What are the good varieties of corn varieties resistant to large spot disease in Northeast China.

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Corn large spot disease, also known as coal streak disease, is one of the important diseases of corn, corn large spot disease is mainly to damage leaves, and in severe cases, it is also harmful to leaf sheaths and bracts. Generally, it starts at the bottom of the leaf and gradually expands upward, but it often starts from the middle and upper leaves. The main symptom is dark brown on the edge of the lesion, ** light brown or black-gray larger lesion, and severe lesions fuse together, causing the whole leaf to die.

Control measures: 1. Choose varieties resistant to large spot disease. When purchasing seeds, attention should be paid to selecting excellent varieties with strong disease resistance, high germination rate, high yield and convergence.

In particular, the dosage of pesticides and insect pests is different for each crop. Different pesticides and herbicides will be poured into the occurrence of corn leaf disease. Corn leaf spot basically occurs in the late growth stage of maize.

As long as the early prevention work is done well. In the later stage of corn, the water moisture is uniform, and the large spot disease of corn leaves will not occur, and the disease is the most serious before and after heading. The appropriate temperature for the onset of the disease is 26 32, but the key condition for the onset of the disease is that there is more rainfall and more rainy days in summer.

In the case of low terrain, high plant density, partial application of nitrogen fertilizer, delicate growth, early sowing, etc., the disease is severe, and the application of organic fertilizer, phosphate fertilizer, potassium fertilizer, and intercropping is implemented, and the disease is mild.

Through wide and narrow row planting, the ventilation and light transmission between plants can be increased, the field humidity can be reduced, and the conditions unfavorable for the infection and morbidity of pathogens can be created. The intercropping of maize with dwarf crops can also effectively regulate the field microclimate, create better growth conditions for plants, and reduce the occurrence of diseases. Agricultural control measures:

Plantar fertilizer was applied, phosphorus and potassium fertilizer were applied to improve plant disease resistance; Intercropping with other crops to improve the ventilation conditions of corn fields and reduce the infiltration of pathogenic bacteria.

The plot with poor soil is heavier than the fertile plot, the planting density is too dense than the normal plant spacing, the plot with poor ventilation is heavier than the well-ventilated plot, and the continuous cropping is heavier than the rotation plot.

50% carbendazim wettable powder can be used to spray corn plants with water at a ratio of 1:500, and corn large spot disease can be cured by spraying for three cycles in a row; Or spray corn plants with 75% bacterium wettable powder at a ratio of 1:400 with water, and spray 3-4 times in a row.

Enhance the disease resistance of corn, and it is necessary to inject some pesticides in advance, and at the same time, it is also necessary to carry out high-temperature fermentation treatment to avoid the peak period of insect infestation.

Intensify cultivation, select excellent varieties, and use professional pesticides to eliminate this pest and disease.

Corn should be protected by pesticides to prevent spot disease during the flowering period, so as not to cause an uncontrollable situation in the later stage.

Pesticides to prevent pests and diseases should be sprayed, and phosphorus and potassium fertilizers should also be used, so that weeding can be done well, and it is also excellent.

Corn leaf spot is a common leaf disease in corn-producing regions around the world. The disease in the summer maize area in China is more serious than that in the spring maize area, which can cause huge losses in the epidemic years.

1) Symptomatic maize will cause great losses from seedling stage to adult stage, especially at the tasseling stage and grain filling stage. The lesions are mainly concentrated on the leaves, generally starting from the lower leaves and gradually spreading upwards. At first the spots have water stains, then they turn yellowish-brown or reddish-brown with darker edges.

The lesion is oval, nearly round or oblong, and the size is 10 15 mm 3 4 mm. Sometimes, 2 or 3 concentric helices are visible within the lesion. (2) Infection route and pathogenesis.

The pathogenic bacteria overwinter in the form of hyphae or conidia in the body of diseased remnants, and produce a large number of conidia in the following month when the temperature is relatively suitable, and spread them through air currents or rainwater. After the spring maize is harvested, the conidia left on the diseased residues in the field can continue to spread to the summer maize field. Therefore, in areas where spring maize and summer maize are mixed, the incidence of summer maize is always more severe than that of spring maize.

