Gerberas are commonly propagated by three methods: division, cuttings and sowing
Everyone has probably heard of the gerbera; it has huge blooms and a wide range of flower colors, making it a flower deeply loved by gardening enthusiasts. As more and more people grow gerberas, mass propagation becomes imperative, so how do you propagate a gerbera? Overall, there are three propagation methods for gerberas: division, cuttings and sowing
Everyone has probably heard of the gerbera; it has huge blooms and a wide range of flower colors, making it a flower deeply loved by gardening enthusiasts. As more and more people grow gerberas, mass propagation becomes imperative, so how do you propagate a gerbera? Overall, there are three propagation methods for gerberas: division, cuttings and sowing. Next, follow along as we look at the specific operations in detail.
1. How to propagate gerberas: division / cuttings / sowing
As a green plant that can be grown indoors, the gerbera's propagation methods are no different from those of other plants; they are mainly divided into sexual propagation and asexual propagation. Asexual propagation is further divided into cuttings and division; sexual propagation is the sowing method. So how do you propagate a gerbera? We will explain in detail how to do each one.
2. The three propagation methods for gerberas
(1) Propagation of gerberas by division
This is the most common propagation method for gerberas. Generally, every three years, when the plant becomes crowded, we can divide it once. Use a knife to divide the plant into several sections, each of which must have one to several top buds and enough roots; disinfect the wounds and pot them up. The specific operations are as follows:
1. Time for division
Gerberas are usually divided in March and April, once every three years.
2. Method of division
Dig out a healthy gerbera that has grown for three years and cut it into several daughter plants. Each daughter plant must carry one to several top buds and enough roots, and should not be divided too small. Then pot them separately, taking care not to plant them too deep; it is best to plant two plants per hole as a group, as this helps increase the number of flowers. After that, simply care for them according to gerbera growing methods.
(2) Propagation of gerberas by cuttings
Cuttings are the most common propagation method for plants, but for propagating gerberas, cuttings are not practical because the operation is very inconvenient, so they are not recommended. Simply put, taking cuttings means cutting off the top, then using the many side shoots that develop for cuttings. The specific operations are as follows:
Choose a robust mother gerbera plant, dig it out and remove the soil, then cut off the thick part of the rhizome, remove the leaves, cut off the growing point, keep the root crown, and finally plant it in a growing box filled with peat. Keep the room temperature at 22-24°C and the humidity at 70%-80%. After about 2 weeks, leaf axillary buds and adventitious buds will successively grow from the root crown, forming shoot cuttings. Compared with taking cuttings from other plants, this is frighteningly troublesome!
After the shoots grow 4-5 leaves, cut them off as cuttings and insert them into a sand bed. After cutting, keep the temperature at 25°C and the humidity at 80%-90%, and they will root in about one month. After rooting, transplant them into nutrient pots and grow them for one month, and small gerbera seedlings will form. One mother plant can be cut for cuttings 3-4 times repeatedly, yielding 10-20 cuttings. It is worth mentioning that new plants from cuttings taken that year can bloom the same year.
(3) Propagation of gerberas by sowing
Gerberas leave seeds behind after flowering, so they can be propagated by sowing. It is worth mentioning that gerberas are self-sterile and must have at least two different gerbera plants cross-pollinating each other in order to set seed. So when we propagate gerberas by sowing, we usually buy seeds from a flower shop; imported ones are of course preferable. The specific operations are as follows:
1. Time for sowing
For propagating gerberas by sowing, you must first choose the right time; you can sow in spring or autumn, with spring sowing in March and May and autumn sowing in September and October.
2. Method of sowing
After buying the seeds, scatter them into prepared potting soil, but gerbera seeds have a low germination rate of only about 50%, so after-sowing care is very important. After sowing, cover with paper to prevent direct sunlight, keep the temperature at 20—25°C, and they will germinate within about two weeks. After about sixty or seventy days, when the seedlings have 3-4 true leaves, transplant them into flower pots or set them out in the open ground, and with proper cultivation they can be seen flowering in 2-3 months.
Overall, gerberas can be propagated by cuttings, division or sowing, but the ones most suitable for the vast number of gardening enthusiasts are division and sowing. So those who want to turn one pot of gerberas at home into many pots should quickly try it themselves; even beginners have a very high chance of success~ That is all for the introduction to gerbera propagation methods, and we hope it can be of help to everyone.
How do gerberas propagate? Gerbera propagation methods
Gerbera flowers are large, elegant and upright, free and easy, with gorgeous colors and elegant charm, giving people a feeling of warmth, peace and enthusiasm. They are also highly decorative, withstand long-distance transport, and last a long time in water, making them an ideal cut flower material. So, do you know how gerberas should be propagated? Let us look at gerbera propagation methods together:
Gerbera propagation methods: commonly by sowing, division, cuttings and tissue culture.
1. Propagation by sowing: Gerbera is a cross-pollinated plant and is self-infertile, so its seed offspring will inevitably vary. Sowing propagation is often used in breeding. Sow in spring from March to May, or in autumn from September to October; it is best to sow immediately after the seeds mature. The optimum germination temperature is 18-20°C, germination occurs 7-10 days after sowing, the seed germination rate is about 50%, and seed viability is short. If the potting soil is too wet, the seedlings are prone to disease and collapse. 60-70 days after sowing, when the seedlings have 2-3 true leaves, transplant them into 10 cm pots. Flowering can be seen 2-3 months after planting out.
2. Propagation by division: carried out from March to May. First lift out the mother plant and cut the underground stem into several daughter plants; each daughter plant must carry new roots and new buds, and potted planting should not be too deep, as the root buds must be exposed above the soil surface. New buds without roots are difficult to keep alive.
Propagation by cuttings: dig out a robust plant, cut off the thick part of the root, remove the leaves, cut off the growing point, keep the root crown, and plant it in peat. Keep the room temperature at 22-24°C and the relative humidity at 70%-80%. Leaf buds and adventitious buds will grow from the root crown to form cuttings. One mother plant can be cut for cuttings 3-4 times repeatedly, yielding 10-20 cuttings. Insert them into a sand bed, and they can root in about 3-4 weeks. New plants from cuttings taken that year can bloom the same year.
3. Propagation by tissue culture: at present, the Netherlands, the United States, Japan, Germany and other countries use materials such as leaves, unfertilized ovules, flower buds, stem tips and rhizomes as explants. The bud differentiation medium is MS medium plus 2 mg/L 6-benzylaminopurine and 0.5 mg/L indoleacetic acid. The subculture proliferation medium is MS plus 10 mg/L kinetin, and the rooting medium is 1/2 MS plus 0.03 mg/L naphthaleneacetic acid. After gerbera explants are induced to sprout, after 4-5 months of test-tube proliferation, they can be bred into batches of test-tube seedlings and put into large-scale production.
You should now understand gerbera propagation methods; we hope the gerbera propagation methods introduced above can be of help to everyone in growing gerberas!
Gerbera Gerbera jamesonii Bolus Gerbera illustrated guide: how to grow gerberas / how to propagate gerberas
Gerbera profileGerbera Gerbera jamesonii Bolus
Gerbera growing methods and precautions Introduction to gerberas
Gerbera (English name: Gerbera), a perennial herbaceous plant of the Asteraceae family, with fine hairs all over the plant, terminal inflorescences, and most leaves basal and pinnately lobed. The plant height is 30-45 cm, the capitulum is solitary, the inflorescence is terminal, and the flower colors include red, white, yellow, orange, purple, etc. It rises 20-40 cm above the leaves, the flower diameter is 10-12 cm, the involucre is disc-shaped and bell-shaped, and the ligulate petals are in 1-2 or multiple whorls in a double form. It usually flowers in all four seasons, most abundantly in spring and autumn.
It is an important material in modern cut flowers. Gerbera flower diameter is relatively large (8 cm-10 cm), flowering time is easy to regulate, and the area under cut flower cultivation is increasing year by year, with ever-widening applications. Gerberas can also withstand long-distance transport, and cut flowers last a long time in water; with proper cultivation methods, each plant can yield 30 cut flowers a year, truly an ideal cut flower. Gerbera flowers are huge, rich in color, and labor-saving to manage, and in warm regions they can supply fresh cut flowers year-round. The main types can be divided into modern cut flower types and dwarf cultivated types, with various flower colors such as white, pink, red and yellow.
