Biological potentials of Landolphia owariensis leaf methanolic extract against pathogenic fungi isolates from different Dioscorea species

Abstract Regarding economic significance, the Dioscoreaceae family, which includes the well-known Dioscorea (yam) species, is the fourth most important tuber crop globally. A basic meal found all across the world, yams encourage and ensure the food security of households. Although they are challenging to preserve and store however a post-harvest deterioration control must be developed. Over the years, Nigerian farmers have employed medicinal herbs to manage post-harvest pest invasion; nevertheless, the scientific basis for this fungal management has not yet been well documented. As a result, Landolphia owarensis leaf extract was used as a biological control, and fungi were isolated from Dioscorea cayenensis , Dioscorea alata , and Discorea rotundata . Samples of yam tubers – both rotten and healthy – were procured in the markets and brought to the lab for fungus isolation and identification. Leaves of Landolphia oweriensis were collected, air-dried, milled, and macerated in pure methanol for 72 h, extracted and concentrated with a rotary evaporator. The agar-well diffusion method was used for the biological control assay against the fungal isolates. The biological control results were presented as mean ± SD (standard deviation) while analysis of variance (Anova) was used to deduce least significant difference (LSD). A total number of 605 fungi isolates were observed in which D . cayenensis had the highest, 50.58 %, D. alata and Discorea rotundata 24.71 % respectively. Aspergillus niger and Aspergillus fumigatus were found in the three species while Aspergillus flavus , Rhizopus stolonifer , Collentotricum spp . and Penicillium spp . in either of the species. L. owarensis methanolic leaves extracts possesses biological potentials against Colletotrium spp., A. fumigatus , A. niger and A. flavus only. The problem of postharvest fungal invasion of Dioscorea species can be solved with the inhibition observed with L. owarensis methanolic leaves extracts as a biological control measure thereby sustaining food security in the world.