Efficient Cultivation Techniques for Magnolia and Main Pest and Disease Control Methods
How do you grow magnolia? Magnolia is a very beautiful flower, and many people want to grow it. Below, we explain magnolia propagation methods, cultivation management and pest and disease control one by one.
1 Propagation Methods
1.1 Sowing
In late September, collect the fruit when it turns red and splits open; collecting too early prevents germination, while collecting too late makes the seeds prone to falling off. After collecting, select plump seeds from healthy, pest- and disease-free trees, spread them in a ventilated place, let the aggregate fruit gradually crack open, remove the seeds and soak them briefly in water, rub off the red fleshy membrane attached to the seed coat, and wash the oil off the seed coat with soda water, then rinse clean with clear water, spread in a ventilated place to dry, store in sand in a wooden box, and sow in the open field in mid-to-late February of the following year. The seedbed should be chosen from new land free of pests and diseases, preferably yellow soil or sandy loam with deep soil layers; set up raised beds and sow in drills. Base fertilizer can be fully decomposed human manure and urine or dried cake residue, dug into the soil before bed preparation. Never use garbage as base fertilizer, to avoid carrying diseases and bacteria. Row spacing 30cm; cover the seeds with burned soil fertilizer or yellow soil mixed with rice husk ash, at a thickness 3 times the seed diameter, and cover the top with rice straw to keep warm and retain moisture. When seedlings emerge in late April, continuously broadcast young grass mixed with crystalline trichlorfon to kill cutworms, 4 to 5 times in a row, with 2 to 3 days between each application. In early May, shade frames can be set up with 40% light transmittance. Remove them in mid-to-late September; shade materials can be China fir or bamboo blinds, and bamboo blinds that can be uncovered and covered at any time are ideal. Land should be chosen appropriately with good drainage; seedlings generally do not suffer serious pests or diseases. Apply quick-acting nitrogen fertilizer 3 to 4 times during the seedling stage; one-year-old seedlings reach 30 to 40cm in height. They can be transplanted in October of that year. If growing large seedlings, transplant in spring of the following year, appropriately cut the main root, control density, and in 3 to 5 years you can produce qualified saplings with a plant height of 3m, a diameter of 6cm, a complete crown, and sparse flower buds.
1.2 Grafting
Usually the rootstock is purple magnolia, wild magnolia seedlings, Magnolia cylindrica and other Magnolia genus plants. Cut grafting is carried out before sprouting in early spring; the scion is 4 to 5cm long with no leaves left. The key operating points are the same as for general deciduous flowering trees; the key to survival is that the scion must be sealed at the top with a bud hole left and wrapped. In daily management, pay attention to wiping off rootstock buds at any time; after survival, do not rush to remove the plastic film binding the wound. Bud grafting can be used. Cut grafting, side grafting, cleft grafting and other methods are all suitable; cleft grafting has a high survival rate and fast growth, and late autumn grafting has a high survival rate.
1.3 Layering
When seed sources are lacking and rootstocks are insufficient, layering is an important propagation method that can make full use of the mother plant. Although the procedure is troublesome, it can solve certain problems. The best mother trees are young trees or large nursery seedlings, because side branches grow vigorously, have strong vitality, and root easily. Without affecting the tree shape, select 2- to 3-year-old full, thick, upward-spreading side branches, and from mid-April to mid-May, perform ring barking 10 to 15cm above the base, with a wound 3cm long. After peeling, use a rough material such as small palm rope to scrape off the residual cambium attached to the xylem, then wrap the wound with plastic film filled with culture soil. The culture soil should generally be chosen for strong water retention, loose texture, and freedom from pests and diseases. Generally take 60% yellow mud mixed with 40% rice husk ash, or use vermiculite, expanded perlite, or fully decomposed cottonseed husks, textile waste, mushroom bed soil, etc. The moisture content should be appropriate, such that water is squeezed out when the hand grips it tightly. To make the wound heal quickly and root early, apply a 0.05% naphthalene acetic acid solution above the wound, and after it dries slightly, wrap it with culture soil. Layer in April, roots begin to form in June, and generally the layer is cut from the tree in late September. Check in July to August; if the culture soil is dry, use a syringe to inject water to replenish it. The longer it remains connected to the mother plant, the more developed the root system and the higher the survival rate. After planting for 2 to 3 years, it can bloom.
1.4 Cuttage
For cuttage propagation, northern regions should do it in June to July. Cuttings from current-year branches of young trees have the highest survival rate. Cuttage generally uses a sand bed, shaded above, with daily misting to retain moisture; roots generally form in 15 to 25 days. Soaking the base in 500mg/L naphthalene acetic acid for 6 hours can increase the rooting rate.