Morphological characteristics of gerberas
Perennial, hairy herb. The rhizome is short, wrapped by remnant leaf stalks, with relatively thick fibrous roots. Leaves basal, rosette-shaped, the blade oblong-elliptic to oblong, 10-14 cm long, 5-6 cm wide, the apex shortly acute or slightly obtuse, the base gradually narrowed, the margin irregularly pinnately lobed or deeply lobed, glabrous above, short-pubescent below, losing hairs when old; the midvein is raised on both sides, thick and especially prominent below, lateral veins 5-7 pairs, arched and connected away from the margin, reticulate veins slightly obvious; petiole 7-15 cm long, with thick longitudinal ridges, more or less hairy. Scapes solitary, or rarely several clustered, 25-60 cm long, without bracts, hairy, the hairs densest at the top, the capitulum solitary at the top of the scape, 6-10 cm in diameter when the ligules spread out at flowering; involucre bell-shaped, about as long as the bisexual flowers, up to 2 cm in diameter; involucral bracts in 2 layers, the outer ones linear or subulate, apex acute, 8-10 mm long, about 1-1.5 mm wide, pubescent on the back, the inner ones oblong-lanceolate, apex caudate-acuminate. 10-14 mm long, about 2 mm wide, the margin dry-membranous, sparsely pubescent on the ridge; receptacle flat, bare, honeycomb-like, 6-8 mm in diameter; outer female flowers in 2 layers, the outer corolla ligulate, the ligule pale red to purplish red, or white and yellow, oblong, 2.5-3.5 cm long, 2-4 mm wide, the apex with 3 teeth, the inner 2 lobes filiform, curled, 4-5 mm long, the corolla tube short, about 1/8 the length of the ligule, staminodes filiform, 3-4 mm long, extending beyond the corolla tube; inner female flowers more slender than the bisexual flowers, tubular and bilabiate, 6-7 mm long, the two lips equal in length, the outer lip with 3 fine teeth or sometimes 2 teeth and 1 lobe, the inner lip 2-parted deeply, the lobes linear, about 4 mm long, curled, staminodes 4-5, linear or filiform, hidden within the corolla tube; central bisexual flowers numerous, tubular and bilabiate, 8-9 mm long, the outer lip large, with 3 teeth, the inner lip 2-parted deeply, the lobes usually broad, curled; anthers about 4 mm long, with long pointed tails; the style branches of both female and bisexual flowers are short, apex obtuse, less than 1 mm long. Achene 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 from November to April of the following year.
Ecological habits of gerberas
It likes an environment that is warm in winter and cool in summer, with circulating air and sufficient sunlight; it is not cold-tolerant and dislikes intense heat. The optimum growing temperature is 20°C-25°C, the optimum winter temperature is 12°C-15°C, and growth stops below 10°C. It is a semi-hardy flower and can tolerate short periods of 0°C low temperature. In South China it can be cultivated as an open-ground perennial flower; in East China it must be covered to overwinter or grown in a greenhouse for cut flower forcing cultivation. It likes fertile, loose, well-drained sandy loam rich in humus, dislikes heavy clay soil, and prefers slightly acidic soil; it can also grow in neutral and slightly acidic soil, but in alkaline soil the leaves are prone to deficiency symptoms. Gerbera flowering time is very easy to regulate; as long as the room temperature is kept above 12°C, the plant will not enter dormancy and will continue to grow and flower. It likes fertile, loose, well-drained sandy loam rich in humus, dislikes heavy clay soil, prefers slightly acidic soil, and is a semi-hardy flower that can tolerate short periods of 0°C low temperature. Gerbera is a light-loving plant, so choose a location with sufficient light for cultivation. Seedlings should not be planted too deep, and the root buds need to be exposed above the soil surface. If light is insufficient, the flower stalks become soft and droop, and cut flower quality is not high.
Economic value of gerberas
Yunnan gerbera seedling producers are mainly concentrated in Kunming, numbering about 20, of which more than 10 are relatively large-scale. The annual output of gerbera seedlings is about 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 loved by growers inside and outside the province, and Kunming has become the center of national gerbera seedling production. After nearly 10 years of development, the gerbera, which ranks fifth on the international cut flower sales list, has continuously expanded its planting scale in Yunnan, and 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 Yunnan fresh flower sales boom has receded, it has ushered in the "golden period" for gerbera seedling sales. Gerbera seedlings sold from Kunming to inside and outside Yunnan Province reached more than 2 million plants in April sales, and a national gerbera seedling production pattern centered on Kunming has basically taken shape.
Volume declined and prices fell back
It is understood that Yunnan gerbera seedling producers 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 appeared, because enterprise production has declined, the total gerbera seedling production has decreased compared with before, to about 15 million plants. Prices have also fallen back, 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 4,500 seedlings planted per mu, the newly added 1,000 mu requires 4.5 million seedlings; for the remaining 4,000 mu, if 1/3 of the gerbera plants need replacing with new seedlings (gerbera growers generally replace seedlings once every two or three years), 6 million seedlings are needed, giving a provincial seedling demand of 10.5 million plants. If 1/3 to 1/2 of gerbera plants are replaced with seedlings, 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 fact, Yunnan gerbera seedling enterprises do not sell much in markets outside the province. Therefore, gerbera seedlings are in a situation of supply exceeding demand, and the sales situation is grim.
In addition, affected by soil continuous cropping obstacles, the gerbera cut flower market is not very prosperous, causing some flower growers in Jinning County, Kunming City, which accounts for nearly half of Yunnan's gerbera planting area, to switch land previously planted with gerberas to roses or carnations, and demand for gerbera seedlings within the province has shrunk. Demand for seedlings in markets outside Yunnan Province is in a growth trend; surveys show that the gerbera planting area in Jiangsu, Liaoning, Shandong and other provinces is increasing.
Seeking joint development
After nearly 10 years of development, many enterprises or research institutions in Yunnan have already possessed relatively strong production technology and experience, collected rich gerbera variety resources, and the gerbera seedlings they produce have formed a certain brand effect, deeply loved by growers inside and outside the province. However, due to reasons such as relatively large losses in long-distance transport of gerberas, post-harvest handling technology not keeping up, and declining quality of seedling mother plants, the development of the gerbera cut flower and seedling business has been affected.
Kunming Tongxin Flower Co., Ltd. has an annual gerbera seedling output of 7 million plants, of which nearly 50% of seedlings 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 seedling propagation coefficient 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 being mainly used 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 a 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 negotiated with the Dutch company Florist and plan to introduce more than 4 million high-quality mother plants from the company, requiring the payment of more than 4.8 million yuan in royalties.
Gerbera Gerbera and daisy differences Gerbera
Scientific name: Gerbera jamesonii
Family: Asteraceae
Origin and distribution: South Africa
Morphological characteristics: with a rosette leaf cluster. Leaves oblong-spatulate, deeply lobed or lyre-shaped pinnately lobed, with white down on the leaf back. Capitulum. Flower colors range from white to various yellows, oranges, rose reds, reds, etc. If the ambient temperature is suitable, it can flower all year round.
Growth habits: Likes mild winters and cool summers. Requires well-drained, humus-rich, deep and fertile soil with a pH value of 6-6.5.
Garden use: Gerbera is mainly used for cut flowers and pot flowers, and can also be used for flower beds when climate conditions are suitable.
Propagation and cultivation: potted, mainly by sowing.
Daisy
Aliases: spring daisy, everlasting daisy
Scientific name: Bellis perennis
Family and genus: Asteraceae, Bellis genus
Habits: A perennial herbaceous plant, often cultivated as an annual or biennial. Likes cool, moist conditions and sufficient sunlight, is relatively cold-tolerant, and can overwinter in the open ground where the surface temperature is not lower than 3-4°C. It has no strict requirements for soil. Flowering period is April-May.
Cultivation: propagated by sowing or division. The optimum seed germination temperature is 22-28°C. In North China, sow in August-September, move into a sunny cold frame in late October to overwinter, and in April of the following year pot them up or plant them into flower beds. During the growing season, as long as proper water and fertilizer are ensured, they will grow well. After flowering, the roots can be divided and planted in pots, placed in a cool place to spend the summer, and after the weather cools in autumn moved into a greenhouse or indoors; with strengthened fertilizer and water management, they can bloom again in winter or the following spring. There are relatively few pests and diseases.
Cultural background, origin and evolution of gerberas
In 1878, Rehman first discovered the gerbera in Transvaal, South Africa, and in the same year Blas sent it to Kew Gardens in England. Lynch of England was the first to carry out hybrid breeding of gerberas; he crossed the gerbera with Gerbera viridifolia Sch.-Bip.; producing hybrids; afterward, Adnet of France selected and bred varieties for cut flowers; after 1950, new varieties were bred in Europe; in 1980 dwarf potted varieties were also bred, flowering almost continuously all year. Japan also achieved excellent results in breeding double gerberas. In addition, people have also bred many distant hybrids, using the gerbera as the female parent and Coreopsis basalis Blake. or Argyranthemum frutescens Sch.-Bip. as the male parent, and their hybrid flower forms mostly resemble the male parent.
Gerbera flower color gene inheritance is rich, and its heterogeneity is very high; its offspring differ greatly in flower form and color. Therefore, excellent hybrid individual plants can be rapidly and massively propagated into clonal lines through tissue culture, so varieties are replaced very quickly with trends. Its flower colors are mainly white, red, pink, orange, purple, etc. In addition, interspecific hybridization and fusion are easy, so besides the above inherent color lines, there are also many intermediate color lines.
