Symptom characteristics of 1
1. 1 black spot disease: small black spots are produced in the calyx depression and stem depression of the fruit, and the black spots do not expand and rot, sometimes green halos appear around the black spots, and there is often a thin layer of powdery pectin on the surface.
1.2 rust spots: scattered or continuous brown rust spots are produced in the calyx depression and stem depression of the fruit, and the fruit points on the surface of the fruit expand into stars.
1.3 red dot disease: within one week after the apple is unpacked, reddish-brown spots appear on the sunny side, and the red dots do not spread, sag or rot.
1.4 Water ripple disease: In the late growth stage of apple, brown wavy water ripples centered on the fruit stalk are produced in the depression of the fruit stalk or calyx or even on the fruit surface, which is called chapping.
2. Etiological characteristics
Apple spot rust is a series of symptoms caused by garden, soil, tree body, medicine, bagging, nutrition, moisture, meteorology and some pests and diseases.
2. 1 apple fruit-setting stage-fluff stage, improper manual spraying technology, excessive pressure of spraying equipment, turning spraying into water spraying, rinsing spraying, or chemical reaction caused by unreasonable pesticide preparation, adding adhesive and penetrant indiscriminately, or too high preparation concentration, causing mechanical damage to the fruit surface and often producing irritating rust spots. This phenomenon is most obvious in drooping fruit stems and depressions, which some people call stem rust. Excessive use or improper mixing of pesticides leads to uneven spread. When sprayed at noon, it will burn if the temperature is too high, especially for bagged fruits. Water vapor is difficult to evaporate, and high temperature is easy to cause phytotoxicity. Spraying highly irritating chemicals, such as organophosphorus and copper preparations, stimulates the fruit surface during fruit period, causing the fruit surface to fall off, or spraying chemicals, the nozzle is too close to the fruit surface, hurting the tender skin. As a result, insects were not killed, which created conditions for the infection of germs and formed disease scars on the surface of fruits.
2.2 During the depilation period of young apple fruit-lenticels formation period, if high-dose pesticides made in China, such as mancozeb, Bordeaux solution or emulsifiable concentrate (containing additives such as benzene, toluene and xylene) are sprayed or bagged immediately, if high temperature and drought are encountered, and foliar calcium supplementation is not carried out in advance, the fruit will suffer from high-temperature phytotoxicity or serious boron or calcium deficiency.
2.3 During the pore-forming period from the young apple peel to the cork stage, if high-dose mancozeb, Bordeaux solution or other copper preparations or mixed high-permeability agents are sprayed, bagging will be carried out before the dew is dry. In case of continuous high temperature and drought, rust spots will appear on fruit stalks or calyx depressions due to hidden phytotoxicity or boron deficiency.
The weather is dry in the young fruit period, the calcium accumulation is insufficient in the critical period of calcium demand and the peak period of calcium absorption, and the weather is good in the fruit expansion period, which leads to serious calcium deficiency and reduced drought resistance in the later fruit period. When the apple is unpacked, the fruit will be hot during the day, dew at night, and the sunny side of the fruit will be burned by the high temperature. If it rains after unpacking, leaf spot will infect the fruit surface and form black and red spots.
2.4 Nutrition supplement in young fruit period of apple. As we all know, the nutrient consumption of fruit trees in the process of germination, budding, leaf opening, flowering, topping, fruit setting and initial differentiation of flower buds all came from the storage nutrition last autumn. After flowering and fruit setting, trees have consumed a lot of nutrients and are in a nutrient deficiency period, so it is difficult to provide sufficient nutritional guarantee for the growth of young fruits. In addition, low temperature, poor illumination, weak photosynthesis, insufficient self-sufficient nutrients, lack of fertilizer and fatigue of fruit trees, slow growth and reduced stress resistance are easy to breed physiological diseases.
2.5 The continuous high temperature and drought in summer, leaves have a lot of ineffective transpiration, roots are poorly absorbed, nutrients can't be supplied in time, peel cells lose water and shrink, heavy rain suddenly falls, cells absorb and expand, cracks appear, germs are impregnated or corked, fruit rust is formed, and black spots are produced. As the saying goes, water has no harvest, but more fat has less harvest. Therefore, in arid areas or dry seasons, attention should be paid to replenishing water.
2.6 The growth rate of apple fruit was inhibited by recessive phytotoxicity or high temperature and drought during the fruit expansion period. Especially in the period of cell volume expansion and continuous high temperature and drought, the cells of apple peel tissue grow slowly and the surface wax layer thickens to improve drought resistance. At this time, if the water is suddenly irrigated, especially when it rains heavily, the water content will increase sharply, and the fruit development will be different inside and outside, which will inevitably lead to the rapid expansion of tissue cells in the fruit and the slow expansion of tissue cells in the peel, which will eventually lead to water ripple disease in the stem depression or calyx depression.
