Biocontrol of Fusarium wilt disease in pepper plant by plant growth promoting Penicillium expansum and Trichoderma harzianum

Plant growth promoting fungi (PGPF) were employed in the present study to biocontrol Fusarium wilt disease in pepper plants. Two of the five fungal isolates were chosen based on biochemical characteristics such as their production of hydrocyanic acid, siderophores, and IAA, phosphate solubilization, and in vitro antifungal activities. The most potent fungal isolates were identified as Penicillium expansum (P. expansum) and Trichoderma harzianum (T. harzianum). Using GC-MS, it was found that PGPF extracts contain compounds with antifungal activity, antioxidants, and plant growth stimulators. The combined effect of T. harzianum and P. expansum increased the protection against fusarial wilt by (76.74%), followed by T. harzianum by (50%), then P. expansum by (17.64%). Significant improvement because of using the mixture (T. harzianum and P. expansum) showed an increase in shoot length (59.4%), root length (129%), and number of leaves (52.6%). Chlorophyll A and B levels in infected plants were consistently raised by 28.71% and 67.58%, respectively; as a result of application the mixture (T. harzianum and P. expansum). Also, there was an increase in soluble proteins and carbohydrates in infected plants treated with (T. harzianum) by 25.42% and 31.78% over untreated infected plants, respectively. It could be recommended that the use of targeted PGPF strains, especially a mixture of T. harzianum and P. expansum could be commercially used as therapeutic nutrients against Fusarium wilt of pepper plants.