The use of plant extracts in the control of Aspergillus niger in the rot of yam (Dioscorea spp.) during storage

Abstract

The storage rot of yam (Dioscorea spp) starts from the field to the storage barn. Fungi pathogens affecting yam tubers are controlled by either synthetic pesticides or plant extracts.The following plant extracts, Vernonia amygdalina (bittter leaf), Azadirachta indica (neem), Ocimum gratissimum (nchuanwu), Pergularia spp. (utazi), Citrus aurantifolia (lime), Allium sativum (gallic), and Capsicum annum (red pepper) were used to control the rot of yam (caused by Aspergillus niger). The ethanol extracts of the test plants were observed to have higher fungitoxic ability than the water extracts on A. niger, which was isolated from the rotten yam tubers. Ethanol extracts of A. indica and O. gratissimum were observed to have the highest percentage fungi growth inhibition, having 68.8% and 65.2% respectively, while A. sativum, and C. annum had the lowest with 36.3% and 40.6% respectively. A. indica was also observed to have the highest severity and A. sativum had the lowest. However, yam tubers which were treated 2 days before inoculation were observed to have more inhibitory effect on the fungi pathogen than those treated 2 days after inoculation.

Keywords: storage-rot, yam-tubers, plant-extracts, fungal-pathogens, severity

International Journal of Agriculture and Rural Development Vol. 6 2005: 74-80