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Recently, many netizens have consulted about the problem of corn heart leaf rolling. Although high temperature and drought in summer can easily cause tacos leaves, not all leaf rolling phenomena are caused by high temperature and drought. Only by prescribing the right medicine can the symptoms be better cured. Today, the editor will talk about the symptoms, causes and prevention methods of corn curls in combination with everyone.
1. Field symptoms and causes
1. The leaves are curled in a garden cylindrical shape
is mainly affected by climatic factors. After the emergence of about 5 to 6 leaves, the temperature difference between day and night is large, and the leaves are affected by low temperatures. After the leaves are drawn out, they are cylindrical. This curl can be automatically unfolded in the later stage and has no effect on later growth and yield.
2. The leaves are upright like whip
The main reason is that the herbicide damage occurs. The agent is not diluted or sprayed unevenly when spraying, or repeated spraying, or unevenly moving speed or spraying more frequently when spraying on the car. For example, the 2,4-D medicine damage symptoms are the leaves are curled and onion-shaped leaves, the stems are brittle and easy to fold, the leaves are dark green, and the male ears are difficult to pull out, the aerial roots are deformed, and the leaves are yellow in severe cases and no female ears; after spraying acetaminine, the medicine damage symptoms are the deformed and twisted leaves into whip-shaped seedlings, and the stem nodes are deformed and swollen. Most of the leaf rolling phenomenon that occurs today is caused by excessive use of herbicides or herbicide residues.
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3, the plant is shorter and the leaves are stiff and rough
This situation is due to viral diseases caused by poisonous insects such as aphids , which bite the leaves, resulting in rough shrinkage.
4, corn plant tillering clusters
This situation is caused by underground pests. After the pest bites the main stem growth point , the growth point is damaged and inhibits the growth point or external factors affect the apical advantage of the main stem, and tillering occurs. In this case, if only one tiller can form spikelets; if it is allowed to grow, there will be no yield.
5, Corn silk sputum
Corn silk sputum sputum sputum in the fields is relatively complex. Curling of the upper leaves of corn is just one type of many symptoms, usually occur in early and mid-July. Some of them are manifested as the top blades are curled and upright along the central vein. After the male ears are deformed and enlarged, they can be seen with black powder in the white film and yellow and white stripes appearing on the leaves. Some are curled loosely, and the male ears can be pulled out, but the flower vessel is deformed and the leaves have yellow stripes. In this case, most of them have no yield.
6. Heart leaves are twisted and cannot spread
This situation may be a symptom caused by the harm of corn thrips. When the leaves are expanded by hand, you will find that there are still corn thrips inside. The insects are mostly active in the heart leaves or young parts of the corn. In addition, corn thrips are punctured and filed with a file-sucking mouthpiece to damage the plant leaves, and there are silver-gray spots on the leaves. In severe cases, it may cause corn heart leaves to become twisted and cannot spread, or twisted, making it difficult for the heart leaves to grow, or the growth points are damaged, tillage, forming multiple corn, and even destroying heavy seeds.
2. Prevention and control technical measures
1. Corn plant with curled leaves in a cylindrical shape
As the temperature rises at night, fields with insufficient soil moisture can be irrigated to gradually restore normal growth. For fields with weak growth, you can also spray foliar fertilizer to promote growth.
2. Corn plant with upright whip-shaped upper leaves
. Mildly, it can gradually resume growth; for heavier ones, artificially expand the leaves and then spray the foliar fertilizer. The key is that when applying corn herbicide, we must strictly grasp the application period, spraying time and dosage according to the specific conditions of soil quality, variety, precipitation, temperature, wind speed, etc., and stir evenly. If there is a drug damage, corresponding remedial measures should be taken immediately depending on the specific situation, such as irrigation, leaf spraying, etc.
3. Corn plant with crude shrinkage
If it occurs earlier, it is generally not able to grow and solid normally, and it is best to remove it early; if it occurs later, although its development is blocked but it still has solid strength, it can be retained (generally, the yield is reduced by 30% to 40%). For rough shrinkage, it is mainly about prevention. Weeds in the fields should be removed frequently. Coated seeds should be vigorously promoted for wheat and corn. During the maturity of wheat, that is, the peak period of aphid migration, spray medicines to prevent lifting in time, eliminate aphids before moving away, reduce poison transmission vectors, and organize growers to eliminate them in a concentrated and continuous manner during prevention and control, otherwise the effect will not be obvious.
4. Corn plant where tillering occurs
If the main stem is seriously injured, remove the tiller as soon as possible; if the main stem is normal, remove the tillering early. For this situation, it is mainly about prevention, and the pest situation in the fields should be detected. Weeds are places for pests to lay eggs on the ground and are also mediators for the transfer of larvae to corn. Therefore, removing weeds in the fields before sowing can eliminate some larvae and eggs, and also eliminate the spawning sites.
5, comprehensive agricultural prevention of silk black sputum
Actively take agricultural measures to enhance the disease resistance of corn. For example, increase the density appropriately, improve the sowing quality, remove the diseased seedlings as soon as possible, and do not feed the diseased plants to prevent the feces from carrying bacteria, and concentrate on treating the residual branches and leaves in the field after harvesting. At the same time, deep land is poured into the land in autumn, and overwinter water is irrigated in winter to reduce the source of bacteria. Accelerate the replacement of new disease-resistant varieties and implement a large-scale crop rotation system.
6, corn thrips prevention and control measures
Use type of coated seeds. 20% thiamethoxam·20% bromocamide suspension seed coating agent, 16% polyimidacloprid and 28% insecticide and acetaminami, with better prevention and control effects.
Source: Seed World
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