Journal Article

Green synthesis of silver nanoparticles using guava leaves: an effective strategy to control chilli fruit rot disease

Gondal, Amjad Shahzad, Khan, Babar Shahzad, Iqra, Ahmed, Raees, Hyder, Sajjad, Iqbal, Mudassir, Mazhar, Saba

2025

Overview

Background Anthracnose, caused by Colletotrichum capsici , is a significant fungal disease affecting chilli crops, leading to yield losses of 10–25%. Traditional control methods, primarily chemical fungicides, not only pose risks to the environment and soil health but also threaten public safety. In contrast, nanotechnology presents a promising eco-friendly alternative, leveraging the unique properties of nanoparticles, such as their small size and high surface-to-volume ratio, to effectively manage fungal infections with minimal environmental impact. Results This study investigates the synthesis, characterization, and antifungal activity of silver nanoparticles (Ag-NPs) synthesized from guava leaf extract against chilli fruit rot. UV-Vis spectroscopy confirmed the synthesis of Ag-NPs with a peak absorption at 431 nm. X-ray diffraction (XRD) analysis revealed a crystalline structure with an average particle size of 42.5 nm, while scanning electron microscopy (SEM) showed spherical nanoparticles with sizes ranging from 30.5 nm to 50.3 nm across different samples. Fourier transform infrared spectroscopy (FTIR) identified functional groups involved in silver ion reduction. Zeta size analysis confirmed particle sizes of 500.1 nm, 1.0 nm, 62.4 nm, 262.8 nm, and 178.8 nm for samples S1 through S5, respectively. In antifungal assays, S1 at 50 ppm exhibited the highest mycelial growth inhibition (47.9%), with significant protective (87%) and curative (93%) effects. Additionally, in in-vitro leaflet assays, S1 demonstrated 86% inhibition of C. capsici at 50 ppm, highlighting its potential as an effective agent for managing chilli fruit rot. Conclusions This study presents a rapid, eco-friendly method for synthesizing Ag-NPs using guava leaf extract, showing their potential in managing chilli fruit rot caused by C. capsici . The results highlight their effectiveness in both protective and curative applications, offering a sustainable alternative to chemical fungicides. Future research should focus on scaling up the synthesis process for industrial applications, exploring the long-term environmental impact, and assessing the broader applicability of Ag-NPs in managing other phytopathogenic diseases across various crops. Summary Silver nanoparticles (Ag-NPs) synthesized from guava leaf extract effectively inhibit Colletotrichum capsici , with 86% antifungal activity at 50 ppm. This study highlights an eco-friendly, rapid synthesis method for Ag-NPs as a promising alternative to chemical fungicides in managing chilli fruit rot disease. Clinical trial number Not applicable. Graphical Abstract

• Publisher: BioMed Central,BioMed Central Ltd,Springer Nature B.V,BMC
• Subject: absorption / Ag-NPs / Agriculture / Aluminum / Anthracnose / Antifungal activity / Antifungal agents / Antifungal Agents - pharmacology / antifungal properties / Antimicrobial agents / Biomedical and Life Sciences / Botanical research / Botanik / Botany / Capsicum - microbiology / Chemical properties / Chilli rot / clinical trials / Colletotrichum - drug effects / Colletotrichum capsici / Control / Control methods / Crops / crystal structure / Crystals / Disease / Disease control / Diseases / Diseases and pests / Effectiveness / electron microscopy / Environmental impact / Food / Fourier transform infrared spectroscopy / Fourier transforms / Fruit - microbiology / Fruit rot / Fruits / Functional groups / Fungal diseases / Fungal diseases of plants / Fungi / Fungicides / Fungicides, Industrial - pharmacology / Green Chemistry Technology - methods / growth retardation / Guava / guavas / Health aspects / Hot peppers / Industrial applications / Infection control / Infrared spectroscopy / Jalapeno / Leaf extract / leaf extracts / Leaves / Life Sciences / Medicine, Botanic / Medicine, Herbal / Metal Nanoparticles - chemistry / Morphology / mycelium / Nanoparticles / nanosilver / Nanotechnology / Pakistan / Particle size / Pathogens / Pesticides / Physiological aspects / Plant Diseases - microbiology / Plant Diseases - prevention & control / Plant extracts / Plant Extracts - chemistry / Plant Leaves - chemistry / plant rots / Plant Sciences / Production processes / Psidium - chemistry / Public safety / Scanning electron microscopy / Silver / Silver - chemistry / Silver - pharmacology / soil quality / Spectrum analysis / Structure / Synthesis / Toxicity / Tree Biology / Ultraviolet spectroscopy / ultraviolet-visible spectroscopy / X-ray diffraction