Detailed Guide to Growing Coreopsis from Seed, Survival Rate up to 95%
Among the propagation methods for coreopsis, there are three: sowing, cuttings, and division, of which sowing is the more commonly used one. However, for successful growing, there are many points to pay attention to. So how do you grow coreopsis? What is the method for growing coreopsis from seed? Below, the editor takes you through it.
Among the propagation methods for coreopsis, there are three: sowing, cuttings, and division, of which sowing is the more commonly used one. However, for successful growing, there are many points to pay attention to. So how do you grow coreopsis? What is the method for growing coreopsis from seed? Below, the editor takes you through it.
1. How to Grow Coreopsis: Sowing
When it comes to how to grow coreopsis, people generally use the sowing method. After countless trials, this method has a relatively high survival rate. However, to succeed with sowing, there are points to note, such as the sowing time, the choice of substrate, and seed pre-treatment. The details are described below, so let's take a look.
2. When to Sow Coreopsis: Early Spring
When propagating coreopsis by sowing, choosing a suitable time is very important. As for when it is most suitable to sow coreopsis, we can choose early spring, because this is a season when all things revive and the climate is also quite suitable for its growth, so choosing to sow at this time will give a relatively higher survival rate.
3. Method for Growing Coreopsis from Seed
1. Substrate Selection: Well-Drained
Before planting coreopsis, we first need to choose a substrate, because only by letting it grow in a suitable substrate can it grow better. This plant prefers loose, fertile sandy loam as a substrate; this kind of soil has good drainage and a certain air permeability, allowing the plant to breathe better.
2. Substrate Disinfection: Sun Exposure or High-Heat Stir-Frying
After choosing the substrate, we also need to disinfect it, to prevent pests or bacteria in it from infecting the plant. When disinfecting, we can break it up and spread it flat under the hot sun for exposure, or put it into an iron wok and stir-fry it over high heat; this way, even if there are pests or bacteria in it, they will be killed.
3. Seed Pre-Treatment: Soaking in Warm Water
Before planting coreopsis, there is another pre-treatment to do, which is to pre-treat its seeds. We can soak its seeds in warm water for 1-2 days, and when the seeds begin to absorb water and swell, take them out and plant them. This can greatly increase the survival rate and also let the seeds germinate faster.
4. Planting Method: Watering by the Pot-Soaking Method
Before planting, we first need to apply an appropriate amount of base fertilizer into the potting soil, then evenly scatter the seeds on the soil surface. After scattering, cover them with 1-2cm of soil and then water. When watering, it is best to use the pot-soaking method, because coreopsis seeds are small in size; if watered directly with a watering can, the seeds are easily washed away.
How Does Coreopsis Reproduce? Coreopsis Propagation Methods / Sowing / Cuttings / Division
Coreopsis is a flowering plant with high ornamental value, and it can be seen in many regions of our country. As more and more people grow it, people are also more concerned about questions regarding its propagation. How does coreopsis reproduce? What are the propagation methods for coreopsis? Below, the editor takes you through it.
1. How Does Coreopsis Reproduce: Sowing / Division / Cuttings
When it comes to how coreopsis reproduces, it is mainly divided into three methods: propagation by sowing, propagation by cuttings, and propagation by division. As long as we operate properly, the survival rates of all three propagation methods are very high. However, there is also a prerequisite, which is that you must be careful when propagating; this point is very important.
2. Coreopsis Propagation Methods
Propagation by Sowing
Seed pre-treatment: Before propagating coreopsis by sowing, we first need to pre-treat its seeds. We can soak its seeds in warm water for 1-2 days, and when the seeds begin to absorb water and swell, take them out and plant them. This can greatly increase the survival rate and also let the seeds germinate faster.
Sowing method: Before sowing, we first need to apply an appropriate amount of base fertilizer into the potting soil, then evenly scatter the seeds on the soil surface. After scattering, cover them with 1-2cm of soil and then water. When watering, it is best to use the pot-soaking method, because coreopsis seeds are small in size; if watered directly with a watering can, the seeds are easily washed away.
Propagation by Cuttings
Cutting selection: Before propagating coreopsis by cuttings, we first need to select cuttings. Generally, it is best to choose branches that grow robustly and are free from pests and diseases as cuttings, as this will give a higher survival rate. If the cuttings we choose look very thin and weak, then it is basically very difficult for them to survive.
Cutting method: Among the propagation methods for coreopsis, propagation by cuttings is considered a relatively simple method. First, we likewise need to apply an appropriate amount of base fertilizer into the soil, then use a chopstick to poke a hole in the potting soil, insert the cutting into it, and water. This operation can prevent the cutting from being damaged when inserted, and is very practical.
Propagation by Division
Besides the above two methods, coreopsis can also be propagated by division. Although not many people use this method, the survival rate is not low at all. We can carry out division propagation when repotting and changing the soil. When repotting, we need to take the plant out of the potting soil, then divide it into several layers, and at the same time shorten the old stems, then plant them separately in pots. After they survive, new shoots and buds will soon sprout.
Gerbera Gerbera jamesonii Bolus Gerbera Guide: How to Grow Gerbera / How Does Gerbera Reproduce
Gerbera ProfileGerbera Gerbera jamesonii Bolus
Gerbera Growing Methods and Precautions Introduction to Gerbera
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, pinnately lobed. Plant height 30-45cm, capitulum solitary, terminal inflorescence, flower colors include red, white, yellow, orange, purple, etc. Rising 20-40cm above the leaves, flower diameter 10-12cm, involucre disc-shaped, bell-shaped, ligulate petals 1-2 or multiple whorls in double-petal form, usually flowering in all four seasons, most abundant in spring and autumn.
It is an important material in modern cut flowers. Gerbera has a relatively large flower diameter (8 cm-10 cm), and flowering regulation is easy. At present, the cut flower cultivation area is increasing year by year, and its application is becoming more and more widespread. Gerbera can also withstand long-distance transport, and cut flowers can be kept for a long time; if cultivated properly, each plant can yield 30 cut flowers per year, making it truly an ideal cut flower plant. Gerbera flowers are large and have rich colors, and management saves labor. In warm regions, it can supply fresh cut flowers year-round. The main types can be divided into modern cut flower types and dwarf cultivation types, with various flower colors such as white, pink, red, and yellow.
Morphological Characteristics of Gerbera
Perennial, hairy herb. Rhizome short, surrounded by remnants of petioles, with relatively thick fibrous roots. Leaves basal, rosette-shaped, leaf blades long elliptic to oblong, 10-14 cm long, 5-6 cm wide, apex shortly acute or slightly obtuse, base gradually narrowed, margin irregularly pinnately lobed or deeply lobed, glabrous above, short pubescent below, losing hair when old; midrib raised on both sides, thicker and especially prominent below, lateral veins 5-7 pairs, curved and connected away from the margin, reticulate veins slightly obvious; petiole 7-15 cm long, with thick longitudinal ridges, more or less hairy. Scape solitary, or rarely several clustered, 25-60 cm long, without bracts, hairy, hairs densest at the top, capitulum solitary at the top of the scape, 6-10 cm in diameter when the ligules spread during flowering; involucre bell-shaped, about as long as the bisexual flowers, up to 2 cm in diameter; involucral bracts in 2 layers, outer layer linear or subulate, apex acute, 8-10 mm long, about 1-1.5 mm wide, pubescent on the back, inner layer oblong-lanceolate, apex caudate-acuminate. 10-14 mm long, about 2 mm wide, margin scarious, sparsely pubescent on the midrib; receptacle flat, naked, honeycomb-like, 6-8 mm in diameter; outer female flowers in 2 layers, outer corolla ligulate, ligule pale red to purplish red, or white and yellow, oblong, 2.5-3.5 cm long, 2-4 mm wide, apex with 3 teeth, inner 2 lobes filiform, curled, 4-5 mm long, corolla tube short, about 1/8 the length of the ligule, staminodes filiform, 3-4 mm long, extending beyond the corolla tube; inner female flowers more slender than bisexual flowers, tubular bilabiate, 6-7 mm long, two lips equal in length, outer lip with 3 fine teeth or sometimes 2 teeth and 1 lobe, inner lip 2-parted deeply, lobes linear, about 4 mm long, curled, staminodes 4-5, linear or filiform, hidden within the corolla tube; central bisexual flowers numerous, tubular bilabiate, 8-9 mm long, outer lip large, with 3 teeth, inner lip 2-parted deeply, lobes usually broad, curled; anthers about 4 mm long, with long pointed tails; style branches of female flowers and bisexual flowers both 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 period November to April of the following year.
