玉米田除草剂苯唑氟草酮的作用特性

Herbicidal characteristics of herbicide-fenpyrazone used in corn

为明确玉米田除草剂苯唑氟草酮(fenpyrazone)的最佳施药条件,以稗Echinochloa crus-galli为测试靶标,采用整株水平测定法研究了温度、光照强度、药后降雨间隔时间和杂草叶龄对其除草活性的影响。结果显示:在气温15~35℃下,苯唑氟草酮药效随温度的升高而升高,在20~35℃范围内,苯唑氟草酮药效趋于稳定,对稗的GR_(50)值在2.8~7.6 g/hm^(2)之间;随着光照强度增强,苯唑氟草酮对稗的活性显著增加,鲜重抑制率在41.19%~90.84%之间;苯唑氟草酮具有很强的耐雨水冲刷能力,施药后降雨间隔时间达到1 h以上,其除草活性与间隔时间即无显著相关性,对稗的GR_(50)值在1.7~2.4 g/hm^(2)之间;杂草叶龄会显著影响苯唑氟草酮的活性,其中1~4叶期的稗最为敏感,该条件下的GR_(50)值小于1.0 g/hm^(2)。综合来看,为保证苯唑氟草酮发挥最大药效,建议应在稗1~4叶期,选择天气晴朗、气温高于20℃的情况下施药,如药后1 h内遇降雨天气,则需进行补喷。研究结果可为苯唑氟草酮在玉米田的进一步推广应用提供科学依据。

In order to determine the best application conditions of fenpyrazone in corn fields,the effects of temperature,light intensity,interval time of rainfall after herbicide application and weed leaf stage on the herbicidal activity of fenpyrazone against barnyard grass Echinochloa crus-galli were studied using whole-plant dose-response experiments in greenhouse.At the temperature of 15-35℃,the efficacy of fenpyrazone was increased with the increase in temperature.At the temperature of 20-35℃,the efficacy of fenpyrazone tended to be stable,and the GR_(50) value for barnyard grass was between 2.8-7.6 g/hm^(2).With the increase in light intensity,the inhibition rate of the fresh weight of barnyard grass by fenpyrazone increased significantly from 41.19%to 90.84%.Fenpyrazone showed strong tolerance to rain erosion and could quickly penetrate the leaf tissues.And there was no significant correlation between its herbicidal activity and the interval time when the rainfall interval after treatment was more than 1 h,with the GR_(50) value of 1.7-2.4 g/hm^(2) for barnyard grass.The weed leaf stage significantly affected the efficacy of fenpyrazone against barnyard grass.The barnyard grass at 1-to 4-leaf stage was the most sensitive,with the GR_(50) value of<1.0 g/hm^(2).In conclusion,to maximize the efficacy of fenpyrazone,it should be applied when the weather is sunny,the temperature is higher than 20℃and the targeted weed of barnyard grass is at the 1-to 4-leaf stage.The herbicide needs to be reapplied in case of rainy weather within 1 h after the application.The results provide a scientific basis for further promoting and applying fenpyrazone in corn fields.