How to Propagate Coreopsis? Detailed Propagation Key Points
Coreopsis is relatively easy to cultivate artificially and has very strong adaptability. Moreover, coreopsis can often propagate on its own. For artificial propagation, sowing or division can be used. In summer, coreopsis can also be propagated by cuttings
Coreopsis is relatively easy to cultivate artificially and has very strong adaptability. Moreover, coreopsis can often propagate on its own. For artificial propagation, sowing or division can be used. In summer, coreopsis can also be propagated by cuttings.
Coreopsis
Sowing propagation of coreopsis is generally carried out in August, or direct sowing in the open field in late April in spring, flowering in July-August, with the flowering period extending to mid-October. Biennial coreopsis will bloom in early spring in late May to early June, with the flowering period extending to mid-October. To make coreopsis bloom more, you can remove spent flowers after flowering, apply fertilizer once in July-August, and by National Day in October it will have abundant flowers and lush foliage.
Cultivation and management are relatively simple. Proper fertilizer and water are required, otherwise it easily affects bud formation and flowering. Therefore, fertilization should be stopped during the flowering period to prevent excessive vegetative growth of branches and leaves. After flowering, the flower stalks should be cut off promptly to promote the sprouting of new shoots at the base. Generally, plants should be renewed after 5-6 years of planting. When cultivating, pay attention to: stop fertilizing during the flowering period to prevent excessive vegetative growth that affects flowering; cut off flower stalks promptly after flowering to promote sprouting of new shoots.
Key Cultivation Points for Coreopsis
The flower color of coreopsis is golden yellow, very attractive. Because of its strong resistance to sulfur dioxide, it is very suitable for planting in flower beds, roadsides and other greening sites. Coreopsis is not difficult to cultivate, is cold-resistant and drought-resistant, and can often propagate on its own.
Coreopsis
Soil:It is best to plant coreopsis in loose, well-aerated soil rich in humus. Before planting coreopsis, loosen the soil. Loosening the soil after rain helps the roots of coreopsis breathe. During the rainy season, weed once a week.
Watering:Coreopsis is easy to cultivate. After planting, water thoroughly once, then control watering to prevent excessive vegetative growth of the plant.
Light:Coreopsis likes direct sunlight. In overly shaded environments, coreopsis tends to grow excessively. It is a short-day plant for indoor settings; short-day conditions can ensure that coreopsis blooms brightly.
Fertilizing:Before planting coreopsis, rotted leaves can be used as base fertilizer in the soil (1 kg/m2). During the transition from the growing period to the flowering period of coreopsis, fertilization should be stopped. After 4 flower buds appear, apply topdressing.
Pruning:When coreopsis grows to 6 cm tall, pinch once. When branches reach 10 cm, pinch a second time, and promptly remove willow buds.
Pests and Diseases:Common diseases of coreopsis include powdery mildew and black spot, caused by rain exposure and miscellaneous bacteria in the soil. Chlorothalonil and thiophanate-methyl can be used alternately, once every 10 days. Common pests of coreopsis include aphids, cutworms and grubs. Omethoate and fenvalerate can be used alternately, once every 10 days.
Gerbera Gerbera jamesonii Bolus Gerbera Illustrated Guide: How to Grow Gerbera / How to Propagate Gerbera
Gerbera ProfileGerbera Gerbera jamesonii Bolus
Gerbera Cultivation Methods and Precautions Introduction to Gerbera
Gerbera (English name: Gerbera), a perennial herbaceous plant of the Asteraceae family, with fine hairs covering the entire plant, terminal inflorescences, most leaves basal, pinnately lobed. Plant height 30-45 cm, capitulum solitary, terminal inflorescence, flower colors include red, white, yellow, orange, purple, etc. Extending 20-40 cm above the leaves, flower diameter 10-12 cm, involucre disc-shaped, bell-shaped, ligulate petals 1-2 or multiple whorls in double form, usually flowering in all four seasons, most abundant in spring and autumn.
It is an important material in modern cut flowers. Gerbera has a relatively large flower diameter (8 cm-10 cm), and its flowering period is easy to regulate. The area under cut flower cultivation is increasing year by year, and its application is becoming more and more widespread. Gerbera can also withstand long-distance transport, and cut flowers have a long vase life; with proper cultivation methods, each plant can yield 30 cut flowers per year, truly an ideal cut flower. Gerbera has large flowers, rich colors, and requires little labor for management. In warm regions, it can supply fresh cut flowers year-round. The main types can be divided into modern cut flower types and dwarf cultivation types, with various flower colors including white, pink, red, yellow, etc.
Morphological Characteristics of Gerbera
Perennial, hairy herb. Rhizome short, surrounded by remnant petioles, with relatively thick fibrous roots. Leaves basal, rosette-shaped, leaf blades oblong-elliptic to oblong, 10-14 cm long, 5-6 cm wide, apex shortly acute or slightly obtuse, base gradually narrowed, margin irregularly pinnately lobed or deeply lobed, glabrous above, short pubescent below, glabrescent when old; midvein raised on both sides, thicker and more prominent below, lateral veins 5-7 pairs, arcuately connected away from the margin, reticulate veins slightly obvious; petiole 7-15 cm long, with coarse longitudinal ridges, more or less hairy. Scapes solitary, or rarely several clustered, 25-60 cm long, without bracts, hairy, hairs densest at the top, capitulum solitary at the top of the scape, 6-10 cm in diameter when ligules spread during flowering; involucre bell-shaped, about equal in length to the bisexual flowers, up to 2 cm in diameter; involucral bracts in 2 layers, outer layer linear or subulate, apex acute, 8-10 mm long, about 1-1.5 mm wide, pubescent on the back, inner layer oblong-lanceolate, apex caudate-acuminate, 10-14 mm long, about 2 mm wide, margin scarious, sparsely pubescent on the midrib; receptacle flat, naked, honeycomb-like, 6-8 mm in diameter; peripheral female flowers in 2 layers, outer layer corolla ligulate, ligule pale red to purplish red, or white and yellow, oblong, 2.5-3.5 cm long, 2-4 mm wide, apex with 3 teeth, inner 2 lobes filiform, curled, 4-5 mm long, corolla tube short, about 1/8 the length of the ligule, staminodes filiform, 3-4 mm long, extending beyond the corolla tube; inner layer female flowers more slender than bisexual flowers, tubular bilabiate, 6-7 mm long, two lips equal in length, outer lip with 3 fine teeth or sometimes 2 teeth and 1 lobe, inner lip 2-parted deeply, lobes linear, about 4 mm long, curled, staminodes 4-5, linear or filiform, hidden within the corolla tube; central bisexual flowers numerous, tubular bilabiate, 8-9 mm long, outer lip large, with 3 teeth, inner lip 2-parted deeply, lobes usually broad, curled; anthers about 4 mm long, with long pointed tails; style branches of female and bisexual flowers short, apex obtuse, less than 1 mm long. Achenes cylindrical, 4-5 mm long, densely covered with white short pubescence. Pappus slightly rough, dirty white when fresh, light brown when dry, 6-7 mm long, united at the base. Flowering period November to April of the following year.
Ecological Habits of Gerbera
It prefers environments with warm winters and cool summers, good air circulation and ample sunlight. It is not cold-tolerant and dislikes extreme heat. The optimal growth temperature is 20°C-25°C, the optimal winter temperature is 12°C-15°C, and growth stops below 10°C. It is a semi-cold-tolerant flower and can tolerate short periods of 0°C low temperatures. In South China, it can be cultivated as an open-field perennial flower; in East China, it must be covered for overwintering or grown in a greenhouse for cut flower forcing cultivation. It prefers fertile, loose, well-drained sandy loam rich in humus, dislikes heavy clay soil, and favors slightly acidic soil. It can also grow in neutral and slightly acidic soil, but in alkaline soil, leaves are prone to deficiency symptoms. The flowering period of gerbera is very easy to regulate; as long as the room temperature is maintained above 12°C, the plant will not enter dormancy and will continue to grow and bloom. It prefers fertile, loose, well-drained sandy loam rich in humus, dislikes heavy clay soil, favors slightly acidic soil, is a semi-cold-tolerant flower, and can tolerate short periods of 0°C low temperatures. Gerbera is a light-loving plant, so choose a location with ample sunlight for cultivation. Seedlings should not be planted too deep; the root crown should be exposed above the soil surface. If light is insufficient, flower stalks become soft and drooping, and cut flower quality is poor.
Economic Value of Gerbera
Gerbera seedling producers in Yunnan are mainly concentrated in Kunming, with about 20 companies, of which more than 10 are relatively large-scale. The annual output of gerbera seedlings is around 20 million plants. Many enterprises or research institutions have collected rich gerbera variety resources and possess strong production technology and experience. The gerbera seedlings they produce are deeply favored by growers within and outside the province. Kunming has become the center of gerbera seedling production in the country. After nearly 10 years of development, gerbera, which ranks fifth on the international cut flower sales list, has continuously expanded its planting scale in Yunnan. Its cultivation area is second only to roses, carnations and lilies, making it a major fresh cut flower species in Yunnan.
Market
In March and April, although the peak season for Yunnan fresh flower sales has passed, the "golden period" for gerbera seedling sales has arrived. Gerbera seedlings sold from Kunming to destinations within and outside Yunnan Province reached more than 2 million plants in April sales. A national gerbera seedling production pattern centered on Kunming has basically taken shape.
Volume Declines, Prices Fall
It is understood that gerbera seedling producers in Yunnan are mainly concentrated in Kunming, about 20 in total, of which more than 10 are relatively large-scale. Affected by the relatively high price of gerbera seedlings, although family-based seedling production households have emerged, due to the decline in enterprise production, the total gerbera seedling production has decreased compared with the previous period, to about 15 million plants. Prices have also fallen, from 0.8 yuan/plant to 1.0 yuan/plant in the same period, down to 0.6 yuan/plant to 0.8 yuan/plant.
Grim Sales Situation
It is reported that growers in Yunnan Province have significantly reduced their demand for gerbera seedlings. In 2005, the planting area was about 5,000 mu, an increase of 1,000 mu over 2004. Calculating at 4,500 seedlings per mu, the newly added 1,000 mu requires 4.5 million seedlings. If one-third of the gerbera plants in the remaining 4,000 mu need replacing with new seedlings (gerbera growers generally replace seedlings every two to three years), then 6 million seedlings are needed, bringing the province's total seedling demand to 10.5 million plants. If one-third to one-half of gerbera plants are replaced with seedlings, then the seedling demand within Yunnan Province is 6 million to 9 million plants. From this it can be seen that the number of seedlings sold outside Yunnan Province cannot be less than 6 million plants. But in reality, Yunnan gerbera seedling enterprises do not sell much in markets outside the province. Therefore, gerbera seedlings are in a situation of oversupply, and the sales situation is grim.
In addition, affected by soil continuous cropping obstacles, the gerbera cut flower market is not doing well, causing some flower growers in Jinning County, Kunming City, which accounts for nearly half of the gerbera planting area in Yunnan Province, to switch from planting gerbera to roses or carnations. Demand for gerbera seedlings within the province has shrunk. Demand for seedlings in markets outside Yunnan Province is growing. Surveys show that gerbera planting areas in Jiangsu, Liaoning, Shandong and other provinces are increasing.
Seeking Joint Development
After nearly 10 years of development, many enterprises or research institutions in Yunnan have acquired relatively strong production technology and experience, collected rich gerbera variety resources, and the gerbera seedlings they produce have formed a certain brand effect, deeply favored by growers within and outside the province. However, due to relatively large losses in long-distance transport of gerbera, inadequate post-harvest handling technology, and declining quality of seedling mother plants, the development of the gerbera cut flower and seedling industry has been affected.
