Symptom Identification and Treatment Methods for Tobacco Thrips Damage on Purple Shamrock
1. Morphological Characteristics The tobacco thrips belongs to the order Thysanoptera, family Thripidae, also known as the onion thrips. The tobacco thrips is tiny, with a body length of 1.1-1.3mm; body color varies greatly, mainly black, brown or yellow; rasping-sucking mouthparts
1. Morphological Characteristics
The tobacco thrips belongs to the order Thysanoptera, family Thripidae, also known as the onion thrips. The tobacco thrips is tiny, with a body length of 1.1-1.3mm; body color varies greatly, mainly black, brown or yellow; rasping-sucking mouthparts; antennae with 6-9 segments, filiform; wings narrow and long, with long and neatly arranged marginal hairs; claws reduced.
2. Occurrence Patterns
The tobacco thrips occurs for more than 12 generations per year in greenhouses, scattering eggs under the leaf epidermis and within leaf veins, with strong reproductive capacity. Adults and nymphs lurk in soil cracks, soil clods, dead branches and fallen leaves, or in bulbs in the field and leaf sheaths of some plants, and can also overwinter in the soil in the "pupa" stage, but overwintering mainly as adults. They begin activity in March-April of the following year. A dry environment without rain is favorable for the growth, development and reproduction of the tobacco thrips, while high temperature and humidity or heavy rain inhibit its activity. Because it fears light, the tobacco thrips often crawls to the leaf surface in the early morning and evening and on cloudy days when humidity is high, and mostly feeds on the underside of leaves and at leaf veins on sunny days. Adults are highly active, able to fly and jump well, and spread and disperse very quickly.
3. Damage Characteristics
The tobacco thrips damages the leaves and flowers of purple shamrock, causing relatively severe harm to the plant. The tobacco thrips uses its rasping-sucking mouthparts to rasp open the plant epidermis and suck its sap. Adults and nymphs mostly cause damage near the petioles and leaf veins. After young leaves are damaged, they become twisted, deformed and grow poorly; after leaves are damaged, discolored purple, yellow or brown markings appear on both the front and back, with tiny spots, and the leaf tissue becomes thickened and brittle, leading to leaf wilting; after flowers are damaged, discolored spots appear. In severe cases, plant growth stagnates and the plant declines and dies.
4. Control Measures
① Agricultural control:
Irrigate and spray water in a timely manner, thoroughly remove plant residues and weeds in the field and surrounding areas, and deep-plow the soil before winter to destroy pupation sites and reduce the tobacco thrips population.
② Physical control:
Use blue water trays or blue sticky boards to trap and kill tobacco thrips.
③ Chemical control:
Select 10% imidacloprid 50g, add 250g of water, and spray twice on the underside of leaves or at the leaf center in the morning and evening. Spray systemic agents such as 40% omethoate and 50% fenitrothion at 1000 times dilution; omethoate affects flower color and should be used with caution. The control effect of thrips and whitefly net EC is also relatively good.
④ Biological control:
Protect and utilize natural enemies of the tobacco thrips such as Orius minutus, Nabis sinoferus, and Aeolothrips fasciatus, which play a significant role in suppressing the rise and fall of its population.
How to Make Purple Shamrock Grow into a Full Pot: Learn Six Techniques for Both Beauty and Vigorous Growth
Among plants in the genus Oxalis, the purple shamrock native to South America is famous for its brilliantly colored flowers. It is not only easy to grow but also grows very quickly. However, to make it both beautiful and fast-growing, some techniques are still needed. So how do you make purple shamrock grow into a full pot? Below, the editor will teach you six techniques.
How to Make Purple Shamrock Grow into a Full Pot
1. Light Should Be Moderate
When planting, it is best to place it in a semi-light environment, such as under the eaves, indoors near a window, on a balcony, and so on. Do not let purple shamrock be exposed to direct sunlight, and at the same time avoid an environment with too little light, otherwise the leaf color will become dull and the plant may also become leggy.
2. Do Not Overwater
In the cultivation methods for purple shamrock, it is best to use sprinkler irrigation when watering. The method is to spray water onto the plant with a spray bottle. Besides being able to wash the leaves, excess water will naturally flow into the soil and be absorbed by the roots. However, note that watering frequency should not be too high; water again after the soil has slightly dried, and absolutely avoid waterlogging.
