After summer, the weather is fine and the temperature rises rapidly. The temperature in the shed may exceed 40°C, which brings a lot of damage to the growth of vegetables, especially the vegetables that are less tolerant to high temperature and strong light, such as pepper. So, what are the main physiological problems that need to be guarded during the hot season? 1, sunburn Sunburn occurs mainly on fruits. The initial epidermis of the victim's victim is grayish leathery, and the surface is thinned and shrunk. The tissue is necrotic and stiff. It seems to be scalded by boiling water; under humid conditions, it is attacked by saprophytic bacteria. Dyeing can grow gray moldy layer and cause the disease to rot, seriously affecting the yield and quality of vegetables and reducing economic benefits. Especially in clear summer, if there is no leaf protection, the fruit surface facing southwest is exposed to strong sunlight for a long time, the local temperature of the fruit surface rises quickly, the evaporation water consumption increases rapidly, the temperature of the sunny surface of the fruit is too high, and the water supply is not high. Burns in time. 2, poor flower bud differentiation Many vegetable farmers have this understanding, that is, loofah, pumpkin, lentils and other vegetables, the number of summer flowers is significantly less, flowering nodes increased, and some even directly without female flowers, greatly affecting the effectiveness of planting vegetables over the summer. What is the reason for this? Because the early and late flower bud differentiation is related to genetic factors, it is directly affected by the temperature and length of sunshine. High-temperature long-day sunshine is usually conducive to the differentiation of male flowers, female flowers are relatively reduced; low-temperature short-day is conducive to female flower differentiation. Therefore, when planting certain over summer vegetables, we must pay attention to seedling management and increase physical measures such as lowering the temperature, shortening the illumination time, increasing the humidity, increasing the concentration of carbon dioxide, or spraying chemical measures such as spraying 40% ethephon 2500-4000 times. The number of female flowers. 3, deformed fruit and more At high temperatures, zucchini, cucumbers, etc. are prone to problems such as long, sharp, large heads, etc., malformed melons or poor color, which reduces or loses the value of commodities. To solve the various physiological problems caused by high temperature and high light, we must start from the following aspects: The first thing to pay attention to is the shade, to avoid direct sunlight in the shed. On the shed film, the use of splashing mud, covering shade nets, spraying cooling agents, etc. can reduce the transparency of the shed film and reduce the illumination in the shed, thereby reducing the temperature of the shed and reducing the problems of sunburn and the like. There is no cost to splash the mud, but shading is not uniform, the effect is difficult to guarantee, and it is easy to be washed by rain. The shading net has good shading effect, but it is troublesome and needs to be covered at any time. Many shading nets selected by the vegetable farmers have too high shading rate, affecting the plants. Normal growth; cooling agent is not easy to clean, it is best to use on the old film. According to their own needs, farmers can choose the appropriate shade. In addition, we must pay attention to maintaining a reasonable number of leaves to avoid direct sunlight on the fruit leading to sunburn. Secondly, various measures must be taken to reduce the temperature in the shed to reduce the high temperature hazards. In the shed, through appropriate pruning, promote the robust growth of plants, and maintain the appropriate leaf index on the plants, can improve the ability of plants to deal with high temperature and strong light. Diligent watering, reasonable topdressing, improving the humidity in the greenhouse, promoting deep roots and leaves, ensuring sufficient water supply to the plants, increasing leaf transpiration, thus effectively reducing the temperature of the leaves, and reducing the danger of high temperature and light. Strengthen ventilation, ensure air circulation inside and outside the shed, and also effectively reduce the temperature inside the shed. Again, attention is paid to improving the tolerance of vegetables in greenhouses to high temperature and strong light. Leaf sprayed with amino acid, fulvic acid foliar fertilizer, etc., can form a protective film on the surface of the blade to improve the ability of the blade to resist high temperature. Fresh Delicious Qinguan Apple,Sweety Qinguan Apple,Fresh Fuji Apple From Yantai,Fresh Fuji Apple Laiwu Manhing Vegetables Fruits Corporation , https://www.manhingfood.com