Major Diseases and Control Methods of Cotton Seedlings

The main diseases of cotton seedlings include anthracnose, blight, brown spot, and red rot, among which anthrax and blight are more common, and the damage to cotton seedlings is also the most serious. First, the main symptoms of each disease and ways of transmission 1, anthrax disease: the leaves and stems of cotton seedlings may be harmful. After the seedling was injured, red-brown nucleus-shaped streak (vertical fissure) appeared on the stem, the lesion became brown after being enlarged, and then blackened and turned rotten, causing the cotton seedlings to fall and die. When the air is wet, orange-red sticky substances are produced on the lesions. A semi-circular brown spot develops on the edges of the leaves when the leaves are infested, and the lesions are red-brown when the air is dry, and when the leaves are severe, the leaves are dead and fall off. The germination temperature of anthracnose spores was 10°C, approximately the same as the initial temperature of germination of cotton seedlings. After germination of the spores, the germ tube invaded from the top of cottonseeds. 2, blight: cotton seedlings in the most vulnerable to disease two weeks after emergence, the base of the stem near the ground from dark brown to dark brown, and gradually sag down rot, so that the site of the disease shrinking shrinkage, severe cotton seedlings fall to death . Rhizoctonia pathogenic bacteria latent in the soil, when appropriate conditions will invade the roots, the next year by wind and rain, harm cotton seedlings, especially buds out of the seed shell to the cotyledon before the most vulnerable. 3. Brown spot: The needle-point purple-red spots began to appear on the leaves of the injured cotton seedlings. The lesions were yellow-brown after the lesions expanded, slightly raised, and scattered small black spots below. The diseased tissue is easily detached and appears perforated, causing severe leaf loss. 4. Red rot: generally harmed before cotyledon excavation, mainly harming rhizome transition zone and cotyledons and true leaves. The radicles were tan-brown after being victimized, gradually rotted, resulting in rotting buds; when the roots were damaged, the color of root tips and lateral roots became yellow, and when they were severe, the whole roots became brown and rot; the cotyledons began to appear yellow water spots, and then gradually appeared irregular Grey red lesions. The pathogenic bacteria of cotton seedlings mainly overwintered on cotton seed, soil and diseased plant residues. In general, low temperature and high humidity are not conducive to the growth of cotton seedlings and are conducive to the infestation of pathogens. The severity of the disease at the seedling stage is related to the seedling age of the cotton seedlings. Generally, the seed coat of the cotton is shedding, and the cotyledon begins to develop disease. When the two cotyledons develop completely, the lateral roots and the true leaves begin to grow. The disease resistance of cotton seedlings will gradually increase, and the disease will gradually ease. Second, the prevention and treatment methods Cotton seedling disease prevention and treatment should be based on prevention, to create favorable conditions for the growth of cotton seedlings unfavorable to bacterial infection, and through the spray chemical agents to control and prevent the occurrence and spread of the disease. 1.Selected cotton seeds: After degreasing seeds, diseased seeds, insects, etc. on the basis of sulfuric acid degreasing (can be selected once after depilation), the emergence rate of cotton seeds can be significantly increased, and cotton seedlings can be enhanced. The resistance to disease. 2, paddy and dry rotation: in the seedling stage more serious and conditional conditions can be rice and cotton rotation. After the cotton field has been planted with rice for 2-3 years and then planted cotton, the disease at the seedling stage can be effectively controlled and generally can be reduced by more than 50%. 3, to strengthen the management of the field: seedbed should pay attention to timely ventilation and hardening seedlings, dry bed temperature, increase potassium fertilizer. Seedbed beds and fields need to be well drained to lower the water table. Strengthen the disease resistance of cotton seedlings by strengthening field management and create environmental conditions that are not conducive to the spread of germs. 4. Seed treatment: Cotton seedlings of coated cotton seedlings have stronger resistance to disease. Uncoated cotton seedlings can be seed-dressed with carbendazim, amizolide, etc. after sulfuric acid degreasing, which can significantly improve the disease resistance of cotton seedlings. . 5. Chemical control: After the onset of cotton seedlings, a 1:1:200 Bordeaux mixture can be used for spray treatment after cotyledon leveling. It can also be sprayed with 25% carbendazim gel suspension 200-300 times, usually once a week. , spray a total of 2-3 times.

