(1) Plant disease-resistant varieties.
Planting disease-resistant varieties is the most basic and effective measure for long-term control of maize great spot. Plant corn varieties with stable disease resistance. Even in the year when the disease occurs, the incidence rate is low. In the mixed area of corn large spot, corn small spot and other diseases, the varieties with multi-resistance should be planted together. , Reasonable layout and reasonable rotation to prevent cross infection of diseases.
(2) Implement crop rotation and eliminate sick and disabled bodies.
A large area of annual crop rotation was implemented, and the severely diseased fields were ploughed in autumn, and the diseased residues were buried in the soil at a depth of 10 cm. Combined with the prevention and control of corn borer, the straw should be treated as soon as possible, and the diseased tissue inside and outside the field should be completely removed, and it should be burned or buried in a concentrated manner to reduce the initial infection source. The diseased body should be fully decomposed for composting, and the pathogens hidden in it should be completely killed.
(3) Strengthen cultivation management.
Reasonable arrangement of corn sowing period. Spring corn should be sown early to advance the growth period and avoid the later hot and rainy season as much as possible. Early sowing of summer maize can reduce the incidence of disease and have a certain effect on disease avoidance and yield increase. Seed selection before sowing is conducive to growing strong seedlings. Apply enough basal fertilizer, increase top-dressing fertilizer, and pay attention to the application of phosphorus and potassium fertilizers. To enhance the disease resistance of corn.
Open the ditch system around the corn field, which is conducive to drainage and stain prevention, and reduces the field humidity. Promote intercropping with cotton, soybean, peanut, sweet potato and other crops. The diseased leaves should be removed in time. The peak period of susceptibility is from the 7-8 leaf stage to the tasseling period. After the diseased leaves are found, they should be removed in time and taken out of the field to be burned or concentrated at high temperature.
(4) Timely spray protection.
Before and after corn tasseling, when the rate of diseased plants in the corn field reached 70% and the rate of diseased leaves reached 20%, spraying was started immediately.
Its effective medicines are: 50% carbendazim WP or 50% thiophanate WP 500-800 times liquid, or 65% dysenzinc WP, 40% Kewen powder emulsion 800-1 000 times liquid, Or 800 times liquid of 50% antibacterial WP, or 1 000 times liquid of 25% fenugreek wettable powder, 1 000 times liquid of 50% isobacteria · poly · manganese zinc wettable powder, or 10% difenoconazole Wettable powder 1 200 times liquid, 0.5% aminoglycan AS 2 500 times liquid, or 70% thiophanate-methyl WP 500 times liquid, 40% Diwenling EC 500 times liquid, 75% chlorothalonil 300-500 times liquid of clear wettable powder, etc., choose any one, spray 2-3 times continuously, the interval is 7-10 d, and the liquid is 75-100 kg/mu each time, and the uniform spraying effect is better.
