Key Cultivation Points for Year-Round Flowering Chrysanthemums and Aphid Control Methods
Chrysanthemum is a typical short-day plant, with a natural flowering period from late autumn to early spring. But by artificially altering its growing environment, year-round flowering can be achieved. If early flowering is desired, forcing cultivation is needed, which means starting about 50 days before the target flowering date, using black cloth covers or black plastic covers for shading treatment, with 10 hours of light per day (usually starting shading at around 5 PM until exposure to light at around 7 AM the next morning; to prevent the influence of moonlight, at night only the lower parts around the shade cover are opened for ventilation), with continuous treatment until the flower buds show color.
If flowering needs to be delayed, inhibitory cultivation must be carried out. Generally, long-day treatment yields good results. Typically, late-flowering varieties are selected, and from before flower bud differentiation in late September, incandescent lamps are used for supplemental lighting until it stops in late October, using approximately one 60-watt bulb per 5 sq m or one 100-watt bulb per 16 sq m, or continuous supplemental lighting for 4-5 hours from sunset, or no supplemental lighting at sunset but giving about half an hour of light around midnight - all have good effects. However, before flowering, the night temperature needs to be maintained above 12°C for normal flower bud differentiation, so this is often done in greenhouses or plastic tunnels.
Below is an introduction to the flowering regulation methods for potted chrysanthemums for several important holidays:
(1) Flowering for New Year's Day
In early August, select robust plants from late-flowering varieties and increase lighting from sunset to midnight until flower bud differentiation begins in mid-October. Keep the room temperature at around 20°C, with a minimum not below 15°C. In this way, they will bloom by New Year's Day.
(2) Flowering for Spring Festival
In August, take softwood cuttings, pot them in mid-September, move them to cold frames or low-temperature greenhouses facing south in late November for cultivation, then move them to medium-temperature greenhouses in mid-December, maintaining 18-20°C. No shading treatment is needed, and they will bloom in early February of the following year.
(3) Flowering for "May Day"
In late November, cut off the above-ground parts of plants that have already flowered, repot them, and place them in a greenhouse for cultivation to promote new shoot germination and growth. In January of the following year, raise the room temperature to around 21°C. In this way, flower buds will form by February, and they will bloom before "May Day."
(4) Flowering for "July 1st"
In mid-April, select overwintered basal shoots and plant them directly into small pots, place them in a greenhouse for cultivation, and start shading treatment from early May, maintaining 10 hours of light per day. In this way, they will bloom before "July 1st."
(5) Flowering for National Day
Usually, short-day treatment for potted chrysanthemums starts in late July, flower buds appear after 1 month, and they can bloom by the end of September. However, if summer chrysanthemum varieties are used, it is only necessary to keep the growing temperature above 10°C without short-day treatment, and they can also bloom around National Day.
Aphid Damage to Chrysanthemums and Control
Common aphids that damage chrysanthemums include green peach aphid, chrysanthemum aphid (Macrosiphoniella sanborni), cotton aphid, black aphid, and others, mainly attaching to chrysanthemum leaves, tender shoots, and flowers (buds), sucking their sap, often causing branches and leaves to become brittle and easily broken, leaves to curl and lose green color, affecting normal growth, and often inducing sooty mold.
Home chrysanthemum growers need to check regularly. Aphids occur in all seasons, and their reproduction rate is very fast, so it is best to eliminate them promptly in the early stages of infestation. We can use 40% omethoate emulsifiable concentrate or 40% dimethoate emulsion at 1500 times dilution, or 50% dichlorvos or 50% fenitrothion at 1000 times dilution for spraying, once a week, for three to four consecutive times. Since aphids easily develop resistance, it is best to alternate several pesticides. When pest infestation is light, we can use a brush dipped in water to wash them off.
Key Cultivation Points for Chrysanthemums in Southern China and Pest and Disease Control Techniques
There are many varieties of chrysanthemums in China, and they are cultivated in many regions. Chrysanthemum can also treat dizziness, eye pain, and externally contracted wind-heat. Currently, the market price of chrysanthemum remains at around 20 yuan per kilogram. Below, let us learn about the propagation methods and pest and disease control cultivation techniques for chrysanthemums in southern China.