Kunming Tongxin Flower Co., Ltd. produces 7 million gerbera seedlings annually, of which nearly 50% are sold to markets outside the province, and some products are also exported to Vietnam and other neighboring countries. Company General Manager Bi Xiaoping said that gerbera tissue culture technology is not difficult, and it is entirely possible for enterprises or research institutions outside Yunnan Province to catch up with or even surpass Yunnan in seedling production. Facing increasingly fierce market competition, for Yunnan gerbera seedlings to gain a firm foothold in the market, they must start from the following 3 points: first, strive to improve seedling quality, extend the hardening-off period, increase the survival rate of finished seedlings, and at the same time control the propagation coefficient of seedlings to reduce indoor contamination and mold infection of seedlings; second, select suitable varieties according to the demand conditions of different regions, such as green-centered varieties mainly for outside the province and black-centered varieties mainly within the province; third, take the path of factory-based and specialized production, expand scale effects, implement small profits but quick turnover, and improve market competitiveness.
In early April, led by the Flower Research Institute of the Yunnan Academy of Agricultural Sciences, heads of enterprises such as Kunming Qianhui, Kunming Yuhui, Kunming Tongxin and Kunming Jinkeyi were invited to a discussion to jointly discuss matters such as establishing the Yunnan Gerbera Seedling Association. At the same time, they will negotiate with foreign breeders in the name of a "large group" to strive to introduce high-quality mother plants and new varieties at low prices. It is reported that they have already held negotiations with the Dutch company Florist, planning to introduce more than 4 million high-quality mother plants from the company, requiring payment of more than 4.8 million yuan in patent fees.
Gerbera Differences Between Gerbera and Daisy Gerbera
Scientific name: Gerbera jamesonii
Family: Asteraceae
Origin and Distribution: South Africa
Morphological Characteristics: With rosette leaf clusters. Leaves oblong-spatulate, deeply lobed or lyrate-pinnately lobed, leaf underside covered with white tomentum. Capitulum. Flower colors range from white to various yellows, oranges, rose reds, reds, etc. If the ambient temperature is suitable, it can bloom year-round.
Growth Habits: Prefers mild winters and cool summers. Requires well-drained, humus-rich, deep and fertile soil with a pH of 6-6.5.
Garden Use: Barberton daisy is mainly used for cut flowers and potted flowers, and can also be used in flower beds when climatic conditions are suitable.
Propagation and Cultivation: Potted, mainly by sowing.
Daisy
Aliases: Spring daisy, life-extending daisy
Scientific name: Bellis perennis
Family and Genus: Asteraceae, Bellis genus
Habits: A perennial herbaceous plant, often cultivated as an annual or biennial. Prefers cool, humid, sunny conditions, relatively cold-tolerant, can overwinter in the open field where ground temperature does not drop below 3-4°C. Not strict about soil requirements. Flowering period April-May.
Cultivation: Propagated by sowing or division. The optimal seed germination temperature is 22-28°C. In North China, sow in August-September, move into cold frames for overwintering in late October, and in April of the following year pot up or plant into flower beds. During the growing season, as long as proper water and fertilizer are provided, it will grow well. After flowering, the roots can be divided and planted in pots, placed in a cool place for the summer, and after autumn cools down moved into a greenhouse or indoor room. With enhanced fertilizer and water management, it can bloom again in winter or the following spring. Few pests and diseases.
Cultural Background, Origin and Evolution of Gerbera
In 1878, Rehman first discovered gerbera in Transvaal, South Africa, and in the same year Blass sent it to the Royal Botanic Gardens, Kew in England. Lynch in England was the first to carry out hybrid breeding of gerbera. He crossed gerbera with green-leaf gerbera (G. viridifolia Sch.-Bip.) and bred hybrids; afterward, Adnet in France selected and bred varieties for cut flower use; after 1950, new varieties were bred in Europe; in 1980, dwarf potted varieties were also bred, with a flowering period of almost year-round continuous bloom. Japan also achieved excellent results in breeding double-flowered gerbera. In addition, many distant hybrids have been bred, using gerbera as the female parent and coreopsis (Coreopsis basalis Blake.) or marguerite (Argyranthemum frutescens Sch.-Bip.) as the male parent, with the hybrid flower types mostly resembling the male parent.
Gerbera has rich flower color gene inheritance and very high heterogeneity, with large differences in flower type and flower color among its offspring. Therefore, excellent hybrid individual plants can be rapidly and massively propagated into clonal lines through tissue culture. As a result, varieties are replaced very quickly with fashion trends. Its flower colors are mainly white, red, pink, orange, purple, etc. In addition, interspecific hybridization is easy to achieve, so besides the above inherent color series, there are also many intermediate color series.
Origin of the Name Barberton Daisy
In the early 20th century, Madagascar, located in southern Africa, was a small country rich in tropical flowers and plants. There was a local girl named Slangyini who, from childhood, loved this kind of wildflower with slightly curved stems and drooping flowers. When she got married, she asked that more of them be arranged in the hall to add to the wedding atmosphere. Relatives and friends from all sides sang and danced, toasting frequently. Unexpectedly, the groom, who had a very low tolerance for alcohol, became drunk after only three rounds of drinks. He drooped his head, bent his waist, and swayed from side to side. The bride had no choice but to support him into the bedroom to rest. Seeing how similar this supporting posture was to the growth form of that wildflower, many girls said in unison: "Oh, the flower really looks like supporting a husband!" From then on, the name "Barberton daisy" (literally "support-husband flower") spread far and wide.
Gerbera is also known as Barberton daisy and is native to southern Africa. With large flowers and beautiful colors, it is an important cut flower decorative material. Large red gerberas are used in bridal bouquets. Together with roses, gladioli and carnations, it is listed among the world's best-selling "four major cut flowers."
Cultivation History
The first person to improve gerbera varieties was the Englishman Irwin Lynch, who crossed G. jamesonii with green-leaf gerbera (G. viridifolia). Later, the Frenchman M. Adent continued to improve it and bred a large number of cut flower varieties. In addition, Japan also bred double-flowered varieties with diverse flower types and colors, collectively called hybrid gerbera (Gerbera jamesonii), used for cut flowers and potted flowers.
Feng Shui
Gerbera can promote women's romantic relationships. The bedroom is probably the most important space for changing a woman's life. Especially when in love, overthinking mostly happens in the bedroom. Love feng shui requires confirming the bedroom arrangement. For example, placing a fresh, long-lasting gerbera by the bedside, with a fragrance that is pleasant and will not easily fade, can encourage oneself.
Gerbera can promote family harmony. Like sunflowers, gerbera is a flower that represents the sun in everyone's mind. The difference is that the latter is tall and imposing, while the former is elegant and upright. If the sunflower is the blazing sun of summer, then the gerbera is like the warm sun of winter, making people feel cozy. Someone once advocated using gerbera as the flower representing Father's Day, because gerbera is also called sun flower, and the sun can also symbolize fatherly love. The feng shui effect of gerbera, the saying that it can make a family live in harmony and love each other, also arose from this.
For people whose Five Elements belong to fire, gerbera is their lucky flower. In Chinese feng shui, it is believed that the types, attributes and placement positions of some plants can affect a person's destiny. Plants also have yin-yang and Five Elements distinctions. Using them appropriately in different directions and environments can produce unexpected regulating effects. In geomancy, it is believed that plants are spiritual and can help people in various aspects to a certain extent. Therefore, plants are often used to regulate environmental energy fields. There are many types of plants with greatly different properties, so there are also many particular considerations when using them. Such plants are called feng shui plants. People whose Five Elements belong to fire should choose red as the main color, because red is the inherent color of fire, or choose the inherent color of wood, cyan, as the main color, because green wood generates and boosts red fire. From a feng shui perspective, this can bring prosperity and good luck to the homeowner and their family. Of course, besides red, gerbera also has many other colors, so gerbera is a lucky star for many people. As the color of gerbera changes, the group of people it blesses differs.
Variety Classification of Gerbera Variety Classification
It can mainly be divided into dwarf potted types and modern cut flower types. Potted types are mainly F1 hybrids, with characteristics such as consistent flowering period, rich color variation, short growth period, uniform habit and strong floriferousness; cut flower varieties have straight flower stalks, and large flower diameter can reach 15 cm, long flowering period, can bloom year-round, long ornamental duration, and vase life as long as 7-10 d. Cut flower types can be further divided into single-layered, semi-double and double types; according to color, they can be divided into bright red series, pink series, pure yellow series, orange-yellow series, pure white series, etc. Different types of varieties on the market can also be divided into:
1. Narrow-petal type Ligulate petals 4-4.5 mm wide, 50 mm long, arranged in 1-2 whorls; inflorescence diameter 12-13 cm, small flower disc, flower stalk 5-6 mm thick, 50 cm long. Annual output per plant more than 30 stems.
2. Wide-petal type Ligulate petals 5-7.5 mm wide, 41-48 mm long, about 60 petals, arranged in 1-3 whorls; inflorescence diameter 11-13 cm, flower stalk 6 mm thick, 50-70 cm long. Annual output per plant more than 20 stems.
3. Large-flowered double type Inflorescence diameter 10-14 cm.
Main Domestic Varieties
Common varieties include the red "Passion", the yellow "Sun Dance", the white "Bianca", etc. Miniature small-flowered types include "Ballroom" (white), "Ballet" (orange), "Sultan" (yellow), "Conga" (red), etc.
No. Variety Flower diameter cm Ligulate flower layers Ligulate flower color Tubular flower color
1 Cathy 10-12 Many Pink Green
2 Chateau 10-12 2-3 Deep purple Deep purple
3 Diablo 10 Many Purplish red Blackish purple
4 Golden Gate 10-12 Many Deep yellow Blackish purple
5 Jolly Disc 12-14 3-4 White Pinkish purple
6 Lorraine 10-12 Many Deep yellow Green
7 Magnum 10-12 Many Deep pink Blackish purple
8 North Star 8-9 3-4 Red Green
9 Oprah 10-12 Many Yellow Green
10 Optima 10-12 Many Orange-red Blackish purple
11 Ramona 10 3-many Red with golden edge Green
12 Sangria 11-13 Many Purplish red Blackish purple
13 Savannah 10-12 3-4 Purplish red Blackish purple
14 Shirley 10-12 4 Deep pink Blackish purple
15 Sunset 10-12 Many Orange-red Blackish purple
16 Twiggy 10-12 Many Blue-purple Yellow-green
17 Venus 10-12 Many Creamy yellow Deep pink
18 Willy 7 Many Deep pink Purplish red
Main Species of the Same Genus
There are about 80 species in this genus, mainly distributed in Africa; 20 species are produced in China, the vast majority concentrated in the southwest region, with no ornamental application seen. Also commonly cultivated for ornamental purposes are:
1. Orange gerbera (G. aurantiaca Sch.-Bip.) Flowers orange-yellow or deep red, back yellow or brown
2. Green-leaf gerbera (G. viridifolia Sch.-Bip.) Leaves entire, smooth; flowers smaller, white, back yellow
Distribution Area of Gerbera
Native to South Africa, with a few distributed in Asia. Now commercial production also exists in Taiwan, China and Guangdong. With the progress of domestic greenhouse technology and the introduction of new foreign greenhouse technology, cultivation is now carried out in South China, East China and Central China.
Garden Use of Gerbera
Its flowers are large, flower stems upright, flower colors brilliant, water-holding time long, cut flower rate high, vase life up to 15-20 days, labor-saving and time-saving in cultivation, and it is one of the world's famous top ten cut flowers. It can also be used in flower beds, flower borders, or greenhouse pot cultivation for decorative display in halls, venues, etc.
