Fungicidal Potentials of Leaf and Bark Extracts of Bryophyllum pinnatum on Cowpea (Vigna unguiculata L.) Seed Fungi

Abstract

In Nigeria, Cowpea (Vigna unguiculata [L.] Walp) is an important grain legume which besides being a food crop serves as a major source of income for rural households. The action of pathogens on stored seeds causes huge post-harvest and economic losses to cowpea farmers in Nigeria. This research was aimed at isolating and identifying the spoilage pathogens of cowpea seed and testing the potentiality of ethanol extracts of Bryophyllum pinnatum on the isolates. Spoilt cowpea seed samples were purchased from different markets in Anambra State. They were transported to Alpha Research Laboratory, Awka in sterile polythene bags for microbial isolation. The spoilage organisms were isolated from the seeds through microbial culture. The media used for the isolation were Sabouraud Dextrose Agar and Potato Dextrose Agar. Pathogenic fungi were isolated from the spoilt cowpea seeds. The findings indicated that Aspergillus aculeatus, Fusarium solani, Penicillium citrinum, Rhizopus stolonifer, and Aspergillus flavus were present. The pathogenicity test also showed that the above organisms were responsible for cowpea spoilage. These isolates were tested for their in-vitro antifungal activity against the leaf and bark extracts of Bryophyllum Pinnatum. The antifungal activity ethanol extracts of Bryophyllum pinnatum on the isolated microorganisms were investigated using the disc method. Three different concentrations (25%, 50%, 100%) of extracts were used for the test. Fusarium solani showed the highest percentage of inhibition with antifungal medication while Penicillium citrinum showed the least percentage of inhibition with antifungal medication. The antifungal potential of Bryophyllum pinnatum extract on spoilage pathogens of stored cocoyam corms encourages more research on the active ingredient of the plant for easy use by farmers as alternative to commercial/ synthetic fungicides.