Cultivation techniques of Lagerstroemia indica

The common propagation methods of Lagerstroemia indica are sowing and cutting, among which the cutting method is better, the survival rate of cutting is higher than sowing, the plant blooms early, the plant grows fast and the seedling yield is high.

Sowing propagation

By sowing and propagating Lagerstroemia indica, a large number of healthy and tidy seedlings can be obtained at one time. The process of sowing and propagation includes seed collection, soil preparation and bed making, seed germination accelerating treatment, sowing time and sowing method.

1, seed collection:

Lagerstroemia indica has a long flowering period from June to September, with flowers and fruits coexisting and orderly fruits. From September to165438+1October, when the capsule turns from green to brown and some individuals start to crack slightly, the fruit sequence is picked, and the mature fruit at the base of the fruit sequence is collected, and the peel is removed. The seeds are stored in containers after drying, and the storage place should be ventilated and dry.

2. Soil preparation before bed

Lagerstroemia indica has strong adaptability to the environment, is drought-resistant and cold-resistant, and has no strict requirements on soil, but it grows best when planted in deep, fertile, loose, slightly acidic and acidic sandy soil. First, the seedbed soil is hoed loose, and the sowing ditch is treated according to the specifications of 20~25cm wide and 2~3cm deep.

3. Seed germination accelerating treatment

In order to make seeds germinate orderly and quickly, seeds should be germinated before sowing. First, the seeds should be disinfected. The common method is to soak in 0.2% potassium permanganate for 1-2 days, and then rinse with clear water for several times to remove the residual potassium permanganate. After cleaning, soak the seeds in warm water at about 45-50℃ for 2-3 days, then take out the seeds and dry them slightly.

4, sowing time and method:

Lagerstroemia indica is usually sown in March-April, outdoors, and the seeds are evenly spread on the flat seedbed. Sprinkle about 2-3 capsules every 3-4cm. After sowing, cover with fine soil about 2 cm thick. After about 10~ 14 days, most seeds germinated. Make sure the soil moisture after coming out. After the seedlings grow two pairs of true leaves, in order to ensure that the seedlings have enough growth space and nutrient area, we can choose to interplant the nursery after the rain, so that the air between the seedlings can circulate and the sunshine is sufficient. During the growing period, we should strengthen management, topdressing thin fertilizer 2-3 times in June-July, preventing drought in summer, watering frequently, and keeping the nursery moist, but remember not to overdo it. The height of seedlings can reach 50 ~ 70 cm in winter. Plants that grow well can bloom in the same year. After defoliation in winter, trim the side branches and open the flower branches in time. Transplanting in early spring of the following year.

Cutting propagation Lagerstroemia indica cutting propagation can be divided into softwood cutting and hardwood cutting.

1. Softwood cutting: Softwood cutting is usually carried out in July-August, when the new branches grow vigorously and have the most vitality, and the cutting survival rate is high. Select semi-lignified branches and cut them into cuttings about 10cm long, leaving 2-3 leaves at the top of the branches. Cut about 8cm deep and water the seedlings. In order to keep moisture and keep warm, the seedbed was covered with a plastic film, and a sunshade net was built to shade the sun. Generally 15-20 days can take root. Uncover the film, keep the sunshade net, and water it properly during the growing period. Branches can reach 70cm in that year, and the survival rate is high.

2. Hardwood cutting: Hardwood cutting is generally carried out from late March to early April before branches germinate. Short and thick annual branches were selected from well-growing mother plants and cut into branches with length of 10~ 15cm and depth of about 8 ~ 13cm. After inserting, water and irrigate, and the seedbed is covered with a layer of plastic film to keep moisture and heat. When the seedlings grow to 15~20cm, the film can be lifted to build a sunshade net. Proper watering during the growth period can make the branches grow to about 80cm.

Layering propagation: Lagerstroemia indica can be propagated by layering throughout the growing season, especially in March-April in spring.

