Taizo Nakagawa

N-フェニルスルホニル-2-クロロイソニコチン酸アミドのイネいもち病に対する作用特性

N-Phenylsulfonyl-2-chloroisonicotinamide (NPSI) showed high protective systemic activity against rice blast when applied via root at a rate of more than 2.2 mg a. i./50 cm2 pot. The activity persisted for more than 4 weeks. NPSI was not curative in controlling the disease, however. Antifungal activity of NPSI against Pyricularia oryzae in vitro was not significant in test for spore germination, appressorial formation, appressorial penetration, mycelial growth, and melanin biosynthesis. As for the rice blast lesions appeared on the leaves of rice plants treated with NPSI, the ratio of the minute brownish lesions to the total number of blast lesions increased. Peroxidase activity was markedly enhanced in the leaves of rice plants pretreated with NPSI, when P. oryzae was inoculated. Efficacy of NPSI against rice blast decreased when abscisic acid (50 ppm) was sprayed on the leaves.