Study on the Resistance of Phytophthora capsici Isolates to Metalaxyl in Gansu

There are 19 strains of Phytophthora capsici collected from 6 different regions in Gansu and these tested strains were isolated by single sporangium and Determined the resistance level of phytophthora capsici infectans to metalaxyl.The results indicated that Phytophthora capsici resistant to metalaxyl had exist significant differences in Gansu province,the strains of non-application can be used as sensitive baseline of Phytophthora capsici to metalaxyl in Huajian townships,Linshui townships,Jinta county of Jiuquan city,EC50 average of 0.13 mg/L.In addition,some strains were higher resistant to mentality from Lanzhou,Tianshui and Wuwei city,the detection rate was 63.2% of moderate and high resistance to strains,and the resistance level of up to 388.0 times,which might be related to the long-term application of metalaxyl in the area.