Ecological Habits of Gerbera
It likes an environment that is warm in winter and cool in summer, with air circulation and sufficient sunlight. It is not cold-tolerant and avoids intense heat. The suitable growth temperature is 20°C-25°C, and the suitable winter temperature is 12°C-15°C. When below 10°C, growth stops. It is a semi-hardy flower and can tolerate short-term low temperatures of 0°C. In South China, it can be cultivated as an open-field 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, avoids 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. Flowering regulation of gerbera is very easy; as long as the room temperature is kept above 12°C, the plant can be kept from entering dormancy and continue to grow and bloom. It likes fertile, loose, well-drained sandy loam rich in humus, avoids heavy clay soil, prefers slightly acidic soil, is a semi-hardy flower, and can tolerate short-term low temperatures of 0°C. Gerbera is a light-loving plant, and a location with sufficient light should be chosen for cultivation. Seedlings should not be planted too deep, and the root crown needs 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 Gerbera
Yunnan gerbera seedling producers are mainly concentrated in Kunming, about 20 in number, among which more than 10 are relatively large in scale. The annual output of gerbera seedlings is about 20 million plants. Many enterprises or scientific research units have collected abundant 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. Kunming has become the center of national gerbera seedling production. After nearly 10 years of development, gerbera, which ranks fifth on the international cut flower sales list, has continuously expanded its planting scale in Yunnan. Its cultivation area is second only to roses, carnations, and lilies, making it a major fresh cut flower category 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 formed.
Volume Declines and Prices Fall
It is understood that Yunnan gerbera seedling producers are mainly concentrated in Kunming, about 20 in number, among which more than 10 are relatively large in scale. Affected by the relatively high price of gerbera seedlings, although household-based seedling production households have appeared, because the production volume of enterprises has declined, compared with the same period, the total production of gerbera seedlings has decreased, 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 at 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 (generally gerbera growers replace seedlings once every two to three years), then 6 million seedlings are needed, and the province's total seedling demand is 10.5 million plants. If 1/3 to 1/2 of the gerbera plants are replaced with seedlings, then the seedling demand within Yunnan Province is 6 million to 9 million plants. From this, it can be seen that the number of seedlings sold outside Yunnan Province cannot be less than 6 million plants. But in reality, Yunnan gerbera seedling enterprises do not sell much in markets outside the province. Therefore, gerbera seedlings are in a situation of 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 originally planted with gerbera to roses or carnations. 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 gerbera planting areas in Jiangsu, Liaoning, Shandong, and other provinces are increasing.
Seeking Joint Development
After nearly 10 years of development, many enterprises or scientific research units in Yunnan have already possessed relatively strong production technology and experience, collected abundant 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 gerbera, inadequate post-harvest handling technology, and declining quality of seedling mother plants, the development of gerbera cut flowers and seedlings 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 the tissue culture technology for gerbera is not difficult, and it is entirely possible for enterprises or scientific research units outside Yunnan Province to catch up with or even surpass Yunnan in seedling production. Facing increasingly fierce market competition, for Yunnan gerbera seedlings to gain a firm foothold in the market, they must start from the following 3 points: first, strive to improve seedling quality, extend the hardening-off period, increase the survival rate of finished seedlings, and at the same time control the propagation coefficient of seedlings and reduce indoor contamination and mold infection of seedlings; second, according to the demand situation in different regions, choose the right varieties, such as green-center varieties mainly for outside the province and black-center varieties mainly within the province; third, take the road 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, responsible persons from enterprises such as Kunming Qianhui, Kunming Yuhui, Kunming Tongxin, and Kunming Jinkeyi were invited to hold 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 held negotiations with the Dutch company Florist and plan to introduce more than 4 million high-quality mother plants from the company, requiring payment of more than 4.8 million yuan in patent fees.
Gerbera Gerbera and Daisy Differences Gerbera
Scientific name: Gerbera jamesonii
Family: Asteraceae
Origin and distribution: South Africa
Morphological characteristics: With rosette leaf clusters. Leaves oblong-spatulate, deeply lobed or lyrate-pinnatifid, leaf backs covered with white down. Capitulum. Flower colors range from white to various yellows, oranges, rose reds, reds, etc. If the ambient temperature is suitable, it can bloom all year round.
Growth habits: Likes climate conditions that are mild in winter and cool in summer. Requires well-drained, humus-rich, deep and fertile soil with a pH value of 6-6.5.
Landscape uses: Barberton daisy is mainly used for cut flowers and potted 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
Habits: A perennial herbaceous plant, often cultivated as an annual or biennial. Likes cool, humid, and sunny conditions, relatively cold-tolerant, and can overwinter in open fields where the ground surface is not lower than 3-4°C. It has low soil requirements. Flowering period April-May.
Cultivation: Propagated by sowing or division. The suitable temperature for seed germination is 22-28°C. In North China, sow from August to September, move into a cold frame in late October to overwinter, and in early April of the following year pot them or plant them into flower beds. During the growing season, as long as appropriate water and fertilizer are ensured, they can grow well. After the flowers fade, the roots can be divided and planted in pots, placed in a cool place to spend the summer, and after the autumn cools, moved into a greenhouse or indoors, with strengthened fertilizer and water management, and they can bloom again in winter or the following spring. There are relatively few pests and diseases.
Cultural Background of Gerbera: Origin and Evolution
In 1878, Rehman first discovered 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 gerbera. He crossed gerbera with green-leaf gerbera (G.viridifolia Sch.-Bip.); bred hybrids; afterward, Adenet 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, with a flowering period almost continuous throughout the year. Japan has also achieved excellent results in breeding double-petaled gerbera. In addition, people have also bred many distant hybrids, using gerbera as the female parent and coreopsis (coreopsis basalis Blake.) or marguerite (Argyranthemum frutescens Sch.-Bip.) as the male parent, and their hybrid flower types mostly resemble the male parent.
Gerbera flower color gene inheritance is rich, and heterogeneity is very high. Its progeny differ greatly in flower type and flower color. Therefore, excellent hybrid individual plants can be rapidly and massively propagated into clonal lines through tissue culture. Therefore, varieties are replaced very quickly with fashion trends. Their 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 Barberton Daisy
In the early 20th century, Madagascar, located in southern Africa, was a small country rich in tropical flowers and plants. A local girl named Slangyini had loved this kind of wildflower with slightly curved stems and drooping flowers 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, frequently toasting each other. Unexpectedly, the groom, who had a very low tolerance for alcohol, became drunk after only three rounds of drinking. 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 similar this supporting posture was to the growth habit of that wildflower, quite a few girls said in unison: "Oh, the flower really looks like it is supporting the groom!" From then on, the name Barberton daisy spread far and wide.
Gerbera is also known as Barberton daisy and is native to southern Africa. Its flowers are large and beautiful, delicate and pleasing to the eye, and it is an important cut flower decorative material. Large red gerbera is used for bridal bouquets. Together with roses, gladioli, and carnations, it is listed among the world's best-selling "four major cut flowers."
Cultivation History
The first person to improve gerbera varieties was the Englishman Irwin Lynch, who crossed G.jamesonii with green-leaf gerbera (G.vurufolia). Later, the Frenchman M.Adent continued to improve it and bred a large number of cut flower varieties. In addition, Japan also bred double-petaled varieties, with diverse flower types and colors, collectively called hybrid gerbera (Gerbera jamesonii), used for cut flowers and potted flowers.
Feng Shui
Gerbera can promote women's 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 all requires confirming the bedroom arrangement. For example, placing a fresh and long-lasting gerbera at the head of the bed, with a fragrance that is somewhat pleasant and will not easily disappear, can encourage oneself.
Gerbera can promote family harmony. Gerbera, like the sunflower, is a flower that represents the sun in everyone's mind, only the latter is tall and imposing, while the former is elegant and upright. If the sunflower is the blazing sun of summer, then gerbera is like the warm sun of winter, making people feel cozy. Someone once advocated using gerbera as the flower representing Father's Day, because gerbera is also called sun flower, and the sun can also symbolize fatherly love. The feng shui effect of gerbera being able to keep a family living in harmony and loving each other arose from this.
For people whose Five Elements belong to fire, gerbera is their lucky flower. In Chinese feng shui studies, 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 Elements distinctions. Using them appropriately in different directions and environments can produce unexpected regulating effects. In geomancy, plants are considered to have spirituality and can be of certain help to people in various aspects. Therefore, plants are often used to regulate environmental qi. There are many types of plants and their properties differ greatly, so there are also 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 luck to the homeowner and their family. Of course, besides red, gerbera also has many other colors, so gerbera is the lucky star of many people. As the color of gerbera changes, the group of people it blesses is different.
Gerbera Variety Classification Variety Classification
It can mainly be divided into dwarf potted types and modern cut flower types. Potted types are mainly F1 hybrids, with characteristics such as consistent flowering period, rich color variation, short growth period, uniform habit, and strong multiflora tendency; cut flower varieties have straight flower stalks, and large flower diameters can reach 15cm, with a long flowering period, can bloom year-round, and a long ornamental time, with a vase life as long as 7-10d. Cut flower types can also be divided into single-petaled, semi-double-petaled, and double-petaled 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 of varieties on the market can also be divided into:
1. Narrow-petal type Ligulate petals 4-4.5mm wide, 50mm long, arranged in 1-2 whorls; inflorescence diameter 12-13cm, flower disc small, flower stalk 5-6mm thick, 50cm long. Annual output per plant more than 30 stems.
2. Wide-petal type Ligulate petals 5-7.5mm wide, 41-48mm long, about 60 petals, arranged in 1-3 whorls; inflorescence diameter 11-13cm, flower stalk 6mm thick, 50-70cm long. Annual output per plant more than 20 stems.
