Sunburn is caused by burns caused by strong sunlight. It is usually caused when the temperature is high or the temperature changes drastically. The trunk and large branches are infected, and the sunny side is irregularly burnt, and it is easy to be infected by rotting bacteria. Cause rot disease.
The disease is a physiological disease. The number of stomata on the leaves is several times less than that of field crops in the same area. When the light is too strong, the stomata are blocked and the transpiration is reduced. When the temperature on the chip is too high, it exceeds its own tolerance, and the chlorophyll is destroyed. In turn, the mesophyll tissue loses water and scorches. Direct sunlight is the direct cause of sunburn.
Peak incidence:
At noon when the sun is very strong in summer, the transducing tissue and cambium cells at the root neck of the seedlings in contact with the soil surface are scalded to death by high temperature, forming a colorless ring with a width of several millimeters, and the transducing channel is destroyed.Cause the seedlings to fall down.
When the seedlings are just unearthed, because their stems are extremely tender, if the surface temperature reaches 32, sunburn will begin to occur. With the growth and development of seedlings, they gradually develop from tender and watery fleshy tissues to lignification, and their temperature tolerance also tends to increase. In addition, the sunburn of seedlings is also closely related to its own genetic factors, soil conditions in the nursery, and technical management of seedlings.
Prevention and treatment measures of Fatong sunburn:
Spraying foliar fertilizer, supplementing nutrients to increase the thickness of the leaves, can effectively resist the occurrence of sunburn.
Timely spraying water and spraying to increase the water content and air humidity of the soil, improve the microclimate of the orchard, and ensure an adequate supply of water are the most fundamental measures to prevent sunburn.
Bagging, covering the fruits that grow on the top of the canopy and the periphery of the canopy with a special sleeve for paulownia, this is the most effective and direct measure to prevent paulownia sunburn.
Deeply turning the garden soil, it can promote the robustness of the root system of the paulownia tree, increase the water absorption range and capacity of the root system, and maintain the balance between the growth of the above ground and the underground.
Paste white paper, smear lime slurry on the sunburn prone to sunburn or paste a piece of white paper on the fruit parts that have slight sunburn, or smear a layer of lime slurry, can prevent the occurrence of sunburn or Reduce the symptoms of sunburn.
Covered with tree trays, moisturizing and cooling. In summer, around the tree trays, along the vertical down of the crown of the root system, spread 10 cm to 13 cm of fresh grass or straw and other mulch to facilitate moisturizing and cooling,promote root activity, adjust soil moisture and the orange orchard The microclimate promotes the normal development of fruits.
Scientifically spray pesticides to avoid spraying pesticides with high concentrations, and avoid spraying pesticides under the scorching sun. During the fruit-bearing period, use lime-sulfur mixture as little as possible. If it is necessary to use lime-sulfur mixture to prevent and control rust ticks, the concentration should be 0.2 Baume, and try to avoid excessive aggregation of the liquid on the fruit surface.