2 Cultivation Management
2.1 Water Management
Magnolia is neither tolerant of waterlogging nor drought. In cultivation and care, strictly follow the principle that it likes moisture but fears waterlogging. In water management, master the point that the soil must be neither too dry nor too wet. Through many years of cultivation practice, the author believes that during cultivation, the soil should be kept moist without standing water. During care, newly planted magnolia should keep the soil moist, which is also an important measure to ensure its survival rate. When watering magnolia that has entered normal management, the green-up water in early spring and the antifreeze water in early winter are indispensable, and should be watered thoroughly. In the growing season, water once a month; stop watering in the rainy season, drain promptly after rain, and prevent root rot caused by standing water. In addition, loosen the soil in time to preserve moisture. During dry periods in the rainy season, irrigate promptly as well; lack of water not only affects the plant's vegetative growth but can also cause flower buds to fall or shrink, affecting the next year's flowering.
2.2 Pruning and Training
To keep the magnolia crown beautiful, improve ventilation and light penetration, promote flower bud differentiation, and ensure large flowers the following year, pruning should be noted. Because magnolia branches have poor wound-healing ability, generally do not prune unless necessary. If the tree shape is unattractive or messy, remove pest- and disease-damaged branches, dead branches, drooping branches, water sprouts, overly dense branches and useless branches to facilitate ventilation, light penetration and a beautiful tree shape. Pruning is carried out before leaf expansion in early spring. Magnolia generally is not headed back, to avoid cutting off flower buds. If pruning is needed, apply Bordeaux mixture to larger wounds to prevent pathogen infection.
3 Pest and Disease Control
3.1 Diseases
Magnolia is a tree species with relatively strong disease resistance. Common diseases include anthracnose, chlorosis and leaf scorch.
Anthracnose mainly harms leaves, with the peak incidence during high temperature and high humidity in summer. This disease is very likely to occur when plant water and fertilizer management is inadequate, ventilation is poor, and growth declines. Control methods: strengthen water and fertilizer management, enhance tree vigor, and improve disease resistance. Remove diseased leaves promptly; in late autumn, clear fallen leaves and burn them in a centralized manner. If disease occurs, spray with 75% chlorothalonil wettable powder at 800 times dilution or 70% thiophanate-methyl at 500 times dilution, once every 10 days; 3 to 4 consecutive sprays can effectively control the disease.
Chlorosis appears as small leaves losing green color, with chlorophyll gradually decreasing, leaves turning yellow or pale yellow, while the veins remain green; as the disease progresses, the entire leaf turns yellow and then gradually whitens, plant growth gradually declines, and eventually the plant dies. Control methods: chlorosis is a physiological disease mainly caused by excessively sticky soil, pH value exceeding the standard, and insufficient iron supply. You can use 0.2% ferrous sulfate solution to drench the roots, or use 0.1% ferrous sulfate solution for leaf spraying, and should apply more farmyard manure.
Leaf scorch disease initially appears as scorched leaf edges, after which the leaves gradually shrivel and dry up. In severe cases, new leaves cannot unfold, and a large number of leaves dry up and fall off. This disease often occurs under poor site conditions, prolonged high temperature, drought, excessively strong light, soil alkalinization, or excessive flowering. Control methods: increase watering frequency and keep the soil moist; apply more organic fertilizer to enhance tree vigor and improve plant resistance; whitewash or wrap the tree trunk.
3.2 Insect Pests
The main insect pests include bagworms, Psilogramma menephron, red spider mites, longhorn beetles, and occasionally underground pests such as white grubs.
If insect pests occur, use 80% dichlorvos emulsifiable concentrate at 800 times dilution or 50% fenitrothion emulsifiable concentrate at 800 times dilution to kill bagworms; use Bt emulsion at 800 times dilution or 50% fenitrothion emulsifiable concentrate at 800 times dilution to kill Psilogramma menephron; use 40% dicofol at 800 times dilution or 5% hexythiazox at 2000 times dilution to kill red spider mites; use Green Weilei at 500 times dilution to kill longhorn beetles; use 50% phoxim emulsion at 1000 times dilution to drench roots and kill white grubs.
Farmer friends who want to grow magnolia should hurry to Huinong Network to learn the key cultivation techniques; more content on flowers, plants and saplings is all on this site, Huinong Network!