3. Large-flowered double-petal type Inflorescence diameter 10-14cm.
Main Domestic Varieties
Common varieties include the red "Passion," the yellow "Sun Dance," the white "Bianca," etc. Miniature small-flowered ones include "Dance Hall" (white), "Ballet" (orange), "Sultan" (yellow), "Kanga" (red), etc.
No. Variety Flower diameter cm Number of 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 Black-purple
4 Golden Gate 10-12 Many Deep yellow Black-purple
5 Jolly Disc 12-14 3-4 White Pink-purple
6 Lorraine 10-12 Many Deep yellow Green
7 Magnum 10-12 Many Deep pink Black-purple
8 North Star 8-9 3-4 Red Green
9 Oprah 10-12 Many Yellow Green
10 Optima 10-12 Many Orange-red Black-purple
11 Ramona 10 3-Many Red with golden edge Green
12 sangria 11-13 Many Purplish red Black-purple
13 Savannah 10-12 3-4 Purplish red Black-purple
14 Shirley 10-12 4 Deep pink Black-purple
15 Sunset 10-12 Many Orange-red Black-purple
16 Twiggy 10-12 Many Blue-purple Yellow-green
17 Venus 10-12 Many Creamy yellow Deep pink
18 Willy 7 Many Deep pink Purplish red
Main Species in the Same Genus
There are about 80 species in this genus, mainly distributed in Africa; 20 species are produced in our country, the vast majority concentrated in the southwest region, and none have been seen in ornamental application. Those commonly seen in cultivation for ornament also include:
1. Orange-yellow 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 relatively small, white, back yellow
Distribution Area of Gerbera
The place of origin is South Africa, with a few distributed in Asia. Now commercial production also exists in Taiwan, China and Guangdong. With the progress of domestic greenhouse technology and the introduction of new foreign greenhouse technology, it is cultivated in South China, East China, and Central China.
Landscape Uses of Gerbera
Its flowers are huge, flower branches upright, flower colors brilliant, water insertion time long, cut flower rate high, vase insertion time can reach 15-20 days, cultivation saves labor and time, and it is one of the world's famous top ten cut flowers. It can also be used to arrange flower beds and flower paths, or potted in greenhouses as decoration for halls, meeting rooms, etc.
Potted gerbera is often used to decorate doorways and halls. Its cut flowers are used for vase insertion and flower arrangement, embellishing desks, display windows, and living rooms. With pink gerbera as the main flower, paired with dendrobium, gypsophila, and orchid leaves, the tone is elegant and the interest is strong. If red gerbera is used as the main flower, paired with sword fern, palm bamboo leaves, dried branches, and dyed walnuts for wall-hanging decoration, it can produce a relatively strong decorative effect. It is commonly cultivated in gardens across our country, mostly as potted plants.
Propagation Methods of Gerbera Propagation is by sowing or division.
Because gerbera is a cross-pollinated plant and is self-incompatible, its seed progeny will inevitably vary. The variation types generally show thinner and softer flower stalks, smaller flower shape, and greatly reduced cut flower value. Therefore, gerbera must be propagated asexually. Division propagation is usually used, but each plant can only produce 5-6 new plants per year. In order to accelerate propagation, cuttings and tissue culture can also be used.
Propagation Methods
Tissue culture is the main method for propagating gerbera. Gerbera tissue culture commonly uses the receptacle as the explant. Flower buds with a diameter of about 2cm are used, disinfected and washed, leaving only the receptacle, cut into 2-4 pieces, and placed on the medium. The medium formula is MS plus BA1.0 mg/L, plus indoleacetic acid (IAA) 0.5 mg/L. At 22°C with 16h 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 BA0.1/L, plus 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 seedlings, remove the callus at the base. The rooting medium formula is 1/2 MS plus naphthaleneacetic acid (NAA) 0.1 mg/I.
After the gerbera explant is induced to sprout, after 4-5 months of test-tube proliferation, thousands of test-tube plants can be produced. The most suitable field transplanting period for gerbera is April. Seedlings transplanted at this time can produce flowers in large quantities 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 the 4th proliferation in mid-February of the following year, and then carrying out test-tube seedling rooting for 2 weeks; after rooting, transplant to the seedling bed, maintain for 1 month, and then move to the field in early April.
Gerbera mostly uses tissue culture for rapid propagation. It can also be propagated by division, with each mother plant dividing into 5-6 small plants; sowing propagation is used for dwarf potted varieties or breeding; single buds or short lateral buds occurring at the stem base can be cut and used for cuttings. Its response to photoperiod is not sensitive, and the length of daylight has no effect on flower number and flower quality. It requires loose, fertile, well-drained, humus-rich, deep soil, slightly acidic sandy loam.
Cultivating gerbera with artificial culture soil can significantly increase yield and quality. Use 5 parts humus, 2 parts perlite, and 3 parts peat to make your own culture soil for planting, but the production cost of this method is relatively high. Field planting can be carried out, selecting loam with a deep soil layer of at least 25 cm or more suitable for gerbera growth for planting. Before planting, sufficient base fertilizer should be applied: 5 tons of livestock manure per mu, 600 kg of chicken manure, 100 kg of superphosphate, 300 kg of plant ash, and the organic fertilizer must be fully decomposed. The fertilizer should be thoroughly mixed with the soil of the planting bed and plowed, made into a form of one ridge and one furrow, with ridge width 40 cm and furrow width 30 cm. Plants are planted on the ridge in double rows staggered. Plant spacing 25 cm. Attention should be paid to leaving the rhizome part slightly exposed above the soil to prevent root rot. Afterward, irrigate in the furrow.
However, because of its fast reproduction rate, it is 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 set seed, it may cause unnecessary trouble.
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 division carrying 4-5 leaves, and plant them separately. The disadvantage of this method is that the propagation speed is slow.
Cutting propagation
Dig up selected robust mother plants, remove the soil from the roots, remove the leaves, and cut off the growing points. Keep the rhizome part and plant it in a planting box for cultivation. Place the planting box under conditions of 22-24 °C and 75%-80% relative air humidity. Afterwards the rhizome part will successively grow axillary buds and adventitious buds, forming cuttings for propagation. Cut off the shoots after they have 4-5 leaves, insert them into soil or another substrate, and cover the surface with a 1-2 cm thick layer of perlite. Keep the temperature at around 25 °C and the relative humidity at 75%-90%; after 3-4 weeks they will root, and the rooted cuttings can then be transplanted.
Cultivation techniques and key points for Gerbera
The suitable temperature for the growing period of Gerbera is 20-25 °C; below 10 °C or above 30 °C it stops growing and 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 insulation equipment such as plastic greenhouses. In summer, shade nets can be used or water sprayed to cool it down, ensuring a year-round supply of cut flowers.
(1) The soil must be sterilized. Gerbera is not particularly strict about soil requirements; loose, breathable sandy soil rich in humus is suitable. Because the pathogens of various diseases harmful to Gerbera can survive in the soil, and the soil also contains underground pests and earthworms that damage the root system, the soil must be sterilized before planting.
(2) Land preparation and fertilization. Because Gerbera is afraid of waterlogging, high-ridge cultivation is generally used. The ridges generally run north-south, with a ridge height of about 30 cm, a ridge width of 1 m, and a furrow width of 40-50 cm. In conjunction with land preparation, apply an appropriate amount of base fertilizer, applying 200 kg of barnyard manure per 100 m.
(3) Planting. Planting is best done on cloudy days or in the evening on sunny days. Except for the high-temperature period from July to September in summer, it can be done at any other time. When planting, be sure to plant shallowly, so that the root crown is exposed above the soil surface, and water thoroughly. Newly planted plants should be shaded with a shade net.
(4) Pay attention to seedling-stage management. Carry out insulation or cooling management according to the weather conditions at the time of planting, controlling the temperature at 20-25 °C so that the plants quickly resume growth. After the seedlings have recovered, apply 1:10 human manure and urine once every two weeks to ensure that each plant has 8-10 healthy leaves before entering the flowering period. When watering and fertilizing, be careful not to let water get into the center of the leaf rosette, otherwise the flower buds are prone to rot.
(5) Fertilizer and water management. Gerbera is drought-tolerant but not tolerant of warmth, and must never be waterlogged. During the seedling stage it should be kept appropriately moist to promote root development. During the growing period, the amount of watering can be determined by the dryness or wetness of the soil: do not water if it is 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, when the weather is hot and water evaporates quickly, the plants enter a semi-dormant state, flower production drops noticeably, and plant growth weakens; at this time pests and diseases are very likely to occur, and this can be combined with topdressing to promote root absorption of nutrients. In summer, loosen the soil in time, clean the roots to prevent disease, control water and fertilizer, and provide shade and rain protection.
(6) Leaf stripping and bud thinning. Gerbera can flower year-round within the range of 5-30 °C, so it has a large fertilizer requirement throughout the growing period. Before flower bud differentiation, increase the application of organic fertilizer and nitrogen fertilizer to promote sufficient plant growth, mainly using monopotassium phosphate and urea, plus an appropriate amount of liquid organic fertilizer, applied as a topdressing once a week. When the plant enters the period when vegetative and reproductive growth proceed together, increase the proportion of phosphorus and potassium fertilizer, generally once a week, while adding an appropriate amount of organic fertilizer. Before the two flowering peaks in April-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, and its growth is not sensitive to light, but it likes ample sunlight. When cultivated in a greenhouse, adding 2-3 layers of plastic film in winter allows it to overwinter safely. Before the first frost arrives in late October, cover with one layer of plastic film; around November, small tunnels should be built over each ridge for insulation. From June to September, 50% shade nets can be used to lower the temperature.
