Studies on Corn Smut Control in Taiwan
C. M. Tseng
The optimal temperature for the germination of teliospore of Ustilago maydis in medium was between 25 and 35 degree C. The germination of teliospore of U. maydis could be stimulated by sucrose, but not influenced by light. Experiment of different inoculation methods at different corn growth stages showed that the sporidia injection method was most effective and stable over all growth stages, whereas the teliospore or sporidia whole inoculation method was unstable except at 3-leaf stage. The results showed that sweet corn varieties were more susceptible to U. maydis than field corn varieties, and the infected percentage of field corn was lower. Among the fungicides used, Captafol and Dithianon were more effective to kill the teliospore and which had no harmful effect to corn seed germination. There was no practical use for corn seed treated with fungicide to control U. maydis in the field and fungicide spraying at corn silking stage only had limited control effect. It was suggested that corn smut disease could be prevented only by sanitary at present. In the infected area, collected and burned off the tomurlike tissue of corn smut before ruptured of fungicide treatment of corn seed after harvested should have some effects to reduce the disease dissemination.
Research Bulletin of Tainan DAIS 22:13~23