Consultation: My greenhouse shed melon seedlings soon, these days, the leaves are generally yellow, the petiole is slender, and there are no leaves after the two true leaves. The top is a bunch of flower buds. What should the experts do? Answer: This is the topping of the fruit of Papaya. It is a physiological disease caused by a bad environment. The main cause of the disease is low temperature and weak light. First, the night temperature is too low, and the nutrients produced by photosynthesis during the daytime can be transported to various organs at a suitable night temperature, while the night temperature is low, especially the soil temperature is low, and the root system is not well developed, and the activity is decreased. The development of the growth site is inhibited. Second, the temperature difference is large. When the night temperature is lower than 10 °C, the nutrients are transported to the faucet less frequently, and the reproductive growth is more than vegetative growth, forming flower buds into clusters. The third is that the soil is dry or wet, causing roots, or excessive application of potassium fertilizer causes flower topping. Fourth, the lack of light, the decline in photosynthesis of the plants caused the leaves to yellow, and the petiole was thin and long. Solution: 1. Remove all the flowers from the top (note: the top buds cannot be removed, otherwise they will form headless seedlings). 2. Spraying regulators that promote stem and leaf growth, such as: brassinolide, Tianda 2116, etc., to promote stem and leaf growth. 3. Foliar spraying 1 or 2 times of 1% urea or 2‰～3‰ of potassium dihydrogen phosphate promotes leaf greening. 4. Try to increase the light. Papaya is a kind of light crop. In the current situation of continuous yin, the curtain should be uncovered as early as possible, the curtain should be covered as soon as possible, and the time should be increased, and the dust on the film should be cleaned in time. Conditional can use some light-filling measures. Such as: hanging reflective film on the back wall, adding light and light in the shed. 5. Pay attention to insulation. Especially for the ground temperature, the temperature during the day is preferably above 23 °C ~ 25 °C, and the night temperature should be above 15 °C. 6. If the weather is restored, you can quickly chase the nitrogen fertilizer. It is best to apply about 5 kg per mu of ammonium nitrate, and combine the topdressing with a shallow water for a sunny day. Disclaimer: Some articles on this website are transferred from the Internet. If legal rights of third parties are involved, please inform this website. phone Xi'an Healthway Biotech Co.,Ltd , https://www.xianhealthway.com