Potted gerbera is often used to decorate doorways and halls, and its cut flowers are used for vase arrangements and flower arrangements, embellishing desks, display windows and living rooms. With pink gerbera as the main flower, paired with Dendrobium, gypsophila and orchid leaves, the tone is elegant and the mood is rich. If red gerbera is used as the main flower, paired with sword fern, palm bamboo leaves, dried branches and dyed walnuts for wall-hanging decoration, a relatively strong decorative effect can be produced. It is commonly cultivated in gardens across China, mostly as potted plants.
Propagation Methods of Gerbera Propagation is by sowing or division.
Because gerbera is a cross-pollinated plant and is self-incompatible, its seed offspring will inevitably show variation. The variation types generally manifest as thinner and softer flower stalks, smaller flower shape, and greatly reduced cut flower value. Therefore, gerbera must be propagated asexually. Division propagation is usually used, but each plant can only produce 5-6 new plants per year. To accelerate propagation, cuttings and tissue culture can also be used.
Propagation Methods
Tissue culture is the main method for propagating gerbera. Gerbera tissue culture commonly uses the receptacle as the explant. Use flower buds about 2 cm in diameter, disinfect and wash them, leaving only the receptacle, cut into 2-4 pieces, and place on the medium. The medium formula is MS plus BA 1.0 mg/L, plus indoleacetic acid (IAA) 0.5 mg/L. Under conditions of 22°C and 16 h of light per day, callus gradually forms, and after 1-2 months shoots form from the callus. Transfer the material that has differentiated shoots to the subculture medium, which is MS plus BA 0.1/L, plus indoleacetic acid 0.1 mg/L. When the leaves of the test-tube plantlets reach 2 cm, transfer to the rooting medium. When transferring seedlings, remove the callus at the base of the test-tube plantlets. The rooting medium formula is 1/2 MS plus naphthaleneacetic acid (NAA) 0.1 mg/l.
After gerbera explants are induced to sprout, after 4-5 months of test-tube multiplication, thousands of test-tube plants can be produced. The most suitable field transplanting period for gerbera is April. Seedlings transplanted at this time can produce a large number of flowers in August. Therefore, callus differentiation into shoots should be completed before mid-October; the 1st test-tube multiplication is from mid-October to mid-November, then once a month thereafter, ending the 4th multiplication in mid-February of the following year, followed by 2 weeks of test-tube plantlet rooting; after rooting, transplant to the seedling bed, maintain for 1 month, and then move to the field in early April.
Gerbera mostly adopts tissue culture for rapid propagation. When using division propagation, each mother plant can be divided into 5-6 small plants; sowing propagation is used for dwarf potted varieties or breeding; single buds or short lateral buds occurring at the neck base can be cut and used for cuttings. The response to photoperiod is not sensitive; the length of daylight has no effect on flower number and flower quality. It requires loose, fertile, well-drained, humus-rich, deep, slightly acidic sandy loam.
Artificial culture soil cultivation of gerbera can significantly increase yield and quality. Mix 5 parts humus, 2 parts perlite and 3 parts peat to make culture soil for planting, but the production cost of this method is relatively high. Field planting can be carried out. Choose loam with a soil layer at least 25 cm deep suitable for gerbera growth for planting. Before planting, apply sufficient base fertilizer: 5 tons of livestock manure per mu, 600 kg of chicken manure, 100 kg of superphosphate, 300 kg of plant ash. Organic fertilizer must be fully decomposed. The fertilizer must be thoroughly mixed with the soil of the planting bed and plowed, made into a form of one ridge and one furrow, ridge width 40 cm, furrow width 30 cm, plants planted on the ridge, double-row staggered planting. Plant spacing 25 cm. Note that the root crown part should be slightly exposed above the soil to prevent root crown rot. Then irrigate in the furrow.
However, because of its fast propagation speed, it has been listed as an invasive alien species in Guangdong, China. If you want to transplant it outdoors, consider carefully, otherwise once the flower seeds open, it may cause unnecessary [issues].
Division Propagation
Because old plants bloom poorly, division is usually done once every 3 years. The method is to dig up the old plant and divide it, with each new plant carrying 4-5 leaves, and plant separately. The disadvantage of this method is that propagation speed is slow.
Cutting Propagation
Dig up selected robust mother plants, remove soil from the roots, remove leaves, and cut off the growing point. Keep the root crown part and plant it in a planting box for cultivation. Place the planting box under conditions of 22-24°C and 75%-80% relative air humidity. Afterward, the root crown part will successively grow axillary buds and adventitious buds, forming cuttings for propagation. Cut off the shoots after they have 4-5 leaves, insert them into soil or other substrate, and cover the surface with 1-2 cm of perlite. Keep the temperature at around 25°C and relative humidity at 75%-90%. After 3-4 weeks they will root, and rooted cuttings can be transplanted.
Cultivation Techniques of Gerbera Key Cultivation Points
The optimal growth temperature for gerbera is 20-25°C. Below 10°C or above 30°C, growth stops and it enters a semi-dormant state. If year-round flowering is desired, the winter temperature needs to be maintained above 12-15°C, and in summer not exceeding 26°C. Therefore, in southern Fujian it can overwinter in the open field, but to obtain high-yield and high-quality cut flowers, it is best to have insulation equipment such as plastic greenhouses. In summer, shade nets can be used or water sprayed to cool down, ensuring year-round cut flower supply.
(1) Soil must be sterilized. Gerbera's soil requirements are not strict; loose, breathable, humus-rich sandy soil is suitable. Because the pathogens of various diseases harmful to gerbera can survive in the soil, and there are also underground pests and earthworms in the soil that damage the root system, soil sterilization must be carried out before planting.
(2) Soil preparation and fertilization. Since Gerbera jamesonii is susceptible to waterlogging, high-ridge cultivation is generally adopted. The ridges usually run north-south, with a ridge height of about 30 cm, a ridge width of 1 m, and a furrow width of 40-50 cm. In conjunction with soil preparation, apply basal fertilizer as appropriate, applying 200 kg of barnyard manure per 100 m.
(3) Planting. Planting is best done on cloudy days or in the evening on sunny days. Apart from the high-temperature period from July to September in summer, planting can be carried out at any other time. When planting, it is essential to plant shallowly so that the root crown is exposed above the soil surface, and water thoroughly. Newly planted plants should be shaded with shade netting.
(4) Pay attention to seedling-stage management. Based on the weather conditions at the time of planting, carry out insulation or cooling management, maintaining 20-25 °C to help the plants quickly resume growth. After the seedlings have recovered, apply 1:10 human urine and manure once every two weeks, ensuring each plant has 8-10 healthy leaves before entering the flowering stage. When watering and fertilizing, be careful not to let water get into the center of the leaf rosette, otherwise the flower buds are prone to rot.
(5) Fertilizer and water management. Gerbera jamesonii is drought-tolerant but not moisture-tolerant, and waterlogging must be strictly avoided. During the seedling stage, the soil should be kept appropriately moist to promote root development. During the growing period, the amount of watering can be determined by the dryness or moisture of the soil: do not water when the soil is not dry, and water thoroughly when you do. In winter, water as little as possible; the soil is better kept slightly dry. In summer, when the weather is hot and water evaporates quickly, the plants enter a semi-dormant state, flower production drops markedly, plant vigor weakens, and at this time pests and diseases are highly likely to occur. This can be combined with topdressing to promote root absorption of nutrients. In summer, it is necessary to loosen the soil in a timely manner, clean the roots to prevent disease, control water and fertilizer, and provide shade and rain protection.
(6) Leaf removal and bud thinning. Gerbera jamesonii can flower year-round within the range of 5-30 °C, so it has a high fertilizer requirement throughout the growing period. Before flower bud differentiation, increase the application of organic fertilizer and nitrogen fertilizer to promote full plant growth, mainly using monopotassium phosphate and urea, plus an appropriate amount of liquid organic fertilizer, applied as a topdressing once a week. When the plant enters the period of simultaneous vegetative and reproductive growth, the proportion of phosphorus and potassium fertilizer should be increased, generally once a week, while adding an appropriate amount of organic fertilizer. Before the two flowering peaks from April to June and in September and November, foliar spraying of KH2PO4 should be carried out as appropriate to meet the needs of reproductive growth.
(7) Humidity and light. Gerbera jamesonii is relatively cold-tolerant, and its growth is not sensitive to light, but it does prefer plenty of sunlight. When cultivated in a greenhouse, adding 2-3 layers of plastic film in winter allows it to overwinter safely. Before the first frost arrives in late October, cover with one layer of plastic film, and around November, small tunnels should be built over each ridge for insulation. From June to September, 50% shade netting can be used for cooling.
(8) Removal of dead leaves. The basal rosette leaves of Gerbera jamesonii readily turn yellow and senesce, and should be removed promptly. This not only benefits the sprouting of new leaves and new flower buds but also improves ventilation and light penetration, preventing the lower young flower buds from failing to receive sunlight and hormones and becoming "hidden buds." In addition, excessive flower buds or deformed flowers should also be removed promptly to ensure that the retained flower stems have sufficient nutrients and to improve the quality of cut flowers. Generally, a one-year-old single plant has 15-20 healthy leaves at peak flowering and can produce 5-6 flowers per month; a two- or three-year-old single plant can retain 20-25 leaves and can produce 7-8 flowers per month.
(9) Harvesting and preservation. Gerbera jamesonii can be picked when the outermost two layers of ligulate florets on the flower head are perpendicular to the flower stem and show the distinctive color of the variety. The best time is in the morning and evening when temperatures are low, as it is easier to pick without damaging the plant. The method is to grip the lower half of the flower stem with your hand and rock it side to side, and it can then be detached. Remove flowers with disease spots, insect spots, or deformities, cover the flower heads with No. 12-15 funnel-shaped plastic bags, then grade them by variety and stem length, bundle them into bunches of 20 with rubber bands, and they are ready for sale. If not sold immediately, they should be placed upright in a bucket or other container with clean water for water culture and preservation, with the water depth preferably covering 5-10 cm of the base of the flower stem.
Cultivation Protocol Soil Preparation
1. Soil tillage and basal fertilizer: Plow deeply once before planting (30-40 cm), apply chemical fertilizer and barnyard manure (apply 2000 kg of decomposed barnyard manure, 5 m3 of humus soil, 65 kg of superphosphate, and 50 kg of compound fertilizer per mu) into the soil, then plow deeply again (15-25 cm).
2. Bed preparation: Dig drainage ditches 70-100 cm deep nearby (depending on the water table level), form high ridges 45 cm high, with a ridge width of 1.0 m and a ditch width of 40 cm.
3. Soil disinfection: Use formaldehyde disinfection and chemical agents such as Vapam (tentative), taking 40% industrial formaldehyde disinfection as an example: dilute to a concentration of 1%, spray evenly over the soil, then quickly cover with plastic film and seal for fumigation. After 2-3 days, remove the film, air-dry the soil for two weeks, then flush with water, and only after another two weeks can planting be carried out. Different disinfectants should be determined according to their instructions and trials. Soil being planted for the first time does not need disinfection.
Seedling Selection
Select seedlings 11-15 cm tall with 4-5 true leaves for planting. Standards for high-quality seedlings: vigorous seedlings, oily green leaves, well-developed root system with many fibrous roots that are white in color, and leaves free of disease spots, insect bite gaps, and mechanical damage.
Planting
Planting time: Planting can be done year-round, but from the perspective of production and sales, April to June is ideal.