(8) Removal of residual leaves. The leaves clustered at the base of Gerbera tend to turn yellow and age, and should be removed in time. This not only benefits the sprouting of new leaves and new flower buds, but also helps ventilation and light penetration, preventing the lower young flower buds from becoming "hidden buds" due to lack of sunlight and hormones. In addition, excessive flower buds or deformed flowers should also be removed in time to ensure that the retained flower stems have sufficient nutrients and to improve cut flower quality. Generally, a one-year-old single plant has 15-20 healthy leaves at full bloom 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 unique to the variety. The best time is in the morning and evening when temperatures are low, as it is easier to harvest then without damaging the plant. The method is to hold the lower half of the flower stem with your hand and shake it from side to side to detach it. Remove flowers with disease spots, insect spots, or deformities, cover the flowers with a No. 12-15 funnel-shaped plastic bag, then grade them by variety and length, tie them in bunches of 20 with a rubber band, 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 preservation, with the water depth ideally submerging 5-10 cm of the base of the flower stem.
Cultivation protocol: soil preparation
1. Soil tillage and base fertilizer: deep plow once before planting (30-40 cm), apply chemical fertilizer and barnyard manure into the soil (apply 2000 kg of decomposed barnyard manure, 5 m3 of humus soil, 65 kg of superphosphate, and 50 kg of compound fertilizer per mu), then deep plow again (15-25 cm).
2. Bed making: dig drainage ditches 70-100 cm deep nearby (depending on the water table), and form high beds 45 cm high, with a bed width of 1.0 m and a ditch width of 40 cm.
3. Soil sterilization: use formaldehyde sterilization and chemical agents such as Vydate (tentative) for sterilization. Taking 40% industrial formaldehyde sterilization as an example: dilute to a concentration of 1%, spray evenly on the soil, immediately cover tightly with plastic film and fumigate in a sealed manner. 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 done. Different sterilizing agents should be determined according to the instructions and trials. Soil used for the first planting does not need to be sterilized.
Seedling selection
Select seedlings 11-15 cm tall with 4-5 true leaves for planting. Standards for high-quality seedlings: robust seedlings, oily green leaves, well-developed root system with many fibrous roots that are white in color, and leaves free of disease spots, insect bite gaps, and mechanical damage.
Planting
Planting time: planting can be done year-round, but from the perspective of production and sales, April-June is ideal.
Planting method: plant 3 rows per bed, with the middle row staggered with the side rows, plant spacing 30 cm, 9-10 plants per sq m, 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 of sunny days; when planting, make deep holes and plant shallowly, with the root crown exposed 1-1.5 cm above the soil surface, otherwise the plant is prone to fungal infection; if the plant is planted too shallowly, it is easy to loosen or pull out the plant when harvesting flowers; after planting, water thoroughly in time.
Cultivation management
1. Management during the seedling stage: after planting, shade with a 70% shade net 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, keeping the daytime temperature at 22-25 °C and the nighttime temperature at 20-22 °C for 1 month; during this period use sprinkler irrigation, preferably in the morning. Make a small hole beside the plant to indicate soil moisture; moisture should not be too dry or too wet, with watering frequency once every 5 days, but this is not fixed and should be determined according to soil structure, weather conditions, etc.; inspect each plant every day, promptly remove diseased plants, and fill in with robust young seedlings.
2. Management during the mature seedling stage: about 1 month after planting, Gerbera enters a period of vigorous growth, and appropriate shading is needed when light is too strong; adjust the temperature to 14-16 °C at night and 18-25 °C during the day as the minimum temperature; apply 0.1% compound fertilizer (N:P:K = 15:15:15) once every 1 week, and spray 0.1% monopotassium phosphate as a foliar fertilizer once every 2 weeks; spray broad-spectrum fungicides, such as 800-**** times dilution of thiophanate-methyl, 2-3 times to prevent disease.
3. Management during the flowering period: after about 3-4 months it enters the flowering period. Apply compound fertilizer with N:P:K = 12:12:17 once every 1 week. Use foliar spraying of trace element fertilizers, generally once every 25 days, each time alternately spraying 0.1-0.2% Ca(NO3)2.4H2O, 0.1-0.2% chelated iron plus 0.1-0.2% borax plus 5-10 ppm sodium molybdate; use drip irrigation for watering, with the watering principle being "do not water if not dry, water thoroughly when watering," and never water from the center of the leaf rosette. Keep the relative humidity in the greenhouse at 80%-85%; weed in time, remove diseased and dead leaves, pull out diseased plants and sterilize the soil in the planting holes with quicklime; during the summer flowering period, pay attention to shading and ventilation for cooling; during the winter flowering period, pay attention to insulation and heating, especially preventing too large a difference between day and night temperatures, so as 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 likes an environment that is warm in winter, cool in summer, well ventilated, and sunny. The suitable growing temperature is 20C-25C during the day and about 16C at night. The suitable flowering temperature is not lower than 15C, and in a growing environment where the daytime temperature does not exceed 26C it can flower year-round. The suitable temperature during the winter dormant period is 12C-15C, and growth stops below 7C. It is not sensitive to photoperiod, and the length of natural daylight has no effect on flower number or flower quality. Gerbera requires loose, fertile, well-drained sandy loam rich in humus, with a deep soil layer and slightly acidic.
II. Propagation
Gerbera is mostly propagated quickly through tissue culture, and can also be propagated by division, with each mother plant able to be 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
Using artificial culture soil to cultivate Gerbera can significantly increase yield and quality. Please refer to the formula: 5 parts humus; 2 parts perlite; 3 parts peat, mixed by yourself as culture soil for planting, but the production cost of this method is relatively high. Field planting can also be carried out, and loam soil with a deep soil layer of at least 25 cm suitable for Gerbera growth should be selected for planting. Before planting, apply sufficient base fertilizer, generally applying 5 tons of livestock manure, 600 kg of chicken manure, 100 kg of superphosphate, and 300 kg of plant ash per mu; the organic fertilizer must be fully decomposed. All fertilizers must be thoroughly mixed with the soil of the planting bed and plowed in, forming a ridge-and-furrow pattern, with a ridge width of 40 cm and a furrow width of 30 cm; plants are planted on the ridges in double rows in a staggered pattern. Plant spacing 25 cm. When planting, care should be taken to expose the rhizome part slightly above the soil to prevent root rot. After planting, irrigate in the furrows.
IV. Management after planting
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. Outside southern China, it cannot overwinter in the open field and requires greenhouse cultivation; outside the Yangtze River basin, it can be cultivated in unheated greenhouses. In summer, a shade net needs to be covered on top of the greenhouse, and the plastic films on both sides of the greenhouse should be opened for cooling. In winter, when the outside nighttime temperature approaches 0C, seal the plastic film tightly, and an additional layer of plastic film must be added inside the greenhouse. On clear and warm days, open the film at the south end of the greenhouse at 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 provided and ventilation 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 touch the center of the leaf rosette, to prevent flower bud rot. In open-field cultivation, pay attention to preventing waterlogging. In addition, fertilization can be combined with irrigation.
4. Topdressing
Gerbera is a fertilizer-loving perennial herbaceous flower with a high fertilizer demand, and 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 sulfate, and 1.2 kg of ammonium nitrate or ammonium phosphate per mu, once every 5-6 days in spring and autumn, and once every 10 days in winter and summer. If high temperatures or relatively low temperatures cause the plant to enter a semi-dormant state, stop fertilizing.
5. Removal of residual leaves
The lower leaves of the basal leaf rosette of Gerbera tend to turn yellow and age, and should be removed in time. 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 are leaf spot, powdery mildew, and viral disease. For leaf spot, spray 800-**** times dilution of 70% thiophanate-methyl wettable powder or 500 times dilution of 50% carbendazim wettable powder. For powdery mildew, use 1500 times dilution of 70% thiophanate-methyl or 1000-1200 times dilution of 75% triadimefon wettable powder for control, once every 7-10 days, spraying continuously two to three times. For viral disease control, strictly control the introduction of seedlings, promptly control aphids to reduce virus transmission vectors, and promptly remove and destroy diseased plants when found. The main insect pests of Gerbera are tarsonemid mites, cotton bollworm, tobacco budworm, beet armyworm, and aphids. For tarsonemid mites, use 1000 times dilution of 40% dicofol for control.
Harvesting
Harvest when the pollen of the outer ring of flowers begins to shed. At harvest, the plant is required to be growing vigorously, with upright flower stems and open flowers. The quality of cut flowers greatly affects their vase life. Never cut flower stems when the plant is wilting or when the flowers are half-closed at night. After harvesting, grade, preserve, package, and market them.
Most of the professional production bases for Gerbera seedlings in China are concentrated in the Yunnan region, and a large number of emerging professional flower seedling producers, represented by the Yunnan Lüxin Flower Seedling Base, are flourishing.
