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The physiological diseases of peach trees mainly include yellowing, heavy disease, cracked fruit, cracked nucleus, fruit softening, etc. Due to the various causes of these symptoms, many fruit farmers cannot properly prescribe the drug, resulting in the physiological disease of peach trees appearing year by year. The trend of aggravation has caused considerable losses to the farmers. This paper analyzes the causes of several common physiological diseases of peach trees, and summarizes the corresponding prevention measures for everyone to learn. (This article is longer, it is recommended to take a closer look)
1 The cause of physiological diseases of peach trees
Peach tree physiological disease refers to the disease caused directly or indirectly by peach trees during their growth and development due to their own physiological defects, genetic diseases or unsuitable environmental factors. Such diseases are not infected by pathogenic organisms and cannot be found in peach trees. Contagious between each other, called a physiological disease or a non-invasive disease. The main causes of peach tree physiological diseases are malnutrition, environmental disorders, improper cultivation, etc., including extreme temperature, soil moisture imbalance, extreme light, extreme pH, lack of oxygen, nutrient deficiency or excessive, and inorganic salt poisoning, atmosphere. Pollution, improper cultivation, etc.
2 Prevention and control of common physiological diseases of peach trees
Cracked nucleus, soft top, soft ditch disease performance. In recent years, many nuclear-producing varieties (lines), such as Piqitao, Okubo, Chongguo Xiangtao, Beijing No.15, have caused nuclear cracking, resulting in browning and decay of the fruit in the near-nuclear and fruit near the nucleus, resulting in secondary pests and diseases. The flavor is light, the meat quality is deteriorated, the peeling is advanced, and the storability is lowered. According to a sample survey, the incidence rate of cleft nucleus disease in normal years is 8.5%~17.6%. In the year when there is more rain 30 days before harvesting, the incidence rate can exceed 32.8%, which seriously affects the commercialization of fruit and the enthusiasm of fruit farmers. In addition, some mid-late maturing varieties, such as the fruit of the peach, the peach, the white peach, the Qinwang peach, the fruit top and the suture are premature and soft, attracting birds, insects (such as patina), bees, etc. Food, and fall off in advance, is not resistant to storage and transportation, seriously affecting the value of fruit commodities, the incidence of fruit peach can reach 14%, and the incidence of late white peach can reach 18%.
cause. There are four main aspects that lead to the comprehensive obstacles of split nuclei, soft tops and soft ditch.
One is the variety and genetic factors. Off-core varieties such as the mid-maturing varieties Okubo, Piqitao, Chongguo Xiangtao, Beijing No. 15 and other serious diseases, while Shanghai Sea Peach, Chunxue, Japan Matsumori, Xia Cris, Late Lake View, Xiahui No. 6, Jing Yan (Beijing) No. 24) mild onset, Zhongyou No. 4, Yanguang, Double Happiness and other early-maturing nectarines do not split the nucleus, and the semi-nuclear cultivar Jinchun does not split the nucleus.
Second, the Taoyuan application of excessive nitrogen and phosphorus nutrients, resulting in insufficient calcium.
The third is due to climatic factors, such as the previous drought and excessive precipitation in the later period.
The fourth is management factors, such as the abuse of herbicides such as glyphosate, the excessive use of paclobutrazol in summer, and the imbalance of soil and water management.
Prevention.
First, choose a variety that is not easy to crack, soft top, soft groove. Secondly, rationally regulate soil moisture, and conditional orchards can adopt integrated technical measures such as sprinkler irrigation, micro-drip irrigation, and integration of fertilizer and water to achieve balanced soil water supply. Promote the soil testing and formula fertilization technology, strictly control the application rate of nitrogen fertilizer and phosphate fertilizer, and spray the commercial chelated calcium (or 0.3% amino acid calcium, or 2% quicklime water) in the early stage of peach growth, young fruit stage and fruit expansion period. When applying the base fertilizer in autumn, increase the application of organic fertilizer, biological bacterial fertilizer, supplement the superphosphate fertilizer, and supplement the potassium fertilizer and the medium and micro fertilizers such as sulfur, magnesium, boron, iron and zinc.
Fruit cracking performance.
Cracked fruit refers to the cracking of the peel in the late growth stage of the peach fruit. The performance is that the fruit has a longitudinal crack in the direction from the fruit top to the fruit stem, and some irregular cracks occur at the top of the fruit, which reduces the value of the commodity and is prone to rot.
cause.