2.7 Some apple orchards with extensive management, such as high underground water level, poor drainage, overgrowth of trees, closed crown, poor ventilation and light transmission, over-reliance on girdling, girdling and other flower and fruit promotion technologies, have poor healing of girdling mouth, and bagged fruits are under the environmental conditions of high humidity, poor ventilation, tender fruit surface and high temperature, which may easily lead to calyx depression or lenticels cracks on fruit stems, forming small black spots and other physiological diseases. In addition, compared with paper bags, black, blue-black and micro-film fruit bags are easy to get sunburned, and the sunburned parts are infected by bacteria to grow black mold or rot.
2.8 It is observed that apple spot defoliation, corn scale and other diseases and insect pests occur in orchards every year. Before and after bagging, the orchard with corn scale was neglected, and mottled leaves were not prevented in time after unpacking. In addition, bagged fruits have poor stress resistance and often suffer from serious diseases and insect pests. For example, after Alternaria leaf spot damages the fruit, irregular black spots appear, and dark green or even black mildew spots can grow on both sides of the diseased part when wet; After the brown spot infected the fruit, it initially showed light brown spots, and gradually expanded into round or irregular shapes, with small black spots on the brown surface; After scab damage, the diseased spots on the fruit surface are pale yellow, round or oval at first, and gradually turn brown or black, and a layer of black velvet is produced on the surface. Insects such as tea wing stinkbug and hemp skin stinkbug harm the fruit, causing cork spots on the surface of the fruit and forming black scars; After scale insects, such as pear fruit borer, harm the fruit, the fruit surface has red and purple spots; After Bemisia tabaci harmed the fruit, black spots appeared on the surface of the fruit and green halo appeared around it.
2.9 Regarding the problem of black erythema on the surface of bagged fruit, the research results of Hebei Agricultural University, Shaanxi Fruit Research Center and Qingdao Agricultural Research Institute of Shandong Province believe that the pathogens are Trichosporon and Polyporus farinosus. Spores of pathogenic bacteria lurk on the surface of young fruits before bagging, and will not get sick, because pathogenic bacteria are weak parasitic fungi of Hemiptera subfamily, which generally do not infect the surface of fruits, and only occur under special circumstances of fruit bagging.
3. Comprehensive prevention and control
3. 1 Long-term neglect of applying farmyard manure and single application of a large number of chemical fertilizers lead to the lack of soil organic matter, which leads to soil hardening, difficult normal growth of roots and reduced absorption capacity. In addition, after years of girdling and cutting, the nutrient operation of the tree is blocked, the tree is weak, the leaves are thin and small, the roots are yellow, and finally the roots are "hungry", the function is out of order, and some mineral elements are temporarily lacking, resulting in physiological diseases. Calcium-nitrogen imbalance, such as water heart disease, tiger skin disease. Calcium deficiency in water heart disease and boron deficiency in fruit shrinkage disease, and dark green or dark red or brown spots appear on the surface of fruit. Re-apply organic fertilizer, conditionally implement soil testing and formula fertilization, and appropriately control the amount of nitrogen fertilizer applied. Applying more organic manure or green manure can loosen soil, improve soil fertility, create good conditions for root growth, and have strong root vitality, which is beneficial to the absorption and utilization of mineral nutrients and the maintenance of water and fertilizer. Practice has proved that this pest is relatively light in orchards with a large amount of organic fertilizer or high organic matter content. In recent years, after the application of organic, inorganic and biological fertilizers in northern fruit areas of China in recent years, the fruit surface is smooth, the waxy layer is thickened, and the fruit commodity rate is significantly improved.
3.2 Implement the system of planting grass in orchard, store water and conserve moisture, improve soil fertility and enhance the resilience of trees; Or strengthen the supporting construction of orchard water conservancy facilities to ensure dry energy irrigation and waterlogging drainage during apple growing period.
3.4 Pay attention to local conditions, choose a reasonable tree shape, and create ventilation and light transmission conditions conducive to the growth and development of fruit trees through shaping and pruning, so as to reduce the occurrence of pests and diseases and improve the commodity rate of fruits.
3.5 Pay attention to the application of trace elements, such as spraying Buxing Fertilizer Boron, Su Le Boron and Intimate High Boron after flowering, and spraying Pudejin, Baojiaxin and Antaisheng. , both sterilization and zinc supplementation, young fruits sprayed with Busdecop and Kangbu fertilizer essence, and iron deficiency chlorosis sprayed with safe chelated iron (produced by EDTA technology). Ensure to meet the needs of fruit trees for trace elements such as boron, zinc, iron and calcium. It should be noted that ferrous sulfate and copper sulfate should be used with caution for young leaves and young fruits, and zinc sulfate, inferior potassium dihydrogen phosphate and potassium dihydrogen phosphate (some of which contain irritating ammonium bicarbonate) should be used with caution for young fruits, so as not to stimulate the fruit surface and cause invisible fertilizer damage.