From July to August, temperatures above 25 in North China are the most suitable for the epidemic of the disease. There are many rainy days, heavy rainfall, and high humidity, and small spot disease will occur severely. (3) select disease-resistant varieties as control methods; strengthen cultivation management, promote robust growth, and improve plant disease resistance; clean the countryside, concentrate on incinerating the sick and disabled, and reduce the source of disease; At the initial stage of the disease, spray 500 times of 50% carbendazim wettable powder, 500 times of 65% mancozeb wettable powder, 500 times of 70% thiophanate-methyl wettable powder, 800 times of 75% chlorothalonil wettable powder or 100-120 times of aqueous solution of agricultural resistance 120, and spray once every 7 days continuously from the end of the heart lobe to the tasseling stage.

Control methods: The prevention and control of corn large spot disease should be mainly based on planting disease-resistant varieties.

Strengthen cultivation management, supplemented by necessary pesticides for prevention and control. The prevention and control measures of cultivation management measures mainly include: timely removal of diseased plant residues in the field after corn harvest; Wheat ridge planting, early sowing at the appropriate time to avoid diseases; In the early stage of the disease, timely removal of 1 3 diseased leaves at the base of the corn stem can reduce and delay the disease damage. After the corn is harvested, it should be ploughed in time, the straw should be treated centrally, and the fertilizer used as a compost fertilizer should be fermented at high temperature; Crop rotation for more than 1 year, etc.

Summary. Hello, choose corn varieties that are resistant to diseases and pests, and select seeds according to the appearance of seeds. The selection of high-quality varieties is a favorable guarantee to increase the yield, the seed packaging bag is well sealed, and the production date, purity and clarity, moisture and germination rate indicated on the seed label are clear.

Avoid varieties that are not suitable for growing in these conditions. Choose excellent varieties that are resistant to pests and diseases. Species are selected according to local precipitation and accumulated temperature.

Choosing a corn variety that suits your local climatic conditions can increase yields and resilience to natural disasters.

Hello, choose corn varieties that are resistant to diseases and pests, and select them according to the appearance of the seeds. The selection of high-quality varieties is a favorable guarantee to increase the yield, the seed bag is well sealed, and the production date, purity and clarity, moisture and germination rate indicated on the seed label are clear. Avoid varieties that are not suitable for growing in these conditions.

Choose excellent varieties that are resistant to pests and diseases. Species are selected according to local precipitation and accumulated temperature. Choosing a corn variety that is suitable for your local climate can increase yields and resilience to natural disasters.

Hello dear, select seeds according to the previous stubble planting. The same variety cannot be planted in the same plot for three or four consecutive years, otherwise the land will be barren and the variety will be degraded. Choose the right variety according to the local production management conditions.

The yield potential of maize varieties is related to the production management conditions, and the varieties with high yield potential need good production management conditions. Bichongling should choose varieties with slightly lower potential judgment but better stable performance.

Select good varieties with excellent performance in comprehensive agronomic traits such as insect resistance, resistance to lead chirality, disease resistance, seed setting, field performance, adaptability, and comparative yield. Defeated.

It is better to use 50% carbendazim wettable powder.

50% dibacyl wettable powder or 90% mancozeb have good control effect on corn large spot disease. Add water 500 times diluted, 50-75 kg of liquid medicine per mu, spray once every 7-10 days, a total of 2-3 times.

Large spot disease is also known as stripe spot, coal streak disease, leaf blight, leaf spot disease, etc. It mainly damages the leaves, leaf sheaths and bracts of corn. The leaf infection first appears with water-stained blue-gray spots, and then expands along the leaf veins to both ends, forming large spots with dark brown, **light brown or blue-gray edges.

In the later stages, the lesions are often longitudinally fissured. In severe cases, the lesions fuse, and the leaves turn yellow and die. When wet, there is a large gray-black mold layer on the lesions.

The lower lobes are the first to occur. In single-gene resistant varieties, it appears as a green-to-green lesion, which is small, parallel to the leaf veins, yellow-green or light brown in color, and dark brown around it. Some present as necrotic plaques.

Corn (Zea Mays L.).It is an annual herbaceous plant of the Poaceae family, also known as bract, bract cob, maize, pearl rice, etc., native to Central and South America, is an important food crop in the world, widely distributed in the United States, China, Brazil and other countries.