In January, the pear trees have entered a dormant phase, which is a good time for winter pruning and pest control. Through plastic pruning, ventilation and light transmission conditions are improved, and an environment that is not conducive to the breeding of diseases and insects is formed, which can effectively reduce the occurrence of diseases and insects. In view of the key points of pear tree management in January, Zhang Yiping, a researcher at the Shanxi Agricultural Biotechnology Research Center and a 110 expert of Shanxi Agricultural Science, proposed the following measures.
Zhang Yiping
Researcher of Shanxi Agricultural Biotechnology Research Center, Shanxi Agricultural Science 110 expert
1. Shape and trim
The pear tree shaping pruning period is divided into winter pruning and summer pruning. Winter pruning is usually carried out during the dormant period from December to February of the following year. Summer summer is actually the entire growth period of pruning, generally customarily called summer pruning.
Most of the nutrients in the tree's body in winter have been sent to the trunk and roots for storage. Pruning loses less nutrients. Methods such as shortening, thinning, shrinking, throwing, wounding, and curving branches are usually used. In summer, nutrient growth is vigorous, which can regulate the distribution of nutrients and promote the differentiation of flower buds. The methods used for pruning and pruning are opening angle, wiping buds, removing germination, thinning branches, and carving wounds.
Stubs: Or short shears, for annual branches, cutting off part of an annual branch is called short shears. Short shears can stimulate the germination of buds on the lower side of the shear, the first bud under the shear is stimulated the most, the farther away from the shear, the less stimulated the bud, and the specific response varies with the degree of stubbing. Short pruning of the backbone branches for many years. Due to the formation of more developing branches. Promote the development of mother branches, can be cultivated into a relatively strong skeleton.
Thinning: Also known as thinning branches, that is, the branches are cut from the base. Remove dead branches, diseased and insect branches, intersecting branches, overlapping branches, long branches, over-dense branches and other branches with no retention value in the canopy, save nutrients, improve ventilation and light transmission conditions, enhance photosynthesis ability, and facilitate flower bud formation. Wounds caused by thinning hinder nutrient transport, while the supply of branches below the wound to the roots is relatively increased. Therefore, thinning has a weakening effect on the growth of branches in the upper part of the shear, and the closer to the shear, the greater the weakening effect. The growth of the lower branches of the shear is used to a certain extent to promote the effect. Do not remove too much at once, causing a large number of wounds, especially do not form a "counterpart wound", so as not to excessively weaken the tree and branch growth potential. Thinning is to be removed from the base, but the wound area is small and easy to heal. If the shear is too long, the formation of stumps is not easy to heal, and can cause decay, or cause latent buds to emit a large number of long branches.
Retraction: Refers to the method of cutting perennials to the branch. Retraction can shorten the length of branches, reduce the amount of shoots and the total growth of mother branches, promote the growth of posterior branches and the germination of latent buds, and facilitate renewal and rejuvenation.
Swinging: also known as slow release, long release, the annual branch is not cut is called swing release. Swing has the effect of slowing down the growth potential and reducing the force of branches. After the long branches are released, the number of medium and short branches occurs. Flat-sloping, drooping branches with moderate growth generally have a good effect of throwing and promoting flower buds. After the flower is thrown into the fruit, it should be retracted in time, otherwise the branches will be extended uniaxially, the resulting parts will be easily moved out, and the branches will be prone to aging; and the fruit setting ability will be reduced, and the load force will be reduced.
Curved branches: The measures of changing the upright or small angled branches to the horizontal or sagging direction by pulling, doping, discping, pressing and other methods are called curved branches. Curved branches can change the tip advantage of the branches. It is conducive to nutrient accumulation, can improve the light condition, and can promote the differentiation of flower buds, especially during the young tree period, curved branches are the best measures for flowering.
Summer pruning is a supplement and auxiliary measure for winter and summer, and its role is mainly to regulate the transportation and distribution of water and nutrients, promote flower buds, especially to promote the fruit of young trees, which cannot be done by winter pruning.
Opening angle: Due to the brittle and hard wood of the pear tree, it is difficult to open the angle in winter. In summer, the sap flows, the branches are tough and soft, the opening angle is easy, and it is not easy to split. Pear trees grow upright, and generally large branches need to be opened artificially, but the angle of the backbone branches should not be opened too large. In the case of rare plantations, the backbone branches open to 50 to 60 degrees. In the case of dense plantations, the small crown-shaped trunk can open to 70 degrees, or near level.
