Biological Control of Post Harvest Rot-Inducing Fungi of White Yam Tubers (Dioscorea rotundata Poir.) in Storage with Antagonistic Biofungicides

An antagonistic study was carried out to assess the potential inhibitory capability of Biofungicides of Bacillus subtilis, Pseudomonas syringae, Trichoderma harzianum, and Trichoderma viride as biocontrol agents against rot-inducing fungi of white yam (Dioscorea rotundata Poir.) tubers in storage. Rot-inducing fungi and Biofungicides used for control were isolated using standard methods. A pathogenicity test was also carried out to ascertain whether the fungi induced rot or not in healthy yam tubers. culture method was used to evaluate the effects of biofungicides. Biofungicides each paired with the pathogenic test fungi served as treatments. Aspergillus niger, Rhizopus stolonifer, Fusarium oxysporum, Aspergillus flavus, and Penicillium Spp were the fungi consistently isolated from rotted yam samples. All fungi identified were pathogenic hence, induced rot in healthy yam tubers after 14 days of inoculation. The most virulent was Aspergillus niger. The degree of rot was evaluated by calculating the percentage inhibition by the Biofungicides. Inhibition of rot ranged from 13.16±0.070a-48.67±0.045a% in Bacillus subtilis to 12.95±0.288a-40.16±0.058a% in Trichoderma viride when paired with the pathogenic test fungi. This study revealed that the Biofungicides have potential to control rot in post-harvest yams. Overall, Bacillus subtilis was the most effective Biofungicides in controlling the pathogenic test fungi. Inference of this study showed that the use of Biofungicides as biocontrol agents is an economically viable way of suppressing post-harvest rot of white yam.