This work evaluates the effect of antifungal agent based on chitosan (CS) or peppermint essential oil (PEO) treatment and their mixtures to control P. digitatum and B. cinerea, identified as the potential plant pathogens. The efficacy of each CS (0.6%) and PEO (0.1–0.6%) or in combination to inhibit spore germination is assessed. The distribution of PEO in the emulsion system is more pronounced along with the increase in the oil level. Either CS or PEO can inhibit the growth of spore and germ tube elongation effectively. The mixtures of CS and PEO exhibit a greater inhibitory action additively or synergistically according to the Abbott index value. Propidium iodide staining test confirms the loss of membrane integrity of spores in response to coating treatment. The combination treatment of CS/0.6% PEO and CS/0.5% PEO can be an effective alternative to inhibit the spore germination, respectively, for P. digitatum by 91.54% and B. cinerea by 100%. Application of the composite coatings obtained in this study can prove to be potential for primary packaging, particularly for fresh postharvest commodities.