De-germination: The budding that occurs at the shear saw during winter pruning generally needs to be removed. However, for the branches that sprout after the renewal and rejuvenation, they should choose their space to retain.
Carved buds: Promote the germination of lateral buds and form more branches. In view of the characteristics of strong trunk, strong growth and weak branching force of pear trees, when the amount of young branches is small, the buds or weak branches in their spatial parts are selected to be carved above them, which promotes the occurrence of strong branches. The timing of carving buds should be mastered, the saplings planted in winter and spring should be operated before germination, the closer to the time of budding, the better, if too early, the loss of moisture in the branches will affect the germination rate of buds, carving buds too late, then the new sprouts grow weakly.
Take the branch softening: For the branches that grow more vigorously, in order to make them form flower buds, you can soften the branches by taking the branches, slightly injure them, inhibit the growth trend, and promote the formation of flower buds.
Ring cutting and ring stripping: Ring cutting and ring stripping is a temporary measure implemented by temporarily intercepting the tree body before flowering, so that the flowering part obtains a relatively sufficient flowering material. Due to the strong germination of pear tree buds, the formation of short branches is easy, and the ring cutting or ring peeling technique is generally not used. Only for excessively strong trees or strong branches are used occasionally.
2. Tree management
Tree selection
Tree shape selection and cultivation system, that is, with the plant line spacing to cooperate, different plant line spacing to choose different tree shapes, at present, the general trend in production is that the tree shape has developed from a large crown shape to a small crown shape. But in the entire production process of the pear tree, the tree shape is not static, in order to pursue early yield, the number of plants planted per unit area increases, the tree shape should be shaped with a small crown, but as the age of the tree increases, the canopy increases, the row spacing changes, the tree shape must also change with the change, and the tree shape treatment should be in a constantly changing state.
In recent years, with the changes in the market and the change of management methods, special attention needs to be paid to the use of three tree shapes: the two-layer happy shape; the slender cylindrical shape; and the trellis happy shape.
Two layers of happy shape
In recent years, in order to adapt to the increasing quality requirements of the market for pear fruits, the management of pear orchards has become increasingly refined, such as flower and fruit thinning, bagging and other operations to put forward requirements for tree height. The traditional trunk is layered, the tree body is tall, the operation is inconvenient, and the level is gradually reduced, and the tree height is reduced. On the other hand, the main trunk is sparsely layered, with the age of the tree, the canopy increases, the light in the body of the tree becomes weaker, the branches are thin, and the abundant flower buds are formed less, and the resulting parts are moved outward and upward, and the quality is also reduced. At this time, the second layer of happiness is formed as the goal of tree shape transformation, and the main branches above the third layer are gradually reduced, changed to fruiting branches, and finally into a two-layer happy shape.
Structural features: the height of the tree is 3 to 3.5 meters, the trunk height is 60 to 80 cm, the whole tree has two layers, generally leaving 5 main branches. The first layer has 3 main branches, with an opening angle of 60° to 70 °, and each main branch has 3 to 4 side branches, and the side branches have fruiting branches. The second layer leaves 2 to 3 main branches 1 to 1.2 meters away from the first layer, and the plane extension direction of the two main branches is staggered with the three main branches of the first layer.
Slender trunk
In order to pursue early harvest, ultra-dense planting cultivation has been valued, row spacing has been compressed from 4 meters × 3 meters to 2 to 4 meters× 0.7 to 1.5 meters, so that the slender cylindrical shape due to the small size of the tree, simple structure, early fruit yield, easy to manage, suitable for dense planting of small row spacing conditions of cultivation, and by the grower's attention.
Structural characteristics: the height of the tree is about 2.5 to 3 meters, the dry height is 50 to 60 cm, and the crown diameter is 1 to 1.5 meters; the resulting branches with large, medium and small similar branches are evenly distributed on the central stem. Generally, the larger fruiting branches are 12 to 15.
The year it was planted
Stemming: Immediately after colonization, 50 to 60 cm in height, 0.5 to 1 cm in the upper part of the full bud in place, and apply a protective agent. Ensure that the center dry upright growth, the growth height of the year is more than 2 meters, the thickness of more than 1 cm.