Disease control of Gerbera: 1. Bacterial diseases of Gerbera
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, chemoorganoheterotrophic. This pathogen mainly infects chicory, lettuce, pea, melon, Chinese cabbage, and many other cruciferous plants, and tomato, clover, etc. can also be affected. The pathogen mainly overwinters in diseased field soil and diseased plant residues, and spreads through rain, agricultural operations, and insect carrying.
2. Viral diseases of Gerbera
2.1 Gerbera spotted wilt
After infection, Gerbera shows symptoms such as fading, necrosis, and dwarfing, 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 inactivation temperature is 40-46 °C, the survival period in vitro is less than 5 h, and the dilution endpoint is 10-3. It is transmitted by mechanical inoculation, and the insect vector thrips transmits it in a persistent manner. 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 formation of patches, with weak growth and a sharp decrease in the number of cut flowers; with continued development, the 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 that are similar in morphology; it is transmitted by mechanical inoculation, and aphids transmit it in a non-persistent manner. The inactivation temperature is 70 °C, the survival period in vitro is 4 days, and the dilution endpoint is 10-3. The host range of this disease is wide, and it is mainly transmitted by sap and aphids.
2.3 Gerbera mottle disease
Chlorotic ring spots appear on the leaves, and some chlorotic spots appear as oak-leaf patterns, with individual tissues near the spots necrotic. When the disease is severe, the leaves become smaller, wrinkled, and brittle; in some varieties the petals are broken in color, the flowers become smaller (deformed), the flower color is not bright, and the plant is stunted. The pathogen is Tobacco mosaic virus (TMV). The particles are straight rod-shaped, 300 nm x 18 nm, and the inactivation temperature is 90-95 °C. The host range of this disease is wide, and it can be transmitted by mechanical inoculation, contact between plants, contaminated soil, farm tools, etc., and can also be transmitted by sap, soil, nematodes, and seeds.
3. Fungal diseases of Gerbera
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 oval yellow-white lesions. The lesions are covered with a white substance, and in severe cases the entire leaf is covered with white powder; later the powder layer becomes gray-white, and the leaves scorch and wither. The pathogen is (Oidium sp.). The mycelium is white and superficial, penetrating host epidermal cells with haustoria to absorb nutrients. Conidiophores are upright, 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 the temperature is high, the 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 the leaves, gradually expanding into circular or nearly circular lesions with dark brown edges, and later black small dots are produced on the lesions. The pathogen is Phyllosticta chrysanthemi. The pycnidia are spherical, embedded, unilocular, with an ostiole. Conidiogenous cells are cylindrical, colorless, smooth, and produce conidia in a holoblastic manner; conidia are elliptical, single-celled, colorless, with a truncated base. It grows very quickly on artificial medium, with abundant aerial mycelium, relatively sparse pycnidium formation, and a membranous pycnidial wall. The pathogen overwinters as mycelium and pycnidia in diseased fallen leaves. Old leaves are more severely affected than young leaves. (2) Cercospora leaf spot. Small 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 edge, and a purple-brown outer ring; dark green mold spots are produced on both the front and back of the leaves. The pathogen is Cercospora chrysanthemi. The mycelium is mostly embedded, often with stromata; conidiophores are thick, of the hyphal type, olive-brown or brown, lighter at the top, 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 blastic, 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 damp and shaded with insufficient light, with 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; the diseased part becomes soft and rotted, and the surface is densely covered with a gray mold layer. 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. The pathogen is Botrytis cinerea, belonging to the subphylum Deuteromycotina, genus Botrytis. Conidiophores are straight or bent, 960-1 200 μm x 16-22 μm in size, clustered in several, brown, smooth, with 1-2 branches at the top. The ends of the branches often swell noticeably, forming colorless or pale bottle-shaped conidiogenous cells. Conidia are short elliptical, 12-18 μm x 9-13 μm in size. 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 base of the stem and causes the stem to rot. In the early stage of the disease, the affected part shows water-soaked soft rot and is brown, gradually spreading to the stem and petiole. Later, black mouse-dropping-shaped sclerotia can be seen inside and outside the stem. The typical symptom of this disease is rapid soft rot at the affected part, densely covered with white flocculent material, or black mouse-dropping-shaped sclerotia, each sclerotium capable of producing 1-9 apothecia. The disease is caused by the fungus Sclerotinia sclerotiorum Fuck. Apothecia are produced on the sclerotia, disk-shaped, with long stalks. Asci are arranged in parallel, with persistent paraphyses among the 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. Plots with cruciferous crops as the previous crop are severely affected. The disease is severe in 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, occurring over a wide area and causing severe damage. The plant is affected throughout the entire growth period, and is most severely affected during the flowering period. The pathogen infects from the base of the stem above ground; the affected part becomes soft, water-soaked, and light black; the plant leaves suddenly wilt and turn purplish red. When the diseased plant is pulled out, the affected part at the stem base breaks easily, and white mold spots can grow on the surface when moist. This disease is mainly caused by Phytophthora cryptogea. Phytophthora cryptogea belongs to the kingdom Chromista, phylum Oomycota, order Peronosporales, family Pythiaceae, genus Phytophthora. Its vegetative body is aseptate, multinucleate mycelium, with hyphal swellings produced, and asexual reproduction produces zoosporangia. Sporangia are pear-shaped or elliptical, without papillae, large, averaging 46 μm x 27 μm in size, with a wide host range. It is heterothallic; sexual reproduction produces oogonia, oospores, and antheridia. Oogonia are spherical and contain one spherical thick-walled oospore; antheridia are single-celled, colorless and transparent, and amphigynous. The pathogen overwinters on residues or in soil, and the overwintering pathogen is the main primary infection source of the disease. Sudden alternating dry and wet soil conditions or frequent intertillage and loosening of the soil cause many wounds on the plant roots; the pathogen invades through the wounds and, when conditions are suitable, spreads through irrigation water or rainwater, causing a major outbreak of the disease. Poorly drained and continuously cropped plots 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 root cortex peels off, there are few fibrous roots, and the plant is easy to pull up. When the disease develops slowly, the leaves of the diseased plant turn purplish red or dark brown and gradually wither; when the disease is severe, the plant dies in a green wilt state. This disease occurs in Italy, Australia, and China, among other countries. Because Gerbera is basically cultivated under protected conditions, this disease can occur year-round, and April-August each year is the period when it occurs more severely. The pathogen overwinters in the soil or in diseased plant residues. Contaminated soil and affected plants are the main sources of infection for this disease. High-temperature and high-humidity weather and heavy clay soil both promote the proliferation and spread of the pathogen. This disease is mainly caused by Fusarium oxysporum. On artificial medium it produces dense mycelium in a loose cottony form; conidiophores are colorless, and conidiogenous cells produce conidia in a phialidic manner by enteroblastic proliferation, producing two types of spores. Microconidia are oval to elliptical, 5-12 μm x 2.5-3.5 μm in size; macroconidia are 27-46 μm x 3-4.5 μm in size, spindle-shaped to sickle-shaped, with a hooked apex and a small pedicel at the base, with 3-5 septa, most commonly 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. tragopgonis), and ring spot mosaic disease (caused by TBRV), etc.
4. Pest: whitefly
Key control techniques: thoroughly remove weeds, insert yellow sticky boards for continuous monitoring, and once pests are found, take measures in time. Choose good pesticides and use them correctly: whiteflies easily develop resistance to pesticides, so pesticides must be rotated. Pesticides with good effects include beta-cypermethrin, abamectin, imidacloprid, etc. Choose dawn for spraying, keep the greenhouse sealed for 4-5 hours after spraying, and spray once again the next morning. Keep the greenhouse ventilated and low in humidity; remove diseased leaves in time; when the disease occurs, spray 1500 times dilution of 70% thiophanate-methyl, or use 20% Junke smoke for fumigation control, once every 7 days, for 2-3 consecutive treatments. In addition, use sulfur fumigation for control: 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, energize and heat for 2 hours, replace the sulfur powder once every 6 days, and continue fumigation for 15 days. During the outbreak period of powdery mildew, fumigate 8-10 h per day, and powdery mildew can be eliminated in about 10 days.
Thrips
Key control techniques: promptly cut off insect-infested flowers, thereby reducing the source of insects 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 1500-2000 times dilution of 5% imidacloprid and then close the greenhouse for 8-10 hours. Fumigation can be carried out at 10 a.m. or 5 p.m. when the temperature is slightly higher, to achieve good efficacy.
Cabbage caterpillar
Key control techniques: for larvae, spray with 2000-2500 times dilution of 10% Chuchujin for control; for older larvae, use 1000 times dilution of beta-cypermethrin for control, once every 7 days, for 3 consecutive times.
Note: the above pesticides were determined after testing according to the reference formula provided by the Resources and Environment Institute.
Phytophthora blight
Key control techniques: soil for continuous cropping must be sterilized with Vydate, 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 placed in the palm and squeezed hard, then it can be watered; in the early stage of the disease, part of the leaf turns red and begins to wilt. Drench the roots with 400 times dilution of 58% phosethyl-Al plus mancozeb, then 7 days later drench the roots with 500 times dilution of 64% Sandofan powder. Apply the pesticide in the early morning or evening when the temperature is low, stop applying when the temperature is above 28 degrees, and apply once every 7 days for 3 consecutive times.
