Abstract

Yield losses due to fungal attacks, post-harvest losses and food spoilage, amongst others present a challenge to food security. There is an ongoing need and search for accessible, affordable and environmentally-friendly alternatives to the use of synthetic pesticides in food production. The aim of this study was to search for affordable potent plant extracts that can be used in smallholder farming system to manage Fusarium related diseases. Extracts from 11 medicinal plant species previously screened against human and animal pathogens in the literature were selected and investigated for their in vitro antifungal activity against five economically important phytopathogenic Fusarium species. Dried leaf powders were extracted with solvents of different polarity and evaluated for antifungal activity using a microdilution method. At least, one of the solvent extracts obtained from a minimum of three plant species demonstrated very strong activity with minimum inhibitory concentration (MIC) less than 0.1 mg/ml against F. equisite, F. oxysporum, F. semitectum, F. chlamydosporum and F. subglutinans. Acetone and ethyl acetate solvent extracts were found in most cases to exhibit stronger antifungal activity compared to water and petroleum ether extracts. However, water extract of Combretum molle was particularly noteworthy as it demonstrated antifungal activity against the tested five Fusarium species. The use of medicinal plant extracts as an antifungal agent presented a cheap, accessible and sustainable source of eco-friendly pesticides useful for crop protection in organic cultivation and small-holder farming.