Control And Resistance Inducing To Powdery Mildew Of Summer Squash (Cucurbita Pepo L.) Seed Plants

Cucurbita pepo L. seed can easily be infected by powdery mildew. The generaloccurrence of powdery mildew is the main restraining factor in seed production. The effect ofchemical control is not good. Besides, this will increase seed production cost and pollute theenvironment. This is against the formation of the seed yield and quality of Cucurbita pepo L.Currently, there are few reports on the researches of powdery mildew control and resistanceinduction for Cucurbita pepo L. seeds. This experiment preliminarily discussescomprehensive prevention and control measures for powdery mildew of Cucurbita pepo L.seeds from two aspects （improving cultivation and management measures of Cucurbita pepoL. seeds and powdery mildew resistance induction） so as to provide technical reference forseed production and improving seed yield and quality of Cucurbita pepo L. The experimentalresults are as follows:1. During seed production in the open field in spring, Cucurbita pepo L. seed should beplanted early in proper period. Under the precondition of no harm from early spring and latefrost, it was better to plant seeds in the open field around April17. The scorching weather inthe late period of fruit setting could be avoided so that the seed fruit could be mature beforethe weather conditions which would easily cause powdery mildew and make powdery mildeweasily spread arrive. This could effectively reduce the harm of powdery mildew to Cucurbitapepo L. seeds and guarantee seed yield and quality.2. Prevention and control effects of Different plant regulation measures were （from highto low）: not pick the heart, only remove male and female flowers above the seed fruit＞leave20leaves for pinching before planting the seed fruit and remove male and femaleflowers above the seed fruit＞leave10leaves for pinching before planting the seed fruitand remove male and female flowers above the seed fruit＞leave7leaves for pinchingbefore planting the seed fruit and remove male and female flowers above the seed fruit.3.5‰KH₂P_O4+0.3‰sucrose solution,50ug/ml salicylic acid and5mmol/L CaCl2weresprayed respectively during Cucurbita pepo L. seedling stage, before and after fruit setting.This could effectively induce seeds to generate certain resistance against powdery mildew,delay development course of seed powdery mildew, beneficial to planting and seedmaturation.4. Different plant regulation measures and different resistance inducing substancesimposed certain influences on the content of soluble sugar and soluble protein of the seeds,C/N content, K content, total phenols content and POD activity. The resistance against powdery mildew was formed through regulating the types of endogenous nutrients of theseeds and the content level and controlling defensive system functions of the seeds.5. The resistance of Cucurbita pepo L. seed and vegetable plant cultivation againstpowdery mildew had certain difference. Under the equal field management conditions, theorder of disease resistance （from high to low） is: cultivation through seed collecting＞hand-pollination vegetable cultivation＞2,4-D fruit protection vegetable cultivation.