Spot disease
Key control techniques: remove diseased leaves promptly when found and destroy them in a centralized manner; in the early stage of the disease, spray 300 times dilution of 2.5% myclobutanil emulsifiable concentrate or 800-**** times dilution of 70% thiophanate-methyl wettable powder, once every 7 days, spraying continuously 2-3 times.
Gray mold
Key control techniques: humidity control 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 crown; to prevent water vapor from condensing on the flowers, gradually open the side greenhouse cover after 10 a.m. on sunny days, avoiding a sharp rise in temperature inside the greenhouse; in the early stage of the disease, spray 1500 times dilution of 70% thiophanate-methyl on the foliage, and combine with smoke agents for control.
5. Physiological diseases
1. Symptoms: dark green spots appear on young leaves; in severe cases, the young leaves and growing points die first, while 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, and an inverted "V"-shaped green part forms at the base of the leaf, with its top extending all the way close to the leaf tip. The leaves become brittle, curved, and even red; new leaves grow few and small, the petioles are slender, the veins of young leaves protrude, inflorescence formation is inhibited, the flower stalks are thin, and the flowers become smaller. Spray with 0.2% magnesium fertilizer twice. Solution: judging from the symptoms, it may be caused by magnesium deficiency.
3. Symptoms: the leaves turn pale yellow, even almost white; the veins remain green at first, but eventually also change color.
Solution: judging from the symptoms, it may be caused by iron deficiency. Spray with 0.02% chelated iron, once every 25 days.
4. Symptoms: small leaves curve, thicken, and become brittle. The growing point dies, and flower buds abort or produce deformed sterile inflorescences.
Solution: judging from the symptoms, it may be caused by boron deficiency. Spray with 0.05% borax, once every 25 days.
5. Symptoms: spots and "mosaic" appear on young leaves; one side of the leaf develops normally while the other side is abnormal, and the leaf curves to the side.
Solution: judging from the symptoms, it may be caused by zinc deficiency.
7. Quality defects
1. Flower stem breakage: transverse cracks appear on the flower stem, and in severe cases the flower stem breaks, with the cracks appearing cut-like.
Solution: use 1-2‰ calcium nitrate and spray once a week.
2. Leaf edge scorch: sudden scorching appears at the tip or the tips of the pinnate lobes of the leaf.
Solution: caused by too high a 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
The diseases of Gerbera include leaf spot, powdery mildew, and viral disease. For leaf spot, spray 800-**** times dilution of 70% thiophanate-methyl wettable powder or 500 times dilution of 50% carbendazim wettable powder. For powdery mildew, use 1500 times dilution of 70% thiophanate-methyl or 1000-1200 times dilution of 75% triadimefon wettable powder for control, once every 7-10 days, spraying continuously two to three times. For viral disease control, strictly control the introduction of seedlings, promptly control aphids to reduce virus transmission vectors, and promptly remove and destroy diseased plants. The main insect pests of Gerbera are tarsonemid mites, cotton bollworm, tobacco budworm, beet armyworm, and aphids. For tarsonemid mites, use 1000 times dilution of 40% dicofol for control. For other pests, use 1000-1500 times dilution of 2.5% deltamethrin or 40% omethoate for control, once every eight to nine days. Spraying has an adverse effect on flower color, so it should not be used during the flowering period.
Spot disease
Because Gerbera is cultivated in protected conditions year after year, the warm, humid environment with poor airflow easily leads 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 the leaves, gradually expanding into large spots with concentric rings (2 mm to 5 mm in diameter). Later 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 can use chloropicrin fumigation to effectively kill the pathogen 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 conditions of low temperature and low humidity, the disease is unlikely to occur.
3. Spray fungicides once every 7 to 10 days, such as 500 times dilution of 75% chlorothalonil, 500 times dilution of 50% captan, or 1000 times dilution of 70% thiophanate-methyl, with obvious control effects.
Control of Phytophthora disease
Gerbera Phytophthora disease, 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. Through several years of cultivation experience, the author has summarized some effective measures and now introduces them to everyone.
1. Disease pattern: Phytophthora overwinters as chlamydospores and oospores in diseased residues or soil. When there is no host, the resting spores can survive for a long time. The pathogen is spread by water flow, soil, and diseased plants.
2. Symptoms: it first infects the root crown of the plant. The leaves of affected plants first turn yellow, then gray-brown, until they wither and die, and the root crown turns black and rots.
3. Control: (1) Select healthy, disease-free plants for cultivation.
2. Sterilize the soil of the nursery before planting. This pathogen mainly spreads through soil, so the nursery must be carefully sterilized before planting. The main sterilization methods are: (1) Chemical sterilization: the chemicals can be a mixture of dexon and quintozene (3:1), at a dosage of 4-6 g/sq m. During sterilization, spray the chemicals on the soil surface, mix the soil evenly, seal with plastic film, seal the greenhouse and fumigate for 30 hours, then remove the covering, ventilate and exchange air, stir the topsoil again, and plant after 15 days. (2) Steam sterilization: release steam into the soil through pipes. This method has relatively high investment costs, but the effect is good.
3. The planting depth for Gerbera should follow the principle of shallow planting, requiring the root crown to be exposed about 1.5 cm above the soil surface, with slight lodging as the standard (gently straighten it after 3 days). Because it has the characteristic of contractile roots, the root crown of the plant will be buried deeply into the soil, giving the pathogen convenience for infection. To be more conducive to the growth and development of young seedlings, the planting method of using a local substrate can be adopted, that is, first dig a circular 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 the disease, captan 0.1g/1 + 1% copper sulfate can be used to drench the rhizosphere; if it is already the late stage of the disease, the diseased plants should be burned immediately, and the surrounding plants and soil should be treated with the above-mentioned chemicals.
Whitefly damage and control
Whiteflies belong to the order Homoptera, family Aleyrodidae, and can be divided into two types: the greenhouse whitefly and the silverleaf whitefly. They are important pests of greenhouse horticultural crops in European and American countries. 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 pest damage have appeared on greenhouse crops such as cucumber, gerbera, rose, and poinsettia. Among the growers surveyed at the author's gerbera production site, 100% had whitefly damage. Many growers consider whiteflies to be the most difficult pest to control and the most damaging pest on gerbera. This is a call for the relevant departments to give this due attention.
(1) Damage characteristics of whiteflies. The Kunming area has warm winters and cool summers, which is very favorable for the reproduction and overwintering of whiteflies. Under greenhouse conditions, whiteflies do not stop reproducing throughout the year. Each female can lay 100-200 eggs, so killing eggs is very important in control, but the vast majority of 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 may perform poorly in another. According to foreign research, to eliminate a relatively severe infestation, pesticide must be sprayed at least once every 3-4 days, for 10-12 consecutive sprays. Whitefly eggs, older nymphs, and pupae have strong resistance to temperature and pesticides. Once various stages occur together on a crop, control becomes very difficult. It can be seen that whiteflies are harder to control than ordinary pests, are more likely to rebound, and cause recurring damage.
The population density of whiteflies has the characteristic of rising exponentially. In the early stage of whitefly infection, they occur only in small patches, and the plants appear to show no symptoms of damage on the surface, so this is often ignored. However, the harm of whiteflies in spreading viruses, weakening plant growth vigor, and seriously affecting shipping quality is already developing. Once it spreads, it may cause recurring 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 whiteflies, and once they occur, measures should be taken promptly.
(2) Inspection of whiteflies. Whiteflies have four forms: egg, nymph, pupa, and adult. Adults lay eggs on the underside of leaves. The eggs are 0.2-0.25mm long and are not easily noticed with the naked eye; they need to be observed with a magnifying glass or microscope, and they are mostly distributed on young leaves. Nymphs and pupae are usually fixed on the middle and lower old leaves and are easy to find. Adults like to rest on the underside of young leaves and mature leaves. Both adults and nymphs can secrete honeydew, which accumulates on the leaves and causes sooty mold. If black, grayish 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 whiteflies like most are lemon yellow and orange yellow, so yellow boards can be hung or set up for monitoring.
Among greenhouse flower crops, the ones that most attract whiteflies and suffer severe damage are: gerbera, Alstroemeria, primrose, scarlet sage, dahlia, geranium, cineraria, gloxinia, fuchsia, hibiscus, clematis, velvetleaf, Solanaceae plants, columbine, and rhododendron. The ones with lighter damage are: chrysanthemum, poinsettia, calceolaria, calla lily, rose, lily, and marigold. The ones not damaged are: cyclamen, carnation, freesia, tulip, narcissus, hyacinth, orchid family plants, lilac, palm family plants, and most succulent plants.
Sometimes flower crops and vegetable crops are rotated or planted in contiguous fields, so it is necessary to know the vegetable crops severely damaged by whiteflies, such as cucumber, tomato, lettuce, green bean, celery, muskmelon, pumpkin, and garlic. Greenhouses and the weeds inside and around greenhouses are breeding grounds for whiteflies. The weeds they like are chickweed, wood sorrel, nettle, dandelion, and others.
