How to grow axillary-flowered Yulan magnolia seedlings? Detailed propagation techniques
Axillary-flowered Yulan magnolia is a relatively good natural variety of Xinyi (Magnolia biondii buds) and has very high medicinal value. So, how do you grow axillary-flowered Yulan magnolia seedlings? Today the editor will talk with you about the propagation techniques for axillary-flowered Yulan magnolia. Let's take a look.
1 Collection and treatment of seeds
Select Yulan magnolia that grows vigorously, has a full crown, good light penetration, plump seeds and no pests or diseases, and collect seeds from August 20 to September 15. When the aggregate fruit gradually turns reddish brown, indicating that it is gradually splitting open and exposing the bright red seed coat, this is the best time for picking.
Then dry it in the sun, usually placing it in a dry and well-ventilated place. When the fruit has completely split open, take out the seeds and pile them for 1-2 d to soften the aril, then rub them in a sieve, rinse with clean water and remove the aril.
Finally, soak and rub them again in wood ash water to remove the oil on the surface of the seed coat, and dry them in the shade in a ventilated place.
Note that they must not be exposed to strong sunlight, as this will affect the seed germination rate. After drying, store them promptly; the storage period is exactly the dormancy period of the seeds.
2 Sunny-bed seedling raising
2.1 Construction of the sunny bed
From December 20 to January 10 of the following year, choose a plot sheltered from the wind, facing the sun and with high, dry terrain to build the bed. The bed is 13 m wide and 10-12 m long from east to west. Build a 60 cm high earth wall along the north edge of the seedbed, cut the east and west side walls into slopes high in the north and low in the south, pile a 20 cm high ridge along the south edge, and leave a 1 m wide walkway and drainage ditch between two beds. Arrange the bed surface 10-15 d before sowing; first repeatedly turn and sun-dry the bed soil.
2.2 Preparation of nutrient soil
Sieve fully decomposed cow dung and other light, loose organic fertilizer, mix in fine sand and garden soil (ratio 4:3:3), apply 150 g of 3% carbofuran granules per bed, mix evenly with the bed soil, then use ferrous sulfate or dexon plus sodium pentachlorophenate, half of each, diluted to a 500-fold solution and spray evenly. This prepares a fertile, loose nutrient bed soil free of pests and diseases.
2.3 Sowing and covering
First pile the nutrient soil in the bed and level it, keeping the thickness at 15 cm; then water it, making sure to water thoroughly, and level the ground; finally sow. If the seeds have been stored in sand, wash them with clean water and dry them, place them on the bed surface at equal spacing of 3 cm x 3 cm at 4-5 kg per bed, then cover with 2 cm of nutrient soil and level it. After sowing, cover with plastic film and seal the four sides tightly, which can increase the internal temperature and humidity and prevent wind and rain, then cover the bed with straw mats.
2.4 Seedbed management
From sowing to emergence takes 60 d, during which management should be strengthened. At 9:00 each day when the temperature rises, uncover the straw mats; at 16:00 cover them tightly and press them down firmly. During seedbed management, good ventilation should be maintained to regulate temperature and humidity, and water and fertilizer should be replenished in time, light intensity increased, and pest, disease, weed and grass control strengthened, so as to provide a good environment for plant growth.
2.5 Transplanting of seedlings
Before lifting the seedlings, water the bed seedlings thoroughly. When lifting, pick up the seedlings and plant them by grade for better results. In early March, decide whether to irrigate according to the moisture conditions of the seedling-raising site; in late March, level the land, make beds and lay 1 m wide plastic mulch.
Plant in early April, using a line for row spacing and digging holes with a small trowel at the required plant spacing. Place the seedlings upright with the roots spread out, bury them 1-2 cm in the soil, firm and press tightly, then water. After the seedlings are planted, if it rains, no watering is needed; if the climate is dry, water thoroughly once.
2.6 Field management
Before August, irrigate appropriately to keep the bed surface moist. Avoid flood irrigation, which causes the bed surface to crust and crack. From early August to late September, when the weather is dry, water generally once every 5-7 d. Apply 5-7 kg of urea per 667 sq m as topdressing. In the late growth stage, spray 01%-03% potassium dihydrogen phosphate on the leaves to increase the degree of lignification. 10 d before freezing, irrigate once with freezing water.
3 Direct seeding seedling raising
3.1 Land preparation and sowing
In early March, choose flat terrain with deep soil, loose and fertile, convenient drainage and irrigation, and a groundwater level below 15 m, using sandy loam or loam for land preparation. Before sowing, plow the nursery land deeply and harrow it finely, and apply sufficient base fertilizer. The bed surface is 60 cm wide, the ditch is 20 cm wide, 10-15 cm high, and 10-15 m long. Before sowing, apply chemicals to control underground pests, usually 3% carbofuran granules at 2-2.5 kg/667 sq m. In mid-to-late March, use the strip placement sowing method. Sow in double rows per bed with 40 cm row spacing, open sowing furrows 3 cm deep and 5 cm wide, with a flat bottom and uniform depth. Then pour water directly into the furrow, and after it has all infiltrated, sow the seeds, keeping plant spacing at about 10 cm. Spray a sterilizing agent, usually 40% carbendazim 500-fold solution. Finally cover with soil, mostly loose manure soil, which can supplement organic matter, or fine sandy soil can also be used.
3.2 Plastic mulch and rice straw covering
Cover with film along the sowing furrows, and after covering, press the two sides of the film firmly with moist soil. When the seeds emerge, remove the film immediately, then cover the bed surface with rice straw, wheat straw, etc., to avoid damaging the seedlings. Note that the covering should not be too thick; it is best if the soil surface is just barely visible. After all seedlings have emerged, clear the rice straw covering to between the seedling rows, which can effectively keep warmth and moisture while avoiding the mass growth of weeds.
3.3 Field management
Same as the field management for sunny-bed seedling raising.
4 Grafting
4.1 Selection of scions
Select branches from mature plants of axillary-flowered Yulan magnolia with excellent and pure quality, early budding and high yield, containing plump buds, as scions. The thickness of the branches should be as similar as possible to that of the rootstock. The cut bud sticks only need to retain the petiole, and grafting should be done while cutting. Grafting is carried out from August 25 to September 30. Xinyi branches have a relatively large pith, so the chip budding method (veneer budding) should be used. Align and press the cambium layers tightly. Wrap tightly from bottom to top with plastic strips overlapping by 1/3 each turn, exposing the grafted bud.
4.2 Management after grafting
After grafting, if the climate is dry, increase the frequency of watering, and check 7-15 d later whether it has survived. If it has not survived, carry out supplementary grafting immediately. Before sprouting the following spring, cut off the rootstock 0.5-1 cm above the grafted bud, and remove the plastic strip at the same time. Then carry out 3-4 rounds of bud removal, and scientifically and reasonably implement watering, fertilizing, hoeing and weeding, and disease and pest control to ensure good growth of the grafted buds. Only through careful tending in the later period can strong plants be produced by the end of the year.
Southern magnolia Magnolia Grandiflora L. Southern magnolia guide: how to grow southern magnolia / how to propagate southern magnolia
Southern magnolia profileSouthern magnolia Magnolia Grandiflora L.
