Abstract
The structure-activity relationships of 3-(3', 5'-dichlorophenyl) imidazolidine-2, 4-dione derivatives were investigated by the agar dilution method using Sclerotinia sclerotiorrun as a test microbe. Several compounds were tested for antimicrobial spectrum in vitro with other pathogenic microbes and for foliage protective activity in green house tests with rice sheath blight, rice brown spot, damping-off of cucumber and kidney bean stem rot. It was found that the antimicrobial activity was enhanced when the 1-position of imidazolidine ring was substituted by an alkyl group but was reduced when the 5-position was substituted by alkyl groups. Generally, 3-(3', 5'-dichlorophenyl) imidazolidine-2, 4-dione derivatives were active against Sclerotiniaceae, Corticiaceae, Dematiaceae, Polvstigmataceae or Pleosporaceae. In green house tests, some of these compounds showed high protective activity against rice sheath blight, rice brown spot, damping-off of cucumber and kidney bean stem rot. Results of the green house tests on the above mentioned diseases correlate well with those of in vitro tests except in the case of kidney bean stem rot.