3. Prune in a Timely Manner
Many flower enthusiasts water reasonably but do not notice that it grows very quickly, so how do you make purple shamrock grow into a full pot? At this point, pruning also needs to be done well. Some branches and leaves intertwine because they grow quickly, which is not only unfavorable for light penetration but also affects the sprouting of new buds. Therefore, during daily care, observe carefully and thin out the branches when a large number of branches and leaves become dense.
4. Change the Potting Soil Regularly
The soil used for growing purple shamrock should be replaced every 1 or 2 years to avoid the soil becoming dry and compacted, poorly aerated, or poorly drained. At the same time, it can also reduce the possibility of pest sources lurking in the soil. The replacement soil is best disinfected to ensure a good soil environment, which is conducive to making it grow into a full pot.
5. Temperature Should Be Suitable
In summer, try to keep the environment where purple shamrock is located below 30 degrees Celsius. If the outdoor temperature is high, it can be moved to a cooler place. In winter, ensure the temperature is above 5 degrees Celsius so that it can enter dormancy smoothly without being frostbitten. Only with proper dormancy can it grow more vigorously in the second year.
6. Prevent Pests and Diseases
The relatively common pests of purple shamrock include purple oxalis mite, tobacco thrips, North China mole cricket, wild slug, and so on, while its common diseases include leaf spot, root rot, and so on. They are extremely harmful to oxalis, but we can reduce the occurrence of pests and diseases by strengthening care and management, and the method is to make the environment suitable.
Gerbera Gerbera jamesonii Bolus Gerbera Profile: How to Grow Gerbera / How to Propagate Gerbera
Gerbera ProfileGerbera Gerbera jamesonii Bolus
Gerbera Cultivation Methods and Precautions Introduction to Gerbera
Gerbera (English name: Gerbera), a perennial herbaceous plant of the Asteraceae family, with fine hairs throughout the plant, terminal inflorescences, 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 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 (8cm-10cm), and flowering time regulation is easy. The cultivated area for cut flowers is increasing year by year, and its use is becoming increasingly widespread. Gerbera can also withstand long-distance transport, and cut flowers last a long time in water; if cultivated properly, each plant can yield 30 cut flowers per year, making it truly an ideal cut flower. Gerbera flowers are large and colorful, labor-saving to manage, and can supply fresh cut flowers year-round in warm regions. The main types can be divided into modern cut flower types and dwarf cultivated types, with various flower colors such as white, pink, red, and yellow.
Morphological Characteristics of Gerbera
Perennial, hairy herb. Rhizome short, surrounded by remaining petioles, with relatively thick fibrous roots. Leaves basal, rosette-shaped, leaf blades long elliptic to oblong, 10-14cm long, 5-6cm wide, apex shortly acute or slightly obtuse, base gradually narrowed, margin irregularly pinnately lobed or deeply lobed, upper surface hairless, lower surface pubescent, losing hair when old; midrib raised on both sides, thicker and more prominent below, lateral veins 5-7 pairs, curved and connected away from the margin, reticulate veins slightly obvious; petiole 7-15cm long, with thick longitudinal ridges, more or less hairy. Scapes solitary, or rarely several clustered, 25-60cm long, without bracts, hairy, hairs densest at the top, capitulum solitary at the top of the scape, 6-10cm in diameter when ligules spread during flowering; involucre bell-shaped, about as long as bisexual flowers, up to 2cm in diameter; involucral bracts in 2 layers, outer layer linear or subulate, apex acute, 8-10mm long, about 1-1.5mm wide, pubescent on the back, inner layer oblong-lanceolate, apex caudate-acuminate, 10-14mm long, about 2mm wide, margin scarious, sparsely pubescent on the dorsal ridge; receptacle flat, naked, honeycomb-like, 6-8mm in diameter; outer female flowers in 2 layers, outer corolla ligulate, ligule pale red to purple-red, or white and yellow, oblong, 2.5-3.5cm long, 2-4mm wide, apex with 3 teeth, inner 2 lobes filiform, curled, 4-5mm long, corolla tube short, about 1/8 the length of the ligule, staminodes filiform, 3-4mm long, extending beyond the corolla tube; inner female flowers more slender than bisexual flowers, tubular bilabiate, 6-7mm 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 4mm long, curled, staminodes 4-5, linear or filiform, hidden within the corolla tube; central bisexual flowers numerous, tubular bilabiate, 8-9mm long, outer lip large, with 3 teeth, inner lip 2-parted deeply, lobes usually broad, curled; anthers about 4mm long, with long pointed tails; style branches of female and bisexual flowers both short, apex obtuse, less than 1mm long. Achenes cylindrical, 4-5mm long, densely covered with white short pubescence. Pappus slightly rough, dirty white when fresh, light brown when dry, 6-7mm long, united at the base. Flowering period November to April of the following year.
