What are the pests and diseases of Lagerstroemia indica?

Lagerstroemia indica has strong adaptability to environmental conditions. Resistant to drought and cold. The requirements for soil are not strict, but it grows healthily and has a long flowering period when planted in fertile, deep, loose and slightly acidic soil; Fear of waterlogging, avoid planting in places with high groundwater level and low humidity; Like light, growth and flowering need plenty of sunshine and a little shade tolerance; It thrives in a warm and humid climate. Lagerstroemia indica also has strong anti-pollution ability, which can resist toxic gases such as sulfur dioxide, hydrogen fluoride and chlorine, so it is also an ideal flower for beautifying the environment in industrial and mining areas and residential areas.

(1) planting 1, ground planting: it should be planted after defoliation in 1 1 until March of the following year. When planting, leave the trunk 100~ 120 cm high and cut off the upper part. After the new spring bamboo shoots grow, choose 3~4 main branches with suitable angles and let them blossom. 2. Potting: Using the seedlings of old branches in the past is a good way to quickly cultivate bonsai. Because the branches of Lagerstroemia indica are soft, potted Lagerstroemia indica can be properly climbed and bound. Generally, when the spring shoots stop growing and the branches tend to be semi-lignified, they are coiled and drawn with thin brown ropes to make bonsai in various postures.

(2) General management of fertilization and pest control of Lagerstroemia indica is relatively extensive. Spraying fertilizer in early March, combined application of nitrogen, phosphorus and potassium: applying phosphorus and potassium once from late May to early June to strengthen branches and promote flowers; Apply a flowering fertilizer at the end of July and the beginning of September. The fertilizer is cake fertilizer and water to make the flowers bloom brightly. If diseases are found, use Bordeaux solution or 600 times carbendazim solution to prevent them.

(3) Pruned Osmunda japonica grows at the top of spring shoots that germinated in the same year, with strong germination and irregular crown, which needs pruning. 1, winter pruning: In order to ensure normal flowering and form large inflorescences, winter pruning is very important. If planted in the ground, cut off the branches of the current year at the height of the main branches, so that the robust branches can blossom in the next year; First, cut off all sprouting branches, diseased branches and overlapping branches. In order to beautify the shape, the top of the full terminal bud of other branches is cut short at ` 1 cm, generally leaving only about 5 cm. 2. Pruning after flowering: After flowering in summer, some residual flowers should be pruned to prevent them from bearing seeds, so as to reduce nutrient loss and promote the germination and flowering of new branches. Pruning in the growing period is not suitable for pruning or shortening the new branches sprouting in spring, otherwise it will easily lead to only long branches without flowering.

Lagerstroemia speciosa, also known as ginger, begonia tree and prurigo tree. , belonging to Lagerstroemia of Lysimachiaceae. Beautiful tree shape and smooth bark. Rich and gorgeous colors, dense and elegant flowers, crape myrtle in summer and autumn, blooming for several months. Therefore, it is called "Hundred Days Red". In the Song Dynasty, Yang Wanli wrote a poem praising "Who knew there would be no day for bonuses?" Wei Zi often blooms for half a year. "As an important tree species for urban and rural greening, it is cultivated in the form of shrubs or small trees in the north, which is suitable for planting in the courtyard, on both sides of the garden road and along the Chi Pan River. Whether planted alone or in combination with other plants, Lagerstroemia indica is pleasing to the eye with its colorful trees and flowers.

1 Lifestyle Lagerstroemia indica is native to China, and enjoys sunshine and mild climate. It has certain cold resistance and drought resistance, especially neutral to slightly alkaline sandy loam, which is more drought-resistant and afraid of waterlogging. Flower buds are formed after the new shoots stop growing, which is beneficial to flower bud differentiation under the condition of high temperature and little rain.

2 Propagation technology Lagerstroemia indica mainly adopts sowing, cutting or ramet propagation, and a large number of green seedlings generally take seed propagation as the main way.