Propagation by ramets: In early spring and March, the sprouting tillers germinated in the rhizosphere of Lagerstroemia indica were separated from the mother plant and planted separately, and watered enough to survive.

Grafting propagation: before the branches of Lagerstroemia indica germinate every spring, thick seedlings are selected as rootstocks, and a knife (3-4 cm deep) is longitudinally split at the top of the rootstock near the periphery, and the split seam must be cut from the core of the tree; Then take a scion with 2-3 buds with a length of 5-8 em and cut it into a wedge shape of 3-4cm on both sides of its base. The outside of the scion is slightly thicker than the inside. Put the thicker side of the scion outside, insert it into the split part of the rootstock to align with the cambium, and then wrap the whole scion with plastic film to expose the bud head. This method can graft branches of different colors on the same rootstock in layers to form a multi-color tree. After 2~3 months of grafting, the film is released, and the length of the ear head can reach 50~80cm. Branches should be cut short in time to avoid being broken by the wind, and thick branches can be cultivated. The survival rate of this cultivation method is over 98%. Lagerstroemia indica cultivation and management are extensive, but it is necessary to cut off dead branches, pests and diseases in time and burn them. In order to prolong the flowering period, the branches that have blossomed should be cut off in time so as to germinate again and grow the next round of flowers. In order to make the trunk thicker, you can cut off many flowers and concentrate on cultivating the trunk. Practice has proved that Lagerstroemia indica can bloom many times a year as long as it is properly managed, as long as 100 ~ 120 days.

Strengthen the light: Wei Zi likes the sunshine, so it must be placed in a sunny place outside during the growing season.

Timely watering: keep the basin soil moist in spring and winter, and water it once every morning and evening in summer and autumn. In case of drought and high temperature, the watering frequency can be appropriately increased every day, and the river water, well water, rainwater and tap water can be stored for 2 ~ 3 days.

Regular fertilization: Too much fertilization on potted Lagerstroemia indica can easily lead to excessive growth of branches and leaves. If lack of fertilizer, it will lead to thin branches, yellow leaves, weak growth potential of the whole plant, few flowers or no flowers. Therefore, it is necessary to apply fertilizer regularly, apply more fertilizer in spring and summer peak season, and apply less fertilizer after autumn. There is no need to apply fertilizer when winter enters the dormant period. Don't fertilize at noon in rainy days and summer when the temperature is high. Fertilization concentration is applied every 10 day from beginning of spring to beginning of autumn, topdressing every half month after beginning of autumn, and fertilization is stopped after beginning of winter.

Reasonable pruning: Lagerstroemia indica is resistant to pruning, with strong branching ability and large growth of new shoots. Therefore, after flowering, residual flowers should be cut off to prolong the flowering period, and long branches, overlapping branches, cross branches, radiation branches and diseased branches should be cut off at any time to avoid consuming nutrients.

Change pots in time: the pot soil of potted Lagerstroemia indica is changed every 2-3 years, and 5 parts of loose mountain soil, 3 parts of pastoral soil and 2 parts of fine river sand are mixed to make cultivation soil. When changing pots, organic fertilizers such as bone meal and bean cake powder can be used as the base fertilizer, but the fertilizer can't directly contact with the roots, so as not to hurt the roots and affect the plant growth. powdery mildew

(1) Symptoms: Powdery mildew mainly harms leaves, and young leaves are more susceptible to infection than old leaves; The disease also harms branches, shoots, buds and buds. At the early stage of the disease, small white spots appeared on the leaves, and after unfolding, they became round or irregular faded patches. After the flowers are infected, the surface is covered with white powder, and the flower spikes are deformed, losing ornamental value. The plants affected by powdery mildew will become shorter, the tender leaves will be twisted and withered, the leaves will become smaller without spreading, and the branches will be deformed. If it is serious, the whole plant will die.

