthesizing a pesticide are also provided.