Fungicides Experimentation of Potato Late Blight

As a result of long-term use of some limited broad-spectrum fungicides on controlling of potato late blight,pathogen resistance to the fungicides was increased,leading to reduced effect for late blight control.To screen the efficient,economical,and safe fungicide which might be used in future production,four fungicides(Ovraclostrobin · Dimethomorph 18.7% WG,Fluopicolide·Propamocarb 68.75% SC,Metalaxyl·Mancozeb 72% WP and Mancozeb 75% WG) were tested for their effect on late blight control at low,medium and high concentrations with the high concentration applied two times and low and medium concentration three times.The control efficiency for Ovraclostrobin·Dimethomorph 18.7% WG applied at the rate of high,medium and low was 71.08%,73.03% and 69.04%,respectively,followed by Fluopicolide·Propamocarb 68.75% SC,with the control efficiency of 62.09%,74.53% and 64.65%,respectively.The control efficiency of Metalaxyl·Mancozeb 72% WP was 56.91%,71.71% and 66.87%,while Mancozeb 75% WG was 46.52%,70.38% and 68.85%,respectively.These results indicated that Ovraclostrobin·Dimethomorph 18.7% WG and Fluopicolide·Propamocarb 68.75% SC had better control efficiency for late blight and remaining two fungicides also had certain effects.It is recommended that these fungicides should be used alternatively in potato production for late blight control.