Auto Chemistry Analyzer

The automatic biochemical analyzer is an instrument that measures a specific chemical composition in body fluids according to the principle of photoelectric colorimetry. Due to its fast measurement speed, high accuracy and small consumption of reagents, it has been widely used in hospitals, epidemic prevention stations and family planning service stations at all levels. The combined use can greatly improve the efficiency and benefits of routine biochemical testing.
principle
The automatic analyzer is to automatically run all or part of the steps of sampling, mixing, warm bath (37°C) detection, result calculation, judgment, display and printing results and cleaning in the original manual operation process. Today, biochemical tests are basically automated analysis, and there are fully automatic biochemical analysis systems designed for large or very large clinical laboratories and commercial laboratories, which can be arbitrarily configured according to the laboratory's testing volume.
Whether it is the fastest-running (9600Test/h) modular fully automatic biochemical analyzer today, or the original manual-operated photoelectric colorimeter for colorimetry, the principle is the use of absorption spectroscopy in spectroscopic technology. It is the most basic core of the biochemical instrument.
Optical system: is a key part of ACA. Older ACA systems used halogen tungsten lamps, lenses, color filters, and photocell assemblies. The optical part of the new ACA system has been greatly improved. ACA's beam splitting system can be divided into front splitting and rear splitting due to different light positions. The advanced optical components use a set of lenses between the light source and the cuvette to convert the original light source. The light projected by the lamp passes through the cuvette to bring the beam to the speed of light (unlike traditional wedge beams), so that the spot beam can pass through even the smallest cuvette. Compared with traditional methods, it can save reagent consumption by 40-60%. After the spot beam passes through the cuvette, the spot beam is restored to the original beam through this group of restoration lenses (wide difference correction system), and is divided into several fixed wavelengths (about 10 or more wavelengths) by the grating. The optical/digital signal direct conversion technology is used to directly convert the optical signal in the optical path into a digital signal. It completely eliminates the interference of electromagnetic waves to the signal and the attenuation in the process of signal transmission. At the same time, the optical fiber is used in the signal transmission process, so that the signal can achieve no attenuation, and the test accuracy is improved by nearly 100 times. The closed combination of the optical path system makes the optical path without any maintenance, and the light splitting is accurate and the service life is long.

Constant temperature system: Since the temperature of the biochemical reaction has a great influence on the reaction results, the sensitivity and accuracy of the constant temperature system directly affect the measurement results. The early biochemical instruments used the method of air bath, and later developed into a dry bath with constant temperature liquid circulation which combines the advantages of dry air bath and water bath. The principle is to design a constant temperature tank around the cuvette, and add a stable constant temperature liquid that is odorless, non-polluting, non-evaporating and non-deteriorating in the tank. The constant temperature liquid has a large capacity, good thermal stability and uniformity. The cuvette does not directly contact the constant temperature liquid, which overcomes the characteristics of the water bath type constant temperature being susceptible to pollution and the uneven and unstable air bath.

Sample reaction stirring technology and probe technology: The traditional reaction stirring technology adopts magnetic bead type and vortex stirring type. The current popular stirring technology is a stirring unit composed of multiple groups of stirring rods that imitate the manual cleaning process. When the first group of stirring rods is stirring the sample/reagent or mixed solution, the second group of stirring rods performs high-speed and high-efficiency cleaning at the same time. The set of stirring bars also undergoes a warm water washing and air drying process at the same time. In the design of a single stirring rod, a new type of spiral high-speed rotating stirring is adopted, and the rotation direction is opposite to the spiral direction, thereby increasing the stirring force, the stirred liquid does not foam, and reducing the scattering of light by microbubbles. Reagent and sample probes are based on the principle of early capacitive sensing, but slightly improved to increase the alarm of blood clots and protein clots, and re-test results according to the alarm level, reducing sample aspiration errors and improving the reliability of test results. . Large-scale biochemical instruments can detect more than 1,000 tests per hour, so automatic retesting is very important. Subjective evaluation of test results and manual retesting can no longer meet clinical needs.

Other aspects: barcode recognition of reagents and samples and computer login. Due to the lack of barcode recognition function of early biochemical instruments, there are more opportunities for errors. In recent years, both imported and domestic chemical instruments have adopted barcode detection. The use of this technology in biochemical instruments has provided technical support for the development of high-speed ACA, and also made the instrument quite supportive. The software development is simple and easy, therefore, barcode detection is the basis for the intelligence of the instrument. Open reagents, as an important factor for hospitals to choose models, whether the instrument supports open reagents is very important. After the reagents are opened, hospitals and scientific research units can choose their own reagent suppliers, and have a greater degree of freedom in measuring the price, the reliability of the test results, and the validity period of the reagents. Ion Selective Electrode Analysis Accessory (ISE), human serum and urine electrolyte indicators are very important, and hospitals can save money by adding ISE to the ACA system.

Bio Chemistry Analyzer, Clinical Chemistry Analyzer, Blood Chemistry Analyzer,Urine Chemistry Analyzer

Jilin Sinoscience Technology Co. LTD , https://www.contoryinstruments.com