Shao Fenggao, Liuhe District, Nanjing City, came to the telephone on April 15 to report that he started to cultivate watermelon seedlings a month ago. The area of ​​the seedbed was 0.6 mu. He recently found that nearly half of the seedlings in the field were wilting and the growth point stopped growing. He asked what caused the occurrence of watermelons and what should be done to the affected seedbeds. On April 16th, he sent a watermelon seedling to the agrotechnical studio 001 together with a seedling tray and substrate. After inspection, Shao Fenggao sent the plug, most of the normal seedlings already have 1 leaf and 1 heart, some seedlings grow weakly, cotyledons are dehydration, new leaves are small and the leaves are yellow, some seedlings only have two tablets. Leaves, small cotyledons or pale leaves, and some even have just emerged to death, lack of seedlings and severe seedlings together accounted for 50%. After unplugging the infected plants, it was found that the roots were generally poorly growing, and the roots and necks were yellow-brown. The seedlings with obvious above-ground symptoms had no root system and were easy to pull out from the substrate. A few weak seedlings just grew new roots. The water content in the nursery substrate is relatively high, and water will seep from the bottom hole soon after it is placed on the ground. According to further enquiries, the seedbed was raised in a greenhouse and a small arch cover, no electric hot wire was laid, the seedbed was low-lying, and the soil was wet when it came to the field after the rain. According to Yang Xingping, a research expert of the West Melon Research Institute of the Jiangsu Academy of Agricultural Sciences, after viewing the diseased seedlings, the roots of the watermelon seedlings were rooted. The excessive humidity in the seedling trays and the low temperature in the seedbeds were the main reasons for the poor growth of the watermelon seedlings. Roots are the physiological diseases that endanger the roots of watermelons, melons and other melons and fruits, and can occur in seedbeds and fields. After rooting occurs, plant growth stagnates in the ground. Long-term no new leaves will accumulate. Cotyledon or true leaves that have grown will turn yellow-green, and the edges will gradually yellow, shrink (but not produce spots), and become coke-like. Finally, it caused some wilting on the ground, and it was easy to pull out from the soil; when it was serious, it became dry and lacking elements. Looking up at the affected plants, we can see that no new roots, adventitious roots, or new roots are found in the roots. The roots of the roots turn yellow, and the original roots gradually become rust-colored and rot. In severe cases, the root bark becomes rusty and occurs. rot. The root cause is mainly due to the discomfort of soil moisture. In the initial stage of nursery or colonization, if the ground temperature is lower than 12°C, and water is excessively used in field management, or in rainy conditions, the soil will cause low temperature and high humidity, lack of oxygen, and new roots will not grow, resulting in poor growth and wilting of melon seedlings. A long time, it is easy to induce roots. Especially in low-lying land and clay land, due to poor drainage, water can not be sprayed and dried in time after rain, or watering too much when transplanting seedlings can cause the occurrence of roots. Yang Xingping suggested that the roots of watermelon seedlings should take measures as soon as possible to reduce moisture, and promote seedlings to grow new roots. In addition, the normally grown seedlings sent by Shao Fenggao have basically reached the requirements for transplanting, and they can be transplanted selectively when the temperature is suitable in the near future. In the future, to prevent the roots of watermelons, attention should be paid to raising seedbed temperature, lowering humidity, and strengthening ventilation. For example, if Gaosao is selected, well-drained plots are used as seedbeds, and it is better to lay electric wires on the surface to ensure that seedbeds can be reached at low temperatures. The temperature requirements and so on. Mini Ultrasonic Cleaner,Diy Ultrasonic Cleaner,Skymen Ultrasonic Cleaner,Best Ultrasonic Cleaner Dongguan Jinwang Ultrasonic Equipment Co.,Ltd , https://www.jwultrasonic.com