Aliases: large-flowered magnolia, lotus magnolia, foreign magnolia
Classification: tree flower
Family and genus: Plantae, Spermatophyta, Dicotyledoneae, Magnoliales, Magnoliaceae, Magnolia
Full bloom period: summer
Southern magnolia is an evergreen tree, up to 30 m tall in its place of origin; bark light brown or gray. Because its flowers are very large and shaped like lotus flowers, it is also called "lotus magnolia." Southern magnolia is native to the Americas, so some also call it "foreign magnolia." It can be used medicinally and also for road greening. Southern magnolia grows best in light and is slightly shade-tolerant when young. It likes a warm, humid climate and has a certain cold resistance. It is suitable for growing in high, dry, fertile, moist, well-drained slightly acidic or neutral soil; when planted in alkaline soil it tends to become chlorotic, and it dislikes waterlogging and poor drainage. The southern magnolia has a majestic and magnificent tree form, large leaves with dense green shade, and flowers like lotus flowers with a rich fragrance. It is a landscaping tree species and is tolerant of smoke...
Southern magnolia cultivation methods and precautions, introduction to southern magnolia
Southern magnolia is an evergreen tree, up to 30 m tall in its place of origin; bark light brown or gray. Because its flowers are very large and shaped like lotus flowers, it is also called "lotus magnolia." Southern magnolia is native to the Americas, so some also call it "foreign magnolia." It can be used medicinally and also for road greening.
Southern magnolia grows best in light and is slightly shade-tolerant when young. It likes a warm, humid climate and has a certain cold resistance. It is suitable for growing in high, dry, fertile, moist, well-drained slightly acidic or neutral soil; when planted in alkaline soil it tends to become chlorotic, and it dislikes waterlogging and poor drainage.
The southern magnolia has a majestic and magnificent tree form, large leaves with dense green shade, and flowers like lotus flowers with a rich fragrance. It is a landscaping tree species, tolerant of smoke and wind, and has strong resistance to toxic gases such as sulfur dioxide, and can be used to purify air and protect the environment.
Southern magnolia is the city tree of Hefei, Anhui; Zhenjiang, Jiangsu; Changzhou, Jiangsu; and Nantong, Jiangsu.
Morphological characteristics of southern magnolia
Southern magnolia is an evergreen tree, up to 30 m tall in its place of origin; bark light brown or gray, splitting in thin scales; branchlets stout, with septate pith; branchlets, buds, lower leaf surfaces and petioles all densely covered with brown or gray-brown short hairs (the lower leaf surface of young trees is hairless). Leaves thickly leathery, elliptic, oblong-elliptic or obovate-elliptic, 10-20 cm long, 4-7 (10) cm wide, apex obtuse or shortly obtuse-tipped, base cuneate, upper surface dark green and glossy; lateral veins 8-10 per side; petiole 1.5-4 cm long, without stipular scars, with a deep groove.
Southern magnolia flowers white, fragrant, 15-20 cm in diameter; tepals 9-12, thickly fleshy, obovate, 6-10 cm long, 5-7 cm wide; stamens about 2 cm long, filaments flat, purple, anthers introrse, connective extended into a short point; gynoecium ellipsoid, densely covered with long hairs; carpels ovate, 1-1.5 cm long, style curled. Aggregate fruit cylindrical-oblong or ovate, 7-10 cm long, 4-5 cm in diameter, densely covered with brown or pale gray-yellow hairs; follicles dehiscing along the back, rounded on the back, with a long beak on the outer side at the apex; seeds nearly ovate or ovate, about 14 mm long, about 6 mm in diameter, outer seed coat red; seeds with the outer seed coat removed have the apex extended into a short neck.
Southern magnolia has large white flowers shaped like lotus flowers and fragrant; it is a beautiful garden ornamental tree species, suitable for growing in moist, fertile soil, and has strong resistance to toxic gases such as sulfur dioxide, chlorine and hydrogen fluoride; it is also tolerant of smoke and dust. The wood is yellow-white, hard and heavy, and can be used as decorative timber. The leaves, young branches and flowers can be used to extract aromatic oil; the flowers are used to make concrete. The leaves are used medicinally to treat high blood pressure. The seeds are pressed for oil, with an oil content of 42.5%.
Southern magnolia is an evergreen large tree, 2-3 m tall. Bark light brown or gray, splitting in thin scales. Branches and buds have rust-colored fine hairs. Stipules separate from the petiole; leaves leathery, blades elliptic or obovate-oblong, with brown short soft hairs on the underside; 10-20 cm long, 4-10 cm wide, apex obtuse or acuminate, base cuneate, upper surface dark green and glossy, lower surface pale green with rust-colored fine hairs, lateral veins 8-9 pairs. Flowers fragrant, white, cup-shaped, 15-20 cm in diameter, opening in the shape of a lotus flower; pedicel sturdy with downy hairs; tepals 9-12, obovate, thickly fleshy; stamens numerous, about 2 cm long, filaments flat, purple, anthers introrse, connective extended into a short pointed tip; gynoecium elliptic, densely covered with long hairs, carpels ovate, 1-1.5 cm long, style curled. Aggregate fruit cylindrical-oblong or ovate, densely covered with brown or gray-yellow hairs, fruit apex with a long beak. Seeds elliptic or ovate.
Southern magnolia flowering period May-June, fruiting period September-October.
Ecological habits of southern magnolia
Southern magnolia grows best in light and is slightly shade-tolerant when young. It likes a warm, humid climate and has a certain cold resistance. It is suitable for growing in high, dry, fertile, moist, well-drained slightly acidic or neutral soil; when planted in alkaline soil it tends to become chlorotic, and it dislikes waterlogging and poor drainage. It has strong resistance to smoke, dust and sulfur dioxide gas, and few pests and diseases. Its root system is deep and wide, and it has strong wind resistance. In particular, seed-grown seedlings have straight trunks, a majestic tree form and strong adaptability.
Southern magnolia likes a warm and humid climate and is widely cultivated from the Yangtze River basin to the Pearl River basin in China, but it is also relatively cold-resistant; south of Beijing and Tianjin, it can be planted in the open as long as irrigation conditions are met. It is a light-loving tree species, relatively shade-tolerant at the seedling stage; it grows best in moist, well-drained acidic and neutral soil, and can also grow in mildly saline-alkaline soil; it is a fertilizer-loving tree species, and 1 application of organic fertilizer should be applied before flowering in spring; in autumn the soil can be deeply turned and decomposed barnyard manure applied; it has very few pests and diseases and strong wind resistance.
Southern magnolia likes a warm, humid climate and requires deep, fertile, well-drained acidic soil. It likes sunlight, but young trees are quite shade-tolerant and are not tolerant of strong sunlight or west-facing sun, otherwise the trunk is easily scorched. It has a relatively strong resistance to smoke, dust and toxic gases. It has few pests and diseases, grows at a medium rate, and after 3 years growth gradually accelerates, with more than 0.5 m of growth per year. The southern magnolia has a majestic and magnificent tree form, thick glossy leaves, and large fragrant flowers, and is an important ornamental tree species for urban greening. It has strong resistance to smoke, dust and sulfur dioxide gas, and few pests and diseases. Its root system is deep and wide, and it has strong wind resistance.
Cultivation techniques of southern magnolia: cultivation management
In the south it is mostly planted in the ground, while in the north it is mostly potted. Potted plants are moved into the greenhouse before "Frost's Descent"; pay attention to ventilation and light, and do not water too much; the potting soil should remain at 40-60% moisture. Keep the room temperature above 3°C for overwintering. Spray water on the leaves once every half month to wash off dust. After "Qingming," move them outside and place them in a sunny, wind-sheltered spot; apply fertilizer water 1-2 times per week, water once a day in summer, and apply fertilizer water twice a week. In hot weather, pay attention to sprinkling water on the leaves to lower the temperature. Repot once every 2-3 years. For ground-planted plants, refer to potted water and fertilizer management, and pay attention to loosening the soil and weeding, and protecting against cold in winter.
