Complete picture and prevention of corn seedling diseases

Corn is the main food crop in my country and is planted in many areas. The stage from corn germination to jointing is called the seedling stage. This stage is the critical period for corn root growth, and disease prevention and control must be done well. Let’s take a look at the complete pictures and prevention of corn seedling diseases.

1. Root rot

Corn root rot is a disease caused by Pythium, and its main symptoms are that the mesocottage and the entire root system gradually turn brown, soften, and rot. Root growth is severely hindered, the plants are short, the leaves turn yellow, and serious seedling death occurs.

Prevention and control methods : Strengthen cultivation management after the disease occurs and spray foliar fertilizer ; cultivate the land with high humidity to disperse moisture and promote root growth and development. For seriously infested plots, you can choose to spray 600 times diluted 72% mancozeb and cypermethrin wettable powder on the base of corn seedlings or irrigate the roots.

2. Top rot

The symptoms are that the upper and middle leaves of the diseased seedlings lose their green color, become deformed, wrinkled or twisted; the marginal tissues show yellow stripes and knife-like notches or the leaf tips die.

Prevention and control methods: In the early stage of the disease, you can use 50% carbendazim wettable powder, 80% mancozeb wettable powder, 5% fungicide and water-cleaning agent, and 72% agricultural streptomycin to spray on the heart. Twisted heart leaves need to be cut open longitudinally with a knife.

3. Seedling blight

Seedling blight usually begins at the 2-3 leaf stage, with the peak incidence at the 3-5 leaf stage. The leaves of the diseased seedlings turn yellow and dry, with scorched edges, and the leaves gradually turn yellow and dry from the bottom to the top; there are fewer root hairs, and the root system turns brown and is poorly developed, causing the above-ground plants to be dwarfed, grow slowly, be poorly developed, and the leaves to wilt or turn yellow.

Prevention and control methods: You can choose to soak the seeds in 500 times dilution of 70% thiophanate-methyl for 40 hours or in 2% formalin solution for 3 hours. After corn is harvested, the soil should be deeply plowed in time to kill the stubble, remove diseased and residual parts, promote the decomposition of diseased and residual parts, and inhibit the reproduction of pathogens.

4. Shrinkage disease

Corn rough dwarf disease is a disease caused by corn rough dwarf virus, which is mainly spread by gray planthoppers. It can be infected throughout the entire growing period and is severely affected in the seedling stage. Symptoms can appear on 5-6 leaves. In the early stage, dotted lines appear at the base of the heart leaf and on both sides of the midrib, gradually spreading to the entire leaf. The diseased seedlings are dark green, the leaves are stiff, wide, short and thick, the heart leaves cannot unfold normally, the diseased plants grow slowly and are dwarfed, waxy white raised stripes appear on the veins on the back of the leaves, and they feel noticeably rough to the touch, the leaves are stiff, the leaf color is dark green, and the internodes are short and thick.

Prevention and control methods: Before and after corn seedlings emerge, spray 1000 times diluted 5% acephate emulsion 1-2 times to kill insects and prevent the occurrence of pests and the spread of viral diseases.

5. Albino seedlings

There are white stripes on the leaves, and in severe cases, the entire plant's leaves turn white. The cause is zinc deficiency in the soil.

Prevention and control methods: Mix 10-15kg of fine soil and 1kg of zinc sulfate evenly, and sprinkle it next to the corn seeds when sowing. For seedlings that have shown zinc deficiency, spray 0.2-0.3kg of zinc sulfate with 100kg of water per 667m2, once every 7 days. Only 2-3 times are needed to restore the seedlings to normal.

6. Dwarf mosaic disease

The disease can occur throughout the entire growth period of corn, with the seedling stage being the most severely affected. Initially, many oval chlorotic spots appear between the veins at the base of the leaf core, arranged in discontinuous stripes of varying lengths along the veins. As the disease progresses, wider chlorotic stripes form on the leaves, especially on new leaves. The chlorophyll decreases, the leaf color turns yellow, the tissue becomes hard, the texture becomes brittle and easy to break. Some leaves have purple-red stripes starting from the tip and edge of the leaves, and finally dry up.

Prevention and control methods: Remove diseased plants and weeds as soon as possible. Corn dwarf mosaic is a viral disease, so it is advisable to use antiviral agents and apply them as soon as possible in the early stage of the disease, spraying once every 7 days.

The above is a complete picture of corn seedling diseases and an introduction to their prevention and control. These are common diseases in the corn seedling stage. For the growth of corn, it is imperative to do a good job of prevention and control.

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