(2) Prevention and control methods:

① Strengthen fertilization and pay attention to drainage to avoid excessive humidity;

(2) Reduce the source of infection, combine pruning in autumn and winter, eliminate diseased branches and burn them centrally, and pay attention to remove diseased buds, diseased leaves and diseased branches in time during the growing season;

③ When the plants get sick, they can be sprayed with 25% triadimefon wettable powder 3000 times, 70% thiophanate-methyl wettable powder 1000 times, or 80% zineb wettable powder 500 times. Several drugs can be used alternately.

Coal stain

(1) Symptoms: When the plant is ill, small black spots are formed on the leaves and branches, and then spread into pieces. In severe cases, the leaves are covered with a layer of black tissue, which affects the photosynthesis of leaves and inhibits the normal growth of new shoots. As time goes on, the leaves turn yellow and fall early, so it is difficult to form flower buds.

(2) Prevention and control methods:

① Strengthen cultivation management, reasonably arrange planting density, and trim diseased branches and redundant branches in time, so as to facilitate ventilation and light transmission, thereby enhancing tree vigor and reducing diseases;

② Before potted Lagerstroemia indica is used, the diseased leaves can be removed or the mold layer on the leaves can be washed with clear water;

(3) The plants harmed by sooty blotch in the growth period can be controlled by spraying 1000 times of 70% thiophanate methyl wettable powder or 1000 times of 50% carbendazim wettable powder.

④ Spraying chemicals to control aphids and scale insects is the main measure to reduce the incidence. Spray 40% omethoate 1000 times or 80% dichlorvos 1500 times in time. The turpentine mixture and petroleum emulsion with the ratio of 10-20 times can also be used to control scale insects.

Lagerstroemia indica brown spot

(1) Symptoms: Lagerstroemia indica brown spot mainly harms leaves. The lesions on the leaves are round or nearly round, and some are irregular, purple-brown to grayish brown. The edge color is light and unclear, and there are gray-black mildew spots on both sides. When there are several diseased spots on the leaves. The whole leaves turn yellow quickly and fall off early. High temperature, high humidity and frequent rainfall are beneficial to the occurrence of the disease.

(2) Prevention and control methods:

① Plow Lagerstroemia indica orchard or roadside Lagerstroemia indica in autumn, and turn the surface fallen leaves into deep soil early next year to reduce the source of infection. Trim it in time to make it ventilated and transparent.

② Spray 1000 times of 50% benomyl wettable powder or 800 times of 75% chlorothalonil wettable powder in time at the initial stage of the disease.

Lagerstroemia indica

Lagerstroemia indica, also known as Lagerstroemia indica, belongs to Homoptera, Aphidoidea and Aphididae.

Occurrence characteristics of (1): Lagerstroemia indica overwinters as eggs in bud axils, bud seams and branches. Wingless viviparous aphids began to appear when the new buds of Lagerstroemia indica were elongated in the following spring. After June, the insect population continued to rise, and with the increase of temperature, winged aphids were constantly produced, which would migrate and spread. The damage of this insect to Lagerstroemia indica occurs every year. The back of young leaves is often covered with pests. After the injury, the new buds are twisted and the young leaves are uneven, which affects the formation of flower buds, shortens inflorescences and even leads to no flowering. At the same time, it can induce sooty blotch's disease and spread viral diseases.

(2) Prevention and control methods

(1) combined with pruning in winter to remove branches of diseases and pests, twigs and over-dense branches can play a role in eliminating some overwintering eggs. Family potted plants should also make the branches as smooth as possible, pay attention to removing the pterygoid cortex at the branches, and focus on burning to reduce the oviposition of overwintering aphids.

② Chemical control: 65,438+00% aphid chlorpyrifos WP 65,438+0,500 times, or 65,438+0,000 times 50% chlorpyrifos EC, 65,438+0,000 times 40% omethoate EC, 65,438+0. At the same time, it can play a dual role.