Ecological Habits of Gerbera
It prefers a warm winter and cool summer, circulating air, and sunny environment; 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. Growth stops below 10°C. It is a semi-cold-tolerant flower and can endure short-term low temperatures of 0°C. In South China, it can be cultivated as an outdoor perennial flower; in East China, it must be covered for overwintering or grown in greenhouses for cut flower forcing cultivation. It prefers fertile, loose, well-drained sandy loam rich in humus, avoids heavy clay soil, and is suitable for slightly acidic soil. It can also grow in neutral and slightly acidic soil, but in alkaline soil, leaves are prone to deficiency symptoms. The flowering time of gerbera is very easy to regulate; as long as the room temperature is kept above 12°C, the plant will not enter dormancy and will continue to grow and bloom. It prefers fertile, loose, well-drained sandy loam rich in humus, avoids heavy clay soil, is suitable for slightly acidic soil, is a semi-cold-tolerant flower, and can endure short-term low temperatures of 0°C. Gerbera is a light-loving plant, so choose a location with sufficient light for cultivation. Seedlings should not be planted too deeply, 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 total, among which more than 10 are relatively large-scale. The annual output of gerbera seedlings is about 20 million plants. Many enterprises or research institutions have collected 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, and 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 species in Yunnan.
Market
In March and April, although the wave of Yunnan fresh flower sales receded, it ushered in the "golden period" for gerbera seedling sales. Gerbera seedlings sold from Kunming to inside and outside Yunnan Province reached more than 2 million plants in April sales, and a national gerbera seedling production pattern centered on Kunming has basically taken shape.
Volume Declines and Prices Fall
It is understood that Yunnan gerbera seedling producers are mainly concentrated in Kunming, about 20 in size, among which more than 10 are relatively large-scale. Affected by the relatively high price of gerbera seedlings, although household-based seedling production households have appeared, because enterprise production has declined, the total gerbera seedling production has decreased compared with the previous period, 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.
Severe Sales Situation
It is reported that the demand for gerbera seedlings among growers in Yunnan Province has clearly shrunk. 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 required 4.5 million seedlings. For the remaining 4,000 mu, if 1/3 of the gerbera plants needed replacement with new seedlings (generally gerbera growers replace seedlings once every two or three years), then 6 million seedlings were needed, and the province's seedling demand was 10.5 million plants. If 1/3 to 1/2 of gerbera plants were replaced with seedlings, then the seedling demand within Yunnan Province was 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 did not sell much in markets outside the province. Therefore, gerbera seedlings are in a situation of supply exceeding demand, and the sales situation is severe.
In addition, affected by soil continuous cropping obstacles, the gerbera cut flower market was not very prosperous, causing some flower farmers 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, and demand for gerbera seedlings within the province shrank. 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 research institutions 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 postharvest 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 seedling production by enterprises or research institutions outside Yunnan Province is entirely possible to catch up with or even surpass Yunnan. Facing increasingly fierce market competition, for Yunnan gerbera seedlings to gain a firm foothold in the market, they must start from the following 3 points: first, strive to improve seedling quality, extend the hardening-off period, increase the survival rate of finished seedlings, and at the same time control the propagation coefficient of seedlings to reduce indoor contamination and mold infection of seedlings; second, according to the demand conditions of different regions, select suitable varieties, such as green-centered varieties mainly outside the province and black-centered varieties mainly within the province; third, take the path of factory-based and specialized production, expand economies of scale, 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 a discussion to jointly discuss matters such as establishing the Yunnan Gerbera Seedling Association. At the same time, they will negotiate with foreign breeders in the name of a "large group" to strive to introduce high-quality mother plants and new varieties at low prices. It is reported that they have already negotiated 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: Differences Between Gerbera and Daisy Gerbera
Scientific name: Gerbera jamesonii
Family: Asteraceae
Origin and distribution: South Africa
Morphological characteristics: With rosette leaf clusters. Leaves oblong-spatulate, deeply lobed or lyrate-pinnatifid, white tomentose on the back. Capitulum. Flower colors range from white to various yellows, oranges, rose reds, reds, etc. If the ambient temperature is suitable, it can bloom year-round.