3.5. 1 Spraying 1000- 1500 times of Buxing Fertilizer Boron, Intimate High Boron or Su Le Boron Solution at the apple flowering stage; After flowering, spray Bustak Science 6000-8000 times or Kangbu Fei Jing 3000-5000 times twice.
3.5.2 Before bagging apples, high-quality calcium lactate (if you are interested in calcium lactate) or calcium fulvate (such as giant gold calcium) or 300-400 times of calcium amino acid must be sprayed continuously for 3-4 times to ensure that the special requirements of bagged fruits for calcium can be met and the occurrence of the above-mentioned undesirable phenomena can be alleviated.
3.5.3 In production, spraying high-quality trace element fertilizer -6000-8000 times twice in August can obviously reduce fruit points, enhance surface cell activity, help prevent bacterial infection and reduce sunburn. In particular, it has obvious curative effect on the phenomenon of hole breaking and self-overflow of bagged peel, which is beneficial to the later coloring of fruit, increasing the thickness of waxy layer, eliminating both sides and improving commodity rate. Spraying 6000-8000 times of Stokop solution once in September can effectively promote the smooth transportation of nutrients in trees, expand the storage capacity of roots, thicken leaves, improve the vitality of trees and enhance the ability to resist pests and diseases.
3.6 When young fruits are used, we should pay attention to the selection of high-quality and efficient pesticides and fungicides, and avoid using pesticides containing heavy metal ions to prevent pollution and damage to the fruit surface. According to reports, improper drug selection in young fruit stage caused unclean fruit surface, large stomata, protruding outward and other phenomena, and its adverse effects far exceeded the bad climate, which should be paid great attention to. Before bagging apples, pay attention to spraying sulfur preparations, such as domestic compound mancozeb, compound carbendazim and compound nail rack. , containing sulfur, usually with the words F or S after the name of the commodity; Carefully spray thiram, thiram, tuijunte and their compound preparations; Carefully spray Bordeaux mixture and other copper preparations such as Rudeboard, green milk copper, copper master and copper handsome; Carefully spray inferior emulsifiable concentrate pesticides, especially some organophosphorus pesticides, such as isocarbophos, dichlorvos, trichlorfon, dimethoate, phoxim, aphids and methomyl. Carefully spray inferior penetrant and synergist which have corrosive effect on fruit surface. Most of these drugs are packed in glass bottles, so pay attention to them. It is suggested to choose advanced dosage forms such as suspension, colloidal suspension and aqueous solution, as well as water dispersible granules, dispersible granules, dry suspension and high-quality wettable powder, such as 43% Dashengfu suspension, 50% Geha gel suspension, 42% Penfulu suspension, 65% Pudejin wettable powder, 70% Nano-octyl wettable powder or 40% Chlorfenuron (hexaflumuron) suspension. If it is necessary to use penetrant or synergist, it is recommended to use the multifunctional water quality optimizer Roushuitong with high quality, high efficiency and safety.
3.7 To advocate the use of high-quality fruit bags, we should first choose large-scale and reliable paper bag manufacturers; Secondly, we should pay attention to the specifications of paper bags, neither too big nor too small. For example, a paper bag with a width of 15 cm and a height of 19.5 ~ 20 cm can hold 85 ~ 90 mm apples. Third, choose the quality of paper bags, with registered trademarks, fine workmanship, moderate ventilation holes, good waxing in the inner bag, uniform waxing, good water resistance, good shading in the outer bag, soft and breathable paper, weatherproof, good adhesion at the bottom of the mouth and firm binding; Fourth, we should choose high-quality double-layer paper bags. Only double-layer high-quality paper bags can wrap high-quality high-grade apples.
After more than 3.8 years of observation, the black spot disease of bagged apples mostly began in late July or early August. If you choose high-quality bactericide with internal absorption and conduction function in mid-July, such as 25% Guinness 6000 times solution or 70% Nano-Xin wettable powder 1200 times solution, etc. Spray continuously for 2 or 3 times with an interval of 10- 15 days.
3.9 In arid areas or years with less precipitation, it is necessary to ensure that apples are watered before and after flowering, before and after bagging, and before and after bagging. Apples should be watered once before bagging and bagging to prevent bagging burn or reduce bagging burn.
3. 10 The traditional techniques of "carving, peeling and pulling" to promote flowers are mostly methods to weaken the tree vigor, and some of them can no longer meet the requirements of modern fruit tree production, especially improper girdling will lead to poor healing, weak tree vigor and tree death. After years of girdling, the surface smoothness of bagged fruit is generally reduced, black spots are increased and fruit cracking is serious. Avoid girdling and flower promotion technology as much as possible in production, pay attention to the rational application of various measures, keep the tree vigorous, ensure proper flowering, and realize high and stable yield.
3. 1 1 The experimental results in recent years show that spraying 43% Dashengfu SC or 42% Fulu SC 800 times solution and 600-800 times You Guo calcium lactate mixture 1 time every day after the apple is unpacked has excellent preventive effect on the surface microcracks and dark spots of the fruit.