Prevention and Treatment of Corn Disease

1. Main types of corn diseases

The main diseases of corn include rough dwarf disease, leaf blight disease, head smut disease, rust disease, stalk rot disease and so on.

2. Disease causes and preventive measures

2.1 Corn rough dwarf disease

Maize rough dwarf disease is a viral disease caused by the virus transmitted by laodelphax striatellus. After the disease occurs, the plants become dwarfed, the leaves are dark green, the internodes are shortened, and the heading is basically impossible. Therefore, the incidence rate is almost equal to the loss rate, and many plots have lost production.

2.1.1 Causes of rough dwarf disease

Corn rough dwarf virus mainly overwintered on wheat and weeds, but also overwintered in virus-transmitting insects. When the corn emerges, the laodelphax striatellus on the wheat and weeds migrates to the corn to feed and spread the virus, causing the corn to become sick. The occurrence and development of rough dwarf disease is closely related to the activities of laodelphax striatellus in the field.

2.1.2 Prevention measures of rough dwarf disease

The Prevention strategy should take comprehensive measures of selecting disease-resistant varieties, strengthening cultivation management and cooperating with chemical control.

1) Choose disease-resistant varieties.

The selection of more disease-resistant varieties in production is the fundamental measure for the prevention and treatment of rough dwarf disease.

2) Adjust the sowing period and farming method

Adjust the sowing date and sow at the right time to avoid the peak of laodelphax striatellus. Remove weeds on the ground and edge of the ground to reduce the source of infection. For early-sown corn with severe disease, it should be removed and replanted as soon as possible. The diseased seedlings should be removed from the plots with mild disease, and the fertilizer should be increased to make the seedlings grow robustly, enhance disease resistance, and reduce disease incidence.

3) Chemical control

Imidacloprid has a very prominent control effect on laodelphax striatellus. The use of corn seed coating agent containing Imidacloprid to treat seeds is an effective measure to control the damage of laodelphax striatellus at the seedling stage and prevent the spread of rough dwarf disease. For the uncoated corn seeds, immediately spray imidacloprid on the corn seedlings, and evenly spray the weeds in the fields and grounds to effectively control the laodelphax striatellus and prevent the re-spreading of the virus.

2.2 Corn leaf blight disease

2.2.1 Causes of leaf blight disease

Corn leaf blight disease are the major foliar diseases on corn. Corn leaf blight disease is a fungal disease belonging to the Deuteromycotina. The pathogenic bacteria overwinter in the sick body and spread by rain and air currents when the weather is favorable the following year.

2.2.2 Prevention measures of leaf blight disease

The prevention strategy is to promote and utilize disease-resistant varieties, strengthen cultivation management, and supplement with necessary chemical control in time.

2.3 Corn head smut disease

2.3.1 Causes of head smut disease

Corn head smut disease is a disease infected by sphacelotheca reiliana at the seedling stage. It is a disease that seriously affects the high yield of maize.

2.3.2 Prevention measures of head smut disease

1) Plant disease-resistant varieties. The use of disease-resistant varieties is the fundamental measure to control head smut disease.

2) Seed treatment. The use of seed coating technology is one of the important measures to effectively control the disease.

2.4 Corn rust disease

2.4.1 Causes of rust disease

In general, corn rust only appears sporadic lesions on leaves in the late mature stage of maize, which does not affect yield. However, it is necessary to prevent the epidemic of corn rust due to the change of varieties and the influence of climate and other factors, which will eventually lead to dry leaves of the diseased corn, premature senescence in the later stage, and incomplete grains, resulting in greater yield reduction.

2.4.2 Prevention measures of rust disease

1) Select high-yielding varieties suitable for local resistance and disease resistance.

2) Strengthen cultivation management, apply fertilizer reasonably, prevent partial use of nitrogen fertilizer, and increase phosphorus and potassium fertilizer reasonably.

3) Chemical control measures. In the early stage of the disease, 25% triazolone wettable powder 800 times liquid can be sprayed, and after 7 days, the prevention and treatment should be carried out again according to the condition. Besides, tebuconazole, difenoconazole, etc. can be used also.

2.5 Corn stalk rot disease

2.5.1 Causes of stalk rot disease

The pathogenic bacteria of corn stalk rot disease are complex and can be infected by multiple pathogenic bacteria or alone, mainly Pythium and Fusarium.

2.5.2 Prevention measures of stalk rot disease

1) Speed up the selection and breeding of pathogen-resistant varieties;

2) In areas or fields with severe disease, when sowing, use zinc sulfate fertilizer as seed fertilizer (3 kg per mu);

3) Increase the application of potassium fertilizer (8 kg of potassium chloride per mu) to improve plant disease resistance and reduce the incidence of disease.