1 Site Selection and Land Preparation
Chrysanthemum has low requirements for planting soil, with well-drained, loose, and humus-rich sandy soil being better. Clay soil and low-lying saline-alkali land are not suitable for planting, and chrysanthemum cannot be continuously cropped. Apply 50-80 kg of NPK compound fertilizer per mu, and if conditions permit, apply 5000 kg of organic fertilizer, deep rotary tillage 2 times, then press and level.
2 Propagation and Transplanting
Mainly use division propagation. In April-May, when chrysanthemum seedlings grow to 15 cm, dig out the whole plant, divide into several plants, and transplant to the field at a spacing of 30 cm x 55 cm. After transplanting, water thoroughly, water again after half a month, and strengthen field management to reduce pest and disease occurrence. Before transplanting, spray or soak with 300 times dilution of carbendazim and 200 times dilution of imidacloprid for 2 min. When watering combined with weeding, irrigate with 150-300 g of trifluralin per mu for weed control.
3 Field Management
After chrysanthemums revive and survive, cultivate promptly to prevent soil cracking and wind damage. Thereafter, follow general management methods for loosening soil and weeding until bud appearance. Generally, in July, apply a single chemical control with paclobutrazol to prevent excessive growth. After bud appearance, water thoroughly once and supplement with trace element fertilizer to lay a good foundation for flowering. Chrysanthemum is intolerant of waterlogging, so drain promptly during rainy periods.
4 Pest and Disease Control
Common chrysanthemum diseases include root rot, downy mildew, and brown spot. They are especially severe during rainy seasons. Use 430 g/L tebuconazole at 2500 times dilution or 80% carbendazim at 800 times dilution for control. Pests are generally aphids, with red spiders occurring in some plots. Use 10% imidacloprid wettable powder at 300 times dilution, 20% acetamiprid at 500 times dilution, or 1.8% abamectin or spirodiclofen at 500 times dilution for control.
5 Harvesting and Drying
Chrysanthemums are generally harvested around Frost's Descent, with the best time being when the flower center has opened 2/3. For medicinal use, cut the whole plant, tie into bundles, stack one pile per half mu, keep ventilated and dry, and seize sunny weather to pick and dry the flowers; white and loose flowers are best. For tea use, promptly cover with a canopy to prevent frost damage, pick and dry in time, following the principle of drying as much as is picked, to avoid affecting quality.
Overall, chrysanthemum has low investment, is easy to manage, and yields relatively high returns, with planting area increasing year by year. However, to achieve high yield, high-yield management techniques for chrysanthemum are key.
Efficient Cultivation Techniques for Potted Jinduo Chrysanthemum and Pest and Disease Control
Today, the editor of Huinong Network introduces the potted cultivation techniques for an autumn chrysanthemum variety called Jinduo. If you are interested in potted cultivation techniques, you are welcome to come and learn more.
1 Jinduo
1.1 Biological Characteristics
This variety has an average plant height of 35 cm and a crown width of 45 cm; root bark is white, old roots are brown, cutting seedlings have fibrous roots, with fibrous roots 15-30 cm long; leaves are dark green, pinnately parted, with a lobe depth of 1.8 cm; leaf length 6.6 cm, width 4.6 cm, petiole length 2.2 cm; average number of flower buds per plant is 980, flower diameter 3.8 cm, with 24 bright yellow ligulate florets and 122 yellow tubular florets; the fruit is an achene, yellow-brown, nearly cylindrical, with longitudinal ribs.
Jinduo prefers a sunny, well-ventilated environment and can adapt to dry summers and cold winters. Jinduo is a typical autumn chrysanthemum variety. In Liaoning, basal shoots emerge from the soil from late March to early April. Basal shoots can be used for cutting propagation or tissue culture propagation. Seedlings are planted in May, the bud stage is September 5, and the initial flowering stage is October 15. It has continuous flowering characteristics, with an ornamental period of more than 3 months. Jinduo has a compact plant type and strong branching, requiring no pinching throughout the entire growth cycle. It is suitable for extensive management and can save a large amount of labor costs. Jinduo's basal shoots are thick, deeply positioned, numerous, and highly cold-resistant. In Liaoning, the perennial roots can safely overwinter in the open field; it has extremely strong disease resistance, and no fungicide spraying is needed throughout the entire growth cycle.
