Behavior of Dioscorea alata Slices Treated with Aqueous Extracts of Ocimum gratissimum and Chromolaena odorata before Inoculation by Colletotrichum sp. in Daloa, Côte d’Ivoire

Yam, Dioscorea spp. (L) is an important foodstuff that plays a key role in the agricultural system in Côte d'Ivoire. This plant is however subject to several diseases during its cultivation and conservation. The losses caused by rots of tubers in storage constitute a major risk for economic profitability and for the food safety of consumers. The development of an effective and environmental friendly control method has been initiated. The objective of this work is to improve the conservation of Discorea alata tubers through the use of aqueous extracts of Ocimum gratissimum and Chromolaena odorata. To do this, three different doses (33 g/l; 39 g/l and 50 g/l) of aqueous extracts of Ocimum gratissimum and Chromolaena odorata were applied to yam slices before inoculation with Colletotrichum sp. Results showed that applying different doses of aqueous plant extract to yam slices before inoculation of the fungal strain caused less rot. The aqueous extracts of the two plants showed antifungal activity against Colletotrichum sp. This antifungal activity was more effective with the 50 g/l dose of Ocimum gratissimum compared to the extract of Chromolaena odorata.