Sweet pepper (Capsicum annuum L.), also known as bell pepper, is one of the most widely grown vegetable crops worldwide. It is attacked by numerous phytopathogenic fungi, such as Fusarium equiseti, the causal agent of Fusarium wilt disease. In the current study, we proposed two benzimidazole derivatives, including 2-(2-hydroxyphenyl)-1-H benzimidazole (HPBI) and its aluminum complex (Al−HPBI complex), as potential control alternatives to F. equiseti. Our findings showed that both compounds demonstrated dose-dependent antifungal activity against F. equiseti in vitro and significantly suppressed disease development in pepper plants under greenhouse conditions. According to in silico analysis, the F. equiseti genome possesses a predicted Sterol 24-C-methyltransferase (FeEGR6) protein that shares a high degree of homology with EGR6 from F. oxysporum (FoEGR6). It is worth mentioning that molecular docking analysis confirmed that both compounds can interact with FeEGR6 from F. equiseti as well as FoEGR6 from F. oxysporum. Moreover, root application of HPBI and its aluminum complex significantly enhanced the enzymatic activities of guaiacol-dependent peroxidases (POX), polyphenol oxidase (PPO), and upregulated four antioxidant-related enzymes, including superoxide dismutase [Cu-Zn] (CaSOD-Cu), L-ascorbate peroxidase 1, cytosolic (CaAPX), glutathione reductase, chloroplastic (CaGR), and monodehydroascorbate reductase (CaMDHAR). Additionally, both benzimidazole derivatives induced the accumulation of total soluble phenolics and total soluble flavonoids. Collectively, these findings suggest that the application of HPBI and Al−HPBI complex induce both enzymatic and nonenzymatic antioxidant defense machinery.

The potato (Solanum tuberosum L.) is one of the most widely consumed vegetable crops worldwide. During storage, potato tubers are vulnerable to various phytopathogenic fungi. Dry rot, caused by Fusarium incarnatum, is a common and serious disease that affects potato tubers, leading to partial or complete decay during storage. The current study assessed the effectiveness of three ethanolic extracts including cinnamon bark (CIB), clove buds (CLB), and avocado seeds (AVS) in controlling potato dry rot under both normal and cold storage conditions. In vitro bioassay demonstrated that all tested extracts exhibited a dose-dependent fungistatic effect against F. incarnatum, with inhibition percentages of 83.33% for CIB, 72.22% for CLB, and 67.77% for AVS at the highest tested concentration. Moreover, dipping potato tubers in the tested extracts markedly reduced the severity of dry rot disease under both normal and cold storage conditions. Additionally, treated tubers showed increased activities of defense-related enzymes, including catalase, peroxidase, polyphenol oxidase, and phenylalanine ammonia-lyase. Furthermore, there were higher levels of total soluble phenolics and flavonoids, along with an increase in lignin content and a reduction in the weight loss of stored potato tubers compared to the control group. Moreover, the extracts mitigated infection stress and lowered malondialdehyde levels in the treated potato tubers. These extracts show potential as environmentally friendly alternatives to chemical fungicides for managing potato dry rot caused by F. incarnatum under normal and cold storage.