Planting method: Plant 3 rows per ridge, with the middle row staggered relative to the side rows, at a spacing of 30 cm, planting 9-10 plants per sq m, and about 1,100 or more plants per greenhouse.
Planting method: 2-3 days before planting, water the soil thoroughly; carry out planting on cloudy days or in the morning and evening of sunny days; when planting, make deep holes and plant shallowly, with the root crown exposed 1-1.5 cm above the soil surface, otherwise the plant is prone to fungal infection; if the plant is planted too shallowly, the plant may be loosened or pulled out when harvesting flowers; after planting, water thoroughly promptly.
Cultivation Management
1. Management during the seedling stage: After planting, shade with 70% shade netting for 7-10 days, and gradually increase light after the seedlings have established. Regulate day and night temperatures by opening and closing the side film and roof film, maintaining a daytime temperature of 22-25 °C and a nighttime temperature of 20-22 °C for 1 month. During this period, use sprinkler watering, preferably in the morning. Make a small hole beside the plant to indicate soil moisture; moisture should be neither too dry nor too wet. Watering frequency is once every 5 days, but this is not fixed and should be determined specifically according to soil structure, weather conditions, and so on. Inspect each plant every day, promptly remove diseased plants, and replant with healthy young seedlings.
2. Management during the established seedling stage: About 1 month after planting, Gerbera jamesonii enters a period of vigorous growth, and appropriate shading is needed when light is too strong. Adjust the temperature to 14-16 °C at night and 18-25 °C during the day as the minimum temperature. Apply 0.1% compound fertilizer (N:P:K = 15:15:15) once every week, and spray 0.1% monopotassium phosphate as a foliar fertilizer once every 2 weeks. Spray broad-spectrum fungicides, such as 800-**** times dilution of thiophanate-methyl, 2-3 times to prevent disease.
3. Management during the flowering stage: After about 3-4 months, the plant enters the flowering stage. Apply compound fertilizer with N:P:K = 12:12:17 once every week. Use foliar spraying of micronutrients, generally once every 25 days, each time alternately spraying 0.1-0.2% Ca(NO3)2.4H2O, 0.1-0.2% chelated iron plus 0.1-0.2% borax plus 5-10 ppm sodium molybdate. Use drip irrigation for watering, with the principle of "do not water when the soil is not dry, and water thoroughly when you do," and never water from the leaf rosette. Keep the relative humidity in the greenhouse at 80%-85%. Weed promptly, remove diseased leaves and dead leaves, pull out diseased plants and disinfect the soil in the planting holes with quicklime. During the summer flowering period, pay attention to shading, ventilation, and cooling. During the winter flowering period, pay attention to insulation and heating, especially preventing too large a temperature difference between day and night to reduce the occurrence of deformed flowers.
A brief introduction to the cultivation techniques is as follows: I. Growing Environment
Gerbera jamesonii is native to South Africa. It adapts to mild climates, is heat-tolerant and slightly cold-tolerant, and prefers environments that are warm in winter, cool in summer, well-ventilated, and sunny. The suitable growing temperature is 20C-25C during the day and about 16C at night. The suitable flowering temperature is not lower than 15C, and in a growing environment where the daytime temperature does not exceed 26C, it can flower year-round. The suitable temperature during the winter dormant period is 12C-15C, and growth stops below 7C. It is not sensitive to photoperiod, and the length of natural daylight has no effect on flower number or flower quality. Gerbera jamesonii requires loose, fertile, well-drained, humus-rich, deep, slightly acidic sandy loam soil.
II. Propagation
Gerbera jamesonii is mostly propagated rapidly through tissue culture, and can also be propagated by division, with each mother plant divisible into 5-6 small plants; seed propagation is used for dwarf potted varieties or breeding; single buds or short lateral buds occurring at the base of the crown can be cut and used for cuttings.
III. Planting
Using artificial growing medium to cultivate Gerbera jamesonii can significantly improve yield and quality. Please refer to the formula: 5 parts humus; 2 parts perlite; 3 parts peat, mixed as a growing medium for planting, but the production cost of this method is relatively high. Field planting can also be carried out, and loam soil with a deep soil layer of at least 25 cm suitable for the growth of Gerbera jamesonii should be selected for planting. Before planting, sufficient basal fertilizer should be applied. Generally, apply 5 tons of livestock manure, 600 kg of chicken manure, 100 kg of superphosphate, and 300 kg of plant ash per mu. The organic fertilizer must be fully decomposed. All fertilizers must be thoroughly mixed with the soil of the planting bed and plowed in, forming a ridge-and-furrow layout, with a ridge width of 40 cm and a furrow width of 30 cm. Plants are planted on the ridges in double rows in a staggered pattern. Spacing is 25 cm. When planting, care should be taken to expose the root crown slightly above the soil to prevent root and crown rot. After planting, irrigate in the furrows.
IV. Post-Planting Management
1. Temperature
Use cultivation facilities to meet as much as possible the temperature requirements of Gerbera jamesonii during the seedling, growing, and flowering stages, so as to facilitate normal growth and flowering. Outside of South China, it cannot overwinter in the open field and requires greenhouse cultivation; outside the Yangtze River Basin, unheated plastic tunnels can be used. In summer, shade netting should be covered over the top of the tunnel, and the plastic film on both sides of the tunnel should be opened for cooling. In winter, when the outside nighttime temperature approaches 0C, seal the plastic film tightly for insulation, and an additional layer of plastic film must be added inside the tunnel. On clear and warm days, open the film at the south end of the tunnel around noon for ventilation for about one hour.
2. Light
Gerbera jamesonii is a light-loving flower and requires full light in winter, but in summer appropriate shading should be provided and ventilation strengthened to lower the temperature and prevent high temperatures from causing dormancy.
3. Irrigation
After planting, the seedling stage should maintain appropriate moisture and practice seedling hardening to promote root development and rapid establishment. During vigorous growth, an adequate water supply should be maintained, watering once every 3-4 days in summer and about once every half month in winter. When watering during the flowering stage, be careful not to let water touch the center of the leaf rosette, to prevent flower bud rot. When cultivating in the open field, pay attention to preventing waterlogging. In addition, watering can be combined with fertilization.
4. Topdressing
Gerbera jamesonii is a fertilizer-loving perennial herbaceous flower with a high fertilizer demand. The ratio of nitrogen, phosphorus, and potassium in fertilization is 15:18:25. When topdressing, special attention should be paid to supplementing potassium fertilizer. Generally, apply 2.5 kg of potassium nitrate and 1.2 kg of ammonium nitrate or ammonium phosphate per mu, once every 5-6 days in spring and autumn, and once every 10 days in winter and summer. If high temperatures or excessively low temperatures cause the plant to enter a semi-dormant state, stop fertilizing.
5. Removal of Dead Leaves
The lower leaves of the basal rosette of Gerbera jamesonii readily turn yellow and senesce, and should be removed promptly. This is beneficial both for the sprouting of new leaves and new flower buds and for ventilation, enhancing plant vigor.
6. Pest and Disease Control
The main diseases of Gerbera jamesonii are leaf spot, powdery mildew, and viral disease. For leaf spot, spray 800-**** times dilution of 70% thiophanate-methyl wettable powder or 500 times dilution of 50% carbendazim wettable powder. For powdery mildew, use 1500 times dilution of 70% thiophanate-methyl or 1000-1200 times dilution of 75% triadimefon wettable powder for control, once every 7-10 days, spraying two to three times consecutively. For viral disease control, strict seedling quarantine should be enforced, and aphids should be controlled promptly to reduce virus transmission vectors; diseased plants should be removed and destroyed promptly. The main insect pests of Gerbera jamesonii include tarsonemid mites, cotton bollworm, tobacco budworm, beet armyworm, and aphids. For tarsonemid mites, 1000 times dilution of 40% dicofol can be used for control.
Harvesting
Harvest when the pollen of the outer ring of florets begins to shed. At harvest, the plant is required to be growing vigorously, with upright flower stems and open flowers. The quality of cut flowers greatly affects their vase life. Never cut flower stems when the plant is wilted or when the flowers are half-closed at night. After harvesting, carry out grading, preservation treatment, packaging, and marketing.
Most of the specialized production bases for Gerbera jamesonii seedlings in China are concentrated in the Yunnan region, and a large number of emerging specialized flower seedling producers, represented by the Yunnan Luxin Flower Seedling Base, are flourishing.
Disease Control of Gerbera jamesonii 1. Bacterial Diseases of Gerbera jamesonii
Gerbera jamesonii spot disease is a bacterial disease caused by Pseudomonas cichorii. The bacterial cells are single, straight or slightly curved, rod-shaped, motile, with multiple flagella; Gram-negative, aerobic, respiratory metabolism, chemoorganotrophic. This pathogen mainly infects various cruciferous plants such as chicory, lettuce, pea, melon, and Chinese cabbage, and can also damage tomato, clover, and others. The pathogen mainly overwinters in diseased field soil and diseased plant residues, and spreads through rain, agricultural operations, and insect carriage.
2 Viral Diseases of Gerbera jamesonii
2.1 Gerbera jamesonii Spotted Wilt
After being affected, Gerbera jamesonii shows symptoms such as discoloration, necrosis, and dwarfing, with deformed flowers. This disease occurs on cultivated Gerbera jamesonii in Italy, France, Spain, and Japan. The pathogen is Tomato spotted wilt virus (TSWV). The virus particles are spherical, 85 nm in diameter, with a lipid envelope. The inactivation temperature is 40-46 °C, the survival period in vitro is less than 5 h, and the dilution endpoint is 10-3. It is transmitted by mechanical inoculation, and the insect vector thrips transmits it in a persistent manner. This disease has a wide host range and is an important pathogen of many crops such as tobacco, tomato, and potato.
2.2 Gerbera jamesonii Mosaic Disease
Diseased plants show leaf chlorosis, deformed leaves, and patch formation, with weakened growth, a sharp decrease in the number of cut flowers, and further progression leads to the death of the diseased plant. It can infect other crops such as common tobacco and Nicotiana glutinosa, producing mosaic symptoms, and infecting zucchini causes chlorotic yellow spots and mosaic symptoms. The pathogen is Cucumber mosaic virus (CMV). The virus particles are spherical, 30 nm in diameter, with three types of particles that are similar in morphology. It is transmitted by mechanical inoculation, and aphids transmit it in a non-persistent manner. The inactivation temperature is 70 °C, the survival period in vitro is 4 days, and the dilution endpoint is 10-3. This disease has a wide host range, and transmission is mainly through sap and aphids.
2.3 Gerbera jamesonii Mottle Disease
Chlorotic ringspots appear on the leaves, and some chlorotic spots appear as oak-leaf patterns, with individual tissues bordering the spots necrotic. When the disease is severe, the leaves become smaller, wrinkled, and brittle; some varieties show broken petal color, smaller (deformed) flowers, less vivid flower color, and stunted plants. The pathogen is Tobacco mosaic virus (TMV). The particles are straight rods, 300 nm x 18 nm, and the inactivation temperature is 90-95 °C. This disease has a wide host range and can be transmitted by mechanical inoculation, contact between plants, contaminated soil, and farm tools, and can also be transmitted by sap, soil, nematodes, and seeds.
