Abstract:

To effectively control the disease of Zizania latifolia and screen out the safe and efficient fungicides, the effects of 7 fungicides on the microspores of Ustilago esculenta were tested in laboratory for evaluating the safety about gall formation of Zizania latifolia. At the same time, the drug resistance experiment of Bipolaris zizaniae and the field efficacy monitoring were used to screen the high-efficiency fungicides. The results showed that among the seven fungicides, pyraclostrobin had the best efficacy with 79.3% on Uromyces coronatus in Tongxiang area and 41.44% on Bipolaris zizaniae in Huangyan area, respectively. However, pyraclostrobin had the greatest effect on the microspores of Ustilago esculenta, and the concentration of 0.01 g/L completely inhibited the growth. Mineral oil had the least effect on the growth of Ustilago esculenta microspores, but the control effects of Zizania latifolia diseases were poor. The mixture of mineral oil and 25% pyraclostrobin suspension could reduce the use concentration while maintaining the high efficacy of the fungicide. In addition, epoxiconazole and picoxystrobin, which had little effect on the growth of Ustilago esculenta microspores, also had a field control effect of more than 40% on Uromyces coronatus. Therefore, when screening high-efficiency fungicides for Zizania latifolia, we should fully detect their safety to Ustilago esculenta, carefully screen the use time of fungicides, so as to avoid seriously affecting gall formation and thus limiting the yield and quality of Zizania latifolia.

Key words: fungicides, Uromyces coronatus, Bipolaris zizaniae, field efficacy, safety