Characteristics of N-Phenylsulfonyl-2-chloroisonicotinamide as an Anti-rice Blast Agent

Studies on 2-Chloroisonicotinamide Derivatives as Rice Blast Control Agents (Part 1)

Abstract

N-Phenylsulfonyl-2-chloroisonicotinamide (NPSI) showed high protective systemic activity against rice blast when applied via root at a rate of more than 2.2mg a. i./50cm² 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 (50ppm) was sprayed on the leaves.