What is the big black grain in rice? Master four agricultural diseases, and rice has high yield and high quality.

When planting rice, some rice farmers told their helpers that the rice grew well in the early and middle stages, but after entering the heading and filling stages, the rice grains turned black, which was called "black rice grains". What happened? Are there any precautions or preventive measures?

There are many factors that lead to "black rice grains" in rice, both external and internal. In this article, the little helper will talk about the related content of rice black particles in detail, and everyone will have the answer after reading it.

In the process of rice planting, improper management will lead to the appearance of black rice grains, such as excessive use of nitrogen fertilizer, excessive watering and unfavorable weather factors. In addition, various diseases are also common causes, and as for varieties, the relationship is not great.

For example, in the process of rice planting, some farmers are worried about the poor growth in the early stage and the excessive use of nitrogen fertilizer.

In this case, on the one hand, there is too much nutrition, and rice grows vigorously.

On the other hand, the root system of rice is relatively shallow, and in the middle and late growth stage, the growth of rice itself is weak, and some rice grains may have black grains.

In terms of irrigation and drainage, if the fields are not watered for a long time, the soil permeability will be poor, the respiration of roots will be affected to some extent, the ability to transmit water and nutrients will be weakened, and the phenomenon of black rice grains may also be caused.

In addition to water and fertilizer, the more common problem is agricultural diseases encountered in rice growth, which is also the focus of this paper.

1, rice blast

Rice blast is a common disease in rice planting, which can occur in the whole growth period from seedling stage to mature stage. According to the disease location, it can be divided into seedling blast, leaf blast, node blast, ear neck blast and grain blast.

After the occurrence of ear neck blast or grain blast, it will be found that there are black (dark brown) spots on the grain by observing the diseased plant, which will lead to the whole grain turning black with the aggravation of the disease.

Rice blast is more likely to occur after continuous rainy weather in the middle and late stages.

In view of rice blast, farmers are more likely to take chemical spraying to prevent and control rice blast besides ploughing and dressing seeds before sowing.

There are many drugs to control rice blast in the market, among which 40% isoprothiolane (dosage 66.7- 100g/ mu), 20% isoprothiolane (60- 100ml/ mu) and 50% thiophanate-methyl (140-200g) are common.

2, false smut

False smut is also one of the common diseases in rice planting, also known as head smut, which mainly harms rice grains and has an impact on rice yield and varieties.

Because of the diseased plant, the ear of rice looks black, which leads to the appearance of black rice grains, which also forms the phenomenon of "black rice grains"

False smut of rice mainly occurs from flowering stage to milk stage. It has been observed that false smut is more likely to occur in fields with too much nitrogen fertilizer. In addition, it mostly occurs in areas with more rainy weather and relatively low temperature at flowering and heading stage.

For the prevention and control of false smut, in addition to reasonable rotation, selection of disease-resistant varieties and reasonable water and fertilizer, the use of pesticides is also a measure taken by most farmers (recommended prevention). Commonly used pesticides are 430 g/L tebuconazole (10- 15ml/ mu) and 75% penconazole azoxystrobin (65438+).

3. Smut of rice grains

Smut of rice grains can also lead to the phenomenon of "black rice grains", which mainly occurs after rice flowering and can always occur until maturity.

In the early stage of false smut, rice grains were not black, but dirty green or yellow. With the aggravation of the disease, rice ears appear black powder. When diseased grains or glume shells crack, black rice grains are formed.

Sowing with disease is a common cause of false smut. In addition, the head smut of rice is more likely to occur in fields with over-dense sowing. At the same time, like false smut, low temperature and rainy weather are easy to occur from heading to maturity.

In addition to seed selection, crop rotation, sowing and topdressing, and reasonable water and fertilizer, 18.7% diniconazole carbendazim (60-70g/ mu), 40% difenoconazole (15-20ml/ mu) and 25.

4. Brown ear disease

Brown ear disease of rice mainly occurs after heading, and the damaged parts are concentrated in the ear.

At the beginning of the disease, the glume in the grain will appear brown or brown, and it will become dark brown or dark brown with the aggravation of the disease.

If it is not prevented in time, once brown ear disease occurs, the whole rice field looks black.

Brown ear disease mainly occurs in plots planted with the same variety all the year round, plots with insufficient straw returning to the field, and plots with partial application of nitrogen fertilizer. It is more likely to occur when rice encounters low temperature, rainy weather and less sunshine after heading.

For the prevention and control of brown ear disease, in addition to selecting resistant varieties, improving the quality of straw returning to the field and reasonable water and fertilizer, the commonly used pesticides are 3% polyoxin (80- 100ml/ mu), 4% Jinggangmycin (100- 125g/ mu) and 2% Chunlei.

To sum up, in the process of rice planting, there is a phenomenon of rice grain blackening, so it is necessary to do a good job of observation and investigation, find out the reasons and prevent it in time (preferably in advance) in order to better improve the yield and quality of rice.