Origin of the name Gerbera (Fulang flower)
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 Slang Yini who had loved this kind of wildflower with slightly curved stems and drooping heads since childhood. When she married, she asked for more of them to be arranged in the hall to add to the wedding atmosphere. Relatives and friends from all sides sang and danced, toasting each other frequently. Unexpectedly, the bridegroom, who had a very low tolerance for alcohol, became drunk after only three rounds of drinks; he bowed his head and bent his waist, leaning east and west, and the bride had no choice but to support him into the bedroom to rest. Seeing how much this supporting posture resembled the growth habit of that wildflower, many girls said in unison: "Oh, the flower really looks like it is supporting the bridegroom!" From then on, the name Fulang flower spread far and wide.
Gerbera is also known as Fulang flower and is native to southern Africa. Its flowers are large and beautiful, with a charming appearance, and it is an important cut flower decorative material. Large red gerberas are used for bridal bouquets. Together with roses, gladioli and carnations, it ranks 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 Gerbera viridifolia (G. vurufolia). Later the Frenchman M. Adent continued to improve them and bred a large number of cut flower varieties. In addition, Japan also bred double varieties with diverse flower forms and colors, collectively called hybrid gerbera (Gerbera jamesonii), used for cut flowers and pot flowers.
Feng shui
Gerberas can promote a woman's romance. The bedroom is probably the most important space for changing a woman, especially when in love, when random thoughts mostly occur 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.
Gerberas can promote family harmony. Gerberas, like sunflowers, are flowers that represent the sun in everyone's minds, except that the latter is tall and imposing while the former is delicate 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 the gerbera as the flower representing Father's Day, because the gerbera is also called the sun flower, and the sun can symbolize fatherly love. The feng shui effect of gerberas being able to keep a family living in harmony and loving each other also arises from this.
For people whose Five Elements belong to fire, the 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 fate. Plants also have yin-yang and Five Element 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, so plants are often used to regulate environmental energy fields. There are many types of plants and their natures differ greatly, so there are many particularities 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, green, as the main color, because green wood generates and strengthens red fire. From a feng shui perspective, this can bring prosperous good fortune to the homeowner and their family. Of course, besides red, gerberas also have many other colors, so gerberas are the lucky star of many people; as the color of the gerbera changes, the group of people it blesses differs.
Gerbera variety classification Variety classification
They 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 diameters can reach 15 cm, with a long flowering period, the ability to flower all year round, and long ornamental duration, with a vase life as long as 7-10 d. Cut flower types can further be divided into single, semi-double and double types; according to color they can be divided into bright red lines, pink lines, pure yellow lines, orange-yellow lines, pure white lines, etc. Different types 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, disc small, flower stalk 5-6 mm thick, 50 cm long. Annual yield 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 yield 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", and the white "Bianca". Miniature small-flowered ones include "Ballroom" (white), "Ballet" (orange), "Sultan" (yellow), and "Canga" (red).
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 cream yellow deep pink
18 Willy 7 many deep pink purplish red
Main species in 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, and have not been used ornamentally. Other species commonly seen in cultivation for ornament 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 gerberas
The place of origin is South Africa, with a few distributed in Asia. Now commercial production also occurs in Taiwan, China and Guangdong. With the progress of domestic greenhouse technology and the introduction of new foreign greenhouse technology, it is cultivated in South China, East China and Central China.
Garden use of gerberas
Its flowers are huge, the flower stems upright, the colors gorgeous, the water-holding time long, and the cut flower rate high; the vase life can reach 15-20 days, and cultivation saves labor and time, making it one of the world's famous top ten cut flowers. It can also be used to arrange flower beds and flower borders, or grown in greenhouses in pots as decoration for halls, meeting venues, etc.
Potted gerberas are often used to decorate doorways and halls, and their cut flowers are used in vases and flower arrangements to adorn desks, shop windows and living rooms. With pink gerberas as the main flower, paired with dendrobium, baby's breath and orchid leaves, the tone is elegant and the mood rich. If red gerberas are used as the main flower, paired with sword fern, palm bamboo leaves, dried branches and dyed walnuts for wall decoration, a relatively strong decorative effect can be produced. They are commonly cultivated in gardens throughout China, mostly in pots.
Gerbera propagation methods Propagation is by sowing or division.
Because gerbera is a cross-pollinated plant and is self-infertile, its seed offspring will inevitably vary. The variation types generally show thinner and softer flower stalks, smaller flower form, and greatly reduced cut flower value, so gerberas must be propagated asexually. Division is usually used, but each plant can only be divided into 5-6 new plants per year. In order to accelerate propagation, cuttings and tissue culture can also be used.
Propagation methods
Tissue culture is the main method of propagating gerberas. Gerbera tissue culture commonly uses the receptacle as the explant, using flower buds about 2 cm in diameter; after disinfection and washing, only the receptacle is kept, cut into 2-4 pieces, and placed on the medium. The medium formula is MS plus BA 1.0 mg/L and indoleacetic acid (IAA) 0.5 mg/L. At 22°C with 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; the medium is MS plus BA 0.1/L and indoleacetic acid 0.1 mg/L. When the leaves of the test-tube seedlings reach 2 cm in length, transfer them to the rooting medium. When transferring the 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 proliferation, thousands upon thousands of test-tube plants can be produced. The most suitable time for field transplanting of gerberas is April; seedlings transplanted at this time can produce flowers abundantly in August. Therefore, callus differentiation into shoots should be completed before mid-October; the 1st test-tube proliferation is from mid-October to mid-November, then once a month thereafter, ending with the 4th proliferation in mid-February of the following year, followed by 2 weeks of test-tube seedling rooting; after rooting, transplant to the seedling bed, maintain for 1 month, and then move to the field in early April.
Gerberas are mostly propagated rapidly through tissue culture, or by division, with each mother plant being divided 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 neck can be cut and used for cuttings. The response to photoperiod is not sensitive, and the length of daylight has no effect on flower count or flower quality. It requires loose, fertile, well-drained, humus-rich, deep, slightly acidic sandy loam soil.
Cultivating gerberas in artificial growing medium can significantly increase yield and quality. A self-mixed growing medium of 5 parts humus, 2 parts perlite, and 3 parts peat can be used for planting, but the production cost of this method is relatively high. Field planting can also be carried out; select loam soil with a deep soil layer of at least 25 cm or more suitable for gerbera growth for planting. Before planting, apply sufficient base fertilizer: per mu, apply 5 tons of livestock manure, 600 kg of chicken manure, 100 kg of superphosphate, and 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 in, forming a ridge-and-furrow layout, with ridges 40 cm wide and furrows 30 cm wide. Plants are set on the ridges in double rows in a staggered arrangement. Spacing between plants is 25 cm. Care should be taken to leave the root crown slightly exposed above the soil to prevent root rot. Then water is applied in the furrows.
However, due to its rapid reproduction rate, it has been listed as an invasive alien species in Guangdong, China. If you want to transplant it outdoors, consider it carefully, otherwise once the flowers open and seeds set, it may cause unnecessary [spread].
Division propagation
Because old plants flower 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 retaining 4-5 leaves, and replant them separately. The disadvantage of this method is that the propagation rate is slow.
Cutting propagation
Dig up selected healthy mother plants, remove the soil from the roots and remove the leaves, and cut out the growing point. Keep the root crown portion and plant it in a growing box for cultivation. Place the growing box under conditions of 22-24 °C and 75%-80% relative air humidity. Afterwards, the root crown will successively produce axillary buds and adventitious buds, forming cuttings for propagation. After the shoot cuttings have 4-5 leaves, cut them off and insert them into soil or other substrate, covering 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 the rooted cuttings can then be transplanted.
Gerbera cultivation techniques and key cultivation points
The suitable temperature during the growing period of gerbera is 20-25 °C. Below 10 °C or above 30 °C, growth stops and the plant enters a semi-dormant state. If year-round flowering is desired, the temperature must be maintained above 12-15 °C in winter and not exceed 26 °C in summer. Therefore, in the southern Fujian area it can overwinter in the open field, but to obtain high-yield, high-quality cut flowers, it is best to have plastic greenhouses or other insulation equipment. In summer, shade nets can be used or water sprayed to lower the temperature, ensuring a year-round supply of cut flowers.
(1) Soil must be disinfected. Gerbera does not have strict soil requirements; loose, breathable, humus-rich sandy soil is suitable. Because the pathogens of various diseases harmful to gerbera can survive in the soil, and soil also contains underground pests and earthworms that damage the root system, soil disinfection should be carried out before planting.
(2) Land preparation and fertilization. Because gerbera is afraid of waterlogging, high-bed cultivation is generally used. The beds generally run north-south, with a bed height of about 30 cm, bed width of 1 m, and furrow width of 40-50 cm. Combined with land preparation, apply appropriate base fertilizer, applying 200 kg of barnyard manure per 100 m.
(3) Planting. The best time for planting is on cloudy days or in the evening on sunny days. Except for the high-temperature period from July to September in summer, planting can be done at any other time. When planting, it must be planted shallowly, with the root crown exposed above the soil surface, and water thoroughly. Newly planted plants should be shaded with shade nets.
(4) Pay attention to seedling stage management. Carry out insulation or cooling management according to the weather conditions during the planting period, controlling the temperature at 20-25 °C, so that the plants quickly resume growth. After the seedlings have recovered, apply 1:10 diluted human manure and urine 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 rotting.
