Pollution-free control techniques of rice diseases and insect pests

I. Agricultural prevention and control

Agricultural control is the basis of pollution-free control of rice diseases and pests, and its basic principle is to create an environment conducive to crop growth and growth, but not conducive to the breeding of diseases and insect pests.

1. Increasing the application of organic fertilizer, gradually reducing the amount of chemical fertilizer in production, relying solely on the application of chemical fertilizer (especially nitrogen fertilizer) and neglecting the cultivation, accumulation and utilization of organic fertilizer is one of the important reasons for the serious occurrence of rice diseases and insect pests. Therefore, we must change the concept, attach importance to the development of animal husbandry, plant green manure and accumulate all kinds of farm manure, and establish a new fertilization model dominated by organic fertilizer and supplemented by chemical fertilizer. In order to increase the source of organic fertilizer, ploughing and sowing green manure or other crops are required in winter to prevent plank fields from overwintering. This can not only reduce the overwintering base of Chilo suppressalis and sheath blight, but also improve the soil. Organic fertilizer is a complete fertilizer, which can fully supply all kinds of nutrients needed by crops, but it is also a late-acting fertilizer, most of which can not be directly used by plants, and must be decomposed into ammonium nitrogen and inorganic salts by microorganisms. to be absorbed. The early stage of rice is the critical period for the need of quick-acting fertilizer (especially nitrogen fertilizer). If the supply of nutrients is not guaranteed, it will inevitably affect the normal tillering and lead to the consequence of not growing in the early stage and greedy green and late ripening in the later stage. Therefore, when increasing the application of organic fertilizer, attention must be paid to solving the above contradiction between supply and demand in order to achieve safe nitrogen uptake by rice (that is, according to the needs of each growth stage, nitrogen fertilizer should be supplied continuously and evenly, but more but less, so that rice can grow stably in the early and middle stages. in the later stage, it is not premature senescence, nor greedy). For example, when using green manure as the main fertilizer source, we must first control the total amount of application, about 1000 kg of fresh grass per 667m2, which should not be too much; secondly, when sowing green manure, we must mix and sow green manure varieties with different degrees of difficulty in decomposition; third, ploughing ahead of time to promote the decomposition of green manure. When using barnyard manure and cake manure as the main fertilizer source, we should try to make it fully mature before fertilization, achieve uniform distribution during fertilization, and pay attention to gap irrigation after transplanting seedlings to promote the decomposition of organic fertilizer. The application of organic fertilizer does not exclude the application of chemical fertilizer, and the two should be combined. It is mastered that 50 kg ~ 100 kg Si-mn compound fertilizer should be applied in time every 667 square meters at the beginning of tillering to promote the early growth and steady growth of grain seedlings and lay a good foundation for pollution-free rice production.

two。 Selection of high-quality, high-yield and disease-resistant varieties to prevent rice blast is required to have the characteristics of resistance to rice blast when selecting high-quality and high-yield varieties. This is because the effect of chemical control on rice blast is poor. The control effect of selecting resistant varieties is good and it is not difficult to achieve. The specific method is to investigate the incidence of panicle and neck rice blast of local varieties and newly introduced varieties during the heading and fruiting stage of rice every year. All varieties with an average incidence of panicle and neck rice blast of 3% to 5% will no longer be planted next year and will be resolutely eliminated. At the same time, high-quality, high-yield and blast-resistant varieties were continuously introduced for trial planting and popularization to gradually replace the varieties that had lost their resistance. As long as we persevere in this work, the occurrence and epidemic of rice blast can be avoided.

3. Advocate the application of silicon fertilizer to enhance the stress resistance of rice rice is a silicon crop, the content of silicic acid in rice plant is as high as 11.3%, relying on natural supply alone can not meet the needs of normal growth, it is necessary to promote the return of rice straw to the field and increase the application of silicon fertilizer. After the accumulation of silicic acid on the stem and leaf surface, it can silicify the stem and leaf surface and inhibit the invasion and expansion of pathogens such as rice blast and flax spot, and it is not easy for Chilo suppressalis to invade and feed, thus reducing the harm of diseases and insect pests. In addition, silicic acid can also promote the absorption and transport of nitrogen, phosphorus and potassium, promote the transport of oxygen in rice plants, enhance the oxidation capacity of roots, ensure the normal growth of rice, and significantly enhance the ability of lodging resistance.

4. Improving the methods of raising seedlings and attaching importance to the cultivation of strong seedlings from the point of view of pollution-free production, there are two aspects that need to be improved in the current methods of raising rice seedlings: first, the application of chemical nitrogen fertilizer in the seedling field leads to the green growth of seedlings, which is easy to attract diseases and insect pests and increase the mechanical damage during transplanting. The area of the seedling field is small, and rotten human and animal manure can be used as base fertilizer to meet the needs of normal growth in the seedling stage. Change potassium sulfate or potassium chloride into topdressing. In this way, we can cultivate seedlings that are not good-looking on the surface, but really healthy. The second is the phenomenon of indiscriminate application of pesticides in seedling fields. Seedling field is the natural enemy of various pests ~ parasitic wasps and rice field spiders transition to Honda bridge field, such as excessive application of pesticides will make it difficult for them to reproduce, it is difficult to play their role in pest control. Therefore, we must change the concept of small fields and protect large fields, and adopt the method of scientific drug use to achieve the purpose of protecting benefits and controlling disasters.

5. The implementation of scientific water management to reduce rice disease water is not only the lifeblood of the normal growth and development of rice, but also one of the causes of diseases. In the aspect of scientific water management, we should adhere to the principle of shallow irrigation at tillering stage, adequate seedling drying, gap irrigation after rewatering, and keeping the field surface moist. In some places, it is easy to lead to serious occurrence of Sclerotinia sclerotiorum, sheath blight and rice blast due to long-term deep irrigation due to water shortage or poor management. this problem must be paid attention to and corrected.