Dual efficacy of Chlorella vulgaris extract and neem seed oil as antifungal agents and plant growth promoters against Fusarium oxysporum in maize

Fusarium oxysporum is a devastating soil-borne pathogen causing vascular wilt in numerous crops, including maize, leading to significant economic losses. The overreliance on chemical fungicides necessitates the exploration of sustainable biocontrol agents. Microalgae like Chlorella vulgaris and botanicals like neem ( Azadirachta indica ) represent promising, eco-friendly sources of antifungal compounds. The antifungal efficacy of Chlorella vulgaris and neem seed extracts was evaluated through in vitro assays and in vivo greenhouse experiments on maize ( Zea mays ) plants. The treated fungi were also imaged using an electron microscope, and the effects of various treatments were compared. C. vulgaris extract exhibited a highly antagonistic effect in vitro and restricted the mycelia of F . oxysporum by 54.6 %, followed by Neem seed oil extract (29.5 %). Scanning electron microscopy (SEM) exhibited acute morphological damage to fungal hyphae. In Vivo, neem seed oil extract was the most efficient in reducing disease incidence (20 %). On the other hand, the disease incidence with the algal extract reached 40 % as compared with the control treatment. Furthermore, both extracts significantly enhanced plant growth parameters, including plant height, chlorophyll content, and fresh weight, in infected maize plants compared to the untreated control. This study confirms that C. vulgaris extract and neem seed oil are effective bio-fungicides against F. oxysporum , with the former showing superior direct antifungal activity in vitro and the latter demonstrating higher efficacy in reducing disease incidence in plants. Their dual role as antifungal agents and plant growth promoters makes them excellent candidates for integrated pest management strategies.