(5) Fertilizer and water management. Gerbera is drought-tolerant but not moisture-tolerant, and waterlogging must be strictly avoided. The seedling stage 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 not dry, and water thoroughly when watering. In winter, water as little as possible, and it is better for the soil to be on the drier side. In summer, the weather is hot and water evaporates quickly; the plants enter a semi-dormant state, flower production drops noticeably, and plant vigor weakens. At this time, pests and diseases are very likely to occur. This can be combined with topdressing to promote root absorption of fertilizer. In summer, timely loosening of the soil, cleaning of roots to prevent disease, controlling water and fertilizer, and shading and rain protection should be carried out.
(6) Leaf removal and bud thinning. Gerbera can flower year-round within the range of 5-30 °C, so it has a high fertilizer demand throughout the growing period. Before flower bud differentiation, increase the application of organic fertilizer and nitrogen fertilizer to promote full plant growth, often mainly using monopotassium phosphate and urea, plus an appropriate amount of liquid organic fertilizer, applied as 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 reproductive growth needs.
(7) Humidity and light. Gerbera is relatively cold-tolerant. Its growth is not sensitive to light, but it prefers sufficient sunlight. When cultivated in greenhouses, 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. Around November, small tunnels should be built over each bed for insulation. From June to September, 50% shade nets can be used to lower the temperature.
(8) Removal of withered leaves. The clustered leaves at the base of gerbera are prone to yellowing and aging and should be removed promptly. This not only facilitates the sprouting of new leaves and new flower buds, but also facilitates 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 nutrition and to improve the quality of cut flowers. Generally, a one-year-old single plant has 15-20 healthy leaves during the peak flowering period 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 can be harvested when the outermost two layers of ray florets are perpendicular to the flower stem and show the color specific to the variety. The best time is in the morning and evening when temperatures are low, as it is easier to harvest without damaging the plant. The method is to hold the lower half of the flower stem with your hand and shake it side to side, and it can then be picked. Remove flowers with disease spots, insect spots, or deformities. Cover the flowers with No. 12-15 funnel-shaped plastic bags, then grade them by variety and length, bundle them in 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 base fertilizer: Before planting, deep plow once (30-40 cm). Apply chemical fertilizer and barnyard manure (per mu: 2000 kg decomposed barnyard manure, 5 m3 humus soil, 65 kg superphosphate, 50 kg compound fertilizer) into the soil, then deep plow again (15-25 cm).
2. Bed preparation: Dig drainage ditches 70-100 cm deep nearby (depending on the water table level), and form high beds 45 cm high, with a bed width of 1.0 m and a ditch width of 40 cm.
3. Soil disinfection: Use formaldehyde disinfection and chemical agents such as Weibomu (tentative), taking 40% industrial formaldehyde disinfection as an example: dilute to a concentration of 1%, spray evenly on the soil, immediately cover tightly with plastic film and seal for fumigation. After 2-3 days, remove the film, air-dry the soil for two weeks, then rinse with water, and only after another two weeks can planting be carried out. Different disinfectant chemicals should be determined according to instructions and trials. Soil used for the first planting does not need to be disinfected.
Seedling selection
Select seedlings 11-15 cm tall with 4-5 true leaves for planting. Quality seedling standards: strong seedlings, oily green leaves, well-developed root system, many fibrous roots, white in color, leaves free of disease spots, insect bite gaps, and mechanical damage.
Planting
Planting time: Planting can be done throughout the year, but from the perspective of production and sales, April to June is ideal.
Planting method: Plant 3 rows per bed, with the middle row staggered from the side rows, spacing between plants 30 cm, planting 9-10 plants per square meter, and more than 1100 plants can be planted 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 on 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 is easily loosened or pulled out when harvesting flowers; after planting, water thoroughly in a timely manner.
Cultivation management
1. Management during the small seedling stage: After planting, shade with 70% shade nets for 7-10 days, and gradually increase light after the seedlings survive; regulate day and night temperatures by opening and closing the side film and top 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 irrigation, preferably watering in the morning. Make a small hole beside the plant to indicate soil moisture. Moisture should not be too dry or too wet. Watering frequency is once every 5 days, but this is not fixed and should be determined according to soil structure, weather conditions, and other specifics; inspect plant by 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 enters a vigorous growth period, 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 at 15:15:15) once every week, and spray 0.1% monopotassium phosphate as foliar fertilizer once every 2 weeks; spray broad-spectrum fungicides, such as 70% thiophanate-methyl 800-**** times solution 2-3 times, to prevent disease.
3. Management during the flowering period: About 3-4 months later, the plant enters the flowering period. Apply compound fertilizer with N:P:K=12:12:17 once every week. Use foliar spraying of micro-fertilizers, generally once every 25 days, each time using 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 for alternating foliar spraying; use drip irrigation for watering, with the watering principle of "do not water when not dry, water thoroughly when watering," and strictly do not water from the center of the leaf rosette. Keep the relative humidity in the greenhouse at 80%-85%; weed promptly, remove diseased leaves and withered leaves, pull out diseased plants and disinfect the soil in the planting holes with quicklime; during the summer flowering period, pay attention to shading and ventilation to lower the temperature; during the winter flowering period, pay attention to insulation and heating, especially preventing too large a difference between day and night temperatures to reduce the production of deformed flowers.
The cultivation techniques are briefly introduced as follows: I. Growing environment
Gerbera is native to South Africa and adapts to a mild climate. It is heat-tolerant and slightly cold-tolerant, and prefers an environment that is warm in winter, cool in summer, well-ventilated, and sunny. The suitable growing temperature is 20 °C-25 °C during the day and around 16 °C at night. The suitable flowering temperature is not lower than 15 °C, and a growing environment not exceeding 26 °C during the day allows year-round flowering. The suitable temperature during the winter dormant period is 12 °C-15 °C, and growth stops below 7 °C. The response to photoperiod is not sensitive, and the length of natural daylight has no effect on flower count or flower quality. Gerbera requires loose, fertile, well-drained, humus-rich, deep, slightly acidic sandy loam soil.
II. Propagation
Gerbera is mostly propagated rapidly through tissue culture, and can also be propagated by division, with each mother plant being divided 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 neck can be cut and used for cuttings.
III. Planting
Cultivating gerbera in artificial growing medium can significantly increase yield and quality. Please refer to the formula: 5 parts humus; 2 parts perlite; 3 parts peat, self-mixed growing medium for planting, but the production cost of this method is relatively high. Field planting can also be carried out; select loam soil with a deep soil layer of at least 25 cm or more suitable for gerbera growth for planting. Before planting, apply sufficient base fertilizer. Generally, per mu, apply 5 tons of livestock manure, 600 kg of chicken manure, 100 kg of superphosphate, and 300 kg of plant ash. 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 ridges 40 cm wide and furrows 30 cm wide. Plants are set on the ridges in double rows in a staggered arrangement. Spacing between plants is 25 cm. When planting, care should be taken to leave the root crown slightly exposed above the soil to prevent root rot. After planting, water is applied in the furrows.
IV. Post-planting management
1. Temperature
Use cultivation facilities to meet as much as possible the temperature requirements of gerbera during the seedling, growing, and flowering stages, so as to facilitate normal growth and flowering. Except in South China, it cannot overwinter in the open field and requires greenhouse cultivation; outside the Yangtze River basin, unheated plastic tunnel cultivation can be used. In summer, shade nets need to be covered on top of the greenhouse, and the plastic film on both sides of the greenhouse should be opened to lower the temperature. In winter, when the outside nighttime temperature approaches 0 °C, seal the plastic film tightly, and additional plastic film must be added inside the greenhouse. On clear and warm days, open the film at the south end of the greenhouse around noon for ventilation for about one hour.
2. Light
Gerbera is a light-loving flower and needs full light in winter, but in summer appropriate shading should be noted, and ventilation should be strengthened to lower the temperature and prevent high temperatures from causing dormancy.
3. Irrigation
After planting, the seedling stage should be kept appropriately moist and the seedlings should be hardened 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 period, be careful not to let water get into the center of the leaf rosette to prevent flower bud rot. For open-field cultivation, attention should be paid to drainage prevention. In addition, fertilization can be combined with irrigation.
4. Topdressing
Gerbera is a fertilizer-loving perennial herbaceous flower with a high fertilizer demand. The ratio of nitrogen, phosphorus, and potassium applied is 15:18:25. When topdressing, special attention should be paid to supplementing potassium fertilizer. Generally, apply 2.5 kg of potassium nitrate, 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 relatively low temperatures cause the plant to enter a semi-dormant state, stop fertilizing.
