Principles and Control Methods of Diseases in Orchards The prevention and treatment of disease in orchards are the same as the pests, and they are all important technical links in fruit tree production. Whether the disease prevention and treatment benefits will significantly affect fruit tree production, quality, tree vigor, orchard uniformity and economic life. An orchard with an epidemic disease will inevitably lead to premature detachment of leaves, dead rot of branches, and fruit rot. Such an orchard is difficult to achieve high quality and high yield, and the economic benefits will not be too high. In orchards, the main pathogen that causes fruit tree disease is fungi. Fungi in the natural world are numerous, widely distributed, and have strong adaptability. They are also harmful to fruit trees. According to incomplete statistics, there are approximately 80 kinds of apple diseases in China, of which more than 70 diseases are caused by fungi, accounting for more than 90%. Relevant data also showed that fungal diseases in diseases of pears, peaches, and grapes are also above 90%. It can be seen that the prevention of diseases in orchards is mainly the prevention and control of fungi. Therefore, it is very necessary to understand some fungal physiological knowledge. The three major factors of fruit tree disease prevalence are: 1 pathogens with strong pathogenicity; 2 a large number of susceptible hosts; 3 suitable environmental conditions for disease onset. With pathogens and susceptible hosts, appropriate environmental conditions often become the dominant factor in disease epidemics. The environmental conditions are divided into meteorological conditions, cultivation conditions and soil conditions, among which the meteorological conditions have the greatest impact. The environmental factors that affect the growth and development of fungi are temperature, humidity, light and pH, among which the former two are the most important. The temperature can affect the spore germination, mycelial growth, sporulation and dormancy. During cold winter temperatures, the fungus produces fruiting bodies and resting spores to adapt to adverse environments. In spring, the temperature rises. The dormant spores grow hyphae and begin a new cycle of infestation. Water is the physiological substance of fungal metabolism. Without water, the fungus loses the basic conditions for vegetative reproduction. Most fungi require a relatively high relative humidity environment, especially in the formation of conidia, some fungi can not produce spores in dry water, can only produce germ tubes; some fungi in dry conditions Protoplasm condensation occurs. Light and pH can also affect the survival and reproduction of fungi, but far less than the temperature and humidity significantly. Many of the conidia of the fungus have pigments that are resistant to intense light, and some of the anti-drying cell walls can survive in high altitudes and travel long distances. Because most fungi can grow in the pH range of 3.0 to 9.0, the spread, infection, and epidemic of the bacteria around the pH level cannot be very small. In the orchard, the fungus lurks through dormancy at different sites. Spring temperatures continue to rise, providing suitable temperature conditions for the reproduction of fungi, but do not have the necessary humidity conditions. In the event of rain, the fungus quickly exerts its amazing ability to reproduce, proliferate a large number of offspring in a short period of time, in the orchard wantonly vicious, against fruit and tree branches and leaves, until it causes visible damage. Spring blooms in spring, and fruit trees begin to grow and develop. At this time, temperature conditions are also suitable for the growth of fungi. The main natural factor limiting their reproduction is moisture. Therefore, sooner or later, the severity of fungal diseases, etc. after spring temperature rises depends on the amount of rain in the spring and the amount of rainfall. After the spring temperature ceases to limit the growth of fungi, the earlier the rainfall and the greater the rainfall, the more serious the occurrence of fungal diseases in the orchard. In such a year, the prevention and control measures taken in production must be advanced accordingly so as not to cause any troubles. The spring rain in the orchard prevents disease and is based on the physiological characteristics of pathogenic fungi. To understand this, in the practice of fruit tree production, relative measures can be taken according to climatic conditions. In relatively dry years and regions in spring, orchards begin to concentrate on preventing disease most of the time in the middle or late May; but in early spring and early spring, the time can be advanced to the end of April, or even April and mid-April. Spring is the critical period for disease prevention in orchards. Whether the measures are appropriate or not will have a great impact on the orchard and production should not be careless. Roundness Measuring Instruments
Roundness meter is a length measuring tool for measuring roundness using the rotary axis method. The roundness meter is a measuring tool for measuring the roundness error of the workpiece using the rotary axis method. Roundness tester is divided into two types: sensor rotary type and workbench rotary type. During measurement, the measured part is installed concentrically with the precision shaft system, and the precision shaft is attached with an inductive length sensor or a workbench for precise circular motion. It is composed of sensor, amplifier, filter and output device of the instrument. If the instrument is equipped with a computer, the computer is also included in the system.
The principle of the roundness meter is the same as that of the coordinate measuring machine. In fact, its working principle is very simple. The coordinate measuring machine is a point acquisition tool. Its principle is to collect points first, and then form a line from points, and then form a three-dimensional model from lines. CMM is a kind of measuring equipment that has a guiding mechanism, a length measuring element, a digital display device in three mutually perpendicular directions, and a worktable that can place the workpiece (not necessarily large or huge). The measuring head can be moved to the measured point easily by manual or motorized means, and the coordinate value of the measured point is displayed by the reading device and the digital display device. Obviously, this is the simplest and most primitive measuring machine. With this measuring machine, the coordinate value of any point in the measured volume can be displayed through the reading device and digital display device.
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The principle and control method of fruit tree disease