Sorghum is the most cultivated cereal in Burkina Faso. However, sorghum is produced extensively without respect for good agricultural and storage practices and the resulting grains are permanently infected by mold species. These mold species cause seeds rot, seedling damping-off and others diseases in field. They also secrete mycotoxins harmful to human health. The main method recommended for their control is seed treatment with chemicals. However, handling pesticides presents high risks of toxicity and ecotoxicity. The search for an alternative method made it possible to identify the essential oil of Cymbopogon citratus which has antifungal properties. This essential oil was then formulated by adsorption on clay in order to facilitate its use in the field. The objective of this study was to test the efficacy of the formulation made with two types of clay against Phoma sorghina and Fusarium moniliforme, the main species of molds encountered, and to evaluate the effect of the formulation on seed germination and seedling growth. Sorghum grains from two varieties were thus coated with the formulations. The grains thus coated were first analyzed to assess the presence of the target molds and then sown in pots containing sterilized fine sand to assess the germination and growth of the seedlings. The formulations significantly reduced grain infection rates from both fungi by more than 70%. The formulation with Sitiéna clay significantly improved germination, plant vigor and root length of both varieties. Field trials are necessary to confirm the efficacy of this formulation and initiate the popularization procedure.