5. Removal of withered leaves
The lower leaves of the basal leaf rosette of gerbera are prone to yellowing and aging 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 include leaf spot, powdery mildew, and viral disease. For leaf spot, spray 70% thiophanate-methyl wettable powder 800-**** times or 50% carbendazim wettable powder 500 times solution. For powdery mildew, use 70% thiophanate-methyl 1500 times solution or 75% triadimefon wettable powder 1000-1200 times solution for control, once every 7-10 days, spraying two to three times consecutively. For viral disease control, strict seedling entry inspection should be enforced, and aphids should be controlled promptly to reduce virus transmission vectors. Diseased plants found should be promptly removed and destroyed. The main insect pests of gerbera include tarsonemid mites, cotton bollworm, tobacco budworm, beet armyworm, and aphids. For tarsonemid mites, 40% dicofol 1000 times solution can be used for control.
Harvesting
Harvest when the pollen of the outer ring of flowers begins to shed. At harvest, the plant should be vigorous, the flower stem upright, and the flower open. The quality of cut flowers greatly affects vase life. Never cut flower stems when the plant is wilting 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 seedlings in China are concentrated in the Yunnan region. A large number of emerging specialized flower seedling producers, represented by the Yunnan Lüxin Flower Seedling Base, are flourishing.
Gerbera disease control 1. Gerbera bacterial diseases
Gerbera 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 chicory, lettuce, pea, melon, Chinese cabbage, and many other cruciferous plants; tomato and clover can also be affected. The pathogen mainly overwinters in diseased field soil and diseased plant residues, and spreads through rain, farming operations, insect carriage, and other means.
2. Gerbera viral diseases
2.1 Gerbera spotted wilt
After infection, gerbera shows symptoms such as fading, necrosis, and stunting, with deformed flowers. This disease occurs on gerbera cultivated 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 thermal inactivation point is 40-46 °C, survival time in vitro is less than 5 h, and dilution endpoint is 10-3. It is transmitted by mechanical inoculation, and the insect vector thrips transmits it in a persistent manner. The host range of this disease is wide, and it is an important pathogen of tobacco, tomato, potato, and many other crops.
2.2 Gerbera mosaic disease
Diseased plants show leaf chlorosis, deformed leaves, and patch formation; growth weakens, the number of cut flowers drops sharply, and with continued development, diseased plants die. 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 similar in morphology. It is transmitted by mechanical inoculation, and aphids transmit it in a non-persistent manner. The thermal inactivation point is 70 °C, survival 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 mottle disease
Chlorotic ringspots appear on leaves, and some chlorotic spots appear as oak-leaf patterns, with individual tissues near the spots becoming necrotic. When the disease is severe, leaves become smaller, wrinkled, and brittle; in some varieties the petals are broken in color, flowers become smaller (deformed), flower color is not bright, and plants are stunted. The pathogen is Tobacco mosaic virus (TMV). The particles are straight rod-shaped, 300 nm × 18 nm, and the thermal inactivation point is 90-95 °C. This disease has a wide host range and can be transmitted by mechanical inoculation, contact between plants, contaminated soil, farm tools, and also by sap, soil, nematodes, and seeds.
3. Gerbera fungal diseases
3.1 Gerbera powdery mildew
This disease mainly harms leaves. In the early stage of the disease, white mold spots appear on the leaves, which gradually expand into circular or long elliptical yellow-white lesions. The lesions are covered with a white coating. In severe cases, the entire leaf is covered with white powder. In the later stage, the powder layer turns gray-white, and the leaves scorch and wither. The pathogen is Oidium sp. The mycelium is white, superficial, and penetrates host epidermal cells with haustoria to absorb nutrients. Conidiophores are erect, unbranched, and produce conidia in a holoblastic manner. Conidia are oblong, single-celled, colorless, produced in chains, and mature successively from top to bottom. 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 leaf spot
There are mainly two types of gerbera leaf spot: (1) Phyllosticta leaf spot. Small purple-brown to tea-brown spots first appear on leaves, gradually expanding into circular or nearly circular lesions with dark brown edges. Later, black small dots form on the lesions. The pathogen is Phyllosticta chrysanthemi. The pycnidia are spherical, immersed, unilocular, with an ostiole. Conidiogenous cells are cylindrical, colorless, smooth, and produce conidia holoblastically; conidia are elliptical, single-celled, colorless, with a truncate base. On artificial medium it grows very quickly, with abundant aerial mycelium, relatively sparse pycnidia formation, and membranous pycnidial walls. The pathogen overwinters in diseased fallen leaves as mycelium and pycnidia. Old leaves are more severely affected than young leaves. (2) Cercospora leaf spot. Small purple-brown spots first appear on infected leaves, gradually expanding into circular or nearly circular lesions, with a dark gray center, slightly raised brown line patterns at the edges, and a purple-brown outer zone. 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. Conidiophores are stout, mycelial type, olive-brown or brown, lighter in color at the apex, unbranched or occasionally branched, clustered on stromatic tissue. Conidia are whip-shaped, straight or slightly curved, colorless, with 3-12 septa. Conidiogenous cells are mostly polyblastic, with sympodial extension, cylindrical, with obvious conidial scars. Conidia are solitary, with a scar at the base, having multiple septa and a smooth surface. This disease mostly overwinters on diseased residues and diseased leaves. It generally occurs severely in environments that are shaded and humid with insufficient light, heavy clay soil, and poor drainage.
3.3 Gerbera gray mold
Water-soaked circular or irregular lesions appear on the stem near the ground of diseased plants, later turning gray-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 gather and form. The pathogen is Botrytis cinerea, belonging to Deuteromycotina, genus Botrytis. Conidiophores are straight or flexuous, 960-1,200 μm × 16-22 μm, clustered in several, brown, smooth, with 1-2 branches at the apex. The branch ends often swell noticeably, forming colorless or pale bottle-shaped conidiogenous cells. Conidia are short elliptical, 12-18 μm × 9-13 μm. The pathogen overwinters as conidia and sclerotia in infected tissues, and disease is likely to occur when humidity is high.
3.4 Gerbera sclerotinia rot
This disease starts from the stem base and causes the stem to rot. In the early stage, the diseased part shows water-soaked soft rot, brown, gradually spreading to the stem and petiole. In the later stage, black mouse-dropping-like sclerotia can be seen inside and outside the stem. The typical symptom of this disease is rapid soft rot of the diseased part, densely covered with white flocculent material, or black mouse-dropping-like sclerotia, each sclerotium capable of producing 1-9 apothecia. This disease is caused by the fungus Sclerotinia sclerotiorum Fuck. Apothecia are produced on sclerotia, disc-shaped, with long stalks. Asci are arranged in parallel, with persistent paraphyses between asci. Asci are club-shaped or elliptical, colorless; ascospores are single-celled, elliptical, arranged in one 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. This disease spreads through contact between diseased plants and healthy plants and through the growth and spread of mycelium in the soil.
3.5 Gerbera root rot
This disease is one of the most important diseases of gerbera, with a wide occurrence area and great degree of damage. The plant is affected throughout the entire growth period, with the heaviest damage during the flowering period. The pathogen infects from the stem base at ground level; the affected part becomes soft, water-soaked, and light black; plant leaves suddenly wilt and turn purplish red. When pulling out diseased plants, the diseased part at the stem base breaks easily, and in moist conditions white mold spots can grow on the surface. This disease is mainly caused by Phytophthora cryptogea. Phytophthora cryptogea belongs to Pseudofungi, Oomycota, Peronosporales, Pythiaceae, Phytophthora. Its vegetative body is aseptate, multinucleate mycelium, with hyphal swellings produced, and asexual reproduction produces zoosporangia. Sporangia are pear-shaped or elliptical, without papillae, large, averaging 46 μm × 27 μm, with a wide host range. Heterothallic, sexual reproduction produces oogonia, oospores, and antheridia. Oogonia are spherical, containing one spherical thick-walled oospore. Antheridia are single-celled, colorless and transparent, amphigynous. The pathogen overwinters on residues or in soil, and the overwintering pathogen is the main primary infection source of this disease. Sudden alternation of dry and wet soil or frequent intertillage and soil loosening causes many root wounds, and the pathogen invades through the wounds. Under suitable conditions it spreads through irrigation water or rainwater, causing severe outbreaks of the disease. Fields with poor drainage and continuous cropping are severely affected. 3.6 Gerbera Fusarium wilt
This disease has symptoms similar to gerbera root rot and occurs throughout the entire growth period of gerbera. The root system of diseased plants is dark brown, the cortex of diseased roots peels off, there are few fibrous roots, and the plant is easily pulled up. When the disease develops slowly, the leaves of diseased plants turn purplish red or dark brown and gradually wither; when severely affected, the plant dies in a green wilt state. This disease occurs in Italy, Australia, and China, among other countries. Because gerbera is basically cultivated under protected conditions, the disease can occur year-round, and April to August each year is the period when the disease is more severe. The pathogen overwinters in soil or diseased plant residues, and infected soil and affected plants are the main sources of infection of 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, loose cotton-like. Conidiophores are colorless, and conidiogenous cells produce conidia by enteroblastic phialidic conidiogenesis, producing two types of spores. Microconidia are oval to elliptical, 5-12 μm × 2.5-3.5 μm; macroconidia are 27-46 μm × 3-4.5 μm, spindle-shaped to sickle-shaped, with a hooked apex, a small foot cell at the base, and 3-5 septa, mostly 3 septa. Chlamydospores are usually formed in large numbers, intercalary or terminal, solitary, occasionally in chains, with smooth or rough walls.
