In Vitro Evaluation of the Pathogenicity of Fusarium oxysporum f. sp. cucumerinum and the Antifungal Efficacy of Hymexazol and Trichoderma viride

الملخص

The present study aimed to evaluate the pathogenicity of Fusarium oxysporum f. sp. cucumerinum and to investigate the effectiveness of Hymexazol and Trichoderma viride as chemical and biological control agents under laboratory conditions. Laboratory experiments confirmed that the fungal isolate was highly pathogenic to cucumber. Seed germination of the susceptible local cultivar decreased to 60%, whereas the resistant imported cultivar maintained 90% germination, compared with 100% in the uninoculated control. Typical Fusarium wilt symptoms were successfully reproduced, and Koch's postulates were confirmed by re-isolation of the pathogen from infected plants. Hymexazol exhibited strong antifungal activity, completely inhibiting the radial growth of F. oxysporum f. sp. cucumerinum at 2000 ppm, while having no inhibitory effect on the growth of T. viride. Furthermore, T. viride showed strong antagonistic activity against the pathogen, completely overgrowing the pathogen colony and being classified as Class I according to Bell's rating scale. These findings demonstrate that Hymexazol and T. viride are compatible control agents and represent promising components of integrated management strategies for Fusarium wilt of cucumber.