Yam is an important crop in Nigeria, where it is produced both as food and cash crop. Fusarium rots of yam are among the most important postharvest pathogens of yam worldwide, causing a lot of postharvest losses in stored yam tubers. Lactic acid bacteria (LAB) lower the pH and create an environment that is unfavorable to pathogens and spoilage organisms. In vitro inhibition of fusarium species by LAB was investigated; mono-culture and multi-cultures were used. The inhibition tests were carried out with pure cultures of LAB and fusarium spp. The pure culture of actively growing Fusarium was inoculated into Potato Dextrose Agar medium aseptically and then incubated at room temperature for 72 h. The diameter of the growing Fusarium was measured, after which less than a loop full of actively growing (18-24 h) LAB isolates were used to inoculate the medium containing the growing Fusarium at a known distance in the same plate. The whole set up was incubated at 300C and inhibition zones on Fusarium by the LAB were observed 24 hourly for 96 h. The tests were carried out for mono-culture and multi-cultures in triplicate. The inhibition zone ranged from 43 to 100% in mono-culture plates and from 40 to 113% in multi-culture plates. The slightly larger inhibition in the multi-culture plate may be due to much pressure on the Fusarium. Hence LAB may be used to control rot caused by Fusarium in in stored yam, which can improve yam tuber storage for better economic growth.
R. M. Omodamiro
Department of Postharvest Technology Programme, National Root Crops Research Institute, Umudike, Nigeria.
P. C. Ojimelukwe
Department of Food Science and Technology, Micheal Okpara University of Agriculture, Umudike, Nigeria.
Dr. R. Asiedu
Yam Barn Unit, International Institute of Tropical Agriculture, Ibadan, Nigeria.
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