The management of plant diseases with natural compounds is highly needed nowadays. The results of this study evidence that the antifungal power of non-phytotoxic EOs can be used to reduce doses of synthetic compounds that are applied to garlic crop. Anisillo and bay EOs have both moderate antifungal activity but no phytotoxic effect. Moreover, some combinations of these EOs with Ip can reduce the fungicide dose by up to 40% due to the synergistic interactions taking place. Therefore, these EOs are a novel alternative to control “white rot” caused by S. cepivorum and can be applied with Ip not only to reduce the amount of chemical fungicide in the soil, but also to reduce the disease incidence and the sclerotia density after white rot disease. Moreover, the persistence of fungicides and the amount of money spent on them can be reduced. Future studies are needed to adjust the applied concentrations.