Seedling cultivation
1. Preparation of culture soil
The culture soil should use loose, fertile organic soil. You can choose 85% mountain topsoil, forest soil or nursery soil and 13% fully decomposed compost, plus 2% superphosphate, mixed and prepared. You can also use half yellow earth and half fired soil, plus 2% superphosphate. Soil that has grown vegetables and highly clayey soil should not be used.
2. Sowing
Level the land inside the greenhouse and make a seedbed. Make container bags from newspaper, with a specification of 15 cm high, 10 cm in diameter, bottomless, cylindrical. Place the cylinders neatly on the seedbed, arranged in a width of 0.8 to 1 m, with length depending on the site, leaving a 30 cm walkway in the middle. Fill the bags with 70-80% culture soil, place one germinated seed, cover with 1 cm of culture soil, cover with rice straw to retain moisture, and water thoroughly with a watering can. Control the temperature inside the greenhouse at 10°C to 25°C, and remove the rice straw promptly when the seedlings emerge.
3. Watering
When fertilizing, be sure to spray water, and the water droplets should not be too large, to prevent the culture soil from splashing out of the containers. The humidity in the greenhouse is high, so watering must be careful and not excessive; water only when dry. When the two true leaves of the seedlings have fully unfolded, spray once with 50% carbendazim wettable powder 600-fold solution. At this time, withhold water appropriately, and water again after the container wall dries, to encourage more lateral roots. One week later, begin topdressing with dilute fertilizer, and thereafter spray carbendazim wettable powder 600-fold solution once every half month and apply dilute fertilizer once, until they leave the greenhouse.
Field planting
1. Site selection: choose a location with convenient transportation and flat terrain for the nursery. The nursery soil should preferably be loam, and the soil layer should be deep, to facilitate lifting seedlings with soil balls. Sandy soil gives good seedling growth, but it is inconvenient for lifting seedlings with soil balls. Soil that is too clayey and poorly aerated and drained is unfavorable for seedling growth.
2. Bed making: combined with land preparation, apply 50-80 kg of potassium dihydrogen phosphate per mu. The seedbed is 1.2 m wide, 15-20 cm higher than the walkway, with unlimited length. The walkway is 30 cm wide.
Southern magnolia cultivation methods and key maintenance points
The seeds contain oil and must not lose water; they dislike sun exposure and excessive dryness, and should be stored by stratification with moist sand. Choose a ventilated, cool room, stack a layer of moist sand and a layer of seeds; the sand should be suitable when squeezed into a ball in the hand and falling apart when released. The stack height should not exceed 50 cm. Check frequently to prevent the seeds from becoming moldy and deteriorating, and replenish water appropriately after some time.
In mid-February, move the southern magnolia seeds and moist sand into the greenhouse, and control the temperature with a layer of film plus a small arched shed and straw curtains, not lower than 15°C at night and not higher than 25°C during the day. When the temperature is too high, ventilate and turn the seeds. When the seeds crack and show white, they can be sown.
The natural tree shape of this species is elliptic-ovate and very beautiful. It has low branching ability and poor sprouting ability, and is not tolerant of pruning, so pruning should be done cautiously; never cut off branches arbitrarily, to avoid affecting the tree shape. In the young tree stage, to make the central leader grow well, pay attention to removing lateral buds around the main branch.
Seedling purchasing channels
Because there have been relatively few southern magnolia seedlings on the market in the past two years, the price of southern magnolia seedlings has greatly increased, and buying southern magnolia seedlings has become the biggest worry for many flower growers. Southern magnolia seedling purchasing mainly includes online purchasing and on-site purchasing. For online purchasing, you need to choose a long-standing reputable company to be more at ease and to buy reliable seedlings. I know one online company called Wanguo Nursery and Horticulture Farm that is relatively formal; for other online seedling purchases, it is better to investigate. For on-site seedling purchasing, it is best to go to the northern Jiangsu area, because being farther north, northern seedlings can better adapt to the climate environment. Southern magnolia grows slowly, so only by choosing good seedlings can you sell them for a good price. Therefore, when buying seedlings for planting, you should buy good seedlings and not just seek a temporary cheap price.
Transplanting techniques for southern magnolia: maintenance and management of newly planted southern magnolia trees
The southern magnolia has a majestic and magnificent tree form, thick glossy leaves, and large fragrant flowers, and is an important ornamental tree species for urban greening. The southern magnolia has a well-developed root system and is most suitable for deep, well-drained acidic sandy loam. Planting holes should be large and deep, and regardless of seedling size, they should be transplanted with soil balls. During transplanting, the leaves should be thinned to ensure survival. Otherwise, heavy transpiration from the leaves may cause the whole plant to verge on death, and finally it may have to be heavily pruned, ruining the tree shape. Apply fertilizer 3-4 times a year to promote the growth and flowering of southern magnolia.
Water management: settling water
Southern magnolia roots are fleshy roots and lose water very easily, so during digging, transport and planting, speed and timeliness are required to avoid excessive water loss affecting survival. After transplanting southern magnolia, the first settling water should be timely and should be watered sufficiently and thoroughly, so that the root system can fully contact the soil and survival is favored. For the first watering, be sure to make a large basin and water thoroughly; 10 g of dissolved rooting agent can be watered into the tree hole with the water to promote new roots. After 7 to 10 days, water a second time. After about 20 days, water a third time.
Misting
After transplanting, to improve the survival rate and reduce transpiration, the tree body should be frequently replenished with water. According to different temperature and humidity conditions, spray water on the crown and tree body in time. Within half a month after transplanting, insist on misting the tree body 3-4 times a day, but the ground must not accumulate water, to ensure the tree body's water needs; afterward, reduce the frequency of misting as appropriate according to weather conditions.
Drainage
If there is excessive rainfall after transplanting, drainage channels need to be opened to prevent water accumulation at the roots, which can cause root rot and death of the southern magnolia.
Trunk protection
The trunk and branches of this tree are most easily scorched by strong sunlight, causing the bark to split and decay, resulting in serious damage. For newly planted southern magnolia, after transplanting carry out whitewashing, and also wrap the trunk with straw rope for about 2 m to reduce water evaporation; during drought, spray water on the straw rope to create a small humid environment.
Staking
After planting, stakes should be set up to fix the trunk and prevent swaying. If no stakes are set up, the trunk will sway, preventing the root system from closely contacting the soil and creating gaps, making the roots very prone to water loss, affecting survival, and also damaging the root system, directly affecting the transplanting effect. Therefore, stakes should be set up immediately after planting; this is a very important task that must not be ignored. Staking method: generally driving stakes cannot provide a fixing effect, so choose 3 m to 4 m long bamboo poles or tripods made of other materials with good stability for fixation. The fixing points should be padded with soft material to prevent damage to the bark.
Pruning branches and removing leaves
Because its branches and leaves are luxuriant, the leaves are large, and newly planted seedlings have a high transpiration rate, they are prone to wind damage, so the leaves should be thinned immediately during transplanting. If the soil ball is loose or too small and the root system is relatively severely damaged, some small branches or superfluous branches should also be thinned. By pruning branches and removing leaves, water evaporation can be reduced and the water supply pressure on the injured root system eased. Pruning should remove inner branches, overlapping branches and pest- or disease-damaged branches, and strive to maintain the integrity of the tree shape; leaf removal should preferably remove 1/3 of the leaves on the branches; too much will cause difficulty for the root system in absorbing water.
Cold protection
Newly transplanted southern magnolia must be protected against cold for 3 to 4 years. After winter begins, build a sturdy windbreak, leaving an opening on the south side facing the sun to receive sunlight. In addition, cover the ground with a layer of rice straw to prevent the roots from freezing.
