High foliar adhesion carvacrol-chitosan nanoparticles assist cotton against Fusarium oxysporum infection

The infection caused by Fusarium oxysporum severely threatens cotton production. Herein, carvacrol-chitosan nanoparticles (CS@CAR) are facilely fabricated using tripolyphosphate as a crosslinker. When the initial mass ratio of chitosan to carvacrol is 1:0.4, the nanoparticles show the best stability and drug loading. Morphological analysis reveals that the CS@CAR nanoparticles possesses a uniform spherical structure with an average diameter of approximately 150 nm. About 51.23 % of total CAR is released within the 48 h in the simulated fungal infection environment. The contact angle of drug-loaded particles decreases by 12.2 and 6.6 ° compares with that of pure water and unloaded particles. The fluorescence intensity of leaves before and after rain erosion is 1.3 times and 1.2 times that of the pure water control group by fluorescence imaging analysis. The bacteriostatic activity of drug-loaded nanoparticles is 6–7 times that of non-drug-loaded nanoparticles. The contents of nucleic acid, protein, and malondialdehyde leaked by spores after treatment with drug-loaded particles are 1.4, 1.5 and 2.3 times those in the non-drug-loaded particle treatment group, respectively. The CS@CAR entirely prevents Fusarium oxysporum from infecting cotton leaves in spore inoculation experiments. The CS@CAR nanoparticles are expected to be used to prevent and control the infection of Fusarium oxysporum on cotton.