Growth habits: Prefers mild winters and cool summers. Requires well-drained, humus-rich, deep and fertile soil with a pH of 6-6.5.
Landscape uses: Gerbera is mainly used for cut flowers and potted flowers, and can also be used in flower beds when climatic conditions are suitable.
Propagation and cultivation: Potted, mainly by sowing.
Daisy
Aliases: Spring daisy, longevity daisy
Scientific name: Bellis perennis
Family and genus: Asteraceae, Bellis
Habits: A perennial herbaceous plant, often cultivated as an annual or biennial. Prefers cool, moist, sunny conditions, relatively cold-tolerant, and can overwinter outdoors when the ground surface is not lower than 3-4°C. It has no strict soil requirements. Flowering period April-May.
Cultivation: Propagated by sowing or division. The suitable germination temperature for seeds is 22-28°C. In North China, sow in August-September, move into cold frames in late October to overwinter, and pot or plant into flower beds in early April of the following year. During the growing season, as long as proper water and fertilizer are ensured, it can grow well. After flowering, the roots can be divided and planted in pots, placed in a cool place to pass the summer, and after autumn cools, moved into a greenhouse or indoors, with strengthened fertilizer and water management, and it can bloom again in winter or the following spring. There are relatively few pests and diseases.
Cultural Background, Origin and Evolution of Gerbera
In 1878, Rehman first discovered gerbera in Transvaal, South Africa, and in the same year Blass sent it to Kew Gardens in England. Lynch in England was the first to carry out hybrid breeding of gerbera. He crossed gerbera with green-leaf gerbera (G. viridifolia Sch.-Bip.); bred hybrids; afterward, Adnet in 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 flowering almost continuous throughout the year. Japan also achieved excellent results in breeding double-flowered gerbera. In addition, people have also bred many distant hybrids, using gerbera as the female parent and Coreopsis basalis Blake. or Argyranthemum frutescens Sch.-Bip. as the male parent, and the hybrid flower shapes mostly resemble the male parent.
The flower color genes of gerbera are rich and highly heterogeneous, and the flower shape and color of its progeny differ greatly. Therefore, excellent hybrid individual plants can be rapidly propagated in large quantities into clonal lines through tissue culture. As a result, varieties are replaced quickly with fashion trends. Its flower colors are mainly white, red, pink, orange, purple, etc. In addition, interspecific hybridization is easy to merge, so in addition to the above inherent color lines, there are also many intermediate color lines.
Origin of the Name Gerbera
In the early 20th century, Madagascar in southern Africa was a small country rich in tropical flowers and plants. There was a local girl named Slangyini who 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 placed in the hall to add to the wedding atmosphere. Relatives and friends from all sides sang and danced and toasted frequently. Unexpectedly, the groom, with a very low tolerance for alcohol, became drunk after only three rounds. 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 that this supporting posture was so similar to the growth form of that wildflower, quite a few girls said in unison: "Oh, the flower really looks like supporting the groom!" From then on, the name gerbera spread widely.
Gerbera is also known as fringed gerbera and is native to southern Africa. The flowers are large and beautiful, with charming colors, and it is an important cut flower decorative material. Large red gerbera is used in bridal bouquets. Together with roses, gladioli and carnations, it is listed among the world's four 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 improvements and bred a large number of cut flower varieties. In addition, Japan also bred double-flowered varieties with diverse flower shapes 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 requires confirming the bedroom arrangement. For example, placing a fresh and long-lasting gerbera at the bedside, with a pleasant fragrance that will not easily disappear, can encourage oneself.
Gerbera can promote family harmony. Gerbera, like the sunflower, is in everyone's mind a flower representing the sun, only the latter is tall and sturdy, 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 warm. Someone once advocated using gerbera as the flower representing Father's Day, because gerbera is also called sun flower, and the sun can symbolize fatherly love. The feng shui effect of gerbera, able to make a family live in harmony and love each other, also arose from this.
For people whose Five Elements belong to fire, gerbera is their lucky flower. In Chinese feng shui, it is believed that the types, attributes and placement positions of some plants can affect a person's destiny. Plants also have yin-yang and Five Elements distinctions. Using them appropriately in different directions and environments can produce unexpected regulating effects. In geomancy, it is believed that plants are spiritual and can help people in various aspects. 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
Mainly can 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 multiflowering ability; cut flower varieties have straight flower stalks, and large flower diameters can reach 15cm, with long flowering periods, year-round flowering, and long ornamental time, and vase life as long as 7-10d. Cut flower types can be further divided into single, semi-double, and double types; according to color, they can be divided into bright red series, pink series, pure yellow series, orange-yellow series, pure white series, etc. Different types of varieties on the market can also be divided into:
1. Narrow-petal type Ligulate petals 4-4.5mm 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 type Inflorescence diameter 10-14cm.
