Effect of Two Biostimulants and a Synthetic Fungicide on Anthracnose (<i>Colletotrichum </i>sp) and Yield of Four Hybrid Clones and One Local Variety of Yam (<i>Dioscorea alata</i>) in Central Côte d’Ivoire

Yam is an important food crop for the people of Côte d’Ivoire. However, it is subject to several parasitic attacks. The most damaging of which is anthracnose, caused by Colletotrichum gloeosporioides. In some varieties and regions, yield losses can be 80% or more. This study evaluated the effect of two biostimulants and a synthetic fungicide on anthracnose and yield in four yam hybrid clones and a local cultivar. The plant material used was yam hybrid clones CNRAiga15/00020. TDa01/00002. TDa01/00012. CNRAiga15/00028 and local variety Ma01. Two biostimulants [solution A “biofungicide” and OCIBIO 5% (essential oil)] and a synthetic fungicide (mancozeb) were used for the different treatments. Observations were made between the second and sixth month after planting. The incidence and severity of anthracnose on developing plants and yield at harvest were observed. The results showed that yam clones were susceptible to anthracnose, with an incidence rate of 100%. But with low severity rates, except for the control plants. Hybrid clones CNRAiga15/00020, CNRAiga15/00028 and TDa01/00012 showed no significant difference between treatments (T2, T3 and T4). A significant difference between treatments was observed for the hybrid clone TDa01/00002 with a severity score of 2. Yield parameters were not significantly different between treatments. T4 with OCIBIO 5% showed some efficacy against yam anthracnose.