Growth rate method was used to test resistance to isoprothiolane (IPT) in 146 isolates of Mag-napothe grisea, from more than 200 disease samples of 20 counties in Guizhou province. The results showed that resistant isolates had occurred in major districts of Guizhou province, but most of them were low resistance to IPT. Resistance frequency in Qiandongnan, Guiyang and Zunyi was 10.96% , 9.59% and 7. 53% , respectively , which was significantly higher than in other districts.
Acta Phytopathologica Sinica
resistance to fungicide