3 Fungal Diseases of Gerbera jamesonii
3.1 Gerbera jamesonii Powdery Mildew
This disease mainly damages leaves. In the early stage of the disease, white mold spots appear on the leaves, which gradually expand into round or long oval yellowish-white lesions. The lesions are covered with a white coating, and in severe cases the entire leaf is covered with white powder. In the later stage, the powder layer becomes grayish-white, and the leaves scorch and wither. The pathogen is (Oidium sp.). The mycelium is white and superficial, penetrating deep into the epidermal cells of the host with haustoria to absorb nutrients. The conidiophores are erect, unbranched, and produce conidia in a holoblastic manner. The conidia are oblong, single-celled, colorless, catenulate, maturing from top to bottom in sequence. This disease is more likely to occur when temperatures are high, relative humidity is 80%-90%, and ventilation in the greenhouse is poor.
3.2 Gerbera jamesonii Leaf Spot
There are mainly two types of Gerbera jamesonii leaf spot: (1) Phyllosticta leaf spot. Small purplish-brown to tea-brown spots first appear on the leaves, gradually expanding into round or nearly round lesions with dark brown edges, and later black dots are produced on the lesions. The pathogen is Phyllosticta chrysanthemi. The pycnidia are spherical, immersed, unilocular, with an ostiole. The conidiogenous cells are cylindrical, colorless, smooth, and produce conidia in a holoblastic manner; the conidia are elliptical, single-celled, colorless, with a flat base. It grows very quickly on artificial medium, with abundant aerial mycelium, relatively sparse pycnidia formation, and a membranous wall. The pathogen overwinters as mycelium and pycnidia in diseased fallen leaves. Old leaves are more severely affected than young leaves. (2) Cercospora leaf spot. Small purplish-brown dots first appear on infected leaves, gradually expanding into round or nearly round lesions, with a dark gray center, slightly raised brown line markings at the edge, and a purplish-brown outer ring. Dark green mold spots are produced on both the upper and lower surfaces of the leaves. The pathogen is Cercospora chrysanthemi. The mycelium is mostly immersed, often with a stroma. The conidiophores are stout, of the mycelial type, olive-brown or brown, lighter in color at the apex, unbranched or occasionally branched, densely clustered on the stroma tissue. The conidia are whip-shaped, straight or slightly curved, colorless, with 3-12 septa. The conidiogenous cells are mostly blastic, with sympodial extension, cylindrical, with obvious conidial scars. The conidia are solitary, with a scar at the base, with multiple septa, and a smooth surface. This disease mostly overwinters on diseased residues and diseased leaves, and generally occurs severely in environments that are damp and shaded with insufficient light, heavy clay soil, and poor drainage.
3.3 Gerbera jamesonii Gray Mold
Water-soaked round or irregular lesions appear on the stem near the ground of the diseased plant, later turning grayish-brown to brown, with the diseased part becoming soft-rotted and densely covered with a gray mold layer on the surface. When seedlings are infected, the stems and leaves near the ground become brown, water-soaked, and rotted, with gray mold produced on the surface, and later small flat sclerotia aggregate. The pathogen is Botrytis cinerea, belonging to the subphylum Deuteromycotina, genus Botrytis. The conidiophores are straight or flexuous, 960-1,200 μm x 16-22 μm, clustered in several strands, brown, smooth, with 1-2 branches at the apex. The branch ends often swell noticeably, forming colorless or pale flask-shaped conidiogenous cells. The conidia are short elliptical, 12-18 μm x 9-13 μm. The pathogen overwinters as conidia and sclerotia in infected tissues, and disease is likely when humidity is high.
3.4 Gerbera jamesonii Sclerotinia Rot
This disease starts from the stem base, causing the stem to rot. In the early stage of the disease, the diseased part appears water-soaked, soft-rotted, and brown, gradually spreading to the stem and petiole. In the later stage, black mouse-dropping-shaped sclerotia can be seen both inside and outside the stem. The typical symptom of this disease is rapid soft rot at the diseased part, densely covered with white flocculent material, or black mouse-dropping-shaped sclerotia, each sclerotium capable of producing 1-9 apothecia. This disease is caused by the fungus Sclerotinia sclerotiorum Fuck. The apothecia are produced on the sclerotia, disc-shaped, with long stalks. The asci are arranged in parallel, with persistent paraphyses between the asci. The asci are club-shaped or elliptical, colorless. The ascospores are single-celled, elliptical, arranged in a single row. The pathogen has a very wide host range. The pathogen overwinters as sclerotia in diseased residues and soil, and produces ascospores the following year to infect and cause damage. Fields with a previous crop of cruciferous plants are severely affected. The disease is severe during the rainy season. The disease spreads through contact between diseased plants and healthy plants and through the growth and spread of mycelium in the soil.
3.5 Gerbera jamesonii Root Rot
This disease is one of the most important diseases of Gerbera jamesonii, with a wide occurrence area and great severity. The plant is affected throughout the entire growth period, with the most severe damage during the flowering period. The pathogen infects from the stem base at ground level, and the affected part becomes soft, water-soaked, and light black; the plant leaves suddenly wilt and turn purplish-red. When the diseased plant is pulled out, the diseased part at the stem base breaks easily, and white mold spots can grow on the surface when moist. This disease is mainly caused by Phytophthora cryptogea. Phytophthora cryptogea belongs to the kingdom Chromista, phylum Oomycota, order Peronosporales, family Pythiaceae, genus Phytophthora. Its vegetative body is non-septate, multinucleate mycelium, with hyphal swellings produced, and asexual reproduction produces zoosporangia. The sporangia are pear-shaped or elliptical, without papillae, large, averaging 46 μm x 27 μm in size, with a wide host range. It is heterothallic, and sexual reproduction produces oogonia, oospores, and antheridia. The oogonia are spherical, containing a spherical thick-walled oospore. The antheridia are single-celled, colorless and transparent, and amphigynous. The pathogen overwinters on residues or in soil, and the overwintering pathogen is the main primary infection source of the disease. Sudden alternating wet and dry soil or frequent hoeing and loosening of the soil causes many wounds on the plant roots, and the pathogen invades through the wounds and spreads through irrigation water or rainwater under suitable conditions, causing a major outbreak of the disease. Fields with poor drainage and continuous cropping are severely affected. 3.6 Gerbera jamesonii Fusarium Wilt
This disease has symptoms similar to Gerbera jamesonii root rot and occurs throughout the entire growth period of Gerbera jamesonii. The root system of the diseased plant is dark brown, the cortex of the diseased roots peels off, there are few fibrous roots, and the plant is easily pulled up. When the disease develops slowly, the leaves of the diseased plant turn purplish-red or dark brown and gradually wilt; when the disease is severe, the plant dies in a green wilt state. This disease occurs in Italy, Australia, and China, among other countries. Because Gerbera jamesonii is basically cultivated under protected conditions, the disease can occur year-round, with April to August each year being the period of more severe occurrence. The pathogen overwinters in soil or diseased plant residues. Contaminated soil and affected plants are the main sources of infection for this disease. High-temperature and high-humidity weather and heavy clay soil both promote the proliferation and spread of the pathogen. This disease is mainly caused by Fusarium oxysporum. On artificial medium, it produces dense mycelium in a loose cottony form. The conidiophores are colorless, and the conidiogenous cells produce conidia in an enteroblastic phialidic manner, producing two types of spores. The microconidia are oval to elliptical, 5-12 μm x 2.5-3.5 μm in size; the macroconidia are 27-46 μm x 3-4.5 μm in size, spindle-shaped to sickle-shaped, with a hooked apex and a small foot-shaped basal cell, with 3-5 septa, mostly 3 septa. Chlamydospores are usually formed in large numbers, intercalary or terminal, solitary, occasionally catenulate, with a smooth or rough wall.
In addition, the diseases of Gerbera jamesonii also include downy mildew (caused by Bremia lactucae), white rust (caused by A. tragopogonis), and ringspot mosaic disease (caused by TBRV), among others.
4 Pest Whitefly
Key control techniques: Thoroughly remove weeds, insert yellow sticky boards for continuous monitoring, and once pests are found, take measures promptly. Choose the right pesticide and use it correctly: Whiteflies easily develop resistance to pesticides, so pesticides must be rotated. Pesticides with good effectiveness include beta-cypermethrin, abamectin, and imidacloprid. Choose dawn for spraying, keep the greenhouse sealed for 4-5 hours after spraying, and spray once more the next morning. Keep the greenhouse ventilated and low in humidity; remove diseased leaves promptly; when the disease occurs, spray 1500 times dilution of 70% thiophanate-methyl, or use 20% Junke smoke for fumigation control, once every 7 days, for 2-3 consecutive treatments. In addition, use sulfur fumigation for control, placing 20-30 g of sulfur powder in each fumigator, after lowering the curtain at 17:00 each day, keep the greenhouse sealed, energize and heat for 2 hours, replace the sulfur powder once every 6 days, and continue fumigation for 15 days. During the powdery mildew outbreak period, fumigate 8-10 h per day, and powdery mildew can be eliminated in about 10 days.
Thrips
Key control techniques: Promptly prune insect-infested flowers to reduce the source of insects in the greenhouse. Fumigating pesticides in the greenhouse is the best control method. Use 300-400 ml of 80% dichlorvos for fumigation for 1 hour, or spray 1500-2000 times dilution of 5% imidacloprid and then close the greenhouse for 8-10 hours. Fumigation can be carried out at 10 a.m. or 5 p.m. when the temperature is slightly higher to achieve good efficacy.
Cabbage Caterpillar
Key control techniques: For larvae, use 2000-2500 times dilution of 10% Chuchujin for spray control. For older larvae, 1000 times dilution of beta-cypermethrin can be used for control, once every 7 days, for 3 consecutive treatments.
Note: The above pesticides were determined after testing according to the reference formulas provided by the Resources and Environment Institute.
Phytophthora Blight
Key control techniques: Continuous cropping soil must be disinfected with Vapam and formaldehyde, among others; see the instructions for usage and dosage. Plant shallowly, with the root crown exposed 1 cm above the surface. Prevent the soil from being too wet; if soil taken from 10 cm below the surface does not form a ball when squeezed firmly in the palm, then it can be watered. In the early stage of the disease, when the leaves partially turn red and begin to wilt, drench the roots with 400 times dilution of 58% phosethyl-Al plus mancozeb, then 7 days later drench the roots with 500 times dilution of 64% oxadixyl plus folpet powder. Apply the pesticide in the morning and evening when temperatures are low, stop application when the temperature is above 28 degrees, apply once every 7 days, for 3 consecutive treatments.
Spot Disease
Key control techniques: Remove diseased leaves promptly when found and destroy them centrally. In the early stage of the disease, spray 300 times dilution of 2.5% myclobutanil emulsifiable concentrate or 800-**** times dilution of 70% thiophanate-methyl wettable powder, once every 7 days, for 2-3 consecutive sprays.
Gray Mold
Key control techniques: Controlling humidity is the key to controlling gray mold. Thin out densely planted and overgrown leaves; increase ventilation and air permeability, and keep air humidity at 75-85%; water from below the plant rosette; to prevent water vapor from condensing on the flowers, after 10 a.m. on sunny days, gradually open the side curtains to avoid a sharp rise in temperature inside the greenhouse; in the early stage of the disease, spray 1500 times dilution of 70% thiophanate-methyl on the leaves, and combine with smoke agents for control.
5 Physiological Diseases
1. Symptoms: Dark green spots appear on young leaves. In severe cases, the young leaves and growing points die first, while the old leaves can still remain normal.
Solution: Judging from the symptoms, it may be caused by calcium deficiency. Spray 0.15% Ca(NO3)2.4H2O on the leaves, once every 25 days.
2. Symptoms: "Mosaic" appears in the mesophyll of old leaves, and an inverted "V"-shaped green part forms at the leaf base, which can also extend up close to the leaf tip. The leaves become brittle, curved, and even red, new leaves grow few and small, petioles are slender, veins of young leaves protrude, inflorescence formation is inhibited, flower stalks are thin, and flowers become smaller. Spray 0.2% magnesium fertilizer twice. Solution: Judging from the symptoms, it may be caused by magnesium deficiency.