In addition, gerbera diseases 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 clear weeds, insert yellow sticky boards for continuous monitoring, and once pests are found, take measures promptly. Choose good pesticides and use them correctly: whiteflies easily develop resistance to pesticides, so pesticides must be rotated. Effective pesticides include beta-cypermethrin, abamectin, imidacloprid, etc. Spray at dawn, keep the greenhouse sealed for 4-5 hours after spraying, and spray once more continuously the next morning. Maintain ventilation and low humidity in the greenhouse; promptly remove diseased leaves; when the disease occurs, spray 70% thiophanate-methyl 1500 times solution, or use 20% Junke smoke for fumigation control, once every 7 days, for 2-3 consecutive treatments. In addition, use the sulfur fumigation method for control: place 20-30 g of sulfur powder in each fumigator each time, after lowering the curtain at 17:00 each day, keep the greenhouse sealed, and heat with electricity for 2 hours, replacing 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 cut off flowers with insects, thereby reducing the insect source in the greenhouse (room). Fumigating pesticides in the greenhouse is the best control method. Use 300-400 ml of 80% dichlorvos for fumigation for 1 hour, or spray with 5% imidacloprid 1500-2000 times solution and then close the greenhouse for 8-10 hours. Fumigation can be carried out at around 10 a.m. or 5 p.m. when the temperature is slightly higher to achieve good efficacy.
Cabbage caterpillar
Key control techniques: For larvae, spray 10% Chuchujin 2000-2500 times solution for control. For older larvae, beta-cypermethrin 1000 times can be used for control, once every 7 days, for 3 consecutive times.
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 Weibomu and formaldehyde, etc.; 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 below 10 cm of topsoil does not form a ball after being squeezed firmly in the palm, then it can be watered; in the early stage of disease, when leaves partially turn red and begin to wilt, drench the roots with 58% phosethyl-Al and mancozeb 400 times solution, then after 7 days drench the roots with 64% Sandofan powder 500 times solution. Apply pesticides in the morning and evening when temperatures are low, and stop applying when the temperature is above 28 °C, applying once every 7 days for 3 consecutive times.
Spot disease
Key control techniques: Remove diseased leaves promptly when found and destroy them centrally; in the early stage of disease, spray 2.5% myclobutanil emulsifiable concentrate 300 times solution or 70% thiophanate-methyl wettable powder 800-**** times solution, once every 7 days, spraying 2-3 times consecutively.
Gray mold
Key control techniques: Controlling humidity is the key to controlling gray mold. Thin out densely planted and overly dense leaves; increase ventilation and air permeability, keeping air humidity at 75-85%; water from below the plant canopy; to prevent water vapor from condensing on flowers, gradually open the side greenhouse film after 10 a.m. on sunny days, avoiding a sharp rise in temperature inside the greenhouse; in the early stage of disease, spray 70% thiophanate-methyl 1500 times solution on the foliage, and combine with smoke agents for control.
5. Physiological diseases
1. Symptoms: Dark green spots appear on young leaves. In severe cases, young leaves and growing points die first, while 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 foliage, once every 25 days.
2. Symptoms: "Mosaic" appears in the mesophyll of old leaves. An inverted "V"-shaped green part forms at the leaf base, and its top can also extend to near the leaf tip. 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. Veins remain green initially, 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: Young leaves curve, 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 crack appearing like a cut.
Solution: Use 1-2‰ calcium nitrate, spraying 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 rinse off the fertilizer solution adhering to the leaves; extend the fertilization interval and reduce the fertilizer concentration, and it will recover naturally after a period of time.
Prevention first, integrated control
Disease control
Gerbera diseases include leaf spot, powdery mildew, and viral disease. For leaf spot, spray 70% thiophanate-methyl wettable powder 800-**** times or 50% carbendazim wettable powder 500 times solution. For powdery mildew, use 70% thiophanate-methyl 1500 times solution or 75% triadimefon wettable powder 1000-1200 times solution for control, once every 7-10 days, spraying two to three times consecutively. For viral disease control, strict seedling entry inspection should be enforced, aphids should be controlled promptly to reduce virus transmission vectors, and diseased plants should be promptly removed and destroyed. The main insect pests of gerbera include tarsonemid mites, cotton bollworm, tobacco budworm, beet armyworm, and aphids. For tarsonemid mites, 40% dicofol 1000 times solution can be used for control. For other pests, 2.5% deltamethrin or 40% omethoate 1000-1500 times solution can be used for control, once every eight to nine days. Spraying pesticides has adverse effects on flower color, so it is not suitable to use during the flowering period.
Spot disease
When gerbera is cultivated in protected areas for consecutive years, the warm, humid environment and poor air flow easily lead to the occurrence of pests and diseases. Among them, one of the most common diseases is gerbera spot disease, which is a disease caused by fungi.
Symptoms: Small purple-brown spots are produced on 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 gray-brown dusty 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: Chloropicrin fumigation can be used to effectively kill pathogenic bacteria and reduce the accumulation of inoculum from the substrate.
2. Regulate temperature and humidity: The most suitable temperature for gerbera growth 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 75% chlorothalonil 500 times solution, 50% captan 500 times solution, and 70% thiophanate-methyl 1000 times solution, with obvious control effects.
Phytophthora rot control
Gerbera Phytophthora rot, also known as rhizome rot, is seriously harmful once it occurs, often causing the death of the entire plant, or even the death of the entire greenhouse, bringing serious economic losses to growers. After 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. In the absence of a host, 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 rhizome of the plant. The leaves of affected plants first turn yellow, then gray-brown, and then wither and die. The rhizome turns black and rots.
3. Control: (1) Select healthy, disease-free plants for cultivation.
2. Before planting, the nursery soil must be disinfected. This pathogen spreads mainly through the soil, so the nursery soil must be carefully disinfected before planting. The main disinfection methods are: (1) Chemical disinfection: a mixture of dexon plus quintozene (3:1) can be used at 4-6 g/sq m. During disinfection, spray the chemical onto the soil surface, mix it thoroughly into the soil, seal with plastic film, fumigate the greenhouse sealed for 30 hours, then remove the covering, ventilate, stir the topsoil again, and planting can be done after 15 days. (2) Steam disinfection: steam is released into the soil through pipes. This method has higher investment costs but gives good results.
3. Gerbera should be planted shallowly as a principle, with the crown exposed about 1.5 cm above the soil surface and slight lodging being acceptable (gently straighten it after 3 days). Because it has contractile roots, the crown of the plant will become deeply buried in the soil, which makes infection by pathogens easier. To better support the growth and development of young seedlings, a method of using local substrate at the planting site can be adopted: first dig a round planting hole about 10 cm in diameter at the planting point, then fill it with sun-sterilized 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 disease, captan 0.1 g/l + 1% copper sulfate can be poured around the root zone. If it is already the late stage of disease, the diseased plants should be burned immediately, and the surrounding plants and soil should be treated with the above chemicals.
Control of Whitefly Damage
Whiteflies belong to the order Homoptera, family Aleyrodidae, and can be divided into greenhouse whitefly and silverleaf whitefly. They are important pests of greenhouse horticultural crops in Europe and America. In the 1980s they became a major pest in northern China and have now spread throughout the country. In the Kunming area, varying degrees of infestation have appeared on greenhouse crops such as cucumber, gerbera, rose, and poinsettia. Among the growers surveyed in the author's gerbera production area, 100% had whitefly damage. Many growers consider whitefly the most difficult pest to manage and the most damaging pest on gerbera. The author takes this opportunity to call on relevant departments to pay attention to this.
(1) Damage characteristics of whitefly. The winter in Kunming is warm and the summer is cool, which is very favorable for the reproduction and overwintering of whitefly. Under greenhouse conditions, whitefly does not stop reproducing throughout the year. Each female can lay 100-200 eggs. In control, killing eggs is very important, but most pesticides only kill adults and do not harm eggs or pupae. Therefore, whitefly resistance to pesticides has become a widespread problem. A pesticide may work very well in one place but perform poorly in another. According to foreign research, to clear a relatively severe infestation, pesticide spraying is needed at least once every 3-4 days, for 10-12 consecutive applications. Whitefly eggs, older nymphs, and pupae have strong resistance to temperature and pesticides. Once various stages of the pest occur together on a crop, control becomes very difficult. It can be seen that whitefly is harder to control than ordinary pests and more likely to resurge, causing repeated cycles of damage.
The population density of whitefly has the characteristic of rising exponentially. In the early stage of whitefly infection, it occurs only in small patches, and the plants show no obvious symptoms of damage on the surface, so it is often overlooked. But the harm of whitefly in transmitting viruses, weakening plant growth vigor, and seriously affecting shipment quality is already developing. Once it spreads, it may cause repeated 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, pupa, and adult. Adults lay eggs on the underside of leaves. The eggs are 0.2-0.25 mm long and are not easily seen with the naked eye; they need to be observed with a magnifying glass or microscope, and they are mostly distributed on tender leaves. Nymphs and pupae are usually fixed on the middle and lower 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 ash-like sooty mold caused by fungal parasitism is found on the leaves, it indicates that the infection has lasted for a relatively long time and is relatively serious. The colors whitefly likes most are lemon yellow and orange yellow, so yellow sticky boards can be hung or set up for monitoring.
