Four passes to control rice sheath blight

In recent years, sheath blight has become the most important disease of rice, and has four major characteristics: first, a wide range of occurrence. Second, there are very few varieties resistant to sheath blight. Third, the harm is becoming more and more serious, even causing lodging through the top. Fourth, the disease is first caused by the lower part of the rice plant, which is easy to ignore and miss the favorable opportunity for prevention and control. It is the key to strictly control the four hurdles in the prevention and control strategy.

1. Salvage sclerotia sheath blight mainly overwinters in rice fields in the form of sclerotia. When overwintering sclerotia passes through winter and spring to early rice transplanting, generally 60% or 70% of sclerotia can germinate. Most of the sclerotia are lighter than water and can float with water for a long time. After irrigation in paddy fields, the sclerotia floating on the water surface can be removed, which can reduce the bacteria source of primary infection and effectively reduce the early incidence of rice. The method of removal is as follows: after raking the field surface, properly deepen the water layer, and then use dustpan and other tools to pick up the wave residue and sclerotia floating on the downwind edge and corner of the field, lift it away from the paddy field, bury it deeply or dry it and burn it.

Second, fertilizer and water management to strengthen fertilizer and water management to improve the disease resistance of seedlings. In the fertilization strategy, we should grasp the following three principles: first, attach importance to base fertilizer, apply more farm manure and organic fertilizer, and the general amount of base fertilizer should account for 60% of the total fertilizer application. Second, the rational collocation of nitrogen, phosphorus and potassium, especially the application of nitrogen fertilizer should not be excessive. Third, topdressing should be early and appropriate, and should be applied in accordance with the principle of "pre-weight, middle control, and post-supplement". In the pipe water, the irrigation methods of shallow, dew, leaving and living should be carried out, that is, the rice should be irrigated frequently in shallow water at the tillering stage, and the field should be properly exposed at the end of tillering stage to control the ineffective tillering and restrain the excessive growth of stems and leaves; after entering the booting stage, live water irrigation should be carried out; when it comes to the filling stage, it is necessary to adhere to dry, dry and wet, so as to promote the seedling growth to be elegant and elegant, and grow old without disease.

Third, the prevention of poisonous soil with Penicillium soil can inhibit the growth and germination of sheath blight mycelium. Within 20 days after rice transplanting, 25 kg of fine soil was mixed with 250 grams of 20% rice foot green per mu, which was evenly sprinkled into the rice field. But when using rice foot green, it must be forbidden to be used at booting stage or late growth stage before booting stage.

4. the occurrence of chemical control of rice sheath blight generally developed slowly in the early stage and increased rapidly in the later stage. Therefore, in the field investigation of strong stress in the peak tillering stage of early rice, when encountered high temperature and high humidity weather, the disease rate in the field should be about 30%, so as to control the spread of the disease. The medicament can choose one pack of Jinggangmycin powder per mu or 0.2 kg of Jinggangmycin water and 50 kg of water, and according to the disease degree and weather conditions, spray 2 times for 3 times. Spraying should be focused on the middle and lower part of the rice plant in order to get a good effect.