The field plot test method was used to determine the control effect of four different first spraying time on apple scab. From the apple flower dew red period,the first spraying treatment was carried out according to the best period of apple growth (T1,T2,T3,T4 and water control CK). Each treatment was sprayed once every 10 days for a total of five times. The disease level of apple scab was investigated on the 10 th and 30 th day after the end of spraying,and the disease leaf rate,disease index and control effect were calculated. The suitable period for screening out the best control of scab was the first application at the apple flower red stage,and the control effect was 98.22％,which was sig-nificanly higher than other treatments.
维普
万方数据