This study’s objective was to evaluate the contributions of benomyl and a melanin biosynthesis dehydratase inhibitor (MBI-D) mixture to preventing the re-emergence of MBI-D-resistant Pyricularia oryzae in rice fields. In nursery boxes, applications of diclocymet or mixtures of diclocymet and tiadinil showed low leaf blast incidences, but MBI-D-resistant isolates were re-selected. However, a management program applying both benomyl and MBI-D-related products to nursery box plants prevented the re-emergence of MBI-D-resistant isolates more effectively than the application of only MBI-D-related products.