Why do cucumbers spray ethephon in summer and autumn?

Why do cucumbers spray ethephon in summer and autumn? How to spray ethephon on cucumbers? Experienced netizens also help to introduce that because cucumber is a monoecious pollination crop, the number of female and male flowers sooner or later has a significant impact on the yield and economic benefits of cucumber. The growth and development stage of cucumber in summer and autumn is in the hot high temperature season, the sunshine is long, and the female flower forms late. Spraying ethephon in cucumber seedling stage can promote the development of female organs, form female flowers at the node position of the main stem of male flowers, reduce the node position of female flowers, thus produce more cucumbers, not only increase yield, but also mature early. After ethephon treatment, the female flowers of cucumber increased, the internodes became shorter, and almost all the female flowers were born within 20 nodes of the plant, but in order to make the young melons sit and develop normally, the management must be strengthened to ensure adequate fertilizer and water supply. In the middle and later stage of cucumber growth, the mixture solution of 0.3% potassium dihydrogen phosphate and 4000 times 802 was sprayed for 5 times to ensure the strong demand for plant vegetative growth and reproductive growth and prevent premature senescence. Therefore, the farming network has sorted out the method of spraying ethephon on cucumbers, which is listed below for netizens' reference. 1. The time of spraying ethephon on cucumber: when two true leaves of cucumber grow, the flower buds in the axils of 2-11 nodes differentiate one after another, but the sex has not been determined, and the effect of spraying ethephon is the best during this period. At the stage of more than 4 true leaves, the sex of the flower bud has been formed, and it is futile to use ethephon. The suitable period of spraying ethephon on cucumber in summer and autumn is the stage of 3 true leaves of 2 Mel. The spraying times are generally 3 times of 1 Mel and once every 10 days of 7 Mel. Second, the concentration of ethephon sprayed on cucumbers: ethephon is used to control the sex of cucumber with a diluent of 0.01% Mel 0.02%, depending on the number of treatments. Generally, 0.02% diluent is suitable for spraying 2 times, and 0.01% diluent is better for 3 times. Third, the method of spraying ethephon on cucumber: you can choose to spray the prepared solution evenly on the leaves and growing points of the whole plant after 4 o'clock in the afternoon on a cloudy day, so as to make the fog particles fine. Attention should be paid to setting aside a certain number of plants without treatment, so that the male flowers can provide pollen for the female flowers in the field. What is the role of plant auxin?