Invivo and Invtro studies of Edophytic Fungi against Anthracnose Disease (Colletotrichum lindemuthianum) of Cowpea Vigna unguiculata (L.) Walp) in Girei, Adamawa State, Nigeria
Rikin M. L.
Chimbekujwo I. B.
Zakari B. G.
Dogari T.
Abstract
Anthracnose disease caused by Colletotrichum lindemuthianum poses a significant threat as a major constraint to cowpea Vigna unguiculata (L.) Walp.) production in Nigeria, leading to yield losses exceeding 50% in affected fields through necrotic lesions on leaves, stems, and pods. This study evaluated the antagonistic efficacy and efficiency of four endophytic fungi—Aspergillus flavus, Aspergillus niger, Fusarium solani, and Penicillium expansum—isolated from healthy cowpea tissues against C. lindemuthianum under in vitro and in vivo conditions in Girei, Adamawa State. In dual-culture assays on potato dextrose agar (PDA), endophytes demonstrated time-dependent inhibition of pathogen radial growth, ranging from 40% to 82.2% by day 15, with Fusarium solani exhibiting the highest efficacy (82.2%) due to rapid mycelial overgrowth and metabolite diffusion. Corresponding reductions in disease severity reached 82.2% for Fusarium solani, significantly outperforming controls (P < 0.05). In vivo pot experiments employed a completely randomized design with three replicates, testing endophyte spore suspensions at 30 × 10^6, 60 × 10^6, and 90 × 10^6 spores/mL, alongside fungicide and untreated controls. Aspergillus niger at 90 × 10^6 spores/mL achieved the maximum disease severity reduction of 69%, comparable to carbendazim (70%), while enhancing plant growth parameters like height and leaf number, though not significantly (P > 0.05). Pathogenicity tests confirmed 100% infection in inoculated seedlings, validating the pathogen's virulence. These findings highlight endophytic fungi as viable, eco-friendly biocontrol alternatives to synthetic fungicides, minimizing environmental risks and resistance development.
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