After the corn comes out later, the leaves will be spotted, and they will slowly die if they don t g

Is plaque common? Is there a **?

Leaf spot, spray with fungicide**.

How corn is maintained.

1. Seedling management.

Emergence-before jointing) 4-5 whole leaves or 7-8 visible leaves. The leaf color is dark green, and the leaves are wide and thick, and the seedling frame is strong, so it should:

1) Squatting seedlings: keep the soil dry and wet, soil moisture accounts for 60 of the water holding capacity in the field, promote the development of the root system to form a swelling root system and deep rooting, to achieve the purpose of squatting seedlings to promote growth, in order to facilitate deep water absorption in the middle and late stages of drought resistance, seedling protection, and harvest.

2) Drought and stain prevention: In case of drought and soil drought, it is necessary to resist drought and protect seedlings. If the corn seedling stage is waterlogged and the low-lying land is waterlogged, it is necessary to open a ditch to drain the water to prevent waterlogging and protect the seedlings.

2. Management of jointing and long spike stage.

It lasted for 30 days before jointing and tasseling, and the vegetative growth and reproductive growth went hand in hand during this period, and the male and female panicles were mainly differentiated and developed.

1) Spring corn seedlings often encounter spring drought after jointing, whether to water or not, depending on the precipitation. In the critical period of maize water demand, the precipitation can not meet the needs, and the threat of drought is often encountered, so the irrigation before and after spring moisture preservation, trumpet stage and heading is an important measure to ensure the high yield of spring maize. Intercropping corn at the end of June and early July, jointing male and female ear differentiation requires a large amount of water, not necessarily in the rainy season, even if the spring water has been watered, due to the high temperature and evaporation loss.

There is also a high risk of drought, and irrigation is necessary to achieve high yields.

2) Irrigation of bud water: 10 days before maize tasseling to 20 days after tasseling is the critical period of corn water demand, which is sensitive to water response. In case of drought, it is necessary to water to prevent drought and resist drought to ensure the development of male and female panicles and the water needs of the subsequent growth period, so as to strive for high yields of large ears.

In case of heavy rain during the above period, the water in the field should be removed in time after the rain, and the soil should be cultivated to prevent lodging in case of strong winds.

3. Management of flowering and fruiting period: (corn from tasseling to flowering-maturity) lasts 45-55 days. During this period, flowering, pollination, grain filling and abundant reproductive growth period determine the constituent yield factors: number of ears, number of grains per ear and grain weight.

1) Watering enough heading and flower water, promoting flowering and pollination, improving seed setting rate, preventing premature aging of stems and leaves, and striving for multi-grain weight of panicles.

2) Watering the seed water: the leaves of the plant are yellow from bottom to top during the grain filling period, and the premature senescence of the plant should be fertilized and watered to increase the grain weight.

3) Drainage: Due to heavy rainfall, the stagnant water in the field should be removed in time.

4) Reasonable dense planting can make full use of light energy, soil power and space, so that the plants are well ventilated and transmitted, so as to reduce empty poles.

5) Scientifically carry out fertilizer and water management, according to the characteristics of each growth period, especially pay attention to the water and fertilizer management of tapping ears, so that corn can get sufficient water and nutrients in the process of growth and development, plant growth and development are good, reduce empty poles, and can regularly apply Woye series water-soluble fertilizer.

6) Do a good job of artificial assisted pollination to ensure that the pollination of female ears completely reduces baldness and grain deficiency.

4. Prevent empty pole baldness and grain deficiency.

There are many reasons for empty pole baldness. For example, the planting density is too large, the light is insufficient, the supply of nutrients is in short supply, and the water is insufficient.

No way. After brown spot disease occurs in corn, corn can be sprayed on the diseased site to destroy the bacteria on the plant. For severely diseased corn, it can be dug directly from the soil, incinerated and sprayed with quicklime to the goaf for disinfection.

Corn planting management:

1. Choose seeds.

Seed selection is the foundation and key step of corn planting, and experienced growers say that they leave the purchased seeds in the ground for two days before planting, so that the bad seeds can be picked out and the good ones can be left for further work. After selecting the seeds, we also need to carry out some seed processing work, such as selecting a small handful from the good seeds, and then soaking them in water for three to four days to see if the number of seeds germinated is so much. If the number of germinations is sufficient, these seeds can be sown into the land.

2. Land preparation. A good piece of land can grow more food, so before planting, growers should go inside the field to see how dry and wet the soil is and how fertile the soil is. If the soil is too dry, it is important to water it in advance and use tools to loosen the soil.

If the fertility is not enough, then the growers need to apply fertilizer first. Usually, fertilization is generally carried out after rainy days, and because the current fertilizers are chemically synthetic, targeted fertilization is required.

3. Emergence. In the process of corn cultivation, we generally plant more than 4,000 seeds on an acre of land, but not all seeds will emerge, some places are dense and some places are sparse, so we need to transplant seedlings, take a small shovel to dig up the roots of seedlings and then transplant them to places where there is a lack of seedlings. If all the seedlings come out, then we will pull out all the seedlings in the dense area to leave nutrients for the other seedlings.

Fourth, watering. We do a watering after planting so that the seeds can come out earlier. When all the seedlings are out, there is no need to continue watering.

5. Fertilization. Reasonable fertilization in the whole growth cycle of corn, suitable for topdressing with green water-soluble fertilizer, fertilization needs to adopt thin fertilizer and frequent application.

Large and small corn spot disease.

Big spot disease. Infringe on leaves. The lesions are oblong, light brown or blue-gray, sometimes slightly darker at the edges, and covered with a black mold layer.

In severe cases, the lesions converge into large long spots, and the leaves die. Small spot disease. It mainly attacks the leaves, and the leaf sheath also occurs occasionally.

The leaf lesions are oval, **yellow-brown, with brown margins. Sometimes the lesions have no distinct margins, but have 1 or 2 concentric whorls. Sometimes the lesions are larger, forming long spots between the veins.

When the weather is humid, a black mold layer develops. When it occurs sharply, the leaves are covered with small spots without wheel stripes and die quickly.

Corn spot disease mainly occurs in July, and the amount of precipitation determines the degree of incidence. Generally, when the diseased corn plants reach 70% of the total, the corn leaves begin to develop from top to bottom, and the incidence rate rises early when the rainfall time is early. If the disease rate of the plant reaches 70% and the disease rate of the leaves reaches 20%, and then there is a heavy rainstorm, the disease will break out in the whole area.

When the plant incidence is 100%, the leaf incidence is 30%, and then encounters continuous rainy weather, it should be prevented and controlled in time. Corn large spot disease is mainly developed by small spot disease, and the spots of severe corn large spot disease can reach about 20 cm, and when several diseased spots are connected together, they form irregular large spots. The spots are water-soaked at first, then slowly turn blue-gray, and finally brown until they die.

If the air is humid after the occurrence of corn spot, black mold will grow on the spots, and it is necessary to decide whether to control it according to the corn sampling inspection. When the plant incidence reaches 100% and the leaf incidence reaches 30%, rainfall obviously needs to be controlled.