abstract there is a great interest in the use of natural antifungal compounds for the control of fungi such as rhizopus stolonifer in the postharvest agricultural system and food industry. in this study, the inhibitory effect of essential oil extracted from satureja richingeri and its major compound, carvacrol, on spore development and mycelial growth of r. stolonifer was investigated. mycelium exhibited higher sensitivity to the oil and carvacrol than that observed for spores. spore treatment with oil and carvacrol for 2 and 3 h led to a complete inhibition of spore germination, after 4 h of incubation. however, continuing the incubation to 6 h resulted in germination of 4.67% of the spores treated with the oil but no germination was detected for those treated with carvacrol. it could be concluded that treatment with s. richingeri essential oil for 3 h would extend the shelf life of agricultural product considerably via inhibition of spore germination.