Jinduo is a strict short-day flower, and flower bud differentiation is regulated by the photoperiod and nighttime temperature. Through experimental research, the daily critical point of Jinduo has been determined to be 12.5 h. Following photoperiod principles, a complete year-round flowering cultivation technique for Jinduo has been developed, which can regulate Jinduo to bloom at any time within a year, achieving year-round production.
1.2 Suitable Planting Regions
Cultivation experiments have shown that this variety is suitable for open-field cultivation in Liaoning. Under potted conditions, precise regulation of the flowering period can be achieved through the complete year-round flowering cultivation technique, and production cultivation can be carried out nationwide.
2 Key Cultivation Technique Points
2.1 Soil
Jinduo has no strict requirements for soil and can be planted in various soils except saline-alkali land. During potted production, peat, cow manure, or crushed straw can be appropriately added to the soil to increase organic matter content and soil fertility, and reduce the weight of the pot soil, which is beneficial for the transportation of potted flower products.
2.2 Seedling Raising
In Liaoning, Jinduo generally overwinters naturally after flowering. In May of the following year, the emerging basal shoots are used for cutting propagation. From late May to early June, potted or open-field cultivation is carried out. For potting, plant 1 seedling per pot; for open-field cultivation, the spacing is 50 cm x 70 cm. To prevent seedling degeneration, seedlings should be virus-free and rejuvenated once every 3 years.
3 Field Management
3.1 Watering
Avoid flood irrigation; throughout the entire growth period, follow the principle of frequent but light watering. After planting, water thoroughly the first time, then water about once every 15 days. When watering, less is better than more, and loosen the soil promptly after watering. In mid-August, when flower bud differentiation begins, appropriately control water to promote the transition from vegetative growth to reproductive growth. After bud appearance, appropriately increase water supply to promote bud expansion. During the full flowering period, ensure water supply, because a large number of flowers open during this period and transpiration increases. Jinduo has strong drought resistance; moist deep soil is sufficient to ensure normal growth. However, it is not tolerant of waterlogging, especially prolonged flood irrigation, which can cause root rot due to excessive soil moisture. Before winter (late November to early December), water once with antifreeze water. In early spring from March to April, due to strong winds in Liaoning, water thoroughly once to promote basal shoot germination.
3.2 Fertilization
Jinduo is relatively sensitive to fertilizer and water. If nitrogen fertilizer is insufficient, plant growth is slow, plants are short, leaves are few and poor in quality, flower stems are shortened, flowers are small, and the number of flowers per plant decreases. Combined use of phosphorus and potassium fertilizers can greatly promote flower stem development. After basal shoots emerge in early spring, apply the first topdressing mainly of nitrogen fertilizer with the first irrigation, at a rate of 30-45 kg/667 sq m. The second application is at the bud stage, adding phosphorus and potassium fertilizers in addition to nitrogen fertilizer, and 0.2% potassium dihydrogen phosphate can be sprayed on the leaves. Stop fertilizing 7 d before flowering.
3.3 Loosening Soil and Weeding
Weed promptly during the growth period, and destroy the hoed weeds to eliminate fungi, insect eggs, and insects. Loosening the soil can improve soil aeration and enhance water storage and retention capacity.
4 Pest and Disease Control
Generally, chrysanthemums are prone to rust, powdery mildew, anthracnose, and phytophthora blight, but Jinduo has extremely strong disease resistance. Generally, no fungicide spraying is needed throughout the growing season, or spraying a broad-spectrum fungicide once every 2 weeks is sufficient. If diseased plants are found, they should be promptly removed to reduce sources of infection. Pests mainly include aphids and cabbage caterpillars. Aphids can transmit viruses, severely reducing the ornamental value of affected plants. For aphid control, spray 10% imidacloprid wettable powder at 1000 times dilution once every two weeks; cabbage caterpillars chew leaves and stem tips of chrysanthemums, and in severe cases the entire plant loses commercial value. Spray 10% cypermethrin emulsifiable concentrate at 1500 times dilution for control.
5 Conclusion
This is a variety suitable for both potted and field cultivation. It has strong growth vigor, bright flower color, beautiful flower shape, drought resistance, cold resistance, and a wide adaptation range. It requires no manual pinching throughout the entire growing season and can naturally take shape. Cultivation and management are simple, and its comprehensive traits reach the international advanced level, with broad prospects for promotion and application.