3. Symptoms: Leaves turn pale yellow, even almost white, and the veins remain green at first, but eventually also change color.
Solution: Judging from the symptoms, it may be caused by iron deficiency. Spray 0.02% chelated iron, once every 25 days.
4. Symptoms: Small leaves curl, thicken, and become brittle. Growing points die, flower buds abort, or deformed sterile inflorescences are produced.
Solution: Judging from the symptoms, it may be caused by boron deficiency. Spray 0.05% borax, once every 25 days.
5. Symptoms: Spots and "mosaic" appear on young leaves, one side of the leaf develops normally while the other side is abnormal, and the leaf curves to the side.
Solution: Judging from the symptoms, it may be caused by zinc deficiency.
7 Quality Defects
1. Flower stem breakage: Transverse cracks appear on the flower stem, and in severe cases the flower stem breaks, with the cracks appearing incision-like.
Solution: Use 1-2‰ calcium nitrate and spray once a week.
2. Leaf margin scorch: Sudden scorching appears at the leaf tip or the tips of the lobes.
Solution: Caused by excessively high fertilizer concentration. Immediately spray clean water to dilute or wash off the fertilizer solution adhering to the leaves; extend the fertilization interval and reduce the fertilization concentration, and it will recover naturally after some time.
Prevention First, Integrated Control
Disease Control
The diseases of Gerbera jamesonii include leaf spot, powdery mildew, and viral disease. For leaf spot, spray 800-**** times dilution of 70% thiophanate-methyl wettable powder or 500 times dilution of 50% carbendazim wettable powder. For powdery mildew, use 1500 times dilution of 70% thiophanate-methyl or 1000-1200 times dilution of 75% triadimefon wettable powder for control, once every 7-10 days, spraying two to three times consecutively. For viral disease control, strict seedling quarantine should be enforced, aphids should be controlled promptly to reduce virus transmission vectors, and diseased plants should be removed and destroyed promptly. The main insect pests of Gerbera jamesonii include tarsonemid mites, cotton bollworm, tobacco budworm, beet armyworm, and aphids. For tarsonemid mites, 1000 times dilution of 40% dicofol can be used for control. For other pests, 2.5% deltamethrin or 1000-1500 times dilution of 40% omethoate can be used for control, once every eight to nine days. Pesticide spraying has an adverse effect on flower color and should not be used during the flowering period.
Spot Disease
Gerbera jamesonii is cultivated under protected conditions year after year. Because the environment is warm, humid, and poorly ventilated, it is prone to pest and disease occurrence. Among them, one of the most common diseases is Gerbera jamesonii spot disease, which is a disease caused by fungi.
Symptoms Small purplish-brown spots are produced on the leaves, gradually expanding into large spots with concentric rings (2 mm to 5 mm in diameter). In the later stage, the flower center rots, with sparse grayish-brown dust-like fungal threads on it.
Disease pattern Generally, the lower leaves are affected first. Excessive nitrogen fertilizer use easily triggers the disease. Heavy clay soil and poor drainage are also important conditions that induce the disease.
Control Methods
1. Soil treatment can use chloropicrin fumigation to effectively kill pathogenic bacteria and reduce the accumulation of inoculum from the substrate.
2. Regulate temperature and humidity. The most suitable temperature for the growth of Gerbera jamesonii is 20 °C to 25 °C, kept above 10 °C at night. Under low-temperature and low-humidity conditions, the disease is unlikely to occur.
3. Spray fungicides once every 7 to 10 days, such as 500 times dilution of 75% chlorothalonil, 500 times dilution of 50% captan, and 1000 times dilution of 70% thiophanate-methyl, with obvious control effects.
Phytophthora Disease Control
Gerbera jamesonii Phytophthora disease, also known as root and crown rot, is severely damaging once it occurs, often causing the death of the entire plant, or even the entire greenhouse, bringing serious economic losses to growers. After summarizing several years of cultivation experience, the author has summarized some effective measures and now introduces them to everyone.
1. Disease pattern Phytophthora overwinters as chlamydospores and oospores in diseased residues or soil. When there is no host, the resting spores can survive for a long time. The pathogen is spread by water flow, soil, and diseased plants.
2. Symptoms: It first infects the root and crown of the plant. The leaves of the affected plant first turn yellow, then grayish-brown, and then die, while the root and crown turn black and rot.
3. Control: (1) Select healthy, disease-free plants for cultivation.
2. Before planting, disinfect the soil of the nursery area. This pathogen mainly spreads through soil, so the nursery area must be carefully disinfected before planting. The main disinfection methods are: (1) Chemical disinfection: The chemicals can be a mixture of dexon and quintozene (3:1), with a dosage of 4-6 g/sq m. During disinfection, spray the chemicals on the soil surface, mix the soil evenly, seal with plastic film, seal the greenhouse for fumigation for 30 hours, then remove the covering, ventilate, stir the surface soil again, and plant after 15 days. (2) Steam disinfection: Release steam into the soil through pipes. This method has a relatively high investment cost, but the effect is good.
3. For Gerbera jamesonii, the planting depth should follow the principle of shallow planting, requiring the root crown to be exposed about 1.5 cm above the soil surface, with slight lodging as the standard (gently straighten it after 3 days). Because it has the characteristic of contractile roots, the root crown of the plant will be buried deep into the soil, giving the pathogen convenience for infection. To better facilitate the growth and development of seedlings, a planting method using local substrate can be adopted, that is, first dig a round planting hole about 10 cm in diameter at the planting point, then fill it with sun-disinfected river sand or a perlite + vermiculite (1:1) substrate, plant the seedling on the substrate, and water thoroughly.
4. When diseased plants are found, if it is the early stage of the disease, drench the rhizosphere with captan 0.1 g/1 + 1% copper sulfate; if it is already the late stage of the disease, immediately burn the diseased plants and treat the surrounding plants and soil with the above chemicals.
Whitefly Damage Control
Whitefly belongs to the order Homoptera, family Aleyrodidae, and can be divided into two types: greenhouse whitefly and silverleaf whitefly. It is an important pest of greenhouse horticultural crops in European and American countries. In the 1980s it became a major pest in northern China, and it has now spread throughout the country. In the Kunming area, varying degrees of pest damage have appeared on greenhouse crops such as cucumber, Gerbera jamesonii, rose, and poinsettia. Among the farmers surveyed by the author in Gerbera jamesonii production areas, 100% had whitefly damage. Many farmers consider whitefly to be the most difficult pest to control and the most damaging pest on Gerbera jamesonii. The author takes this opportunity to call on relevant departments to attach importance to this.
(1) Damage characteristics of whitefly. The Kunming area is warm in winter and cool in summer, which is very favorable for the reproduction and overwintering of whitefly. Under greenhouse conditions, whitefly does not stop reproducing throughout the year. Each female insect lays 100-200 eggs. In control, killing eggs appears very important, but the vast majority of pesticides only kill adults and do not harm eggs and pupae. Therefore, whitefly resistance to pesticides has become a widespread problem. A pesticide may be very effective in one place but may be very ineffective in another. According to foreign research, to eliminate a relatively severe infestation, it is necessary to spray pesticides at least once every 3-4 days, for 10-12 consecutive sprays. The eggs, older nymphs, and puparia of whitefly have strong resistance to temperature and pesticides. Once various insect stages occur mixed on crops, control becomes very difficult. It can be seen that whitefly is more difficult to control than ordinary pests, more likely to resurge, and continuously causes cyclical damage.
The population density of whitefly has the characteristic of rising exponentially. In the early stage of whitefly infection, it occurs only in spots and patches, and outwardly the plant shows no obvious symptoms of damage, so it is often overlooked. However, the harm of whitefly spreading viruses, weakening plant growth vigor, and seriously affecting shipment quality is already developing. Once it spreads, it may cause cyclical damage in the greenhouse for many years and be difficult to completely eliminate. Therefore, in daily flower production management and the process of introducing seedlings, attention should be paid to the inspection and control of whitefly, and once it occurs, measures should be taken promptly.
(2) Inspection of whitefly. Whitefly has four forms: egg, nymph, puparium, and adult. Adults lay eggs on the underside of leaves, 0.2-0.25 mm long, not easily noticeable with the naked eye, and need to be observed with a magnifying glass or microscope; they are mostly distributed on tender leaves. Nymphs and puparia are usually fixed on the middle and lower layers of old leaves and are easy to find. Adults like to attach to the underside of tender leaves and mature leaves. Both adults and nymphs can secrete honeydew, which accumulates on the leaves and causes sooty mold. If black gray sooty mold caused by fungal parasitism is found on the leaves, it indicates that the infection has already lasted for a relatively long time and is relatively severe. The colors whitefly likes most are lemon yellow and orange yellow, so yellow boards can be hung or set up for monitoring.
Among greenhouse flower crops, the ones that most attract whitefly and are severely damaged are: Gerbera jamesonii, Alstroemeria, primula, Salvia splendens, dahlia, pelargonium, cineraria, gloxinia, fuchsia, hibiscus, clematis, Abutilon, Solanaceae plants, columbine, and rhododendron. The ones with lighter damage are: chrysanthemum, poinsettia, Calceolaria, calla lily, rose, lily, and marigold. The ones not damaged are: cyclamen, carnation, freesia, tulip, narcissus, hyacinth, Orchidaceae plants, lilac, Palmae plants, and most succulent plants.
Sometimes flower crops and vegetable crops are rotated or planted in contiguous blocks, so it is necessary to know the vegetable crops severely damaged by whitefly, such as cucumber, tomato, lettuce, kidney bean, celery, muskmelon, pumpkin, and garlic. Weeds in and around the greenhouse are breeding grounds for whitefly. The weeds it likes are chickweed, Oxalis, nettle, dandelion, and so on.
(III) Control of Whiteflies
1. Prevention first, cultivate insect-free seedlings. Seedlings, crop residues and weeds carrying insects are important pathways for the spread of whiteflies, so before planting a new crop, weeds and previous crop residues must be thoroughly removed, and the ground left empty for a period. When introducing seedlings and potted flowers, carefully check for nymphs or eggs, and whether many leaves are missing. Once a greenhouse is infected with whiteflies, the movement of its crops in and out must be handled very carefully to prevent all greenhouses from becoming infected. Yellow sticky boards should be placed in the greenhouse for monitoring at any time. The field should be inspected regularly to check growth conditions and whether pests or diseases are occurring. Hanging white or silvery-white plastic strips at the greenhouse entrance can repel adult insects from entering.
2. Choose good pesticides and use them correctly. Whiteflies easily develop resistance to pesticides, so it is necessary to know more about the available types of pesticides in order to select them. For pesticides to which they originally have no resistance, pest resistance will only develop in the second generation, so for pesticides with good trial results, they can be used continuously for at least one generation or more, until resistance is found. Attention should be paid to correct pesticide application methods, and it is not advisable to change pesticides frequently. The table below lists pesticides with good results that have been tried domestically and abroad, for reference.
