Minimum effective dosage of oxathiapiprolin for the control of potato late blight

Potato late blight caused by the fungus of Phytophthora infestans ( Mont.) de Bary was a worldwide destructive disease in crop of potato (Solanum tuberosum L.). In order to make a better use of 10% oxathiapiprolin OD, in 2018-2019, field experiments were conducted to determine the minimum effective control dosage (the dosage whose control effect equated to or was higher than 80%) for the control of potato late blight. The results indicated that the control effect by the treatment dosage of 9.75-14.6 a.i.g/hm² was more than 8.0% at the 14th days after second spray. This dosage was the minimum effective control value, which was 50.0%-25.0% lower than that recommended by pesticide registration. Its work could provide basis for the reduction and accurate application of the pesticide.