Analysis on sensitivity of Magnaporthe grisea pathogenic race in Guizhou to isoprothiolane

The sensitivity of the rice blast fungus on fungicide may be changed because of the variety of pathogenic race. Thirty isolates obtained from rice blast specimen collected from 3 areas-Huangping,Kaiyang, Tongzi in Guizhou Province were assessed through inoculation. The sensitivities of above isolates were investigated using suppression method of mycelium growth rate and conidia germination in the present study. The results showed that the total 3 race populations including 13 different races were identified. The predominant race of Kaiyang, Tongzi and Huangping was ZA1, ZA11,and ZB15, respectively. And the most insensitiveness isolates to isoprothiolane was scored from Tongzi area, the average EC50 was 4.21 滋g/mL.The most sensitiveness isolates to isoprothiolane was scored from Huangping area,the average EC50 was 2.59 滋g/mL. The sensitivity of different pathogenic race in same area to isoprothiolane were different. The sensitivity of same pathogenic race in the different areas to isoprothiolane was also different. There were also particular differences in the sensitivity of same pathogenic race in the same area.