What is rice leaf blast? How to prevent and cure?

What is rice leaf blast? How to prevent and cure?

Rice leaf blast is a common disease, farmers should pay attention to careful identification.

The disease occurs on the leaves of seedlings or adult plants after the three-leaf stage, and generally occurs from tillering to jointing stage. the disease spots on leaves are often different in shape, size and color due to the difference of weather and disease resistance of varieties. It can be divided into four types: chronic type, acute type, white spot type and brown spot type, of which the former two kinds of harm are the most important. Chronic plaque is diamond-shaped or spindle-shaped, generally 1 to 1.5 cm long, 0.3 to 0.5 cm wide, reddish brown to grayish white, with necrotic lines at both ends. Acute plaque is nearly round or irregular, dark green, and there is a dense gray mildew layer on the back of the plaque. The appearance of acute disease spot can be regarded as the forerunner of disease pandemic in the field.

What is rice leaf blast? How to prevent and cure?

Control techniques of Rice Leaf blast

1. Select disease-resistant varieties and pay attention to variety matching and rotation.

two。 Rice seed treatment before sowing: soaking seeds with 45% promethazol; applying grafting fertilizer and grafting medicine before transplanting: one week before transplanting, urea 3-5kg per mu of seedling field was applied to enhance plant disease resistance, combined with the control of leaf blast and the delivery of grafting drugs to prevent borer and planthopper. You can also soak the seedlings with 20% tricyclazole wettable powder for 5 minutes, remove the heap and cover for 30 minutes before planting.

3. Reasonable fertilizer and water management, adequate application of basic fertilizer, early topdressing, proper application of nitrogen to control seedlings in the middle stage, and fertilization in the later stage. Avoid applying too much or too late nitrogen fertilizer, and pay attention to increasing the application of phosphorus and potassium fertilizer. Water management should be based on the principles of planting seedlings in shallow water, turning green in deep water, dividing iniquity in thin water, and drying the field enough.

4. Chemical control. Leaf plague should be detected and controlled as early as possible, and chemical control should be carried out in time if acute disease spots are found in the disease center or leaves from the tillering stage.

Commonly used agents: 6% spring ramycin wettable powder 30-40 g / mu, or 75% tricyclazole wettable powder 30-40 g / mu or 40% Fuji No. 1 EC 100ml / mu. Spray 45-60 kg of water with any of the above chemicals, and control again after 8 days. Spray should be supplemented in case of rain within 4 hours after spraying, in order to achieve the ideal control effect.