Spread the buds and pull the branches: after germination, wipe the buds below 30 to 40 cm from the ground; when the length of the new shoots is about 15 cm, select the trunk of the robust branches, let them grow upright, and the rest of the branches are carried out by bracing, holding, plucking and other angles to control growth. Leave 3 to 4 small lateral branches at the base, which can increase the photosynthetic area, which is conducive to the growth of the trunk and plays a role in stabilizing the tree, and can also bear fruit in the second year to control the tree potential.
The second year of planting
Carved Buds: The key technique for carving buds to make the cultivation of slender cylindrical shapes. The germination time is within one week before and after the germination of the young tree buds; the number of carved buds is all the buds below 30 cm from the top of the central stem annual branch, and the carved bud site is 0.5 to 1 cm above the bud; the carving depth reaches xylem; the carved bud arc is 1/3 of the thickness of the main trunk, which is crescent-shaped; and the hair pigment is applied immediately after engraving.
Continue to open the angle: usually the bud is ideal, the new shoots will naturally grow, when the length of the new shoots is about 15 cm, the angle between the new shoots and the trunk is less than 50 °, the use of a long 6 cm toothpick to support the branches, so that it and the trunk reach 60 ° ~ 70 °. The second year the tree form is initially formed.
The third year of colonization
Flowers begin in the spring of the third year. The bare parts of the trunk continue to be carved and opened at an angle. When pruning in summer, the upright branches on the back of the lateral branches (fruiting branches) are removed and extended uniaxially. Except for the extra thicker upright branches. The base of the lateral branches is opened at an angle, and the top is sparsely squeezed.
Trellis cultivation
Pear tree trellis cultivation refers to the cultivation method of erecting pillars in pear orchards, and the top of the pillars is set up with a crisscross-like steel wire mesh similar to a grape trellis, and the main branches, side branches, and fruit branches of the pear tree are tied to the shelf. Because the cultivation of pear trees in trellises can reduce the losses caused by typhoon attacks, and it is convenient for the daily management of orchards, the yield per unit area is high, and the quality of pears and fruits is good, so it has become the main way of cultivating pear trees in Japan, accounting for more than 90% of the total area.
In recent years, because all the main branches, side branches and fruit branches of the trellis pear tree are fixed on the shelf surface built by steel wire, the entire canopy is one layer, the ventilation is good, the branch formation is easy to control, the results are stable, the fruit quality is good, the management operation is convenient, and the labor intensity can be effectively reduced, which is increasingly attracting domestic attention.
There are many types of domestic scaffolding, in order to reduce the cost, cement columns and metal mesh wires are used to build a mesh surface in China. The main types are horizontal trellises, trapezoidal trellises, arched trellises and so on.
Horizontal scaffolding construction method: pillar diagonal column, side column, hanging column three kinds. The corner columns are made of 12 cm × 12 cm × 330 cm cement columns, and the four corners of the trellis are erected. The side columns are made of 10 cm × 10 cm × 285 cm cement columns erected around the trellis, one every 3 meters. The hanging column adopts 8 cm × 8 cm × 400 cm cement column or 5 cm diameter galvanized steel pipe, evenly distributed in the trellis, and its role is to lift the mesh line and keep the trellis level without sinking. A hanging column can lift 80 to 120 square meters of shelf surface. The mesh surface is woven with steel strands and galvanized iron wire No. 8 to form a 50 cm square mesh. Generally, the height of the trellis is 180 to 200 cm, and it is appropriate to exceed the top of the manager's head by 15 to 20 cm.
In the trellis cultivation, the pear tree tree shape is selected cup shape. There are 3 to 4 main branches, 3 side branches are configured on each main branch, the distance between adjacent side branches on the same main branch is 70 to 80 cm, and 10 to 12 fruit branches are configured on each side branch.
After planting, the pear seedlings are fixed to dry 80 to 100 cm, and the 3 to 4 full buds under the shear are located in 3 or 4 directions respectively. After germination in the spring, when the new shoots reach 50 cm, adjust the opening angle of the new shoots to 45 degrees with a bamboo pole, and when pruning in winter, select the full buds to be short, and cultivate them as the main branches as soon as possible. When pruning in the winter of the following year, the main branch is still shortened at the full shoot of the extended branch, and the long branches on the back and the competing branches are removed, and the moderate branches that germinate from the side buds are retained, so that they are 90 degrees at an angle between them and the main branch, and are tied horizontally to the shelf. In the third year, the main branch pruning also leaves full buds and begins to cultivate the side branches. The rest of the branches take advantage of the results.