Maintenance and management of southern magnolia trees after survival
1. Fertilizer and water management: watering
Water timely according to local environmental conditions.
Fertilizing: during the growth period or after flowers fade, apply dilute manure water 1-2 times to promote flower bud differentiation. Only in this way can the leaves be green and the flowers abundant, with larger and more fragrant flowers the next year, and the disease resistance of the plant enhanced.
2. Hoeing and weeding
This is an important part of healthy plant growth; loosen the soil promptly after watering to facilitate the balance of soil water, fertilizer, air and heat.
3. Pruning
At any time, cut off dead branches, diseased branches or overly dense branches, as well as sprouting branches on the rootstock, to concentrate nutrients for preserving buds and flowers. Pruning can also make the plant shape more attractive. After flowering, promptly remove faded buds to reduce the consumption of tree nutrients.
Survival rate
Southern magnolia is an evergreen tree of the Magnoliaceae family, with thick leathery leaves and white, fragrant flowers, and it likes moist, fertile soil. It is favored by people for its upright trunk form, glossy dark green leaves and large pure white flowers. In landscaping construction, large trees often need to be transplanted, but at present transplanting large southern magnolia trees is somewhat difficult, and the survival rate is often not ideal. Based on many years of southern magnolia planting experience, Hunan Hongbo Flower and Tree Base now introduces its technical key points as follows:
1. Season
Transplanting large southern magnolia trees is best in early spring, but the plum rain season is the best. About half a month after Spring Festival, southern magnolia is still in dormancy, sap flow is slow, and metabolism is slow, so it can be transplanted at this time. After transplanting, when the temperature rises in late spring, the root system first begins to sprout, grow and repair, and with careful management, it will basically not affect the growth of the southern magnolia that year. In addition, during the plum rain season rainfall is heavy and air humidity is high, so the survival rate of southern magnolia transplanted at this time is very high. However, when transplanting, note that it is best to choose cloudy or overcast weather, and try to avoid rainstorms or high-temperature weather.
2. Soil ball
The size of the soil ball is the key to the success or failure of southern magnolia transplanting. In East China, the soil ball diameter is generally 8 to 10 times the tree's diameter at breast height, which can ensure that the root system is less damaged and the tree vigor is easy to restore. If the soil ball is too small, the root system is severely damaged, causing difficulty in water absorption and affecting tree survival. The soil ball should be dug into a spindle shape, not a plate shape or conical shape, and the soil ball should be tightly bound with straw rope to prevent it from loosening during transport.
3. Water
Southern magnolia roots are fleshy roots and lose water very easily, so after digging, transporting and planting large southern magnolia trees, the trunk should be wrapped with straw rope for about 1.5 m-2 m to reduce water evaporation; during drought, water can be sprayed on the straw rope to maintain a humid environment [9], to avoid excessive water loss affecting survival. After transplanting southern magnolia, the first settling water should be timely and should be watered sufficiently and thoroughly, so that the root system can fully contact the soil and survival of the large tree is favored. If there is excessive rainfall after transplanting, drainage channels also need to be opened to prevent water accumulation at the roots, which can cause root rot and death of the southern magnolia.
4. Pruning
Leaf removal: by pruning branches and removing leaves, water evaporation can be reduced and the water supply pressure on the injured root system eased. Pruning should remove inner branches, overlapping branches and pest- or disease-damaged branches, and strive to maintain the integrity of the tree shape; leaf removal should preferably remove 1/3 of the leaves on the branches; otherwise it will reduce transpiration pull and cause difficulty for the root system in absorbing water.
5. Application of the efficient rooting agent "Sushenggen" in transplanting large southern magnolia trees
"Sushenggen" is a new, non-toxic, efficient, broad-spectrum plant rooting agent introduced from the United Kingdom by experts from the Zhengzhou Ping'an Landscape Plant Protection Technology Research Institute. It contains 90% sodium salt raw powder and more than 30 active rooting ingredients. Each 20 g bag can be diluted with 2 tons of water for root irrigation of transplanted seedlings; when diluted with 200 kg of water, it can be sprayed on the leaves of transplanted seedlings and can likewise achieve excellent root-promoting effects. Its specific function is the dual function of supplementing the exogenous auxin needed for plant rooting and promoting the synthesis of endogenous auxin, and it can cause the meristematic tissue cells of adventitious root primordia to differentiate and produce clustered explosive rooting. In the process of seedling transplanting, it promotes the recovery of injured root systems and is the preferred plant growth regulator for improving the effectiveness of seedling raising and transplanting in arid areas. "Sushenggen" has now launched five varieties: general-purpose Sushenggen; orchid and osmanthus special Sushenggen; pine, cypress and fir special Sushenggen; flowering shrub special Sushenggen; and walnut special Sushenggen. These five types can all be dissolved directly in water without alcohol or soaking aids, can be stored at room temperature, and are more broad-spectrum.
(1) About 25 days before transplanting southern magnolia, use orchid and osmanthus special Sushenggen at 2 g diluted with 20 kg of water to spray the leaves of the tree to be transplanted, which can induce a large number of new secondary roots and favor survival after transplanting.
(2) Or after transplanting southern magnolia, use orchid and osmanthus special Sushenggen at 2 g diluted with 40 kg of water for root irrigation of the transplanted tree; in 25-30 days a large number of new secondary roots can be induced.
(3) Or after transplanting southern magnolia, use orchid and osmanthus special Sushenggen at 2 g diluted with 20 kg of water to spray the leaves of the transplanted southern magnolia; the effect is the same as above.
If any one of the above measures can be adopted, the transplanting survival rate can be effectively increased.
Issues to note during use
(1) Do not use metal containers to prepare the Sushenggen stock solution; prepare it and use it immediately, and the prepared solution must not be left for more than 2 hours.
(2) Orchid and osmanthus special Sushenggen can be used for root irrigation treatment of transplanted southern magnolia and can also be sprayed on the leaves.
(3) Sushenggen easily absorbs moisture and becomes paste-like, which does not affect the effect.
6. Other issues to note: after transplanting large southern magnolia trees, wrap the trunk with straw rope for about 2 m to reduce water evaporation; during drought, spray water on the straw rope to create a small humid environment. After planting, set up support wood to fix the trunk to prevent swaying and damage to the root system. Generally driving stakes cannot provide a fixing effect; you can choose 3 m to 4 m long moso bamboo or tripods made of other materials for fixation. If the weather is dry after transplanting, spray water on the crown or set up high-altitude misting to lower leaf temperature.
Propagation Methods of the Southern Magnolia
The southern magnolia is commonly propagated by sowing and grafting.
① Sowing: Because the seeds easily lose their viability, they should be sown immediately after being collected in October. If sowing in spring, they should be stored in stratified moist sand to prevent the oil in the seeds from volatilizing and affecting the
germination rate. Sow in March in spring; seedlings emerge in May. The seedlings grow slowly, so sowing should be done somewhat densely. After sowing, provide shade and keep moist, and protect against cold in winter. They can be transplanted the following year to grow larger saplings.
② Grafting: Yulan magnolia, purple magnolia, and others can be used as rootstock. Do cleft grafting or root grafting in spring, and cut grafting in autumn; the survival rate is very high. Approach grafting can also be done in spring.
