Rice belongs to the annual grass family, and it belongs to the top three food crops along with wheat and corn, and rice yields the first of the three. Since ancient times, the issue of food and clothing has been the most important task that determines the security of the people, and in the process of solving the problem of food and clothing for the people, the hybrid rice studied by Academician Yuan Longping has made an indispensable contribution.
According to the characteristics of planting methods and growth cycles, China's rice is mainly divided into four types: indica rice and japonica rice, medium and late ripening, rice and dry rice, non-glutinous rice and glutinous rice.
The rice planting area is mainly divided into six areas, which are divided into South China Rice Cultivation Area, Central China Rice Cultivation Area, Southwest Rice Cultivation Area, Northeast Rice Cultivation Area, North China Rice Cultivation Area, and Northwest Rice Cultivation Area. However, it is mainly cultivated in the south, accounting for about 93% of the country's rice planting area.
In the process of rice planting, there will be more diseases and insect pests, such as rice white leaf blight, rice seedling disease, rice pattern blight, rice blast, rice aspergillosis, rice borer (dihua borer, three borer), rice bush leaf curl borer, rice planthopper, etc., seriously reducing the quality and yield of rice, causing huge economic losses to the people, and seriously threatening China's food security. Rice white leaf blight and rice malignant seedling disease are mainly harmful from the seedling stage to the panicle extraction stage, which will not be discussed in this article. Rice dinatural, tertiary borer and large borer are harmed by larvae, and the control method is similar, which is attributed to the analysis of rice borer. The following is an analysis of the occurrence of three worms and three diseases that mainly occur in the middle and late rice, and the corresponding solutions are given.
<h1>Three diseases: rice blight, rice blast, and rice aspergillosis</h1>
1. Incidence of rice blight
Rice blight can be infected from the seedling stage to the jointing stage. It mainly harms the leaf sheath, and initially forms dark green water-soaked spots, and forms cloud-like spots with the development of the disease. It is easy to cause the leaf stem to die, the grain weight to decrease, and the symptoms of dry white spikes. Preparations need to be made for control at the seedling and tillering stages.
Pathogenesis features:
There are more rainy days in the seedling stage and tillering stage, and the humidity in the field is large, which is easy to occur and spread diseases.
The planting density is too large, and after the tillers of rice, the ventilation in the field is poor, the growth is hindered, and the chance of staining blight increases.
Sufficient water and fertilizer conditions grow faster, or the seedlings are weak and susceptible to infestation by striated blight bacteria.
The planting is not sunburned, increasing the incidence of blight.
2. Incidence of rice blast
Rice blast is mainly divided into 5 types, namely seedling plague, leaf plague, festival plague, ear neck plague, and grain blast. In the early stage of rice growth (seedling stage, tillering stage, jointing stage), it is easy to occur seedling and leaf blast. In the middle and late stages of rice growth (after the panicle extraction stage), it is easy to occur arthrobial blast, panicle neck blast and grain blast, which is easy to cause internodal breakage, dry white ears and blackening of rice. Greatly reducing the yield and quality of rice, it is one of the important diseases in the rice cultivation process in the world.
Continuous rainy weather is prone to onset and spread.
Rice paddies are irrigated for a long time, and the root system is not breathing smoothly and is susceptible to disease.
The planting density is too large, and the poor ventilation in the field is susceptible to disease.
Excessive application of nitrogen fertilizer causes growth, reduced resistance, and easy infection.
3. Incidence of aspergillosis
Aspergillosis, also known as smut disease, is an irreversible disease. In the ear extraction stage and flowering stage of rice, it is susceptible to the infestation of pathogens, which reduces yield, affects quality, and is harmful to the human body. Therefore, the prevention of aspergillosis in the early stage is very important.
The onset of rain during the flowering period of the ear is severe.
Rice continuous cropping is seriously affected throughout the year.
Varieties with early panicle extraction have a milder incidence.
Excessive application of nitrogen fertilizer or panicle fertilizer is prone to infection.
<h1>Three insects: rice borer, rice bush curly leaf borer, rice planthopper</h1>
1. Occurrence of rice borers
Rice borers include three species: dihua borer, triple borer and large borer, also known as drill heartworm. Among them, the dichodermic borer and the trimorphic borer are pests of the Lepidoptera borer family, while Daming is a pest of the Lepidoptera Noctuidae, and these three pests are all endangered by larvae. Each season, the occurrence of the second borer varies from 1-5 generations, the occurrence of the three-way borer occurs from 2-7 generations, and the occurrence of the large borer occurs in 3-6 generations. The larvae burrow into the stem and leaf sheath to cause harm. It can have an impact from tillering to maturity in rice, forming dead heart seedlings and dead sheaths in the early stage of growth, easy to form dead pregnant ears and dry white ears in the early stage of maturity, and easy to form grains in the late stage of maturity. Both can reduce yields.