The rest of the management is like traditional techniques, such as flower thinning and fruit thinning, auxiliary pollination, bagging, etc.
3. Pest control
Clearing the garden: After the leaves have fallen and after the pruning is completed, remove all the stumps, fallen leaves, rotten fruits, and weeds to transport them outside the garden, bury them deep or burn them. Spores due to many diseases overwinter on diseased leaves or branches.
Scraping the bark: Carefully scrape the old bark on the trunk and thick backbone branches, and pay attention to the eggs or cocoons of the insects that may be hidden in the gaps under the skin.
Main trunk whitening: the main role is to eliminate diseases and insect pests such as insect eggs and larvae, prevent the main trunk from burning, frost damage, and prevent hares from nibbling on the bark.
The whitening agent can be configured according to 10 parts of water, 3 parts of quicklime, 0.5 parts of salt, 0.5 parts of stone sulfur compound, and 0.1 parts of soybean flour.
Spray once the cleansing agent. The qingyuan agent commonly used is a 3 to 5 degree lime sulfur compound (referred to as a stone sulfur compound), (45% crystalline stone sulfur compound can be used 60 to 80 times liquid; 29% water agent can be used 30 to 50 times liquid). or targeted choice of fungicides or fungicides.
In addition, pear small heartworms are mostly seriously occurring in pear, peach and apple mixed planting gardens, which is difficult to control. For example, it is recommended to move out of the pear garden with peach, apricot, plum and other trees.
The main pests and diseases of pear orchards in different places are different, and for the purpose of prevention and control, the wintering situation of common diseases and insect pests in Pear Orchards in Shanxi is introduced as follows:
Pear scab disease affects new shoots, leaves and young fruits. Mainly hyphae and conidia overwinter under the scales of shoot buds, on diseased leaves, and on diseased fruits;
Pear rust is mainly based on the invasion of leaves and young shoots. In winter, the rust spores formed on the pear trees should be transferred to the cypress for overwintering, and the pear rust should be completely removed, and it has been proposed that the cypress cannot be planted within 5 kilometers of the pear orchard, if possible, the cypress near the pear orchard should be removed, and if impossible, the fungicide should be sprayed on the cypress to eliminate the overwintering rust spores.
Pear black spot disease is mainly about attacking leaves, young shoots and young fruits. Pathogens overwinter in conidia and mycelium on diseased branches, shoots, and fruits.
Pear rot Disease The pathogen infects the deciduous layer of the main trunk and coarse backbone branches, forming new spots and overwintering on the old spots. The depth of the disease's invasion is mostly limited to the surface layer of the bark, and it rarely rots through the bark, but it will weaken the tree, grow poorly, and in severe cases, it will reach deep into the xylem, resulting in dry branches and death. When scraping the bark in autumn and winter, it is generally necessary to pay attention to the new disease spots, completely scrape off, for the old disease spots, such as the discovery of new ulcer surfaces to scrape the diseased tissue to apply protective agent, scraped bark collection and burn.
Pear rotunda mainly affects the branches. After the branches are damaged, prototype or oval spots of 3 to 20 mm in diameter are formed with skin holes as the center, which are brown to gray-brown, and the central protrusion of the diseased part forms a hard wart. The pathogen overwinters on the affected branches with hyphae and conidia. When scraping the bark. Care should be taken to scrape off the rotunda warts thoroughly.
Pear heartworms overwinter in old mature larvae in cocoons in trunk bark crevices, in the soil at the base of the trunk, and on nearby weed roots.
Pear large heart-eating worms overwinter in small larvae in white cocoons within the affected buds.
Pear star caterpillars overwinter in cocoons in cracks in the bark as juveniles.
Pear moth: Overwinters in invasive mycoidal moths.
Pear yellow mealybug overwinters in cracks in the bark with eggs.
Pear aphids overwinter with fertilized eggs in cracks in the bark and between the axillary buds.
Pear lice overwinter as adults overwintering under bark cracks and leaves.
Pear stem bees overwinter as old mature larvae in the second year of infancy.
Pear leaf swollen ticks overwinter under the affected leaves and bud scales.
Pear golden edge gidding insect The skin surface of the infested part of the branch becomes black like rot disease spots, and in the later stage, the cortex is longitudinally cracked or the phloem part is separated from the woody part, and the branches often dry out and die. Larvae of different ages overwinter at the cortical layer of the affected branches, trunks or xylems.
Editor: Wang Dawei Review: Shen Hongtao
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