Enhanced Pepper Resistance to Sclerotium rolfsii Through Root Development and Enzyme Modulation by Hexaconazole and...

Southern blight, caused by the soil-borne fungus Sclerotium rolfsii (S. rolfsii), poses a significant threat to pepper (Capsicum annuum L.) production, necessitating the development of effective chemical control strategies. This study investigated the physiological responses of pepper plants to S. rolfsii infection and evaluated the efficacy of the fungicides hexaconazole and azoxystrobin. The results demonstrated that hexaconazole, applied at 50 μg·mL^-1, provided outstanding protective activity (97.56%). In contrast, azoxystrobin, at a higher concentration of 100 μg·mL^-1, exhibited optimal overall control, with 88.62% protective and 49.06% curative activity. Beyond direct pathogen suppression, both fungicides mitigated disease impact by safeguarding host plant growth, promoting root system development, and enhancing defense responses through the induction of key antioxidant enzymes, namely, peroxidase (POD) and catalase (CAT). Consequently, the application of hexaconazole and azoxystrobin significantly reduced disease progression and protected normal plant growth. These findings provide a scientific basis for effective management of southern blight in pepper and elucidate how fungicides with distinct modes of action can enhance plant resistance by modulating the antioxidant system.