Green Silver Nanoparticles for Phytopathogen Control

Plant diseases bring radical problem in the agriculture sector. Phytopathogens mediate diseases that pose considerable loss of yield and quality deterioration which eventually bring down the crop yield and the rural economy. The present study is, thus, focused on developing the optimized protocol for the synthesis of silver nanoparticles (AgNPs) by green chemistry approach and revealing their antimicrobial potential against phytopathogens. The synthesis of AgNPs was carried out by using aqueous plant extracts of three medicinal and aromatic plants, namely Allium cepa (onion), Allium sativum (garlic) and Zingiber officinale (ginger). AgNPs were characterized by various analytical techniques including UV–visible spectra, PSA, FTIR, TEM and XRD analysis. The AgNPs were spherical with size ranging from 1 to 10 nm, crystalline in nature and relatively stable up to 3 months after synthesis. The AgNPs conferred strong antimicrobial activity against selective bacterial and fungal phytopathogens. The antimicrobial activity of the AgNPs was observed against Erwinia sp., Pseudomonas syringe , Bacillus megaterium , Fusarium graminearum , F. avenaceum and F. culmorum. The effective concentration against bacterial pathogens was found to be between 50 µg/ml (garlic/ Erwinia sp.) and 130 µg/ml (onion/ B. megaterium ). In the case of fungal pathogens, the range was 90 µg/ml (garlic/ F. avenaceum ) to 110 µg/ml (onion/ F. graminearum ) for an effective dose.