Rice blast is a common disease in rice cultivation and it is also difficult to control a disease. Once the incidence of light reduced by 10-20%, severe reduction of 40-50% or even no income. Rice blast is an ascomycete subphylum fungus Pyricularia oryzae. It overwinters with mycelium and conidia on rice seeds and stacked straw. In the following year, when the temperature is appropriate, the mycelium germinates and produces conidia, which becomes the initial source of infection. The conidia flowed into the rice plants with the wind, and when the temperature and humidity were appropriate, the conidia produced appressorium and grew mycelium into the rice tissue. The optimum temperature for conidial infestation is 24-28 degrees, and the humidity is 90% or more. It is best to have water droplets or water film on leaves for more than 6-7 hours. Rice blast can be divided into seedlings, leafhoppers, knots, ears and grains. 1 seedlings: rice seedlings occurred in the previous four-leaf rice seedlings, usually the base of the rice seedlings is grayish black, and the heart is yellow and distorted. 2 Leafhopper: The rice borer that occurs on rice leaf surface is divided into acute rice blast, chronic rice blast, brown rice blast and white point rice blast according to the lesion appearance. Acute rice blast: water-stained spots, round, oval, spindle-shaped, when the humidity is large, there is gray green mold layer. Chronic type: shuttle-like or oval-like disease, the center is gray, the gray-white periphery is a brown circle, the brown periphery is a yellow halo, and both ends of the lesion have a brown extended thin line like a long tail, and the back of the lesion is gray Green mold layer. Brown point type: Ye Zhengmiao has brown spots and no mold layer on the back of the leaves. This is a manifestation of low humidity and resistance products. White point type: There are round or oval spots on the leaves, and there is no mold layer on the back of the leaves. Generally, it occurs on the tender rice seedlings. 3 knots. Occurrence of rice blast on the rice pole festival, gray spots, mold layer. 4 ear 瘟. Occurs on the neck of the ear, and the diseased spot is brown and necrotic. When the humidity is high, the mold layer can be seen. The ear of rice is dry due to water loss. 5 grain pods. Rice blast that occurs on grains. Causes of rice blast: 1, climatic factors. Proper temperature and high humidity are conducive to occurrence and epidemic, especially temperature 24-28 degrees, humidity more than 90% and the leaves with water droplets lasting more than 6-7 hours do not stem the most conducive to disease. Especially during the tillering stage of rice, the heading stage coincides with the appropriate temperature and high humidity, and it is easy to develop rice blast disease. 2, breed resistance. Nowadays, there are various varieties in the seed market. The variety of high quality rice and super rice, together with the promotion of low cadmium absorption and resistance to rice cultivars in recent years, lay the foundation for the occurrence of rice blast, and many varieties are planted year after year with reduced resistance. 3, cultivation and management issues. Partial application of nitrogen fertilizer and excessive application of nitrogen fertilizer caused rice seedlings to be green for a long time, the degree of silicification was low, and the resistance decreased. At the same time, the luxuriant foliage makes it impossible to ventilate and transmit light through the shading of the fields. 4, control problems. Farmers do not see pests and do not fight drugs, rice blast disease can be the main prevention, in particular, panicle blast, once the disease is difficult to control. In some places, there is no defense against rice blast, and there is no awareness of rice blast, and I do not know how to deal with rice blast. There is also the problem of improper use of drugs that delays the best timing of drug use. Rice blast prevention and control program: 1, species selection. To select and introduce varieties that are strongly resistant to rice blast, and to formulate regular rotation planting systems to ensure that strong resistance does not decline. 2, seed disinfection. In order to reduce the seed infection and the source of the initial infestation of rice blast, and to strengthen the disinfection of the seeds, it is optional to sterilize them with strong chlorinated or prochloraz or cynomodin during soaking. 3, scientific and rational layout of planting. It is best not to focus on large-area planting for susceptible varieties, and not to develop a single variety for a long period of time in the epidemic area of ​​rice blast. For low cadmium accumulation varieties, we must also choose strong resistance and implement the annual rotation system. 4, strengthen the cultivation and management. Scientific fertilization, formula fertilization, to avoid partial nitrogen fertilizer, strengthen water management, do wet irrigation, exercise resistance to rice seedlings. 5, scientific and rational medication. Mainly prevention, comprehensive prevention. For Ye Yu, it mainly concentrates on the period from the tillering period to the jointing period. 75% tricyclazole 2000 times can be used for protection. Found that there is a leafhopper, find the center of the disease with Fuji No. 1 800 times the focus of treatment, and no near diseased fields with tricyclazole plus pyraclostrobin Water protection drugs. For the panicle blast, it can be sprayed once with 75% tricyclazole plus 40% Fuji No. 1 or with pyraclostrobin plus prochloraz in water 5-7 days before rice heading. Spray once again at the earing stage. Dried Brown Smooth Shiitake Mushroom Dry Shitake,Soaking Dried Shiitake Mushrooms,Rehydrating Shiitake,Dried Sliced Shiitake Mushrooms SHANDONG JOIN & SHARE AGRICULTURAL DEVELOPMENT CO., LTD , https://www.joinsharemushroom.com