(3) Control of whiteflies
1. Give priority to prevention and cultivate insect-free seedlings. Seedlings, crop residues, and weeds carrying insects are important routes for the spread of whiteflies, 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 whiteflies, the movement of its crops in and out must be handled very carefully to prevent all greenhouses from becoming infected. Yellow 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 and diseases are occurring. Hanging white or silver-white plastic strips at the greenhouse entrance can repel the invasion of adults.
2. Choose pesticides well and use them correctly. Whiteflies easily develop resistance to pesticides, so it is necessary to know more about the available pesticide types in order to select them. For pesticides to which they were not originally resistant, pest resistance will develop only in the second generation. Therefore, for a pesticide with good trial results, it can be used continuously for at least one generation or more, until resistance is found. Attention should be paid to correct pesticide application methods, and it is not advisable to change pesticides frequently. The table below lists pesticides with relatively good results that have been tried domestically and abroad, for reference.
Category English name Chinese name or trade name Precautions
Organophosphorus acephate acephate has a fumigant effect
chlorpyrifos chlorpyrifos, chlorpyrifos
etrimfos etrimfos
Carbamate methomyl methomyl, Lannate has a certain ovicidal effect
Pyrethroid sumicidin fenvalerate
Propoxur+methoxychlor propoxur + methoxychlor
Cypermethrin cypermethrin
Alphamethrin alpha-cypermethrin
fluralinate cyfluthrin
Acaricide mitac amitraz, has a fumigant effect
Chitin synthesis inhibitor pesticide buprofezin
Other Tempo endosulfan
abamectin abamectin spray concentration 1000 times
Diazinon diazinon
imidacloprid imidacloprid
3. Application of the high-temperature sealing method. In the process of controlling whitefly infestation, conventional spraying methods have problems such as low control efficacy, rapid decline in efficacy, and easy development of resistance. Whiteflies attach to the underside of leaves and suck the leaf sap, easily forming dead angles where pesticides cannot reach by contact, especially when the plants are growing luxuriantly. When disturbed, whiteflies can fly several meters away, thereby avoiding contact with the spray solution. Therefore, even if a pesticide to which resistance has not developed is used, its control efficacy is limited. The growth, development, and reproduction of whiteflies are closely related to temperature. The developmental threshold temperature of eggs is 7.2°C, and the optimum temperature for survival is 20-28°C. Above 30°C, egg and larval mortality is high, adult lifespan is shortened, egg laying is reduced, and they may even stop reproducing. Whiteflies are poikilothermic animals, so above 30°C their respiration rate rises greatly, making it easy for them to inhale more pesticide.
In the practice of whitefly control, the author adopted high-temperature sealing, combining the advantages of fumigation and spraying, targeting the weaknesses of the pest and making full use of solar energy and the greenhouse effect, and achieved remarkable control results. The method is to mix a pesticide with a fumigant effect and a pesticide with an ovicidal effect (such as chlorpyrifos + Lannate), and add an appropriate amount of washing powder as a surfactant. 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 create sealed conditions and maintain the temperature between 30-35°C for more than one hour. In summer, pull the shade net and delay the spraying time to prevent the temperature inside the tunnel from rising excessively. When there are no sealed conditions, spraying during the high-temperature period in the afternoon is also more effective than spraying in the morning. When the temperature is high, the greenhouse or tunnel can easily rise above 30°C even without sealing. At this time, it is better to spray in the morning when the temperature is lower, seal the tunnel for 1-2 hours, and use a shade net to cool it if necessary, so there will be no concern about excessively high humidity causing disease.
4. Other methods. Very effective methods for controlling whiteflies also include fumigation, smoke fumigation, and smoke methods, which are introduced in other books. Biological control is a more scientific method and should be vigorously popularized and applied.
Mosaic disease
1. Symptoms. The leaves appear mosaic-like, and sometimes markings also appear on the petals. The pathogens include cucumber mosaic virus (CMV) and tobacco mosaic virus (TMV).
2. Control methods. (1) Remove weeds in the flower garden and its surroundings at any time, and promptly use insecticides to control aphids. (2) Use 10% trisodium phosphate to disinfect cutting tools such as flower shears.
Root rot
1. Symptoms. The symptoms of this disease are similar to those of Fusarium wilt, but there is no pink spore mass in the diseased part. Water-soaked soft rot appears on the stems and roots and turns black. The rotting phenomenon is obvious. The pathogen includes Phytophthora cryptogea Pethy-br et Laff., belonging to the subdivision Mastigomycotina. The sporangia are obpyriform, and the oospores are yellow and spherical. It is both parasitic and saprophytic, and the optimum growth temperature is 25°C.
2. Control methods. (1) Select and breed disease-resistant varieties. (2) Before planting in 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 prevent the spread of 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. The leaves of affected plants turn yellow, then gray-brown, until they wither and die, and the root crown turns black and rots.
Control methods:
①Select healthy, disease-free plants for cultivation.
②This pathogen mainly spreads through the soil, so the nursery site must be carefully disinfected before planting. The pesticide can be Dexon plus quintozene (3:1), with a dosage of 4-6 grams per square meter. During disinfection, spray the pesticide on the soil surface, mix it evenly with the topsoil, seal it with plastic film, and at the same time seal the greenhouse for fumigation for 30 hours, then remove the covering, ventilate and exchange air, and stir the topsoil again. Planting can be done after 15 days. Steam can also be released into the soil through pipes. This method has relatively high investment costs, but the effect is better.
③When planting, the root crown should be exposed about 1.5 cm above the soil surface, with slight lodging as the standard. Because it has the characteristic of contractile roots, the root crown of the plant will become deeply buried in the soil, making it easier for the pathogen to infect. To facilitate the growth and development of seedlings, a cultivation method using local substrate can be adopted. That is, first dig a round planting hole with a diameter of about 15 cm at the planting point, then fill it with sun-disinfected river sand or a substrate of perlite + vermiculite (1:1), then plant the seedling on the substrate, water thoroughly, firm the roots, and then enter normal daily management. This can achieve immediate results.
④When 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 the disease, the diseased plants should be pulled out and burned immediately, and the above-mentioned chemicals should be used to treat the surrounding plants and soil.
2. Virus-infected diseased leaves have indistinct yellow-green spots, and new leaves become narrow. During high-temperature periods, the markings are not obvious. Growth is weak, the number of cut flowers drops sharply, and as it continues to develop, the diseased plants will wither and die.
Control methods:
①Remove diseased plants.
②Thoroughly eliminate aphids, the vectors that transmit the virus.
③In greenhouses with poor ventilation, scale insects often occur and should be removed promptly.
3. For whiteflies, imidacloprid, dichlorvos, phoxim, and methamidophos all have relatively good control effects. However, if a single product pesticide is used, resistance is easily developed, so it is best to use mixed pesticides or alternate multiple pesticides, and avoid using the same pesticide continuously many times. For those that have developed resistance, organophosphorus pesticides can be mixed with Lannate solution plus pyrethroid pesticides.
4. Leafminers have peak damage periods in April-May and October-November. Abamectin, avermectin, abamectin, or dimehypo mixed with fenvalerate can be used for killing.
Causes of root rot
In midsummer, especially under drought and water shortage conditions, the petal color of gerbera becomes dark and dull; while flowers blooming during the suitable-temperature period of September-October or March-June of the following year have bright colors. 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 with 50% light transmittance, and spray the leaves to increase air humidity and lower temperature;
In winter, sufficient warmth should be provided to prevent freezing. The night 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, not only is the brightness lost, but the shape of the petals also becomes incomplete.
Therefore, ensuring that the plants are not damaged by mites throughout the growing 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 for root rot are excessive soil moisture around the roots, long-term water accumulation in the rhizosphere, or long-term rainfall in open fields, which can cause the death of gerbera plants.
Gerbera pot cultivation techniques Potted production
In daily production of potted gerbera, the following points need attention.
1. The production greenhouse must be equipped with 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, preferably not higher than 30°C, and not lower than 13°C. Generally, the average daily production temperature is 18°C to 19°C, and ventilation should be provided above 19°C. At the same time, the night temperature should not be too high, otherwise it will affect normal flower bud differentiation. The ideal night temperature should be between 15°C and 18°C.
3. Use a medium with good air permeability and drainage performance, 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, watering must be done from below, and bottom infiltration can be used; during high-temperature periods, watering from above the plants can be done, but care must be taken to prevent fungal mold starting from the center of the plant.
5. Gerbera prefers fertilizer. In summer, the ratio of nitrogen to potassium when fertilizing is 2:1, and in winter it is 1.5:1. The pH value of the fertilizer should be 5.5 to 6.0.
6. The most suitable day length for gerbera during growth is 11 hours to 13 hours, so artificial supplementary lighting can be carried out when light is low. Generally, the requirement for artificial supplementary lighting is 3500 to 4000 lux per square meter. It should be noted that supplementary lighting should be carried out 4 weeks after the plants are potted.
7. From potting to flowering, gerbera needs 8 to 9 weeks if produced in summer, and 11 to 12 weeks if produced in winter. The pot size is 10 cm to 15 cm. About 30 pots can be produced per square meter in the greenhouse, but care should be taken to spread them out in time when the plants grow to a certain size.