Lagerstroemia indica scale

Coccidia Lagerstroemia belongs to Homoptera Coccidae, which harms flowers and trees such as Lagerstroemia indica and pomegranate.

(1) Hazard characteristics: Female adults and nymphs suck juice on bud axils, leaves and branches, which often leads to weak tree vigor and poor growth; Moreover, a large amount of honey dew secreted by it will induce serious sooty blotch, which will lead to the blackening of leaves and branchlets and lose their ornamental value. It is one of the main pests that harm Lagerstroemia indica. The generation generations of this insect vary from region to region, with 2-4 generations a year, overwintering with eggs or nymphs, and the overwintering state of scale insects is fertilized females, 2nd instar nymphs or eggs. It varies from place to place. Usually overwinter in the cracks of branches. Early June to mid-July and late August to September are the peak periods of nymph hatching every year. Silkworm pupae reproduce quickly in warm and high humidity environment, and dry heat is unfavorable to their development.

(2) Prevention and control methods

(1) Strengthen quarantine, prevent bacteria from flowing into human body, apply fertilizer rationally, enhance plant insect resistance, keep ventilation and light transmission, and avoid excessive plant density, and combine pruning in winter and early spring to burn insect branches. When the number of insect mouths is small, it can be scraped manually.

② Chemical control. Spraying 10- 15 times of turpentine mixture or 40-50 times of engine oil emulsion 1-3 times in winter to eliminate overwintering female insects; Before germination, spray 3-5% sulfur mixture or 3-5% diesel emulsion to kill overwintering nymphs; Nymphs are the key to control. One is to spray 500 times of 50% carbaryl wettable powder or 1000 times of 5% phoxim emulsifiable concentrate on the soil surface around the roots in early spring. During the incubation period, when the shell is not thickened and the pesticide is easy to penetrate, spray it every 7 7- 10/time for 2-3 times continuously, and choose 40% omethoate emulsion, 80% dichlorvos emulsion, 50% phoxim emulsion and 25% iminophosphate emulsion 1 00.

sawfly

Sawflies belong to HYMENOPTERA sawflies superfamily.

(1) Damage characteristics: Larvae swarm, eating leaves and mesophyll, eating up the tender leaves of the plant, leaving only a few main veins, affecting the photosynthesis of the plant, affecting the flowering period of Lagerstroemia indica, reducing its ornamental value, and even leading to death. Sawflies have 2-8 generations each year, overlapping generations, and cocoon in the soil for the winter. Adults emerge from April to May. Adults emerge during the day and mate the next day. Females only mate 1 time in their lifetime, and males can mate many times. After mating, the female bees lay eggs in the branch cortex, usually as deep as xylem, and the egg period is 7- 19 days. As hatching approaches, the cracks in the spawning ground crack, and the hatched larvae climb out of the cracks and onto the tender tips.

(2) Prevention and control methods:

(1) Combine soil ploughing in winter and spring to eliminate overwintering cocoons.

(2) Look for the shoot tips and leaves that lay eggs, and manually remove the shoot tips, leaves or larvae that are still clustered after hatching.

③ Spraying 500-fold Bt emulsion, 3,000-fold 2.5% deltamethrin emulsifiable concentrate, 2,000-fold 20% fenvalerate and 1500-fold 25% diflubenzuron No.3 suspension during the larval damage period.

Yellow thorn moth

Yellow thorn moth, of medium size, larvae are spiny caterpillars, commonly known as pepper, which is one of the main leaf-eating pests of Lagerstroemia indica.

Occurrence characteristics of (1): The damage is mainly caused by the bite of larvae.

(2) Control method: physical control is the main method, combined with winter pruning, to remove overwintering cocoons from branches, so as to eliminate or reduce insect sources; It is best to use pesticides before larvae spread, spraying 80% dichlorvos EC 1000 times and 2.5% deltamethrin EC 2000 times.