Among greenhouse flower crops, the ones that attract whitefly most and suffer severe damage are: gerbera, alstroemeria, primula, salvia, dahlia, pelargonium, cineraria, gloxinia, fuchsia, hibiscus, clematis, abutilon, solanaceous plants, columbine, and rhododendron. Those with lighter damage are: chrysanthemum, poinsettia, calceolaria, calla lily, rose, lily, and marigold. Those not damaged are: cyclamen, carnation, freesia, tulip, narcissus, hyacinth, orchid family plants, lilac, palm family plants, and most succulent plants.
Sometimes flower crops and vegetable crops are rotated or planted in contiguous areas, so it is necessary to know the vegetable crops severely damaged by whitefly, such as cucumber, tomato, lettuce, green bean, celery, melon, pumpkin, and garlic. Greenhouses and the weeds inside and around greenhouses are breeding sites for whitefly. The weeds it likes are chickweed, wood sorrel, nettle, dandelion, and so on.
(3) Control of whitefly
1. Give priority to prevention and cultivate insect-free seedlings. Seedlings, crop residues, and weeds carrying insects are important pathways for the spread of whitefly, so before planting a new crop, weeds and previous crop residues must be thoroughly removed, and the ground should be left empty for a period. When introducing seedlings and potted flowers, carefully check whether there are nymphs or eggs and whether many leaves are missing. Once a greenhouse is infected by whitefly, 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 silver-white plastic strips at the greenhouse entrance can repel adult invasion.
2. Choose pesticides well and use them correctly. Whitefly easily develops resistance to pesticides, so it is necessary to know more about the available pesticide types in order to select them. For pesticides to which there is originally no resistance, pest resistance will only develop in the second generation. Therefore, for a pesticide with good trial results, it can at least be used continuously for more than one generation 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 relatively good results tried domestically and abroad, for reference.
Category English name Chinese name or trade name Precautions
Organophosphates acephate acephate has fumigant action
chlorpyrifos chlorpyrifos, chlorpyrifos
etrimfos etrimfos
Carbamates methomyl methomyl, Lannate has some ovicidal action
Pyrethroids sumicidin fenvalerate
Propoxur+methoxychlor propoxur + methoxychlor
Cypermethrin cypermethrin
Alphamethrin alpha-cypermethrin
fluralinate cyfluthrin
Acaricide mitac amitraz, has fumigant action
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 whitefly pest management, conventional spraying methods have the problems of low control efficacy, rapid decline in efficacy, and easy development of resistance. Whitefly attaches to the underside of leaves and sucks leaf sap, easily forming dead angles that pesticides cannot contact, especially when plants are growing luxuriantly. When disturbed, whitefly can fly several meters away, thereby avoiding contact with the spray liquid. Therefore, even if a pesticide to which resistance has not developed is used, its control efficacy is limited. The growth, development, and reproduction of whitefly 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, egg and larval mortality is high, adult lifespan is shortened, egg laying is reduced, and reproduction may even stop. Whitefly is a poikilothermic animal, so above 30°C its respiration rate rises greatly, making it easy 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 pest's weaknesses and making full use of solar energy and the greenhouse effect, and achieved significant control results. The method is to mix a pesticide with fumigant action and a pesticide with ovicidal action (such as chlorpyrifos + Lannate), 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 shade nets and delay the spraying time to prevent the temperature inside the tunnel from rising excessively. When sealed conditions are unavailable, 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 sealing. At this time, it is better to spray in the morning when the temperature is lower, keep the tunnel sealed for 1-2 hours, and use shade nets to cool it if necessary, so there is no concern about excessive humidity causing disease.
4. Other methods. Very effective methods for controlling whitefly also include fumigation, smoke fumigation, and fogging, 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-like, and sometimes markings also appear on petals. Pathogens include cucumber mosaic virus (CMV) and tobacco mosaic virus (TMV).
2. Control methods. (1) Clear weeds in the flower garden and its surroundings at any time, and use insecticides promptly 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 Fusarium wilt, but there is no pink spore mass in the diseased part. Water-soaked soft rot appears on stems and roots and turns 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, with an optimum growth temperature of 25°C.
2. Control methods. (1) Select and breed disease-resistant varieties. (2) Before planting in a flower bed 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 avoid spreading the pathogen. The diseased soil must also be dug out and replaced with new soil.
Greenhouse Pests and Diseases
1. Phytophthora disease first infects the root crown. Affected plants turn yellow, then gray-brown, and then die. The rhizome turns black and rots.
Control methods:
(1) Select healthy, disease-free plants for cultivation.
(2) This pathogen spreads mainly through the soil, so the nursery soil must be carefully disinfected before planting. A mixture of dexon plus quintozene (3:1) can be used at 4-6 g/sq m. During disinfection, spray the chemical onto the soil surface, mix it thoroughly with the topsoil, seal with plastic film, and at the same time seal the greenhouse for fumigation for 30 hours, then remove the covering, ventilate, 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 higher investment costs but gives better results.
(3) Planting requires the root crown to be exposed about 1.5 cm above the soil surface, with slight lodging being acceptable. Because it has contractile roots, the root crown of the plant will become deeply buried in the soil, which makes infection by pathogens easier. To benefit the growth and development of young seedlings, a cultivation method using local substrate can be adopted: 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, firm the roots, and afterward 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, the diseased plants should be pulled out and burned immediately, and the surrounding plants and soil should be treated with the above chemicals.
2. Leaves infected by the virus 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 as it continues to develop, the diseased plant will die.
Control methods:
(1) Remove diseased plants.
(2) Thoroughly eliminate aphids, the vectors that transmit the virus.
(3) In greenhouses with poor ventilation, scale insects often occur and should be removed promptly.
3. For whitefly, imidacloprid, dichlorvos, phoxim, and methamidophos all have relatively good control effects. However, if a single product 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 cases where resistance has developed, organophosphorus pesticides can be mixed with Lannate water plus pyrethroid pesticides.
4. Leafminer has peak damage periods from April to May and from October to November. Abamectin, Aifuding, Abading, or dimehypo mixed with fenvalerate can be used for control.
Causes of Root Rot
The color of gerbera in midsummer, especially under drought and water shortage, is dark and dull. In contrast, flowers blooming during the suitable-temperature period of September-October or March-June of the following year are brightly colored. This shows that gerbera is relatively sensitive to temperature and light intensity. In summer it is necessary to keep the soil moist and not drought-stressed, cover with a shade net of 50% light transmission, and spray the leaf surface to increase air humidity and lower temperature.
In winter, sufficient warmth should be provided to avoid 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. In addition, mites are a major enemy in gerbera cultivation. Once damaged, the flowers not only lose their brightness, but the shape of the petals also becomes incomplete.
Therefore, ensuring that the plants are not damaged by mites throughout the entire growth period is a particularly important link in guaranteeing the brilliant colors of gerbera.
The cause of root rot in gerbera 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 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 plants.
Potted Gerbera Techniques Pot Production
In the daily production process of potted gerbera, the following points need attention.
1. The production greenhouse must have ventilation, shading, and heating facilities. If conditions permit, it should also be equipped with benches, ground fabric, or an irrigation system. The greenhouse must be sealed to prevent insects from entering.
2. The temperature in the greenhouse should be controlled between 15°C and 25°C, with the maximum not higher than 30°C and the minimum not lower than 13°C. The average daily production temperature is generally 18°C to 19°C, and ventilation should be provided once it exceeds 19°C. At the same time, the night temperature should not be too high, otherwise normal flower bud differentiation will be affected. The ideal night temperature should be between 15°C and 18°C.
3. Use a medium with good air permeability and drainage, preferably a substrate mixed with peat and perlite. The pH value is 5.5 to 6.0, and the EC value is 0.7 to 1.0, which is beneficial for the absorption of trace elements.
4. Potted gerbera 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, water must be applied from below, and bottom infiltration can be used. During high-temperature periods, water can be applied from above the plants, but care must be taken to prevent fungal mold starting from the center of the plant.
5. Gerbera relatively likes 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 daylength for gerbera during growth is 11 hours to 13 hours, so artificial supplementary lighting can be used under low light. Generally, the requirement for artificial supplementary lighting is 3500 to 4000 lux per sq m. It should be noted that supplementary lighting should be carried out 4 weeks after the plants are potted.
7. From potting to flowering, gerbera requires 8 weeks to 9 weeks for summer production and 11 weeks to 12 weeks for winter production. The pot size is 10 cm to 15 cm. About 30 pots can be produced per sq m in the greenhouse, but attention should be paid to spacing the plants in time once they grow to a certain size.