Grafting propagation
For grafting the southern magnolia, magnolia (Mulan, Xinyi) is commonly used as the rootstock. The magnolia rootstock is propagated by cuttings or sowing, and can be used as rootstock once its trunk diameter reaches about 0.5 cm. From March to April, take vigorous branches of the southern magnolia with terminal buds as scions; the scions are 5 to 7 cm long, have 1 to 2 axillary buds, and the leaves are removed. Use the cleft grafting method to graft at 3 to 5 cm above the ground on the rootstock. After grafting, mound soil around it, leaving the top of the scion slightly exposed, to encourage the wound to heal. The side grafting method can also be used, with the graft union about 5 to 10 cm above the ground. In some areas, Tianmu magnolia, Tutou magnolia, and others are used as rootstock; the grafted saplings grow faster and the results are even better. Transplanting should be done in spring, and to improve the survival rate, the saplings must be moved with a soil ball.
Sowing propagation
1. Harvesting and seed storage: The fruit of the southern magnolia ripens from September to October. When ripe, the fruit splits open, revealing the red aril. It should be harvested promptly when the fruit is slightly split and the aril has just turned red-yellow. After the fruit is harvested, place it in a shady spot to air-dry for 5 to 6 days to encourage splitting, then take out the seeds with the aril, soak them in clean water for 1 to 2 days, rub off the aril, and remove the shriveled seeds; the aril can also be removed by rubbing with plant ash. Mix the clean white seeds with kerosene or zinc phosphide to prevent damage by rodents.
2. Sowing: There are two sowing periods: sowing immediately after harvest (autumn sowing) and spring sowing. The seedbed should be a fertile, loose sandy soil, deeply plowed, with weeds and insects eliminated and sufficient base fertilizer applied. After the bed surface is leveled, open sowing furrows 5 cm deep, 5 cm wide, and about 20 cm apart, and sow in rows, distributing the seeds evenly in the furrows, then cover with soil and press lightly.
3. Management of sown seedlings: The seedlings can be transplanted when they have 2 to 3 true leaves. Because growth is slow during the seedling stage, weeds must be removed and the soil loosened frequently. From May to July, apply topdressing 3 times, using fully rotted, dilute manure water.
Disease and Pest Control of the Southern Magnolia
The southern magnolia has a well-developed root system and is best suited to deep, well-drained acidic sandy loam. The planting hole should be large and deep, and regardless of the size of the sapling, it should be transplanted with a soil ball. When transplanting, the leaves should be thinned to ensure survival. Otherwise, heavy transpiration from the leaves can cause the whole plant to be on the verge of dying, and in the end it has to be heavily pruned, ruining the tree's shape. Apply fertilizer 3 to 4 times a year to promote the growth and flowering of the southern magnolia. The fertilization timing is basically the same as for the yulan magnolia. Watering should be done to keep the soil moist, and mist the leaves once every 15 days to keep them clean and dust-free. Increase watering frequency in the dry season, and ensure good drainage during the plum rain season.
When planting the southern magnolia in the open ground, trees and shrubs should be planted around it to provide lateral shade, avoiding sunscald on the trunk that would cause poor growth. The southern magnolia branches in a regular pattern and is mostly allowed to grow freely without shaping or pruning. If it is a grafted sapling, rootstock shoots often sprout at the base of the trunk and should be cut off promptly. In early summer, the trunk of the southern magnolia can be protected by whitewashing and wrapping with straw rope to prevent sunscald. For potted southern magnolia, the growing medium is a mix of 3 parts leaf mold, 2 parts sand, and some organic fertilizer. During the growing season, apply diluted liquid fertilizer once a week; in summer, water once a day and apply fertilizer water twice a week; during hot periods, mist the leaves frequently to lower the temperature. Move it into a greenhouse before Frost's Descent; a room temperature of 3°C is enough for it to overwinter. Pay attention to ventilation and light, water less, keep the soil moist, and mist the leaves once every 15 days to wash off dust. After Qingming Festival, it can be moved out of the greenhouse and placed in a sunny, sheltered spot.
Southern Magnolia Leaf Spot
Symptoms:
It occurs on the leaves of the southern magnolia. In the early stage, the spots are brown round spots, which expand into circular spots that are grayish-white inside with red-brown outer edges, and the area around the spots becomes chlorotic; in the later stage, the spots dry up and bear black granular bodies.
Occurrence pattern:
The pathogen overwinters on the diseased residues of the host. The disease is severe in the rainy season and prone to occurrence under high temperature and dry conditions.
Control methods:
① Remove diseased residues promptly.
② Spray fungicides such as carbendazim and thiophanate-methyl regularly.
Cottony cushion scale relative (Drosicha corpulenta)
Occurrence pattern: Two generations occur per year, parasitizing bud axils, tender shoots, leaves, and branches. July and September are the peak outbreak periods.
Optimal control timing: Early to mid-April and mid to late August.
Control agents: Huabao, imidacloprid, and others.
Note: The southern magnolia is also harmed by other scale insects such as the cottony cushion scale, tortoise wax scale, horned wax scale, and watery hard scale; control agents can refer to those for Drosicha corpulenta.
Taiwan subterranean termite (Coptotermes formosanus)
Occurrence pattern:
It is amphibious in soil and wood, with large and relatively concentrated colonies, and the nest is built in hidden places; worker ants forage everywhere through ant trails, and the colony's dispersal and reproduction is completed by long-winged reproductive ants. The swarming flight of reproductive ants has relatively strict requirements for temperature, humidity, air pressure, rainfall, and other conditions. May and late June to August are the peak damage periods.
Control methods:
① Place baits such as "Yike" in the ant trails.
② Avoid mechanical damage to the trees.
③ Strengthen maintenance and management, and fill tree holes promptly.
The common pests and diseases of the southern magnolia include anthracnose, white alga disease, dry rot, and scale insects. So how should we prevent and treat them?
1. Anthracnose
This disease mostly starts from the leaf tip or leaf margin. In the early stage, it appears as water-soaked irregular spots, light coffee-colored, with small black dots on them. In the later stage, the spots gradually spread, and the large ones can reach about 1/4 of the leaf area. It mainly harms mature or old leaves, and diseased leaves fall off easily.
Control method: Spray with a 500-fold dilution of 50% carbendazim wettable powder.
2. White alga disease
In the early stage of the disease, small grayish-white to yellow-brown round spots appear on the leaf surface, then gradually expand into radial or fibrous textures, with the surface appearing brown and velvety-swansdown-like and slightly raised, and in the later stage becoming smooth grayish-white spots.
Control method: Pay attention to ventilation and light transmission, and drain promptly after rain; after infection, spray with a 500-fold dilution of 50% thiophanate-methyl for control.
3. Dry rot
This disease mostly occurs on 1- to 2-year-old branches and trunks. In the early stage, the cortex becomes soft and easy to fall off, and the subcutaneous tissue turns red-brown and tends to crack. As the disease progresses, the surface gradually dries and turns gray, the subcutaneous tissue turns black-brown, and small black dots grow.
Control method: Pay attention to protecting the wounds from pruning branches, and apply a protective agent promptly; after infection, apply an 800-fold dilution of 70% thiophanate-methyl for control.
4. Scale insects
The southern magnolia is prone to harm by scale insects, among which the shield scale is relatively severe, sometimes forming a dense layer on the branches and trunks. In addition to sucking tree sap, scale insects can also cause sooty mold, causing poor tree growth. Control method: During the hatching period of scale insects, when the nymphs have not yet secreted wax, spray with pyrethroid insecticides.
Distribution Range of the Southern Magnolia
The southern magnolia is native to South America and is distributed in North America and in China's Yangtze River basin and south of it; in northern places such as Beijing and Lanzhou, it has been introduced and cultivated artificially.
The southern magnolia is also relatively common in Shanghai, Nanjing, and Hangzhou in the Yangtze River basin.