Occurrence characteristics:
The first generation of drill hearts began to harm in mid-to-late May. Generally, the harm is most serious in July and August.
Prevention and control are more difficult, mainly because of the increase in drug resistance due to the use of a single agent for many years.
The insect population base is large, mainly because rice has been planted for many years and the straw has been returned to the field, which increases the insect source base.
In the early stage, adult insects concentrate on laying eggs, and the insect infestation occurs seriously.
2. Occurrence of rice bush curly leaf borer
Rice bush leaf curl borer, also known as leaf curling insect, as the name suggests, is a larval hazard, showing symptoms such as leaf curling adult buds. The larvae nibble on the leaf flesh inside and lose the ability to photosynthesize. As a result, the grain of rice grain increased, and the weight of 1,000 grains decreased, which affected the yield.
In cloudy days with rainy and humid air, clump leaf borer occurs severely.
Fields with a high number of weeds in the field occur severely.
Because the rice bush curly leaf borer has a greening line, the growth trend is strong, and the leaves are thick green, which is conducive to the occurrence of insect infestations.
Areas with inconsistent growth periods, which provide adequate food for pests at various stages, occur severely.
3. Occurrence of rice planthoppers
Rice planthopper is a migratory pest, there are three main species, divided into brown planthopper, white-backed planthopper and gray planthopper. It is a sucking pest that mainly sucks up the sap of rice leaves. At worst, it causes the leaves to lose green, and at worst, it causes the leaves and plants to wither and die.
It has strong migratory flight and spreads from south to north with the monsoon. July and August is the high incidence of rice planthoppers.
When the temperature returns after rain, it is easy to occur in the case of adequate nutrition in the field.
The planting density in the field is too large, the ventilation is poor, the microclimate characteristics are obvious, and the occurrence of rice planthoppers is serious.
<h1>Five prevention and control</h1>
1. Prevention and control of rice blight
In the first 30 days of the rice harvesting period, the drug was used for control, and 24% of the thiafuramide was selected, and 10ml was sprayed with 15 kg of water per mu of water consumption of 30-45 kg, and the base of the crop was sprayed evenly. When the onset is more severe, the drug is taken again every five days or so.
2. Prevention and control of rice blast
For the prevention and control of rice blast, the use of drugs mostly use rice blast and its compounds, such as 35% C ring. Oryx, 30% hexazole. Oryx, 40% fluorocyclic. Rice blast spirits and so on. The first medication was carried out from the rice rupture stage to the initial panicle stage, and the dosage was 40-80ml per mu of water 15-30kg, and in the case of more rain, the drug was used again in the panicle stage.
3. Prevention and control of aspergillosis
Use 30% benzo. Propiconazole and 43% gluconazole were prevented and treated, and the control effect was significantly better than that of 5% 250g/mu of jinggangmycin. The dosage is benzo. Propiconazole 15ml/mu, valconazole 18ml/mu mixed with water 30kg for spraying. The period of use is consistent with the period of prevention and control of rice blast.
4. Control of rice borer and rice bush curl leaf borer
Before the control of rice borers, egg-killing preparations were used for prevention to reduce the population base of the insects. 10% pyridoxine 10 ml or 15% flulingurea 5 g can be used for egg killing. After the occurrence of insect infestations, methyl dimensions are mostly used. Indigovirus, Avi. Insect mite nitrile, insecticide mono, bromocyanidamide, etc. are used alternately to prevent and control insect pests according to the incidence of insect pests and delay drug resistance.
5. Prevention and control of rice planthoppers
For the control of rice planthoppers, the resistance to the first generation of nicotin is relatively large, and it is not recommended to use. It is recommended to use the second generation of new nicotinic products for control, such as 25% pyrithoea. Thiazide, 20% enprime, 25% thiazezine, 30% thiosetoteamine and so on are controlled. There are two kinds of control methods, the first is foliar spraying; the second is field application, it is recommended to use 25% thiamethoxine 200g / mu, because the second generation of new nicotin preparations have strong systemicity, relatively labor-saving, better control effect, longer effectiveness.
In the process of rice planting, field management and pest control are one of the important means to ensure high and stable rice yields. Only by grasping the occurrence of diseases and insect pests and adopting appropriate methods to stop losses in time before they occur can we ensure a good harvest of the year.
I hope that my article will help you grow rice. If there are any deficiencies, you are welcome to add and comment.