Evaluation of the potential of topically applied salicylic acid-encapsulated chitosan nanoparticles to protect tomato against Fusarium wilt

In recent years, there has been a growing emphasis on eco-friendly methods to protect plants from pathogens, aiming to enhance crop yields while minimizing pesticide use. In this context, we synthesized salicylic acid-encapsulated chitosan nanoparticles (SA-CNPs) and evaluated their effectiveness in safeguarding tomato plants against Fusarium wilt caused by Fusarium oxysporum f. sp. Lycopersici (FOL). SA-CNPs at concentrations of 0.01%, 0.05%, 0.1%, 0.15%, and 0.2% w/v were prepared using ionic gelation and characterized through scanning electron microscopy, zeta potential, X-ray diffraction, and Fourier transform infrared spectroscopy techniques. The results revealed an average particle size ranging from 30 to 300 nm, with zeta potential values − 30 to − 53 mV, confirming exceptional stability. Encapsulation efficiency varied from 19 to 90%. In antifungal tests, 0.2% SA-CNPs exhibited 76% inhibition rate using a food poisoning technique. Topical application of SA-CNPs increased the activities of plant defence enzymes and antioxidant enzymes in tomato plants. In an in vitro study, the percent efficacy of disease control (PEDC) demonstrated that 0.1% and 0.15% SA-CNPs provided 50% and 45% efficacy, respectively, in controlling FOL infection in tomato plants. These findings confirm the efficacy of SA-CNPs in reducing Fusarium wilt by leveraging their antifungal properties and enhancing antioxidant and plant defence enzymes.