Uses and Purposes of the Southern Magnolia: Ornamental Value
The crown of the southern magnolia is ovate-conical, and the twigs and buds are covered with rusty-colored hairs; the tree is majestic and magnificent. The southern magnolia has a beautiful tree shape and large, fragrant flowers. It is an excellent environmentally friendly courtyard tree and is suitable for factory and mine greening, and it is closely related to human survival.
Greening role
The southern magnolia is an evergreen tree of the genus Magnolia in the family Magnoliaceae. Its crown is rounded and its form is beautiful, and it has a certain cold tolerance, making it a very good greening tree species.
Medicinal or Dietary Therapeutic Value of the Southern Magnolia
The medical information and health dietary therapy information on Hugarden Network is for reference only and cannot be used as a basis for diagnosis or medical treatment. Any health problem should be consulted with professional medical staff, and any disease treatment should follow a doctor's advice.
Ultimate flower-protecting task: Love yourself, start from reality, and strictly follow a doctor's advice. For illness, do not be careless, do not delay, do not give up hope; face it bravely, warm the silent world with love, and care for the flower field in your heart with your heart.
Character of the Traditional Chinese Medicine
Character identification: The flower buds are conical, 3.5-7 cm long, 1.5-3 cm in diameter at the base, light purple or purple-brown (there are also light yellow varieties, such as the first image in this entry). There are 9-12 petals, broadly obovate, with relatively thick white texture, and the inner layer is lotus-petal-shaped. Stamens are numerous, the filaments are wide and relatively long, and the anthers are yellow-brown and linear. Carpels are numerous, densely covered with long hairs. The pedicel is 0.5-2 cm long, with distinct nodes. Texture hard, easily broken. Aromatic odor, bland taste.
Chemical Composition
The leaves contain partheflolide, peroxycostunolide, peroxyparthenolide, magnograndiolide, costunolide diepoxide, melanpomagnolide A and B, anonaine, and liriodenine.
The xylem contains magnoflorine, candicine, magnolidin, magnolenin, magnosidin, syringin, acanthoside B, magnolenin C, and mono-O-methylhonokiol. The root bark contains magnolialide. The seeds contain magnolol, honokiol, and 3,5-diallyl-2-hydroxy-4-methoxybiphenyl (that is, mono-O-methylhonokiol); the seed oil mainly contains hexadecanoic acid, octadecanoic acid, and β-sitosterol.
In addition, the southern magnolia also contains 4,10-dioxo-7-cyclocolorenone.
Pharmacological Effects
1. The flower buds have a slow hypotensive effect on anesthetized or non-anesthetized animals.
After intravenous injection of 2 mg/kg of magnoflorine contained in the bark, anesthetized cats immediately show a hypotensive effect, with blood pressure decreasing by 50%-60%, lasting 90-120 min. Intravenous injection of 6 mg/kg also has a significant hypotensive effect on dogs with renal hypertension.
2. Muscle relaxation and ganglion-blocking effects
The magnoflorine contained in the bark has a curare-like effect and a ganglion-blocking effect, and this effect can be antagonized by anticholinesterase drugs such as neostigmine bromide.
3. Other effects
The phenolic components in this product also have antibacterial and antifungal effects. The magnolol contained in the bark also has an anti-ulcer effect; 5-200 mg/kg has a significant preventive effect on water-immersion stress ulcers in rats.
Nature and Flavor
Pungent in flavor, warm in nature.
Meridians entered: lung, stomach, and liver meridians.
Functions and indications: Dispel wind and scatter cold, promote qi and relieve pain; mainly for externally contracted wind-cold, headache and nasal congestion, distending pain in the epigastrium and abdomen, vomiting and diarrhea, hypertension, and migraine.
Usage and dosage: Oral administration: decocted in water, flowers 3-10 g; bark 6-12 g. External use: appropriate amount, pounded and applied.
Landscape Uses of the Southern Magnolia
The southern magnolia has thick, glossy leaves and large, fragrant flowers, and its tree posture is majestic and magnificent, making it one of the precious tree species. After its aggregate fruit matures, the follicles split open to reveal bright red seeds, which is also quite beautiful. It is best planted singly on broad, open lawns or arranged into flowering tree clusters. Because its crown is huge and the flowers bloom at the branch tips, it is not suitable for placement in small courtyards, otherwise its ornamental effect cannot be fully brought out. The flowers are large and fragrant, so it can be planted as a solitary specimen, in opposite pairs, in clusters, or in groups, and can also be used as a street tree.
The southern magnolia has an elegant tree posture, stays evergreen through the four seasons, and has few pests and diseases, so it is an excellent street tree species. It can not only provide necessary shade for pedestrians in summer, but also beautifully enhance the street scene. However, when planting, try to choose somewhat larger saplings; a trunk diameter of 3-6 cm and a height of about 2.8 m is more suitable. If too small, it is easily damaged; if too large, the transplant survival rate is low. When greening roads, planting the southern magnolia together with color-leafed tree species can produce a significant color contrast, making the street scene's colors more vivid and rich. In green belt applications, interplanting the southern magnolia with red-leaf plum and combining it with osmanthus, pittosporum balls, and others not only gives a sense of layering in space, but also brings great variation in color, breaking the monotony of the sequential space and producing a harmonious sense of rhythm, achieving very good results.
The southern magnolia can be used in courtyards, parks, amusement parks, and cemeteries. Large trees can be planted singly on lawns or in rows on both sides of pathways; medium and small ones can be planted in groups on flower terraces. The southern magnolia has strong resistance to sulfur dioxide, chlorine gas, and others, and can be planted in areas with severe air pollution. It is especially harmonious with Western-style architecture, so it is more suitable for Western-style courtyards.
Cultural Background of the Southern Magnolia: Poetry
The emerald branches, full of strength, draw the wind long, piercing the silver blossoms with jade-snow fragrance.
A kindred spirit knows the goodness of one's heart, and through the curtain gently loosens the white rainbow garment.
These are verses describing the southern magnolia from Shen Tong's "Ode to Yulan" in the Qing Dynasty, and it is now even crowned by the world with the reputation of "the fragrant lotus of the land."
Cultivation History
The southern magnolia tree is native to the Americas and was an extremely precious tree species during the Qing Dynasty. However, in Hefei, an inland city, there are many tall southern magnolia trees, all over a hundred years old. So why were there so many precious southern magnolias more than a hundred years ago?
This actually has to do with Li Hongzhang. During the Sino-French War, the soldiers of the Huai Army bravely took the lead and defeated the enemy. The Huai Army general Liu Mingchuan led troops in bloody battles in Taiwan, China, repelling France, which was then known as a world-class power; the famous general Wang Xiaoqi cooperated with Feng Zicai to win the great victory at Zhennan Pass, while another Huai Army general, Wu Jie, while guarding Zhenhai, personally fired a cannon and wounded the invading army's leader Courbet. Courbet later died at Penghu from anger and his wounds.
When Cixi heard that a victory had been won, she was overjoyed, and after the war she rewarded merit and planned to bestow high offices and gold and silver jewelry on the Huai Army generals. Li Hongzhang thought to himself, we Hefei people now hold too many high offices; as the saying goes, a tall tree catches the wind, and we have long incurred people's resentment. To seek more rewards would be like wearing a straw raincoat to put out a fire - bringing disaster upon oneself. So he quickly stepped forward and said, "As the saying goes, it takes a thousand days to maintain an army but only a moment to use it. The Huai Army soldiers eat the Qing Dynasty's stipend rice, so it is only right for them to be loyal to the country. It is enough to provide pensions for the wounded and sacrificed soldiers; no extra rewards are needed. Besides, the treasury is empty just after the war, and rewards for the more than a hundred thousand Huai Army soldiers would not be a small sum."
