Rice blast is one of the most important diseases of rice, which can lead to a significant reduction in yield. In severe cases, the yield is reduced by 40%-50%, and even the grain is not harvested.

First, the symptoms of damage

Rice blast can occur in every part of the rice during each growth period. According to its onset and location, it can be divided into seedlings, leafhoppers, knots, panicles, and grains. Among them, leafhoppers are the most common, and panicles and necks are the most serious.

1. Miao Miao: occurred in the seedlings before the 3 leaf stage, mainly caused by seed bacteria, the base of diseased seedlings become dark brown, the upper part was yellow-brown or reddish-brown and dead. When wet, the surface of diseased seedlings often has gray green mold layer.

2. Leafhoppers: Seedlings can occur from the 3 leaf stage to the panicle stage. The type, shape and color of lesions vary according to weather, species, and age of lesions. They can be classified into chronic, acute, and white spots. There are four types of brown spots, of which the first two are the most important ones. Chronic lesions, diamond-shaped or spindle-shaped, generally 1-1.5 cm long and 0.3-0.5 cm wide, red-brown to gray-white, with necrotic lines at both ends. The acute lesions are nearly round or irregularly shaped, dark green, with a gray mold layer on the back of the lesion. The appearance of acute lesions can be seen as a precursor to field disease pandemics. White spot type lesions are white or grayish white, round or irregularly round, and these lesions are not common. They usually occur when the weather is fine or dry after a rainy day.

3. Frugality: Mostly occur at the first and second nodes below the ear, black, and the diseased section is sag and easily broken. Gray moldy when wet.

4. Panicle blast: Occurs in the ear, neck, and branch stalks. After the cervix and branch sensation, the lesions are dark brown in the initial stage and dark brown later. When the humidity is high, gray mold layer occurs on the lesions. The disease is early and heavy. The tassels of the tassel were dead and white spikes. The tassels that had late onset had more cereals, poor rice quality, and reduced yield.

5. Grain pods: Occur in the husks and escarpments. The early onset lesions appear elliptical, grayish, and the lesions are not obvious after maturation of the grain. The onset of disease is brown, oval or irregular. Grain pods are an important source of initial infestation of seedlings in the following year.

Second, the law of transmission and incidence

The pathogens overwintered on rice straw and rice with conidia and mycelium. The conidia produced in the following year were transmitted to rice plants by wind and rain, germinating and invading the host to spread the disease to adjacent cells, forming a central disease strain. The conidia formed in the diseased part were re-infested by wind and rain. Seeding the seed with bacteria can cause seedling emergence. Proper temperature and high humidity, in the presence of rain, fog and dew, are conducive to disease. Mycelial growth temperature limit 8-37 °C, the optimum temperature 26-28 °C. Spore formation temperature limit 10-35 °C, 25-28 °C optimum, relative humidity more than 90%. Spore germination requires the presence of water for 6-8 hours. Appropriate temperature can form appressorium and produce invading filaments, penetrate the epidermis of rice plants, and spread nutrients between cells. Rainy weather, lack of sunshine or weather when it is sunny, or there are clouds or condensation conditions sooner or later, the condition expanded rapidly. Variety resistance varies by region, season, age, and race. Indica varieties are generally better than glutinous varieties. The resistance of the same variety at different growth stages is also different. The seedlings are susceptible to disease at the 4 leaf stage, tillering stage and heading stage, and the disease incidence is light at the round culm stage. The same organ or tissue is severe at the young tissue stage. The heading was weak when the ear was eared. Partial application of nitrogen fertilizer is beneficial. Deep water irrigation in early or long-term irrigation is poor in root development, and disease resistance is weak.

Third, control methods

1. Vigorously promote good, high-yield and disease-resistant varieties and pay attention to the rational combination of varieties and replacement of suitable varieties; and strengthen the dynamic monitoring of the physiological races and variety resistance changes of pathogens.

2. Reduce bacteria sources and disinfect seeds. With 20% tricyclazole 1000 times soaking seeds for 24 hours, and properly handle the disease stems left behind in the field to minimize the initial infestation source.

3. Do a good job of field management such as fertilizer and water to cultivate and enhance the disease resistance of plants. Do enough base fertilizer, early application of top dressing, the appropriate control of nitrogen in the middle of the seedlings, seedlings to see the late fertilizer. Water should implement the principle of “before, during, after, wet, alternating between wet and dry”.

4. Strengthen forecasting and timely spraying and disease prevention. The prevention and control of rice blast disease should be based on prevention and supplemented by chemical control. It is advisable to use 75% tricyclazole 75%, 40% rice bran 150ml, or 1 mu per mu during the opening period to the beginning of heading and heading stage. No. 80 ml + 75% Fengdeng 20g or Mu with 75% rice WP 20-25g. Hand sprayer is watered with 50 kg spray; motor sprayer is watered with 15 kg spray.

Dried Fruit

Dried fruit products as the name implies, dried fruit products are pre-treated fruits after selection, washing and dehydration to the water content of 15 ~ 25% products. The volume of dried fruit is about 11 ~ 31% of that of Fresh Fruit, and the weight is about 10 ~ 25% of that of fresh fruit, so it can significantly save the cost of packaging, storage and transportation, and it is easy to eat and carry. Common dried fruits are raisins, red dates, dried mango, dried kiwi, dried strawberry and so on.

Dried Fruit,Dried Mango,Raisins,Red Dates,Dried Kiwi,Dried Strawberry

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