Technical points of integrated control of diseases and insect pests of Shatian pomelo

It is understood that since the 1980s, large-scale Shatian pomelo planting bases have been established in various parts of Meizhou, and the economic benefits have been increasing. In the practice of planting Shatian pomelo for many years, the cultivation techniques of many farmers have been improved to a great extent, but due to the large area and a wide variety of diseases and insect pests, the new types of diseases and insect pests are increasing continuously. it constitutes a serious obstacle to the current development of high-quality, high-yield and high-efficiency pomelo production. According to the occurrence law of pomelo diseases and insect pests, a set of disease prevention and control is summarized as follows: 1. Clear garden in winter and spring, clean and tidy December to February of the following year, the temperature is low, general diseases and insect pests enter the overwintering state. At this stage, we should do a good job in clearing the pomelo garden, first cutting off the branches of diseases and insect pests, withered branches, shade branches and diseased leaves, and then spraying once to remove the source of the disease and eliminate the pesticides of overwintering pests, such as stone-sulfur mixture, turpentine mixture and so on. In early spring in February, the garden was cleared for the second time before the shade of spring shoots, and the application at this time could not only control overwintering anthracnose and scab, but also control shellfish and other pests. 2. It is recommended to keep grass and make it simple and reasonable. The recommended method of keeping grass in pomelo orchard plays a good role in increasing the coverage of pomelo orchard, reducing the temperature of pomelo orchard in summer, increasing humidity and preventing soil erosion, and can provide abundant food and habitat for natural enemies. Increase the species and number of natural enemies and stabilize the biological community. It is understood that in pomelo orchards planted with patchouli thistle or green manure, the temperature of the crown of pomelo trees in summer is 5 ℃ lower than that of uncovered orchards, the relative humidity is about 5% higher, and the adult mites of red spiders are 60% lower. 3. Wiping buds to control shoots and interrupting the food chain of diseases and insects. Leaf miner is one of the serious pests in the new shoot stage of pomelo, which is rarely damaged in the spring shoot stage, and only a small amount of 2-3 instar larvae can be seen in late March. The most common occurrence occurs in summer and autumn from May to October every year, especially the young trees shoot 4-5 times a year, the damage is particularly serious. Therefore, it is necessary to focus on artificial sprouting, zero and leave the shoots, and put them together after 80% of the fruit trees and 80% of the new shoots in the orchard are puffed out, the summer shoots are planted in May-early June, and the autumn shoots are released before early August. Fertilization paid attention to pre-shoot fertilizer and strong shoot fertilizer, the pre-shoot fertilizer was applied 15 days before shoot release, mainly chemical nitrogen fertilizer, and strong shoot fertilizer was applied 10 days after shoot release, mainly phosphorus and potassium fertilizer. Then spray control was carried out according to the insect situation in the field. Wiping buds and controlling shoots has a significant effect on the control of canker, anthrax, aphids, wood lice and other diseases and insect pests in the new shoot stage. 4. Strengthen the cultivation and management, enhance the tree potential and improve the resistance of the tree to diseases and insect pests. Pomelo needs a large amount of fertilizer, but people often apply chemical nitrogen fertilizer mainly, ignoring the application of phosphorus, potassium, boron, magnesium, zinc and other trace elements, so that the yield and quality are affected. Therefore, pomelo trees should be fertilized according to the soil formula. Scientific fertilization of what is missing and what is missing, reasonable combination of nitrogen, phosphorus, potassium and trace elements can not only improve yield and quality, but also improve plant disease resistance. Effectively reduce the occurrence of a variety of diseases. For several years, the soil hardening is aggravated due to fertilization, and many lands will obviously see the ground whitening. Golden Shield is the key recommendation for pomelo trace fertilizer, which not only replenishes the trace elements needed by pomelo trees, but also improves soil consolidation. Increase fertilizer effect and so on. In addition, dry soil, lack of fertilizer and water, resulting in weak tree potential, irregular new shoots, often resulting in anthrax, red spiders, rust spiders, wood lice and other diseases and pests. Therefore, pomelo orchard should be irrigated and fertilized in time in the dry season, which can not only prevent the occurrence of many kinds of diseases and insect pests and physiological diseases, but also enhance the tree potential and improve the resistance to diseases and insect pests. 5. Scientific use of drugs to protect and utilize natural enemies. The pomelo tree spits, blossoms, bears fruit and dormancy, which constitutes the seasonal change of the biological population in the pomelo orchard, which leads to the rise and fall of the biological population in the pomelo orchard. According to the law of this change, the appropriate control period and corresponding pesticides should be selected according to the control index. Mainly grasp the four key periods of control: (1) from March to mid-May, the temperature is suitable, during this period, it is conducive to the invasion of diseases; pomelo orchard new shoots, rich food, conducive to the occurrence of pests. Most diseases and insect pests have their first peak in this season, but the number of natural enemies of insect pests is relatively small, and the damage of diseases and insect pests can not be controlled. This is also the best time to depress the annual base of diseases and insect pests. Chemical control is mainly adopted in this period. The main diseases and insect pests are canker, anthrax, scab, red spider, shell worm, leaf roll moth, flower bud maggot, orange gall midge, weevil and so on. In recent years, the damage of scab and orange gall midge is prominent, so we should do a good job in the prevention and control of this disease. The control period of scab is mainly from flowering to young fruit stage, that is, from one month to one and a half months after flowering, and the chemical control of orange gall mosquitoes should be the combination of ground spraying and crown spraying, and the first generation control is the key. The time is from the end of March to the middle of April. (2) from late May to June, it mainly controls red spider, rust spider, brown rot blight, leaf miner, scale insect, anthracnose and so on. (3) from July to September, with high temperature, strong sunshine, less Rain Water in the early stage and drought in the later stage, the general pests have finished feeding and entered the summer mat, the species and number of insect pests decreased, while the number and species of natural enemies of insect pests increased continuously. In the pomelo orchard with good control effect in spring, the pomelo orchard can no longer apply pesticide control, pay attention to protect natural enemies, strengthen fertilizer and water management, create an excellent ecological environment of pomelo garden and stabilize the population of natural enemies. At this stage, because red rust spiders damage fruits and leaf moths harm summer and autumn shoots, field control should be strengthened, and attention should be paid to check the damage degree of red spiders in grapefruit orchards sprayed with Bordeaux liquid in spring. At the same time, prevent and cure canker and anthrax. (4) from October to November, the climate was mild, and the second peak of diseases and insect pests occurred. Although the number of insect population is large at this time, the population and number of all kinds of natural enemies are very large, which play a significant role in inhibiting the pests. Therefore, at this stage, the protection and utilization of natural enemies should be strengthened, the application of pesticides should be reduced as much as possible, and attention should be paid to checking the occurrence and damage of Phytophthora cinerea and orange gall mosquitoes. If the fruit of orange thunder gall mosquito is found, it should be removed in time, and the fruit should be picked up. Centralized burning or deep burial treatment. It is necessary to strengthen the prevention and control of Phytophthora blight before fruit picking.