Category English name Chinese name or trade name Precautions
Organophosphates acephate acephate has a fumigant effect
chlorpyrifos chlorpyrifos, chlorpyrifos
etrimfos etrimfos
Carbamates methomyl methomyl, Lannate has a certain ovicidal effect
Pyrethroids sumicidin fenvalerate
Propoxur+methoxychlor propoxur+methoxychlor
Cypermethrin cypermethrin
Alphamethrin alpha-cypermethrin
fluralinate cyfluthrin
Acaricide mitac amitraz, has a fumigant effect
Chitin synthesis inhibitor pesticide buprofezin
Others Tempo endosulfan
abamectin abamectin spray concentration 1000 times
Diazinon diazinon
imidacloprid imidacloprid
3. Application of the high-temperature sealed method. In the process of controlling whitefly infestation, conventional spraying methods have the problems of low control efficacy, rapid decline in efficacy, and easy development of resistance. Whiteflies attach to the undersides of leaves and suck the leaf sap, easily creating dead angles that pesticide contact cannot reach, especially when plants are growing luxuriantly. When disturbed, whiteflies can fly several meters away, thereby avoiding contact with the spray solution, so even if a pesticide to which they have not developed resistance is used, its control efficacy is limited. The growth, development and reproduction of whiteflies are greatly related to temperature. The developmental threshold temperature of eggs is 7.2°C, and the optimum survival temperature is 20-28°C. Above 30°C, the mortality of eggs and larvae is high, adult lifespan shortens, fewer eggs are laid, and they may even stop reproducing. Whiteflies are poikilothermic animals, so above 30°C their respiratory frequency rises greatly, making it easy for them to inhale more pesticide.
In the practice of whitefly control, the author adopted high-temperature sealing, combining the advantages of fumigation and spraying, targeting the weaknesses of the pest and making full use of solar energy and the greenhouse effect, and achieved remarkable control results. The method is to mix a pesticide with a fumigant effect with a pesticide with an ovicidal effect (such as chlorpyrifos + Lannate), and add an appropriate amount of washing powder as a surfactant, and spray between 3:30 and 5:30 in the afternoon. Before spraying or while spraying, close the vents of the greenhouse or plastic tunnel to form sealed conditions, and maintain the temperature between 30-35°C for more than one hour. In summer, pull the shade net and delay the spraying time to prevent the temperature inside the tunnel from rising excessively. In the absence of sealed conditions, spraying during the high-temperature period in the afternoon is also more effective than spraying in the morning. When the temperature is high, the greenhouse or tunnel can easily rise above 30°C even without being sealed. At this time, it is advisable to spray in the morning when the temperature is lower, keep the tunnel sealed for 1-2 hours, and use a shade net to cool down if necessary, so there will be no worry about excessive humidity causing disease.
4. Other methods. Very effective methods for controlling whiteflies also include fumigation, smoke fumigation and smoke methods, which are introduced in other books. Biological control is a more scientific method and should be vigorously popularized and applied.
Mosaic disease
1. Symptoms. Leaves appear mosaic-shaped, and sometimes markings also appear on petals. The pathogens include cucumber mosaic virus (CMV) and tobacco mosaic virus (TMV).
2. Control methods. (1) Remove weeds in the flower garden and its surroundings at any time, and promptly use insecticides to control aphids. (2) Use 10% trisodium phosphate to disinfect cutting tools such as flower shears.
Root rot
1. Symptoms. The symptoms of this disease are similar to those of wilt disease, but there is no pink spore mass in the diseased part. The stem and root show water-soaked soft rot and turn black. The rotting phenomenon is obvious. The pathogen includes Phytophthora cryptogea Pethy-br et Laff., belonging to Mastigomycotina. Sporangia are obpyriform, and oospores are yellow and spherical. It is both parasitic and saprophytic, and the optimum growth temperature is 25°C.
2. Control methods. (1) Select and breed disease-resistant varieties. (2) Before planting in flower beds where this disease occurred the previous year, first mix dexon 1000-1500 times solution with the soil for sterilization. (3) When diseased plants are found, pull them out and burn them at any time to prevent the spread of the pathogen. The diseased soil must also be dug out and replaced with new soil.
Greenhouse diseases and insect pests
1. Phytophthora disease first infects the root crown. The leaves of affected plants turn yellow, then grayish-brown, until they wither and die, and the root crown becomes black and rotten.
Control methods:
(1) Select healthy, disease-free plants for cultivation.
(2) This pathogen mainly spreads through the soil, so the nursery ground must be carefully disinfected before planting. The pesticide can be dexon plus quintozene (3:1), with a dosage of 4-6 grams per square meter. During disinfection, spray the pesticide on the soil surface, mix it evenly with the topsoil, seal it with plastic film, and at the same time seal the greenhouse for fumigation for 30 hours, then remove the covering, ventilate and exchange air, and stir the topsoil again. Planting can be done after 15 days. Steam can also be released into the soil through pipes. This method has a relatively large investment cost, but the effect is better.
(3) When planting, the root crown should be exposed about 1.5 cm above the soil surface, with slight lodging as the standard. Because it has the characteristic of contractile roots, the plant's root crown will be buried deep in the soil, making it easier for the pathogen to infect. To facilitate the growth and development of seedlings, a cultivation method using local substrate can be adopted, that is, first dig a round planting hole about 15 cm in diameter at the planting point, then fill it with sun-sterilized river sand or a perlite + vermiculite (1:1) substrate, then plant the seedling on the substrate, water thoroughly, press the roots firmly, and then proceed with normal daily management. This can achieve immediate results.
(4) When diseased plants are found, in the early stage captan 0.1 g/L + 1% copper sulfate can be used to drench the roots. In the late stage of disease onset, the diseased plants should be immediately pulled out and burned, and the surrounding plants and soil should be treated with the above-mentioned pesticides.
2. Virus-infected diseased leaves have indistinct yellow-green spots, and new leaves become narrow. During high-temperature periods, the markings are not obvious. Growth is weak, the number of cut flowers drops sharply, and if it continues to develop, the diseased plants will wither and die.
Control methods:
(1) Remove diseased plants.
(2) Thoroughly eliminate aphids, the vectors that transmit the virus.
(3) When cultivated in poorly ventilated greenhouses, scale insects often occur and should be removed promptly.
3. For whiteflies, imidacloprid, dichlorvos, phoxim and methamidophos all have good control effects. However, if a single variety of pesticide is used, resistance is easily developed, so it is best to use mixed pesticides or alternate multiple pesticides, and avoid using the same pesticide continuously many times. For those that have developed resistance, organophosphorus pesticides can be mixed with Lannate water plus pyrethroid pesticides.
4. Leafminers have peak damage periods in April-May and October-November, and can be killed by mixing abamectin, avermectin, abadin or dimehypo plus fenvalerate.
Causes of root rot
The color of Gerbera jamesonii becomes dark and dull in midsummer, especially under drought and water shortage conditions; while flowers blooming during the suitable-temperature period of September-October or March-June of the following year are brightly colored. This indicates that Gerbera jamesonii is relatively sensitive to temperature and light intensity. In summer, the soil must be kept moist and not allowed to dry out, a shade net with 50% light transmittance should be used for covering, and water should be sprayed on the leaves to increase air humidity and lower temperature;
In winter, sufficient warmth should be provided to prevent freezing. The nighttime temperature should not be lower than 10°C, and the daytime temperature should not be lower than 15°C. These are all very beneficial for improving the brightness of Gerbera jamesonii. In addition, mites are a major enemy in Gerbera jamesonii cultivation. Once affected, not only does it lose its brightness, but the shape of the petals also becomes incomplete.
Therefore, ensuring that the entire growth period is free from mite damage is a particularly important link in guaranteeing the brilliant colors of Gerbera jamesonii.
The cause of root rot in Gerbera jamesonii is mostly root rot disease occurring in the roots, and once it occurs, it is difficult to cure completely. The external conditions that produce root rot disease are excessively high soil moisture around the roots, long-term water accumulation in the root zone, or long-term rainfall in open fields, which can cause the death of Gerbera jamesonii plants.
Potted cultivation techniques of Gerbera jamesonii Pot production
In the daily production process of potted Gerbera jamesonii, attention should be paid to the following points.
1. The production greenhouse should be equipped with ventilation, shading and heating facilities. If conditions permit, it should also be equipped with benches, ground cloth or an irrigation system. The greenhouse should be sealed to prevent insects from entering.
2. The temperature in the greenhouse should be controlled between 15°C and 25°C, with a maximum not higher than 30°C and a minimum not lower than 13°C. Generally, the average daily production temperature is 18°C to 19°C, and ventilation should be provided once it exceeds 19°C. At the same time, the nighttime temperature should not be too high, otherwise it will affect normal flower bud differentiation. The ideal nighttime temperature should be between 15°C and 18°C.
3. Use a medium with good air permeability and drainage performance, preferably a mixed substrate of peat and perlite. A pH value of 5.5 to 6.0 and an EC value of 0.7 to 1.0 are beneficial for the absorption of trace elements.
4. Potted Gerbera jamesonii is very sensitive to water, so the correct watering time must be ensured. Water in the morning or evening, and keep the plants relatively dry at nightfall. When the plants begin to grow roots, watering must be done from below, and a bottom seepage method can be used; during high-temperature periods, watering from above the plants can be done, but care must be taken to prevent fungal mold starting from the center of the plant.
5. Gerbera jamesonii relatively prefers fertilizer. In summer, the ratio of nitrogen to potassium when fertilizing is 2:1, and in winter it is 1.5:1. The pH value of the fertilizer should be 5.5 to 6.0.
6. The most suitable day length for Gerbera jamesonii during growth is 11 hours to 13 hours, so artificial supplemental lighting can be carried out during low-light periods. Generally, the requirement for artificial supplemental lighting is 3500 to 4000 lux per square meter. It should be noted that supplemental lighting should be carried out 4 weeks after the plants are potted.
7. From potting to flowering, Gerbera jamesonii requires 8 weeks to 9 weeks if produced in summer; winter production requires 11 weeks to 12 weeks. The pot size is 10 cm to 15 cm. About 30 pots can be produced per square meter in the greenhouse, but care should be taken to spread them out in time once the plants have grown to a certain size.
Gerbera jamesonii - postharvest handling
Harvesting: For single-petaled varieties, the flowers can be harvested after 2-3 rounds of stamens have matured, while double-petaled varieties should be harvested when more mature. Flowers harvested too early will have a shortened vase life. After harvesting, they must first be placed in water immediately, and the water must be very clean. Before placing fresh flowers in water, 2-5 cm of the hairy, lignified bottom flower stalk must be cut off so that the flower stalk can absorb water. Vase life is one of the most important components of the commercial value of cut flowers. Postharvest handling is very important for the vase life of Gerbera jamesonii. If cut Gerbera jamesonii flowers enter the market without postharvest handling, it will ultimately be difficult to satisfy consumers, which in turn will reduce the consumption of Gerbera jamesonii. The methods introduced below can extend the vase life of Gerbera jamesonii.
Harvesting cut flowers
Gerbera jamesonii flowers can only be harvested when one or two rounds of stamens have released pollen. Harvesting too early will shorten the vase life. This is because when harvested too early, the energy stored in the outer ray florets is not enough to complete their development. When harvesting flowers, the entire flower stalk should be picked rather than cut, because the part left after cutting will rot and infect the sensitive roots, and will also inhibit the sprouting of new flower buds. After the harvested flowers are sorted, cut off 2-4 cm from the bottom of the flower stalk. When cutting, cut at an angle, which can prevent the xylem vessels from being squeezed. The bottom of the flower stalk is composed of very narrow xylem vessels, which hinder water transport. After cutting them off, the flower can absorb water more easily, which is very important for avoiding cracking and bending of the flower neck. In addition, when harvesting flowers, air may be sucked into the vessels and prevent the flower from absorbing water. Cutting off part of the flower stalk also removes the air bubbles in the vessels.
