Enhancing localized pesticide action through the plant foliage by silver-cellulose hybrid patches

Efficacy and efficiency of pesticide application in the field through the foliage still faces many challenges. There exists a mismatch between the hydrophobic character of the leaf and the active molecule, low dispersion of the pesticides on the leaves’ surface, runoff loss and rolling down of the active molecules to the field, decreasing their efficacy and increasing their accumulation to the soil. We produced bacterial cellulose-silver nanoparticles hybrid patches by in situ thermal reduction under microwave irradiation in a scalable manner and obtaining AgNPs strongly anchored to the BC. Those hybrids increase the interaction of the pesticide (AgNPs) with the foliage and avoids runoff loss and rolling down of the nanoparticles. The positive anti-bacterial and anti-fungal properties were assessed in vitro against the bacteria Escherichia coli and two agro-economically relevant pathogens: the bacterium Pseudomonas syringae and the fungus Botrytis cinerea. We showed in vivo inhibition of the infection in Nicotiana benthamiana and tomato leaves, as proven by the suppression of the expression of defense molecular markers and reactive oxygen species production. The hydrogel-like character of the bacterial cellulose matrix increases the adherence to the foliage of the patches.We acknowledge financial support from the Spanish Ministry of Economy and Competitiveness (MINECO) with grants 2016-78002-R (AGL) and RyC 2014-16158 (NSC), MAT2015-64442-R, FIP and through the “Severo Ochoa Programme for Centres of Excellence in R&D” (SEV-2015-0533 and SEV-2015-0496). This work was also supported by the CERCA Programme / Generalitat de Catalunya, the Generalitat de Catalunya for the 2017SGR765 project.Peer reviewe