2. 1 sowing and propagation 10 June ——10 June, timely harvest the capsules on the healthy mother plants, dry them in the sun, peel them, and then screen them for fine storage. Sow in February-March of the following spring, which can be planted in the open field or spread. Water should be sprayed frequently after emergence to keep the soil moist. Topdressing urea 1 time per month, with the dosage of 2kg per mu. Cut the grass in time to conserve moisture. Before freezing in late June, 10, the soil should be cultivated to prevent cold and winter. In the third year, it can be planted in the ground to continue cultivation, with the row spacing of 0.50m×0.50m, and it can be planted in the garden next spring.

2.2 Before the spring germination of cutting propagation, select 1 year-old stout branches and cut them into 15 cm long. The seedbed should be loose sandy loam with good drainage, the scion should be inserted into the soil for 2/3, and then the plastic film micro-arch shed should be used for heat preservation and shade. It can take root in 20 days. Planting in the field in the next spring and continuing to cultivate, and coming out of the garden in the third year.

2.3 Before ramet propagation and spring germination, plant some root plants.

3 cultivation and management techniques

3. 1 Water and fertilizer management Throughout the growing season, the soil should always be moist. Water 1 time in spring drought 15 days or so, and water 1 time in autumn flowering period should not be too large, just water1time in about 20 days. Pour enough antifreeze water before winter. Because the flower buds of Lagerstroemia indica were formed that year, in order to make Lagerstroemia indica blossom every year, it is necessary to maintain sufficient fertility in the soil to facilitate the differentiation of flower buds. 2-4 kg of organic fertilizer can be applied to each plant in early spring, and a small amount of inorganic fertilizer can be applied in May-June.

3.2 plastic pruning Lagerstroemia speciosa plastic pruning is mainly in dormancy period, supplemented by growth period.

3.2. 1 natural Lagerstroemia indica can choose 3-4 big branches as main branches before leaving the garden, and 1-2 branches with good angles and balanced growth can be selected as side branches in the future. When pruning every year, the upper branches with large angles should be selected as extension branches, and the upper branches should be moderately shortened to expand the crown. This tree shape is easy to shape, has good air permeability and can blossom in three dimensions. This kind of tree is suitable for planting in large space.

3.2.2 Hierarchical shape of trunk This tree needs obvious hierarchical shape of trunk and main branches. The main branches are evenly distributed on the trunk. Generally, 3-5 main branches are selected, and 1-2 side branches are selected for each main branch. Cut off the useless branches that disturb the tree. This kind of tree conforms to the natural development law of Lagerstroemia indica, and has a high crown, which is suitable for garden cultivation and solitary cultivation.

3.2.3 Control the pruning of Lagerstroemia indica at flowering stage to form seeds. Due to the consumption of a lot of tree nutrients, the buds planted on the branches in that year could not germinate, but germinated into new branches the next year after overwintering. If the new shoots of Lagerstroemia speciosa are cut short at the beginning of August, all flower branches and 1/3 branches will be cut off, and fertilizer and water management will be strengthened. 3-4 buds under the cut can differentiate into flower buds after 1 month and bloom again before 1 month.

3.2.4 Different pruning methods should be adopted in different garden environments. Pruned Lagerstroemia indica trees are beautiful, natural and colorful. In the garden, if matched with Qiu Shu, it is an excellent tree species to decorate autumn scenery. Planting natural and happy Lagerstroemia indica in Chi Pan and by the river will have the scenic interest of "low flowers and small pool, light flowers and light pool heart"; If placed in front of evergreen trees, red flowers will be more beautiful and moving in the green leaves.

4 Pests and Diseases Control The pests and diseases of Lagerstroemia indica include bituminous coal disease, powdery mildew, scale insects and aphids. Bituminous coal disease mostly occurs on the leaves and branches of Lagerstroemia indica, which is caused by pathogens spread by scale insects and aphids. 40% omethoate 1000- 1200 times should be sprayed in time, generally 2-3 times. Powdery mildew often harms young leaves, and 70% thiophanate-methyl wettable powder 800- 1000 times can be sprayed for 3-5 times.