| The paper was to study optimum chemical agents and control periods against rice false smut (Ustilaginoidea virens) in single cropping middle-late rice. Taking chemical agents (triadimefon, armure,jinggangmycin) as main treatments and spraying periods (within 7 d before initial heading stage, within 7 d before initial heading stage + initial heading stage, initial heading stage) as assisted treatments, the field efficacy trial and optimum control period of U. virens in single cropping middle-late rice were studied using Huanghuazhan and Jinnongsimiao as experimental materials in 2013. Three
chemical agents, triadimefon, armure, jinggangmycin, extremely reduced diseased panicle rate and disease index of U. virens, but there was no significant difference among three chemical agents. Spraying period did not have significant impact on diseased panicle rate and disease index of U. virens, whereas spraying within 7 d before initial heading stage and during initial heading stage had relatively good control effect. Yield increased significantly after application of three chemical agents, and armure led to greater increase. The reason for yield increase was that seed setting rate significantly increased, and the number of filled grains per panicle significantly increased. Although spraying period influenced yield, the difference was not significant. |
