A Research on the Chemical Resistance of Rice Leaf Blight Bacteria to YEKUNING in vivo.
Wang Wenxiang. Xia Jing, Gu Jiangtao, Xia Hongshi (Plant Protection Institute, Anhui Academy of Agricultural Sciences, Hefei 230031).
The experiments in vivo in net house showed that the chemical resistance of Rice Leaf Blight Bacteria developed rapidly on YEKUNING and DIKUSHUANG After 250 ppm YEKUNING was sprayed once the resistance of the bacteria in all sprayed leaves increased. The resistance of the bacteria in three of ten those leaves was more than 5 times that of sensitive ones. After 250 ppm YEKUNING was sprayed twice the bacteria in all sprayed leaves were chemical resistant ones. Their EC50 increased at least 11 times that of sensitive ones and they could overcome 16000ppm YEKUNING. When YEKUNING was used as a preventive agent, the rate of resistance appearance was lower than as a curative agent. This chemical resistance of the bacteria could explain the differences in the effects of using stage and times of YEKUN-ING and could provide us with the theoretical basis of correct use of YEKUNING.