Cixi said, "My dear minister's loyal heart for the country is understandable, but if there is no reward at all, it would also be unfair to the Huai Army soldiers who shed blood and sacrificed their lives."
Li Hongzhang thought about it and agreed. Although declining high office and generous pay could win a good reputation for the Huai Army, the soldiers had fought bloody battles, and without rewards morale would suffer, and he would have no way to explain it to the Huai Army generals back home. Ah, he had it. Li Hongzhang thought of the American envoy he had just met and suddenly had an idea. The American envoy had brought southern magnolia trees to China. The Huai Army generals had all started from fortified villages, and in Hefei there were fortified villages large and small. If southern magnolia trees bestowed by the Empress Dowager were planted in those villages, how glorious that would be!
Having made up his mind, Li Hongzhang said, "I have heard that the American envoy has just presented 108 southern magnolia trees as tribute. However high an office our Huai Army soldiers hold, they are still loyal to the country, and the rank of office means the same to them; gold and silver jewelry is gone once spent. It would be better for the Empress Dowager to bestow southern magnolias on the Huai Army. The Jianghuai region where our Huai Army is located is suitable for the growth of southern magnolias, and they will surely grow more and more luxuriantly. Seeing these southern magnolias, one can think of the court's grace toward us ministers, and it would not be in vain for our loyal hearts in serving the country."
This made Cixi even happier; she could settle the matter without spending a single coin. "It is rare for my dear minister to understand the country's situation. Very well, approved. Attendants, bestow all the southern magnolia trees on the Huai Army."
Thus, these 108 southern magnolia trees were transported over a thousand miles back to the Huai Army's hometown of Hefei. Each general who had rendered merit received a southern magnolia to plant in his own courtyard. These southern magnolia trees were majestic and magnificent, with thick, bright leaves, and everyone who saw them praised them, saying the trees were beautiful and also praising Grand Secretary Li for knowing how to handle matters.
After Li Hongzhang died, two southern magnolias and two pomegranates were planted in the Li Hongzhang Memorial Hall. What a coincidence. A hundred years later, the city tree of Hefei happened to be the southern magnolia, and the city flower was the pomegranate.
In addition, there is a southern magnolia in Liu Laowei, the former residence of Liu Mingchuan, the first governor of Taiwan, China, said to have been planted by Liu Mingchuan himself. The tree is 160 years old and 18 m tall.
At Juxing Central School (Zhang Laowei) in Mingchuan Township, Feixi County, a southern magnolia has a tall, upright trunk, grows luxuriantly, and has a large number of flowers and fruits. The tree is about 160 years old and 16 m tall. Zhang Laowei was the estate of the Qing Dynasty Huai Army general Zhang Shusheng and was converted into a middle school after liberation. This tree was a precious tree bestowed on the Zhang family by Empress Dowager Cixi and had always been relatively well protected, but unfortunately in the early morning of April 4, 2006, it was struck by lightning, and the main leader was split; the remaining trunk is 7 m. In addition, Empress Dowager Cixi originally bestowed two southern magnolias on Zhang Laowei; the other was even thicker and stronger, and died in the 1960s after being blown down by a storm, which is regrettable.
At Nongxing Middle School (Zhou Laowei) in Zipeng Town, Feixi, there is a southern magnolia, 160 years old and 14 m tall. It was also a precious tree bestowed on the Zhou family by Empress Dowager Cixi and had always received exceptional courtesy; the school has built a flower terrace and put up a label to protect it.
Spiritual Symbol
The southern magnolia belongs to the family Magnoliaceae and is also called the foreign magnolia and the lotus magnolia. The southern magnolia is an evergreen tree with thick leathery leaves and large, fragrant flowers; its tree posture is majestic and magnificent, the species is relatively precious, and its lifespan is long. This tree is relatively widely planted in Kunshan. The character "Guang" implies Kunshan's broad-mindedness and spirit of embracing all rivers and learning widely from others' strengths; the character "Yu" implies the city character of "Kunshan has jade, and the jade lies in its people"; the character "Lan" implies Kunqu Opera, the "ancestor of a hundred operas," as this "orchid of the opera garden." Moreover, these three characters are basically open-mouth sounds, with beautiful tones. In addition, the southern magnolia is also the city tree of Changzhou; it was adopted by the third session of the eighth Changzhou Municipal People's Congress on March 22, 1983, designating the southern magnolia as Changzhou's city tree, symbolizing Changzhou's spirit of vigorous upward striving.
National Flower and City Flower Status of the Southern Magnolia
The southern magnolia is the city tree of Changzhou, Nantong, and Lianyungang in Jiangsu Province, Hefei in Anhui Province, and Yuyao in Zhejiang Province.
Flower Language of the Southern Magnolia
The flower language of the southern magnolia: endless life and passing down from generation to generation. Another saying for the southern magnolia's flower language: beauty, nobility, fragrance, and purity.
Southern Magnolia Images
Main Pests and Diseases Occurring on Flowers and Trees in Autumn and Their Control
After entering autumn, temperature and humidity are moderate and light is relatively good, creating favorable conditions for the breeding, reproduction, and infection of some pathogens, often causing certain flowers and trees to suffer serious harm. Several common pests and diseases and their symptoms and control methods are introduced below:
Brown spot disease
It mainly harms leaves. In the early stage of the disease, brown spots appear on the leaf surface, and as the disease continues to develop, the spots gradually expand and merge into large spots, which are mostly irregular due to the restriction of leaf veins. There is a chlorotic halo around them. The edges are red-brown and the centers grayish-white. In the later stage, small black dots (pycnidia) are produced in the center of the spots. When the disease is severe, the spots cover the entire leaf. The leaves of affected plants fall off easily, and in severe cases not a single leaf remains on the whole plant, forming a bare stem, and finally the whole plant gradually dies from the bottom upward. Among these, flowers such as rhododendron, narcissus, jasmine, clove, osmanthus, Chaenomeles speciosa, lotus, water lily, and photinia are severely harmed.
Control method: Promptly prune diseased branches and leaves and burn them in a centralized manner to reduce the pathogen. Before the disease occurs, spray 1:1:200 Bordeaux mixture once every 7-10 days, which can have a preventive effect. In the early stage of the disease, spray a 500-fold dilution of 65% zineb wettable powder or a 1000-fold dilution of thiophanate-methyl. A 200-fold dilution of 50% carbendazim can also be used to drench the roots.
Powdery mildew
Powdery mildew is mostly distributed on the upper surface of large-leaf boxwood leaves, and also grows on the underside of leaves. Individual spots are circular and white, and after the spots expand and merge with each other they become irregular. When the powdery white mycelium and spore layer on the surface are wiped off, the original diseased area appears as yellow circular spots. In severe cases, infection of new shoots can reach 100%. Sometimes diseased leaves become wrinkled, and diseased shoots become distorted, deformed, and shrunken.
Control methods: ① Properly thin branches to enhance plant ventilation; when propagating by cuttings, do not use too high a density, and so on - these are all issues to pay attention to in preventing this disease. ② Chemical control: spray a 2000-fold dilution of 20% triadimefon, or a 500-fold dilution of 50% thiophanate-methyl or 50% carbendazim, immediately when the disease first appears, repeat once after about 10 days, and spray 4-5 times.