Main Domestic Varieties
Common varieties include red "Passion," yellow "Sun Dance," white "Bianca," etc. Miniature small flowers include "Ballroom" (white), "Ballet" (orange), "Sultan" (yellow), "Conga" (red), etc.
Serial number Variety Flower diameter cm Ligulate flower layers Ligulate flower color Tubular flower color
1 Cathy 10-12 Many Pink Green
2 Chateau 10-12 2-3 Deep purple Deep purple
3 Diablo 10 Many Purple-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 Purple-red Black-purple
13 Savannah 10-12 3-4 Purple-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 Cream yellow Deep pink
18 Willy 7 Many Deep pink Purple-red
Main Species in the Same Genus
There are about 80 species in this genus, mainly distributed in Africa; 20 species are produced in China, the vast majority concentrated in the southwest region, and none have been seen in ornamental applications. Those also commonly cultivated for ornament 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 smaller, white, back yellow
Distribution Region of Gerbera
The origin is South Africa, with a few distributed in Asia. Commercial production now also occurs in Taiwan, China and Guangdong. With the progress of domestic greenhouse technology and the introduction of new foreign greenhouse technology, it is cultivated in South China, East China, and Central China.
Landscape Uses of Gerbera
Its flowers are huge, flower branches upright, flower colors brilliant, water-holding time long, cut flower rate high, vase life can reach 15-20 days, and cultivation saves labor and time, making it one of the world's famous top ten cut flowers. It can also be used in flower beds and flower borders, or as greenhouse potted plants for decoration in halls, meeting rooms, etc.
Potted gerbera is often used to decorate doorways and halls, and its cut flowers are used in vases and flower arrangements to adorn desks, display windows, and living rooms. With pink gerbera as the main flower, paired with Dendrobium, baby's breath, and orchid leaves, the tone is elegant and the mood is rich. If red gerbera is used as the main flower, paired with sword fern, palm bamboo leaves, dry branches, and dyed walnuts for wall decoration, it can produce a relatively strong decorative effect. It is commonly cultivated in gardens across China, mostly as potted plants.
Propagation Methods of Gerbera Propagation by sowing or division.
Because gerbera is a cross-pollinated plant and 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 is usually used, but only 5-6 new plants can be divided from each plant each year. To accelerate propagation, cuttings and tissue culture can also be used.
Propagation Methods
Tissue culture is the main method for propagating gerbera. Gerbera tissue culture commonly uses the receptacle as the explant. Use flower buds about 2cm in diameter, disinfect and wash them, leave only the receptacle, cut into 2-4 pieces, and place on the medium. The medium formula is MS plus BA 1.0 mg/L, plus indoleacetic acid (IAA) 0.5 mg/L. 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, which is MS plus BA 0.1/L, plus indoleacetic acid 0.1 mg/L. When the leaves of the test-tube plantlets reach 2cm long, transfer them to rooting medium. When transferring plantlets, remove the callus at the base of the test-tube plantlets. The rooting medium formula is 1/2 MS plus naphthaleneacetic acid (NAA) 0.1 mg/I.
After Gerbera explants are induced to sprout, going through 4 to 5 months of test-tube multiplication, they can produce thousands upon thousands of test-tube plantlets. The most suitable period for transplanting Gerbera to the field is April; seedlings transplanted at this time can produce flowers in abundance by August. Therefore, callus differentiation into shoots should preferably be completed before mid-October; the 1st test-tube multiplication takes place from mid-October to mid-November, then once a month thereafter, with the 4th multiplication finishing by mid-February of the following year, followed by 2 weeks of test-tube plantlet root formation; after rooting, they are transplanted to a seedbed, cared for for 1 month, and then moved to the field in early April.
Gerbera is mostly propagated by tissue culture for rapid propagation; division propagation can also be used, with each mother plant divisible into 5 to 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. It is insensitive to photoperiod, and day length has no effect on flower count or flower quality. It requires loose, fertile, well-drained, humus-rich, deep, slightly acidic sandy loam soil.
