Abstract
Effects of aniti-blast fungicides, Kasugamycin (KSM), KSM + Phthalide, Phthalide, IBP, Isoprothiolane (IPT), EDDP were examined in the field where KSM-and IBP-resistant strains had been occurred. Disease development in the KSM-and IBP-treated blocks were not significantly different from that in the untreated block. As compared with the proportion in the untreated block, the ratio of resistant strains to KSM became higher when KSM and KSM Phthalide were applied, whereas it became lower when Phthalide, IBP, IPT and EDDP were applied. The ratio of resistant strains to IBP became higher when IBP, IPT and EDDP were applied, whereas it became lower wnen Phthalide, KM and KSM Phthalide were applied. The resistant strains both to KSM and IBP were observed in this field.
