Abstract:

To find out effective prevention and control measures of apple powdery mildew, the method of combining general survey and fixed-point survey was adopted. The occurrence period and harm degree of powdery mildew in apple orchards were investigated regularly. By field control test, the control effects of biological agents, inducers and highly effective chemical agents were evaluated. The results showed that apple powdery mildew occurred from April to May in spring, and around September in autumn. It was found that the incidence of powdery mildew on ‘Huashuo’ was more severe than that on ‘Fuji’. The field screening results showed that the control effect of 8% pyrimidine nucleotide antimicrobial was 75.27%, followed by 10% polyantimycin with a control effect of 62.09%. The three kinds of inducers had certain effect on the control of apple powdery mildew, and the effect of 50 μg/mL salicylic acid treatment was the best, up to 66.85%. The control effect of oxalic acid treatment with high concentration was more than 50%. The treatment effect of 5% amino-oligosaccharide 2000 times was close to that of 50 μg/mL salicylic acid, which was 65.26%. Among the 5 commonly used chemical agents, 50% propiconazole had the best control effect against powdery mildew, which was as high as 98.59%, followed by 10% phenylecloprazole (92.80%), and 5% hexaconazole, 30% picoxystrobin and 40% myclobutanil also had satisfying control effect, which were all above 80%. The results of this experiment can provide technical guidance for the technology integration and demonstration of apple pest integrated control system in the future.

Key words: apple, powdery mildew of apples, pesticide, screening, control effect