Anthracnose
The disease mainly occurs on leaves, and can also infect petioles, tender branches, stems, and flower buds and petals. After leaves are infected, in the early stage small circular pale white water-soaked spots appear, then gradually expand, appearing gray-brown with brown edges, slightly raised. Finally, the center of the spot fades to grayish-white to white; this diseased part is extremely thin, translucent, and easily perforated. Some also start from the leaf tip and then spread into the leaf. The spots can often reach 1/3-1/2 of the entire leaf surface, and finally the leaf dies. Some continually fall off, and severely affected plants often have not a single leaf left on the whole plant. When petioles are infected, the diseased part turns brown and is slightly sunken, spreading along the leaf to the main vein, branch veins, and even the entire leaf turning brown; the spot continues to spread downward, from the petiolule to the rachis, twigs, and even the stem turning brown and dying. Under humid conditions, pale red sticky matter, which is the spore disc produced by the pathogen, often appears on the spots. Affected plants, in mild cases, have their normal growth and development affected and lose ornamental value; in severe cases, the whole plant dies. Flowers such as camellia, Chinese rose, Milan, white orchid, lily, southern magnolia, nandina, lilyturf, clivia, cactus, plum blossom, and orchid are prone to this disease.
Control methods: Strengthen cultivation management, appropriately increase the application of phosphorus and potassium fertilizers, avoid applying too much nitrogen fertilizer, do not water too much, and do not let the potting soil become too wet; at the same time, enhance ventilation and light transmission and reduce humidity. When diseased leaves and diseased petioles are found, they should be pruned and burned immediately, and dead plants should be removed promptly. When the disease occurs, spray a 500-fold dilution of 50% carbendazim wettable powder or a 1000-fold dilution of 70% thiophanate-methyl, as well as an 800-fold dilution of 75% chlorothalonil, once every 10-15 days, continuously 2-3 times, alternating the chemicals to improve the control effect.
Graphium sarpedon (blue triangle butterfly)
It mainly harms camphor trees, nanmu, laurel, white orchid, Michelia figo, Cinnamomum burmannii, avocado, citrus, and others. Newly hatched larvae first eat the eggshell, then feed on the leaf flesh on the underside of tender leaves; after the 3rd instar their food intake increases, and they can eat the leaves entirely, with 2- to 3-year-old saplings suffering the most severely. This seriously affects the growth, development, and ornamental value of the plants.
2-3 generations occur per year, overwintering as pupae suspended on the branches and leaves in the middle and lower parts of the host. They emerge successively from mid-April to late May. The larval stages of the overwintering generation and the first to third generations are respectively from mid-May to mid-June, early July to mid-August, and late August to late September. Adults emerge at night, and 1-2 days after emergence they fly among the forest, feeding on flower nectar as supplementary nutrition. After several days they seek mates, copulate, and lay eggs. They lay 1 egg at the tip of a tender leaf, occasionally 2. Each female lays 18-34 eggs. The larvae have 5 instars and molt once every 4 days; the larval body grows with each instar, and the 5th instar larva has the largest food intake, with each larva consuming 1-5 camphor leaves per day. When mature, the larva crawls to hide behind small hidden branches and leaves, fixes its tail with silk, and pupates in 2-3 days. The egg stage is generally 4-6 days, the larval stage about 20 days, and the overwintering pupal stage about 90 days. The suitable temperature for larval development is 20-28°C.
Control methods: ① During the adult egg-laying period, inspect camphor seedlings in the nursery and promptly remove the eggs laid on the tips. ② In the early stage of larval occurrence, spray a 1500-fold dilution of 40% isocarbophos emulsifiable concentrate. ③ In combination with winter management, remove overwintering pupae.
Crape myrtle felt scale (Eriococcus lagerstroemiae)
It mainly harms crape myrtle, pomegranate, mulberry, and others. Adults and nymphs pierce and suck on bud axils, leaves, and branches, secreting honeydew, causing branches and leaves to turn black and leaves to fall off, affecting growth and losing ornamental value.
2-3 generations occur per year. It overwinters as nymphs in cracks in branches and trunks. The following year they continue to feed and cause harm. In April, mature male nymphs pupate and emerge, and mate with females, dying shortly after mating. Female adults begin laying eggs in early May. First-generation nymphs hatch from late May to early June. Second-generation female adults lay large numbers of eggs in early to mid-August. From late August to early September, large numbers of nymphs hatch, and development is uneven. There is generational overlap. The insects are mostly distributed in cracks and depressions of branches and trunks. A few are distributed at the base of the underside of leaves, and on branches there are more on the shaded side than the sunny side.
Control methods: 1) Use a bamboo strip or a bristle brush to scrape off the insect-infested branches from the trunk and limbs. 2) At the end of the nymph hatching period, spray 2—3 times in succession, using 25% phosmet at 600—800 times dilution, or 40% chlorpyrifos EC at 1500—2000 times dilution. 3) In combination with pruning, remove and burn the infested branches.
Nettle caterpillars
These include the yellow nettle caterpillar, the brown-edged green nettle caterpillar, and the flannel moth caterpillar. They mainly damage Bischofia polycarpa, poplar, willow, elm, black locust, cherry blossom, red maple, crabapple, wintersweet, crape myrtle, osmanthus, and Japanese euonymus.
Two generations occur per year, with larvae overwintering in cocoons in shallow soil. Adults hide by day and fly and are active at night, and are phototactic. Adults mate and lay eggs. Eggs are often laid in clusters of several dozen on the underside of leaves, arranged in a fish-scale pattern. The egg stage lasts 5—7 days. Newly hatched larvae do not feed; after the 2nd instar they feed on the shed skin and leaf mesophyll; after the 3rd and 4th instars they eat through the leaf epidermis; after the 6th instar they feed inward from the leaf margin.
Control methods: 1) Because newly hatched nettle caterpillar larvae are gregarious and the damaged leaves show transparent dead patches, making them conspicuous, manual labor can be organized to pick off the infested leaves. 2) Use light traps to kill adults of various nettle caterpillar species and prevent egg laying. 3) Spray before the larvae reach the 3rd instar. Use 20% diflubenzuron suspension concentrate at 10000 times dilution, 50% phoxim EC at 2000—3000 times dilution, or 50% malathion EC at 1000 times dilution. 4) In combination with winter pruning, cut off pupae and cocoons and burn them in a concentrated way; in combination with measures such as loosening the soil around the tree base and fertilizing, dig out and destroy other nettle caterpillar cocoons in the soil.
Euonymus looper
It mainly damages Euonymus bungeanus, boxwood, Euonymus alatus, elm, poplar, willow, and others. Larvae gather on leaves to feed; after eating all the leaves they gnaw the bark of young branches, causing the whole plant to die.
Two—3 generations occur per year, overwintering as pupae. Adults rest by day in concealed places among branches and leaves, and emerge at night to move about, mate, and lay eggs. Eggs are laid on the underside of leaves, arranged in double rows or in blocks. Egg masses contain several dozen to over a hundred eggs. Hatching mostly occurs in the morning from 5:00—8:00; the larvae gather on the underside of leaves to cause damage, chewing leaves and the bark of young branches. Mature larvae spin silk and drop to the soil to pupate. Adults are not strong fliers and have strong phototaxis.
Control methods: 1) During the adult emergence period, use light traps to kill them. 2) Because adults are not strong fliers and gather on the upper and lower parts of host plants in the early morning and evening, use simple tools to capture and kill them. 3) During the larval damage period, spray 50% phosmet EC at 200 times dilution, 50% fenitrothion EC at 500 times dilution, or 25% carbaryl wettable powder at 300—500 times dilution, which gives good control results. 4) At the peak of adult egg laying, remove egg masses and newly hatched larvae on weeds around the root zone; plowing the soil around the root zone in winter can kill overwintering pupae.