Cultivation and Pest and Disease Control of Purple Magnolia
Purple magnolia, also known as Xinyi, is native to central China. It prefers a warm, humid and sunny environment, is relatively cold-tolerant, but not drought- or saline-alkali-tolerant, fears waterlogging, and requires fertile, well-drained sandy loam.
Propagation: Commonly use division, layering and sowing propagation. Division can be carried out in spring or autumn; dig out mother plants with dense branches and plant them separately, and prune the root system and shorten the branches. For layering, choose one- to two-year-old branches; in early spring, the mound layering method or buried shoot method can be used for propagation. For sowing, collect seeds in September, store in sand in winter, sow in spring of the following year, and germination occurs 20-30 days after sowing.
Cultivation: Transplanting can be carried out in autumn or before flowering in early spring. Small seedlings can be dipped in mud slurry, while large seedlings must be transplanted with a soil ball. Fertilize once before and once after the flowering period, mainly with phosphorus and potassium fertilizer. In summer high temperatures and autumn dry seasons, maintain soil moisture. After flowering and before new shoots sprout, cut off dead branches and dense branches and shorten water sprouts.
Application: Purple magnolia is a famous early spring ornamental flowering tree. When it blooms in early spring, the tree is full of purplish-red flowers, with a graceful and modest bearing and a distinctive charm. It is suitable for planting in classical gardens in front of halls and behind courtyards, and can also be planted alone or scattered in small courtyards.
Growth Habits and Pest and Disease Control of Southern Magnolia
Since last winter and this spring, some nursery stock producers in Shucheng County have reported that southern magnolias cultivated in nurseries successively showed unexplained leaf drop and death. After careful on-site investigation, technicians from the county forest inspection bureau confirmed the occurrence of anthracnose, stem rot and other diseases.
In order to help the broad masses of forest farmers and nursery stock producers master and apply southern magnolia pest and disease control techniques, the growth habits and key pest and disease control techniques of southern magnolia are briefly introduced as follows. Southern magnolia belongs to the Magnoliaceae family, Magnolia genus, also known as lotus magnolia and bull bay. It is an evergreen tree, with leathery leaves, rust-colored tomentum on the underside, a glossy surface, and slightly revolute margins.
The flowers are large, white like lotus, and fragrant. It can grow to 30 meters. The crown is ovate-conical, and the tree form is beautiful. It is an important ornamental tree species for urban greening and is suitable for factory and mine greening.
Southern magnolia prefers light when growing, but is slightly shade-tolerant when young.
It prefers a warm and humid climate and has a certain cold resistance. It is suitable for growing in dry, fertile, moist and well-drained slightly acidic or neutral soil; planting in alkaline soil easily causes chlorosis, and it avoids standing water and poor drainage. It has relatively strong resistance to smoke, dust and sulfur dioxide gas, and has few pests and diseases. Its root system is deep and wide, and its wind resistance is strong. In particular, seed-grown seedlings have straight trunks, majestic tree vigor, and strong adaptability.
Common pests and diseases of southern magnolia include anthracnose, white alga disease, stem rot, and scale insects, four kinds in total.
1. Anthracnose.This disease mostly starts from leaf tips or leaf margins. In the initial stage, it shows water-soaked irregular lesions, pale coffee-colored, with small black dots on them. Later, the lesions gradually spread, and 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 methods:Spray with 50% carbendazim wettable powder at 500 times dilution.
2. White alga disease.In the initial 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 swan down-like and slightly raised, and later becoming grayish-white smooth lesions.
Control methods:Pay attention to ventilation and light penetration, and drain promptly after rain; after infection, spray with 50% thiophanate at 500 times dilution for control.
3. Stem rot.This disease mostly occurs on 1- to 2-year-old branches and trunks. In the initial stage, the cortex becomes soft and falls off easily, and the subcutaneous tissue is reddish-brown and prone to cracking. As the disease progresses, the epidermis gradually dries and turns gray, the subcutaneous tissue becomes dark brown, and small black dots grow.
Control methods:Pay attention to protecting pruning wounds and apply protectant promptly; after disease occurs, apply 70% thiophanate at 800 times dilution for control.
4. Scale insects.Southern magnolia is prone to damage by scale insects, among which shield scale insects are relatively serious, sometimes forming a dense layer on branches and trunks. In addition to sucking tree sap, scale insects can also cause sooty mold, causing poor tree growth.
Control methods:During the scale insect hatching period, when the nymphs have not yet secreted wax, acetamiprid and chlorpyrifos can be used in combination for control, and pyrethroid insecticides can also be added for spraying and killing.