The first is the characteristics of the variety. The fleshy soft varieties are more likely to crack fruit than the meaty close varieties, such as Jingyan (late white 24) than the brittle and easy to crack fruit. Early-maturing varieties are more susceptible to cracking than mid-late-maturing varieties, such as Matsusaka (mature in mid-June), which is more susceptible to cracking than fragrant peach (mature in mid-July). Early-maturing nectarines are generally easier to crack than peaches. For example, Zhongyou No. 5 nectarine is more susceptible to cracking than fragrant peaches. This is caused by the structure of nectarine fruit. The nectarine epidermal cells are mostly longitudinally arranged and loose. It is neat and has cracks, the number of epidermal cells is small, the external pressure is weak, and it is easy to crack. The common peach peach epidermis cells are mostly horizontally arranged, with many layers, neatly arranged, tight, and the fruit surface has different lengths. More hair, no pores, strong pressure resistance, not easy to crack fruit. Second, the environmental conditions are not good. For example, if there is too much rain before and after the hard core period, the groundwater level is too high, and the soil is too wet, it is easy to cause cracking. The third is improper cultivation and management. Such as partial application of nitrogen fertilizer, lack of phosphate fertilizer, etc., resulting in tree length, orchard closed; neglecting summer pruning, planting density is too large, pests and diseases are serious, and the use of paclobutrazol for several times a year is easy to cause cracking.
Prevention.
One is to choose a variety that is not easy to crack. In some areas, the ripening period of nectarines (mid-late May to early June) is in the rainy season, which leads to the general cracking of nectarines. It is recommended to reduce the cultivation area of ​​nectarines, and cultivate a few varieties that are more resistant to cracking or adopt rain-proof cultivation. Do not plant varieties that have a heavier cracking effect in the local area, and do not plant varieties that do not adapt to the local ecological environment.
The second is reasonable irrigation. Irrigation can promote the high water content of the pulp cells, avoid the soil and air too dry or too wet, can effectively reduce the cracking fruit, and the conditional orchard can promote sprinkler irrigation, micro-drip irrigation and integrated irrigation of fertilizer and water to provide stable growth and development of peach. The soil moisture ensures a steady increase in pulp cells and reduces cracking. In the long-term drought, you should dilute the thin irrigation, it is not appropriate to drench the water at one time. Fertilization should be applied organic fertilizer, do a good job of formula fertilization, not apply nitrogen fertilizer, increase phosphorus and potassium fertilizer, timely add calcium fertilizer, plant legume green manure in the line, castration cover orchard in the early stage of full bloom, LS cloth or other can also be used The material covers the orchard and should be drained in time during the rainy season.
The third is to do a good job in disease prevention. Peach trees have many diseases. In spring and summer, there are mainly peach anthracnose, scab, perforation, leaf spot, etc. In the early stage, protective fungicides such as mancozeb and propidium zinc should be sprayed. Prevention and treatment of dimethomorph and the like. The fourth is to optimize fruit management. Timely thinning and bagging, for the high temperature and heavy rain in the summer of July to August, the area where the late ripe peach cracking is heavier must be bagged. The fifth is to promote long branch pruning. From the perspective of results, fruit farmers generally believe that the technology is simple and easy to learn, saves labor and time, eases the tree, and is conducive to fruit set and quality. Winter shears will be longer than 70 cm, long branches with sub-tips and weak branches less than 30 cm, strips of diseased insects, retaining 50 to 70 cm of strong branches. The whole tree focuses on retaining the result branches of 0.3~0.6 cm in diameter. The results of drooping branches and thin branches are easy to crack and should be eliminated.
Yellowing disease performance.
The veins remain green, and the veins are chlorotic. In severe cases, the whole leaves are yellowed, and finally whitening, leading to the death of young leaves, small fruit, yellowish white, poor quality, and serious fruit drop before harvest.
Causes.
There are many reasons for yellowing, mainly root knot nematode damage, soil moisture, fertilizer, phytotoxicity, etc. This paper introduces a common cause: iron deficiency yellowing. Although the demand for iron in peach trees is small, it is indispensable for its growth and development. Because iron is not easy to move in peach trees, it first appears yellow on young leaves. Iron deficiency causes chlorophyll vinegar to form chlorophyll and yellow leaves, which seriously affects material and energy metabolism. Iron deficiency yellowing is seriously harmful during drought and rapid growth of peach trees.