Gerbera - Postharvest Treatment
Harvesting: For single-petaled varieties, the flowers can be harvested when 2-3 rounds of stamens have matured. Double-petaled varieties should be harvested when more mature, as flowers harvested too early will have a shortened vase life. After harvesting, they must be placed in water immediately, and the water must be very clean. Before placing fresh flowers in water, cut off 2-5 cm of the hairy, lignified bottom part of the flower stem so that the stem can absorb water. Vase life is one of the most important components of the commercial value of cut flowers. Postharvest treatment is very important for the vase life of gerbera. If gerbera cut flowers enter the market without postharvest treatment, it will ultimately be difficult to satisfy consumers, which in turn will reduce gerbera consumption. The methods introduced below can extend the vase life of gerbera.
Harvesting Cut Flowers
Gerbera flowers should only be harvested when one or two rounds of stamens have shed pollen. Harvesting too early will shorten 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, the entire flower stem 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 stem. Cut at an angle to avoid crushing the xylem vessels. The bottom of the flower stem is composed of very narrow xylem vessels, which hinder water transport. After cutting, the flower absorbs water more easily, which is very important for avoiding cracking and bending at the flower neck. In addition, when harvesting, air may be drawn into the vessels and prevent the flower from absorbing water. Cutting off part of the stem also removes air bubbles in the vessels.
Postharvest Pretreatment
After cut flowers are harvested, the stems should be immediately immersed in buckets and transported to a cool place. The water and buckets used must be very clean and must be cleaned and disinfected before each use to prevent bacterial growth, because bacteria will block 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 kill bacteria, 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 must not exceed 4 hours. Too long a treatment time will damage the stems, shown by brown markings on the stems or bleaching of color. For longer treatment, 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 must 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 stems in preservative solution for 6-24 hours. During treatment, immersing more of the stem in water helps the flower absorb water, and a length of 10-15 cm is ideal. Too high an ambient temperature will cause the flower to lose too much water through transpiration, so 10-15°C is ideal. Water loss will cause gerbera flowers to age, so drying and wind must be avoided throughout the entire postharvest treatment 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 cut flowers from ethylene damage. Ethylene is an aging hormone and will shorten the vase life of gerbera. Truck engine exhaust contains ethylene, so during loading, turn off the truck engine. The preservative solution for gerbera consists of the following components: sucrose, 3 g/l citric acid, 150 mg/l dipotassium hydrogen phosphate with seven molecules of water of crystallization (K2HPO4·7H2O) 75 mg/l. Sucrose provides energy for gerbera to continue opening during the process and also promotes 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 relative humidity of 90%-95% and temperature of 2-5°C. During storage and transport, gerbera can tolerate relatively long 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 that they have the typical characteristics of the variety, are free from damage and contamination, and have good visual effect: 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 length difference among cut flowers of the same grade should not exceed ±2 cm of the standard.
Packaging and Transport
During transport, lower the ambient temperature to 6-9°C, which slows down the life activities of the flowers and preserves energy for use when they reach consumers. Reusing cartons is more economical, but they can become places where bacteria breed. Therefore, cartons should not be reused too frequently. In short, cleanliness and hygiene must be maintained throughout the entire postharvest treatment process in order to effectively extend the vase life of gerbera. After gerbera arrives at the destination, the bottom of the stem will become dry. Use a clean knife to cut off a little of the stem at an angle, then immerse it in clean preservative solution. If no preservative solution is available, a low-concentration bleaching powder solution can also be used.
Gerbera - Daily Management Humidity Management
It likes relatively high air humidity. Too low air humidity will speed up 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 dislikes extreme heat. When the summer temperature is above 34°C, growth is obviously poor. It is not tolerant of frost and cold, and when the winter temperature is below 4°C, it enters dormancy or dies. The most suitable growth temperature is 15-25°C. It is generally sown 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 obviously become smaller, the internodes of the branches will shorten, the basal 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 flowering and being kept indoors for a period (10-15 days), it should be moved outdoors to a place with shading (and insulation) for maintenance for a period (about one month), and alternated in this way to help the plant 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 and 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 "Huabao"-"Huabao"-clear water-"Huabao"-"Huabao"-clear water (at least two "Huabao" applications per week must be ensured). The interval period is about: 1-4 days for outdoor maintenance; shorter intervals on sunny days or during high temperatures, longer intervals or no watering on cloudy and rainy days or during low temperatures; 2-6 days for indoor maintenance; shorter intervals on sunny days or during high temperatures, longer intervals or no watering on cloudy and rainy days or during low temperatures. 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 fertilizer and water control. Fertilizer and water management follows the cycle of "Huabao"-clear water-clear water-"Huabao"-clear water-clear water. The interval period is about: 3-5 days for outdoor maintenance; shorter intervals on sunny days or during high temperatures, longer intervals or no watering on cloudy and rainy days or during low temperatures; 4-7 days for indoor maintenance; shorter intervals on sunny days or during high temperatures, longer intervals or no watering on cloudy and rainy days or during low temperatures. 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 task is to do a good job of fertilizer and water control. Fertilizer and water management follows the cycle of "Huabao"-clear water-clear water-"Huabao"-clear water-clear water. The interval period is about 7-10 days. The interval is shorter on sunny days or during high temperatures, and longer or no watering on cloudy and rainy days or during low temperatures. Watering time should be arranged as much as possible at noon on sunny days when the temperature is relatively high.
Maintenance Points Temperature
Cultivation facilities should meet the temperature requirements of gerbera during the seedling stage, growth stage, and flowering stage to facilitate normal growth and flowering. Except in South China, it cannot overwinter in open fields and should be cultivated in greenhouses. Outside the Yangtze River basin, it can be cultivated in unheated plastic tunnels. In summer, shade nets need to be covered on top of the tunnel, and the plastic film on both sides of the tunnel should be opened to lower the temperature. In winter, when the outdoor night temperature approaches 0°C, the plastic film should be lowered, and plastic film must be added inside the tunnel. On clear and warm days, open the film at the south end of the tunnel for ventilation for about one hour.
Light
It is a light-loving flower. In winter it needs full light. In summer, attention should be paid to appropriate shading, strengthening ventilation, and lowering the temperature to prevent high temperatures from causing dormancy.
Irrigation
After planting, the seedling stage should maintain appropriate moisture and practice seedling hardening to promote root development and rapid 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. Cultivation should also prevent waterlogging. Fertilization can be combined with irrigation.
Topdressing
Gerbera 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, 1.2 kg of ammonium nitrate or ammonium phosphate per mu, once every 5-6 days, and once every 10 days. If high temperature or excessively low temperature causes the plant to enter a semi-dormant state, stop fertilizing.
Removing Dead Leaves
The lower leaves of the basal leaf rosette easily turn yellow and age. Removing them in time is beneficial for the sprouting of new leaves and new flower buds, helps ventilation, and strengthens plant growth.
Selection of Gerbera Fresh Cut Flowers
The junction between the flower stem and the flower head of gerbera is relatively thin and soft, while the flower head is large and heavy, so it easily bends down from the neck. Therefore, when selecting, choose ones with short and thick stems, so that the neck is stronger and can support the flower head.
Only a small section at the bottom of the gerbera stem is solid; the stem above is hollow. However, gerbera 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 and taking it home, put it in water as quickly as possible, and try not to cut off the solid stem section at the bottom.
Arranging
The "neck" of gerbera is thin, and the flower head easily droops and causes decline. Therefore, every possible method should be used to fix the neck, such as wrapping it with soft wire for reinforcement and then covering it with green tape.
Gerbera petals decline from the outside inward. Therefore, when the outer petals are not good, they can be directly pulled off, and the remaining flower center is also quite ornamental. Because gerbera petals are very easily damaged and leave scars, they must be handled carefully.
The water level only needs to reach one third of the stem length, because the stem is soft and easily rots, so the water level should not be too high.
Preservation Methods
Gerbera bought from the flower market does not need its roots cut, especially do not cut off the hard node at the bottom of the stem. Just place it directly in water. Put in less water, enough to immerse its hard bottom. The flower bucket should be relatively tall, preferably reaching the flower head. Gerbera whose roots have been cut easily rots at the stem and rots especially quickly.
If newly received stock shows dehydration, first put it directly into water. If it has not recovered after a few hours, then cut the bottom of the stem into a slanted opening and put it into water.
If there is no dehydration, then the bent stem is normal. If you want to straighten the flower head, it is actually very simple. Just take it out and lay it flat, or wrap it in paper for one or two hours and then put it into water.
The Flower Language of Gerbera
The flower language of gerbera symbolizes mystery, mutual respect and love, perseverance, and fearlessness of hardship. It likes to pursue a rich life. Single-petaled varieties represent warmth, while double-petaled varieties represent commendable passion. In the Shanghai area, people like to use gerbera to make bouquets to decorate the bridal room during wedding celebrations. Using its homophonic meaning, it conveys the idea that the newlyweds respect and love each other and that the wife supports her husband in achieving his career. Gerbera has a radial flower shape and is often used as the main body in flower arrangements, often combined with sword fern and asparagus fern.
The flower language of gerbera is -- eternal happiness. Its most commonly used flower language in China: elegant. noble. reclusive.
Gerbera pictures