Primary Reasearch On The Application And Effect On Cucumber Powdery Mildew (Sphaerotheca Fuliginea) By Using Salicylic Acid

Two cucumber varieties: Jinchun No.3 and Changchunmici were used in this experiment. Jinchun No.3 was used as the resistant variety, and Changchunmici as the suceptibale variety. There were 3 treatments: treatment 1, using pesticieds to control cucumber powdery mildew; treatment 2, using SA to control powdery mildew, concentration 5mmol/L, spraying every two weeks; treatment 3, combining pesticides and SA to control powdery mildew. This research was looking into the disease control results in spring and autumn crops comparing 3 treatments. In this experiment, Plot yields, disease index, resovabale protein, CAT, SOD and vitamin C were tested on each of the treatments. The result showed: (1) In Spring crop, treatment 1 had the best plot yield; treatment 3 was in the middle; treatment 2 was the worst among the three. In Autumn crop, treatment 1 had the best plot yield; treatment 2 was in the middle; treatment 3 had the lowest yield. Treatment 3 and treatment 1 had similar disease control result. Treatment 2 had the worst desease control result. (2) The effect of different treatments on the content of sovable protein. Content of sovable protein in treatment 2 of resistant variety was the highest, treatment 1 middle, treatment 3 the lowest. Content of sovable protein in treatment 2 is 7.84% higher than treatment 1's, but treatment 3's is 17.65% lower than treatment 1's. Content of sovable protein in treatment 2 of susceptible variety was the highest, treatment 1 middle, treatment 3 the lowest. Content of sovable protein in treatment 2 is 0.62% higher than treatment 1's, but treatment 3's is 10.22% lower than treatment 1's. (3) The effect of different treatments on the activity of CAT. Activity of CAT in treatment 2 of resistant variety was the highest, treatment 3 middle, treatment 1 the lowest. Activity of CAT in treatment 2 is 16.26% higher than treatment 1's, and treatment 3's is 15.06% higher than treatment 1's. Activity of CAT in treatment 1 of susceptible variety was the highest, treatment 3 middle, treatment 2 the lowest. Activity of CAT in treatment 2 is 8.55% lower than treatment 1's, and treatment 3's is 2.32% lower than treatment 1's. (4) The effect of different treatments on the activity of SOD. Activity of SOD in treatment 1 of resistant variety was the highest, treatment 3 middle, treatment 2 the lowest. Activity of SOD in treatment 2 is 8.47% lower than treatment 1's, and treatment 3's is 5.92% lower than treatment 1's. Activity of SOD in treatment 2 of susceptible variety was the highest, treatment 3 middle, treatment 1 the lowest. Activity of SOD in treatment 2 is 4.76% higher than treatment 1's, and treatment 3's is 2.99% higher than treatment 1's. (5) The effect of different treatments on the content of vitamin C. The content of vitamin C in treatment 1 of either resistant variety or susceptible variety was the highest.