Control of Yam Rot using Leaf Extracts of Utazi Gongronema latifolia and Moringa oleifera

Dioscorecea rotundata are among the most important tropical root crop. Yams are a staple crop in many parts of Africa and Southeast Asia. Besides their importance as food source, yams also play a significant role in the socio-cultural lives of some producing regions like the celebrated new yam festival in West Africa, a practice that has also extended to overseas where there is a significant population of the tribes that observe it. This research was carried out on the antimicrobial effect of the leaf extracts of Gongronema latifolia and Moringa oleifera for the control of Dioscorecea rotundata tuber rot caused by Fusarium oxysporum, Penicilium oxalicum, Fusarium solani, Botryodiploidia theobromae, Rhizopus spp, Aspergillus niger and Aspergillus flavus. The highest percentage occurring organisms were P. oxalicum, Rhizopus sp, F. oxysporum, and A. niger. Qualitative phytochemical screening of the extracts was conducted which revealed the presence of alkaloids, flavonoids, tannins, saponins, sterols and phenols. The zone of inhibition of the leaf extracts of G. latifolia and M. oleifera revealed that M. oleifera gave higher inhibition of F. oxysporum (at all concentrations), A. niger and A. flavus. However, G. latifolia gave higher inhibition of A. niger and A. flavus at different concentrations. The study revealed that A. flavus was the most susceptible organism to the effect of the leaf extracts of G. latifolia and M. oleifera while F. oxysporum and A. niger were the most resistant organisms against these leaf extracts. There was significant difference in the inhibitory activity of the leaf extracts of G. latifolia and M. oleifera against F. oxysporum, A. niger and A. flavus at different concentrations. Hence, G. latifolia and M. oleifera leaves could be the best alternative ways of reducing and controlling rot by farmers these extract can be easily prepared by farmers.