Gerbera - postharvest handling
Harvesting: For single-petaled varieties, the flowers can be harvested after 2-3 rounds of stamens have matured; double-petaled varieties should be harvested when more mature, as flowers harvested early will have a shortened vase life. After harvesting, they must first be placed in water immediately, and the water must be very clean. Before placing the fresh flowers in water, 2-5 cm of the hairy, lignified bottom peduncle must be cut off so that the peduncle can absorb water. Vase life is one of the most important components of the commercial value of cut flowers. Postharvest handling is very important for the vase life of gerbera. If gerbera cut flowers enter the market without postharvest handling, 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 be harvested only when one or two rounds of stamens have shed pollen. Harvesting too early will shorten the vase life. This is because when harvested too early, the energy stored in the outer ray florets is not enough to complete their development. When harvesting, the entire peduncle 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 harvesting and sorting the flowers, cut off 2-4 cm from the bottom of the peduncle. Cut at an angle to avoid crushing the xylem vessels. The bottom of the peduncle is composed of very narrow xylem vessels, which hinder water transport. After cutting, the flowers absorb water more easily, which is very important for avoiding cracking and bending at the flower neck. In addition, during harvesting, air may be sucked into the vessels and prevent the flowers from absorbing water. Cutting off part of the peduncle also removes air bubbles in the vessels.
Postharvest pretreatment
After the cut flowers are harvested, the peduncles 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 clog the vessels and prevent the flowers from absorbing water. During pretreatment, the pH of the water should be adjusted to 3.5-4.0 with chloride (bleaching powder). Too high a pH value will create ideal living conditions for bacteria. Bleaching powder can both lower the pH value of the water and sterilize, and the calcium chloride in it can also help extend the life of cut flowers. Studies show that the appropriate amount of bleaching powder added is 50-100 mg/l, and the treatment time must not exceed 4 hours. Too long a treatment time will damage the peduncle, shown as brown markings on the peduncle or bleaching of color. For long treatments, the concentration of bleaching powder should be reduced, with a maximum of 25 mg/l and a minimum of 3 mg/l. 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 peduncles in preservative solution for 6-24 hours. During treatment, immersing more of the peduncle in water helps the flowers absorb water, and a length of 10-15 cm is ideal; too high an ambient temperature will cause the flowers to lose too much water through transpiration, so 10-15°C is ideal. Water loss will cause gerbera flowers to age, so drying and wind must be avoided throughout the entire postharvest handling process. It is best to raise the relative humidity of the environment to 70%. In addition, during preservative solution treatment, care must be taken to prevent cut flowers from ethylene damage. Ethylene is an aging hormone and will shorten the vase life of gerbera. Exhaust gas emitted by truck engines contains ethylene, so during loading, the truck engine should be turned off. Gerbera preservative solution 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 can also promote water absorption by the flowers. Citric acid lowers the pH value of the preservative solution, thereby preventing bacterial growth.
[Fresh-keeping management] Cut flowers can be stored in an environment with a relative humidity of 90%-95% and a temperature of 2-5°C. During storage and transport, gerbera can tolerate relatively long dry storage. However, after opening the box, they must be inserted into water as soon as possible. Commercial 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 first-grade cut flowers is about 60 cm; the length of second-grade cut flowers is about 55 cm; the length of third-grade cut flowers is about 50 cm. The difference in length of cut flowers of the same grade should not exceed ±2 cm of the standard.
Packaging and transport
During transport, lower the ambient temperature to 6-9°C. This slows down the life activities of the flowers and preserves energy for use when they reach the consumer. Reusing cardboard boxes for packaging is more economical, but they can become places where bacteria grow. Therefore, cardboard boxes should not be reused too frequently. In short, cleanliness and hygiene must be maintained throughout the entire postharvest handling process in order to effectively extend the vase life of gerbera. After gerbera arrives at the destination, the bottom of the peduncle will become dry. Use a clean knife to cut off a little of the peduncle at an angle, then immerse it in clean preservative solution. If there is no preservative solution, a low-concentration bleaching powder solution can also be used.
Gerbera - daily management Humidity management
It likes relatively high air humidity. If the air humidity is too low, it will accelerate the withering of individual flowers. It also fears rain, and the leaves need to be kept dry at night. The optimum relative air humidity
is 65-75%. It likes a warm climate and avoids extreme heat. When the summer temperature is higher than 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. Generally, sowing is done in autumn and winter to avoid high summer temperatures.
Light management
In spring, summer, and autumn, it needs to be maintained under shaded conditions. When the temperature is relatively high (daytime temperature above 25°C), if it is placed in direct sunlight for maintenance, the leaves will become noticeably smaller, the internodes of the branches will shorten, the lower leaves will turn yellow and fall off, and growth will be very slow or it will enter a semi-dormant state. In winter, because the temperature is not very high, it should be given direct sunlight to facilitate photosynthesis and the formation of flower buds, flowering, and seed setting. After being maintained indoors for a period during the flowering period (10-15 days), it should be moved outdoors to a place with shading (and warmth retention) for maintenance for a period (about one month), and alternated in this way, which helps the plant accumulate nutrients and continue flowering.
Fertilizer and water management
Like other herbaceous flowers, it has a relatively high demand for fertilizer and water, 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 growing seasons. Fertilizer and water management follows the cycle of "Hua Bao"-"Hua Bao"-clear water-"Hua Bao"-"Hua Bao"-clear water (at least two "Hua Bao" applications per week must be ensured). The interval period is approximately: 1-4 days for outdoor maintenance; shorter intervals on sunny days or during high temperatures, and longer intervals or no watering on rainy days or during low temperatures; 2-6 days for indoor maintenance; shorter intervals on sunny days or during high temperatures, and longer intervals or no watering on rainy days or during low temperatures. Summer: During the high-temperature period in summer, it often enters a dormant state and has little demand for fertilizer and water, and may even require fertilizer and water control. Fertilizer and water management follows the cycle of "Hua Bao"-clear water-clear water-"Hua Bao"-clear water-clear water. The interval period is approximately: 3-5 days for outdoor maintenance; shorter intervals on sunny days or during high temperatures, and longer intervals or no watering on rainy days or during low temperatures; 4-7 days for indoor maintenance; shorter intervals on sunny days or during high temperatures, and longer intervals or no watering on 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 dormancy period, the main work is fertilizer and water control. Fertilizer and water management follows the cycle of "Hua Bao"-clear water-clear water-"Hua Bao"-clear water-clear water. The interval period is approximately 7-10 days; shorter intervals on sunny days or during high temperatures, and longer intervals or no watering on 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 key 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 requires greenhouse cultivation. Outside the Yangtze River Basin, it can be cultivated in unheated plastic tunnels. In summer, a shade net needs 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 additional plastic film must be covered 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 and needs full light in winter. In summer, appropriate shading should be provided, ventilation should be strengthened, temperature should be lowered, and dormancy caused by high temperature should be prevented.
Irrigation
After planting, the seedling stage should maintain appropriate moisture and control water 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. During cultivation, care should be taken to prevent waterlogging. Fertilization can be combined with watering.
Topdressing
Gerbera is a fertilizer-loving perennial herbaceous flower with a high fertilizer demand. The ratio of nitrogen, phosphorus, and potassium in fertilization is 15:18:25. Special attention should be paid to supplementing potassium fertilizer. Apply 2.5 kg of potassium nitrate per mu, and 1.2 kg of ammonium nitrate or ammonium phosphate, once every 5-6 days, and once every 10 days. If high temperature or relatively low temperature causes the plant to enter a semi-dormant state, then stop fertilizing.
Remove residual leaves
The lower leaves of the basal leaf rosette tend to turn yellow, wither, and age. Removing them in time is beneficial for the sprouting of new leaves and new flower buds, is beneficial for ventilation, and enhances plant growth vigor.
Selection of gerbera fresh cut flowers Selection
The junction between the gerbera flower stem and the flower head is relatively thin and soft, while the flower head is large and heavy, so it easily bends down from the neck. Therefore, when selecting, short and thick flower stems must be chosen so that the neck can support the flower head with more strength.
Only a small section at the bottom of the gerbera flower 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 into 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 the flower to decline. Therefore, every possible means should be used to fix the neck, such as wrapping it with soft wire for reinforcement, then covering it with green tape to conceal it.
Gerbera petals decline from the outside inward. Therefore, when the outer petals are not good, they can be pulled off directly, and the remaining flower center part is also quite ornamental. Because gerbera petals are very easily damaged and leave marks, they must be handled carefully.
The water level only needs to reach one third of the length of the flower stem, because the flower stem is soft and easily decays, so the water level should not be too high.
Fresh-keeping methods
Gerbera bought back from the flower market does not need its roots cut, especially do not cut off the hard node at the bottom of the root. Just put 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 part. Gerbera whose roots have been cut easily rot at the stem, and rot particularly quickly.
If newly received stock shows dehydration, first put it directly into water. If it has not recovered after a few hours, then slightly cut the bottom of the root into a slanted opening and put it into water.
If there is no dehydration, then it is a normal bent-stem phenomenon. Making its flower head straight 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, and double-petaled varieties represent commendable passion. In the Shanghai area, people like to use gerbera to make bouquets to decorate the bridal chamber during wedding celebrations. Using its homophonic meaning, it conveys the idea that the newlyweds respect and love each other and that the wife supports the husband in achieving his career. The gerbera flower shape is radial 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