Postharvest pretreatment
After the cut flowers are harvested, the flower stalks should immediately be immersed in a bucket and transported to a cool place. The water and buckets used should be very clean and should be cleaned and disinfected before each use to prevent bacterial growth, because bacteria will clog the vessels and prevent the flowers from absorbing water. During pretreatment, the pH of the water should be adjusted to 3.5-4.0 with chloride (bleaching powder). Too high a pH value will create ideal living conditions for bacteria. Bleaching powder can both lower the pH value of the water and sterilize, and the calcium chloride in it can also help extend the life of cut flowers. Studies show that the appropriate amount of bleaching powder added is 50-100 mg/L, and the treatment time cannot exceed 4 hours. Too long a treatment time will damage the flower stalks, manifesting as brown markings on the flower stalks or bleaching of color. For long treatments, the concentration of bleaching powder should be reduced, with a maximum of 25 mg/L and a minimum of 3 mg/L. When below 3 mg/L, bleaching powder should be replenished. The treatment site should not be exposed to sunlight, otherwise the useful components of the bleaching powder will decompose and become ineffective.
Preservative solution treatment
After pretreatment is completed, immerse the flower stalks in preservative solution for 6-24 hours. During treatment, immersing more of the flower stalk in water is beneficial for the flower to absorb water, and a length of 10-15 cm is ideal; too high an ambient temperature will cause the flowers to lose too much water through transpiration, so 10-15°C is ideal. Loss of water will cause Gerbera jamesonii flowers to age, so dryness and wind must be avoided throughout the entire postharvest handling process. It is best to raise the relative humidity of the environment to 70%. In addition, during preservative solution treatment, care must be taken to prevent the cut flowers from being harmed by ethylene. Ethylene is an aging hormone that will shorten the vase life of Gerbera jamesonii. Exhaust gas emitted by truck engines contains ethylene, so during loading, the truck engine should be turned off. The preservative solution for Gerbera jamesonii consists of the following components: sucrose, 3 g/L citric acid, 150 mg/L dipotassium hydrogen phosphate containing seven molecules of water of crystallization (K2HPO4·7H2O) 75 mg/L. Sucrose provides energy for Gerbera jamesonii to continue opening during the process and can also promote water absorption by the flowers. Citric acid lowers the pH value of the preservative solution, thereby preventing bacterial growth.
[Preservation management] Cut flowers can be stored in an environment with a relative humidity of 90%-95% and a temperature of 2-5°C. During storage and transportation, Gerbera jamesonii can tolerate longer dry storage. However, after opening the box, they must be inserted into water as soon as possible. Commercially available preservative solutions can also be used to extend vase life.
[Grading] Harvested flower materials should be graded on the premise of having the typical characteristics of the variety, being free of damage and contamination, and having good visual effects: the length of grade-one cut flowers is about 60 cm; the length of grade-two cut flowers is about 55 cm; the length of grade-three cut flowers is about 50 cm. The difference in length of cut flowers of the same grade should not exceed ±2 cm of the standard.
Packaging and transportation
During transportation, lower the ambient temperature to 6-9°C, so that the life activities of the flowers are slowed down, preserving energy for use when they reach consumers. Reusing cardboard boxes for packaging is more economical, but they can become places where bacteria grow. Therefore, cardboard boxes should not be reused too frequently. In short, throughout the entire postharvest handling process, cleanliness and hygiene must be maintained in order to effectively extend the vase life of Gerbera jamesonii. After Gerbera jamesonii arrives at its destination, the bottom of the flower stalk will become dry. Use a clean knife to cut off a little of the flower stalk at an angle, then immerse it in clean preservative solution. If there is no preservative solution, a low-concentration bleaching powder solution can also be used.
Gerbera jamesonii - daily management Humidity management
It likes relatively high air humidity. Too low air humidity will accelerate the withering of individual flowers. It also fears rain, and the leaves need to be kept dry at night. The optimum relative air humidity
is 65-75%. It likes a warm climate and fears intense heat. When the summer temperature is above 34°C, growth is obviously poor; it is not tolerant of frost and cold, and enters dormancy or dies when the winter temperature is below 4°C. The most suitable growth temperature is 15-25°C. Generally, sowing is done in autumn and winter to avoid high summer temperatures.
Light management
In spring, summer and autumn, it needs to be maintained under shaded conditions. When the temperature is relatively high (daytime temperature above 25°C), if it is placed in direct sunlight for maintenance, the leaves will noticeably become smaller, the internodes of the branches will shorten, the lower leaves will turn yellow and fall off, and growth will be very slow or it will enter a semi-dormant state. In winter, because the temperature is not very high, it should be given direct sunlight to facilitate photosynthesis and the formation of flower buds, flowering and fruiting. After the flowering period, after maintaining it indoors for a period of time (10-15 days), it should be moved outdoors to a place with shading (and warmth) for maintenance for a period of time (about one month), and alternating in this way is beneficial for the plant to accumulate nutrients and continue flowering.
Fertilizer and water management
Like other herbaceous flowers, it has relatively high fertilizer and water requirements, but the fertilization (and watering) principle of "light fertilizer applied frequently, small amounts but many times, complete nutrition" should be followed, and after fertilizing, the leaves and flowers should be kept dry at night: Spring and autumn These two seasons are its peak growth seasons. Fertilizer and water management follows the cycle of "Hua Bao"-"Hua Bao"-clear water-"Hua Bao"-"Hua Bao"-clear water (at the very least, "Hua Bao" must be guaranteed twice a week). The interval period is approximately: 1-4 days for outdoor maintenance; shorter intervals on sunny days or during high-temperature periods, longer intervals or no watering on cloudy and rainy days or during low-temperature periods; 2-6 days for indoor maintenance; shorter intervals on sunny days or during high-temperature periods, longer intervals or no watering on cloudy and rainy days or during low-temperature periods. Summer During the high-temperature period in summer, it often enters a dormant state and has low fertilizer and water requirements, and may even need controlled fertilizer and water. Fertilizer and water management follows the cycle of "Hua Bao"-clear water-clear water-"Hua Bao"-clear water-clear water. The interval period is approximately: 3-5 days for outdoor maintenance; shorter intervals on sunny days or during high-temperature periods, longer intervals or no watering on cloudy and rainy days or during low-temperature periods; 4-7 days for indoor maintenance; shorter intervals on sunny days or during high-temperature periods, longer intervals or no watering on cloudy and rainy days or during low-temperature periods. Watering time should be arranged as much as possible in the morning when the temperature is lower, and the leaves should be kept dry at night.
The plants should also be sprayed frequently. Winter During the winter dormant period, the main work is to control fertilizer and water. Fertilizer and water management follows the cycle of "Hua Bao"-clear water-clear water-"Hua Bao"-clear water-clear water. The interval period is approximately 7-10 days; shorter intervals on sunny days or during high-temperature periods, longer intervals or no watering on cloudy and rainy days or during low-temperature periods. Watering time should be arranged as much as possible at noon on sunny days when the temperature is relatively high.
Key maintenance points Temperature
Cultivation facilities should meet the temperature requirements of Gerbera jamesonii during the seedling stage, growth stage and flowering stage, facilitating normal growth and flowering. Except in South China, it cannot overwinter in open fields, so greenhouse cultivation is carried out. Outside the Yangtze River basin, unheated plastic tunnel cultivation can be used. In summer, a shade net needs to be covered on top of the tunnel, and the plastic films on both sides of the tunnel should be opened to lower the temperature. In winter, when the outdoor nighttime temperature approaches 0°C, the plastic film should be lowered, and plastic film must be added inside the tunnel. On clear and warm days, uncover the film at the south end of the tunnel for ventilation for about one hour.
Light
A light-loving flower. In winter it needs full light; in summer attention should be paid to appropriate shading, strengthening ventilation, lowering temperature, and preventing high temperatures from causing dormancy.
Irrigation
After planting, the seedling stage should maintain appropriate moisture and exercise the seedlings to promote root development and rapid seedling establishment. During the vigorous growth period, sufficient water supply should be maintained, watering once every 3-4 days, and once every half month in winter. When watering during the flowering period, care should be taken not to let water touch the center of the leaf rosette, to prevent flower bud rot. During cultivation, attention should be paid to preventing waterlogging. Fertilization can be combined with irrigation.
Topdressing
Gerbera jamesonii is a fertilizer-loving perennial herbaceous flower with high fertilizer demand. The ratio of nitrogen, phosphorus and potassium in fertilization is 15:18:25. Special attention should be paid to supplementing potassium fertilizer. Apply 2.5 kg of potassium nitrate per mu, 1.2 kg of ammonium nitrate or ammonium phosphate, once every 5-6 days, once every 10 days. If high temperature or relatively low temperature causes the plant to enter a semi-dormant state, then stop fertilizing.
Remove residual leaves
The lower leaves of the basal leaf rosette easily turn yellow and age. Removing them promptly is beneficial for the sprouting of new leaves and new flower buds, is beneficial for ventilation, and enhances plant vigor.
Selection of fresh cut Gerbera jamesonii flowers Selection
The junction between the flower stem and flower head of Gerbera jamesonii is relatively thin and soft, while the flower head is large and heavy, and easily bends down from the neck. Therefore, when selecting, short and thick flower stems must be chosen, so that the neck can have more strength to support the flower head.
Only a small section at the bottom of the Gerbera jamesonii flower stem is solid, and the flower stem above is hollow. However, Gerbera jamesonii mainly relies on this solid part to absorb water, so if the solid bottom has been cut off, do not choose it! After buying it home, put it into water as quickly as possible, and try not to cut off the solid stem section at the bottom.
Arranging
The "neck" of Gerbera jamesonii is thin, and the flower head easily droops and causes it to wither. Therefore, every possible means should be used to fix the neck, such as wrapping and reinforcing it with soft iron wire, then covering it with green tape to conceal it.
The petals of Gerbera jamesonii wither from the outside inward. Therefore, when the outer petals are not good, they can be directly removed, and the remaining flower center part is also quite ornamental. Because Gerbera jamesonii petals are extremely easy to damage and leave scars, they must be handled with care.
Soak in water up to one third of the length of the flower stem, because the flower stem is soft and easy to rot, so the water level should not be too high.
Preservation methods
Gerbera bought back from the flower market does not need its roots cut, especially do not cut off the hard node at the bottom of the root. Just place it directly in water, with less water, soaking only to its hard bottom. The flower bucket should be relatively tall, preferably reaching the flower head part. Gerbera with cut roots easily rots at the stalk, and rots especially quickly.
If newly received stock shows dehydration, first place it directly in water. If it has not recovered after a few hours, then slightly cut the root bottom into a slanted opening and place it in water.
If there is no dehydration, then it is a normal bent-stem phenomenon. Straightening its flower head is actually very simple: just take it out and lay it flat, or wrap it in paper for one or two hours and then place it in water.
The flower language of Gerbera jamesonii
The flower language of Gerbera jamesonii symbolizes mystery, mutual respect and mutual love, perseverance, and fearlessness of hardship. It likes to pursue a rich life. Single-petaled varieties represent warmth, while double-petaled varieties represent commendable enthusiasm. In the Shanghai area, people like to use Gerbera jamesonii to tie bouquets to decorate the bridal chamber during wedding celebrations. Using its homophonic meaning, it takes the meaning that the newlyweds respect and love each other and that the wife supports her husband in achieving success in his career. The flower shape of Gerbera jamesonii is radial and is often used as the main body of flower arrangements, often paired with Nephrolepis cordifolia and Asparagus setaceus.
The flower language of Gerbera jamesonii is -- eternal happiness. Its most commonly used flower language in China: elegant. noble. reclusive.
Gerbera jamesonii pictures