Many farmers will encounter the phenomenon of rolling leaves when planting tomatoes. Sometimes the leaves of tomato are rolled up, sometimes the leaves of tomato are rolled down. The reasons for different directions are different, and the prevention and treatment methods are different. Therefore, it is necessary to analyze the cause of the disease.
First, the reason for the leaf roll
1. Tomato encounters high temperature and dry weather and cannot replenish water in time.
High temperature and strong light enhance the transpiration of the leaves, and the lower leaves of the plants are easily curled up. Especially in the vents, the tomato leaf is often heavier.
2. The drug concentration is too large to cause phytotoxicity
The surface of the blade will be discolored or spotted and the blade will curl upwards.
3, the amount of nitrogen fertilizer application is too much
The increase of soil solution concentration will cause the tomato leaflets to turn over and roll up; the high concentration of soil solution in the saline-alkali area will also cause the leaves to curl upwards.
4, topping too early
It is easy to breed axillary buds, and the phosphoric acid in the leaves has nowhere to transport, leading to aging of the leaves and curling of the leaves.
5, viral diseases are generally spread by poisonous insects such as aphids and whiteflies
The affected tomato leaves will appear chlorotic, smaller, shrinking, curling and other symptoms. Leaf curling is mostly manifested on the heart leaf and the upper leaf, which is easy to occur under high temperature and strong light.
Prevention and treatment
1. After the tomato is planted, it will be drought-resistant before the fruit setting. After the fruit is placed, it will be watered and fertilized at the right time, and the shade net will be covered in summer to prevent high temperature and drought.
2, in the summer hot season should try to reduce the concentration of the drug, once the phytotoxicity can be sprayed in time or the regulator to ease.
3, the use of nitrogen fertilizer in the tomato growth period should not be excessively applied to the application of phosphorus and potassium fertilizer, especially in the summer to prevent the growth of tomato plants should be controlled. It is also necessary to choose to plant tomatoes in non-saline areas, and soil-free cultivation or soil improvement measures can be implemented in saline-alkali land.
4, the removal of tomato side branches is also called snoring, generally when it grows to more than 7 cm. If the snoring is too early, the assimilation area of ​​the leaves is reduced, too much leaves are removed, and the growth of the aboveground parts of the plants affects the development of the root system. The water absorption and the ability to absorb fertilizer are weakened to induce the leaf rolling. It is common to have a tomato to branch, snoring, and picking leaves too much.
5, viral disease leaf: First, cut off the virus vector media aphids, whitefly, you can choose 70% imidacloprid or acetamiprid or white powder è™± 1 and so on. At the same time, the effects of spraying viral agents such as vegetable virus disease or + zinc fertilizer + regulator are more significant.
Second, the reason for the leaf roll
1, the temperature difference between day and night in summer is small
In order to prevent the loss of fruit caused by the growth of tomato, some vegetable farmers sprayed with naphthalene acetic acid is correct, but when the concentration is too large, the tomato leaves will show rewinding on the first and second days after spraying, and the leaves will return to normal on the third day. The concentration is 20-30PPM, but the concentration of naphthaleneacetic acid is more than 50PPM. The rewinding time may be longer, and some will fall.
2. The soil in the early stage was too dry, and the water was suddenly too large in the later stage.
Will cause the transpiration of the leaves to be inhibited, and the leaves will show a rewind when they show self-protection.
3. When the flowering period is 2,4-D, the concentration is too large or sprinkled on the leaves.
Thicken, shrink, or curl the blade. In addition, it is cultivated in the field in the spring, and 2,4-D butyl ester is sprayed around the wheat field to prevent weeds in the wheat field, and the liquid floating is also easy to cause phytotoxicity to cause the blade to deform.
4, topping too early
It is easy to breed axillary buds, and the phosphoric acid in the leaves has nowhere to transport, leading to aging of the leaves and curling of the leaves.
5, sassafras harm
After the tomato is damaged, the leaves become thicker and become smaller and harder. The opposite side of the leaf is rust-colored and oily, the leaf edge curls to the back, the tender stem is rust-colored, the tip of the neck is dead, and the flower bud deformity cannot flower.
Prevention and treatment
1. The regulator can be relieved when the rewinding is serious.
2, to avoid excessive drought, but do not water too much after the drought, especially pay attention to avoid pouring large water at noon at high temperatures.
3, the concentration of 2,4-D sputum should not be too high, the amount of use should not be too large, be careful not to spray the drug on the leaves should not be sprayed, try to stay away from the 2,4-D butyl ester Vegetable greenhouse area or when closed.
The phenomenon of tomato leaf rolling can not be underestimated, because it will affect the growth and development of tomato, which will affect the flowering result and cause the tomato to reduce production. Therefore, farmers should take immediate measures to treat the leaf rolling phenomenon.
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