Prevention.
Prevention and control of iron deficiency should be based on reducing groundwater level, controlling salt and alkali, increasing soil organic matter, improving soil structure and physical and chemical properties, and increasing soil permeability. Cooperating with other control methods can achieve good results. A peach orchard with high soil pH, high calcareousness and high phosphorus content is prone to iron deficiency chlorosis. For every 1 increase in pH in the soil, the solubility of iron decreases by 1000 times. When the phosphorus content is high, it combines with iron to form iron phosphate, forming a water-insoluble precipitate, and the roots cannot be absorbed. Adding organic fertilizer and applying appropriate amount of physiological acid fertilizer and sulfur powder and gypsum to reduce the pH value of rhizosphere soil can activate iron in soil. Control salt damage, reduce groundwater, cover the ground, plant legume green manure, and bury it. Timely supplementation of iron by foliar application of 0.3% sulphuric acid sulphate or 1000~1500 mg/kg of nitroxanthate or Dutch chlorophyllin (EDDHA-Fe), or vinegar soaking sulphuric acid Ferrous or chelating iron.
Replantation
Disease performance.
Peach replanting disease is also called peach continuous cropping obstacle. When the peach garden is heavy, the newly planted peach trees show extremely slow growth, the tree body is short, the leaves are yellow, the resistance is decreased, the gum disease is increased, the production is slow, the yield is low, and the quality is low. Poor, even the phenomenon of whole plant death. Peach replanting disease is widely distributed in peach growing areas around the world. In recent years, with the rapid development of the peach industry, many fruit farmers have planted a large number of peach trees in front of and behind the house, in the homestead, and even in the old Taoyuan, Liyuan, Liyuan, and Liyuan (both Rosaceae fruit trees). Therefore, replantation has a tendency to increase. The cause of the disease.
The cause of replanting disease is quite complicated. It is generally believed that the main roots of peach trees, especially the decay of old peach trees, after the decay of the toxic substances produced by root rot, have a toxic and mutually exclusive effect on replanting peach trees, especially It is the hydrolysis of phlorizin from the old peach tree in the soil to form hydrocyanic acid and benzaldehyde, which is harmful to the replanting of the young peach tree. Secondly, it is caused by the imbalance of some nutrients, especially some trace elements, or the abnormality of soil acidity and alkalinity caused by replanting of peach trees. In addition, an increase in root-knot nematodes and soil pathogenic microorganisms can also cause replantation disorders.
Prevention.
The following pathways should be taken to reduce or overcome replantation.
First, when the peach trees were replanted on the old site of the old orchard, the planting hole was staggered from the original peach tree, and the soil was deeply changed before planting the tree, and the whole garden was sprayed with 1.8% avermectin 500 times liquid for disinfection, and the new planting hole was set. The old soil within 1 m of the inner diameter is dug up and removed (preferably using machinery), the roots are completely removed, and the mature garden soil that has not been planted with peach trees is backfilled. The practice of planting in previous years showed that the original peach trees were not completely removed in the first two years of the growth of the newly planted peach trees, leaving some of the live piles that did not affect the new peach trees to grow in an appropriate amount, and then all removed after three years, which can effectively alleviate Replanting obstacles.
The second is to choose excellent varieties. Planted with large seedlings or container seedlings, and planted in late autumn and early spring, which are most suitable for planting.
The third is to strengthen cultivation management. Improve the soil micro-ecological environment, remove the roots, leaves, rotten fruits and malignant weeds of Rosaceae plants such as old peach trees, concentrate burning or deep burial, plant legume green manure, and increase the application of decomposed organic fertilizer. For old orchards that cannot be excavated for various reasons, soil disinfection should be done before planting. The commonly used soil disinfectants are bromine toluene, chloropicrin (trichloronitromethane) or formalin. When used, the fumigant is placed in a polyethylene film bag with many small holes, buried in the middle and lower part of the excavated planting hole in autumn, and planted in the early spring of the next year, which can better prevent replanting obstacles, such as in the soil. For root-knot nematodes, 80% dibromochloropropane should be applied to the soil 15 kg before the planting, and the ditch should be applied (ditch depth about 20 cm, groove distance 30 cm), watering 4500 kg/ha. Covered with soil after application, it can kill root-knot nematodes in the soil.
The fourth is to choose resistant rootstocks. Good rootstocks can improve the ability of plants to resist root-knot nematodes and reduce the risk of replantation disorders.
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