Cultivating Gerbera with artificial potting soil can significantly increase yield and quality; a self-mixed potting soil of 5 parts humus, 2 parts perlite and 3 parts peat can be used for planting, but this method has relatively high production costs. Field planting is also possible; choose loam soil suitable for Gerbera growth with at least 25 cm of deep soil layer for planting. Before planting, apply sufficient base fertilizer: 5 tonnes 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. The fertilizer must be thoroughly mixed with the soil of the planting bed and plowed, forming a ridge-and-furrow layout with ridges 40 cm wide and furrows 30 cm wide; plants are planted on the ridges in double rows in a staggered arrangement. Spacing between plants is 25 cm. Care should be taken to leave the root crown slightly exposed above the soil to prevent root crown rot. Then irrigate in the furrows.
However, because of its rapid reproduction rate, it has been listed as an invasive alien species in Guangdong, China. If you want to transplant it outdoors, consider it carefully, otherwise once the flowers open, unnecessary [consequences] may arise.
Division propagation
Because old plants flower poorly, division is usually done once every 3 years. The method is to dig up the old plant and divide it, with each new plant carrying 4~5 leaves, and replant separately; the drawback of this method is slow propagation speed.
Cutting propagation
Dig up a selected robust mother plant, remove soil from the roots and remove the leaves, and cut out the growing point. Keep the root crown portion and plant it in a growing box for cultivation. Place the growing box under conditions of 22~24 °C and 75%~80% relative air humidity. Afterwards, axillary buds and adventitious buds will successively grow from the root crown portion, 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 1~2 cm of perlite. Keep the temperature at around 25 °C and relative humidity at 75%~90%; after 3~4 weeks they will root, and the rooted cuttings can then be transplanted.
Cultivation techniques for Gerbera: key cultivation points
The suitable temperature during 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, in winter it needs to be maintained above 12~15 °C, and in summer not exceeding 26 °C; therefore in the southern Fujian area it can overwinter in the open field, but to obtain high-yield, high-quality cut flowers, it is best to have plastic greenhouses and other insulation equipment, and in summer shade nets can be used or water sprayed to cool down, ensuring a year-round supply of cut flowers.
(1) The soil must be disinfected. Gerbera is not very demanding about soil; loose, breathable, humus-rich sandy soil is suitable. Because the pathogens of various diseases harmful to Gerbera can survive in the soil, and there are also underground pests and earthworms in the soil harming the root system, soil disinfection must be carried out before planting.
(2) Land preparation and fertilization. Because Gerbera fears waterlogging, high-bed cultivation is generally used; beds generally run north-south, with a bed height of about 30 cm, bed width of 1 m, and furrow width of 40~50 cm. Combined with land preparation, apply base fertilizer appropriately; apply 200 kg of barnyard manure per 100 m.
(3) Planting. The best planting time is on cloudy days or in the evening of sunny days. Except for the high-temperature period from July to September in summer, when planting is not suitable, it can be done at all other times. 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 management during the seedling stage. Carry out insulation or cooling management according to the weather conditions at the time of planting, controlling at 20~25 °C, so that they quickly resume growth. After the seedlings recover, apply 1:10 human manure and urine once every two weeks, ensuring each plant has 8~10 healthy leaves before entering the flowering period. When watering and fertilizing, be careful not to let water fall on 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 humidity-tolerant, 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 how dry or wet the soil is: do not water if not dry, and water thoroughly when watering. In winter, water as little as possible; the soil is better slightly dry. In summer, the hot weather causes rapid water evaporation, the plants enter a semi-dormant state, flower production drops markedly, plant vigor weakens, and at this time pests and diseases are very likely to occur; this can be combined with topdressing to promote root absorption of fertilizer. In summer, promptly loosen the soil, clear the roots and prevent disease, control water and fertilizer, and shade and protect from rain.
(6) Leaf stripping and bud thinning. Gerbera can flower year-round within the range of 5~30 °C, so its fertilizer demand is high throughout the growing period. Before flower bud differentiation, increase the application of organic fertilizer and nitrogen fertilizer to promote full plant growth, often mainly with monopotassium phosphate and urea, plus an appropriate amount of liquid organic fertilizer, applied as a topdressing once a week; when the plant enters the period of simultaneous vegetative and reproductive growth, the proportion of phosphorus and potassium fertilizer should be increased, generally once a week, while adding an appropriate amount of organic fertilizer; before the two flowering peak periods of April to June and September and November, foliar spraying of KH2PO4 should be carried out as appropriate to meet the needs of reproductive growth.
(7) Humidity and light. Gerbera is relatively cold-tolerant; its growth is not sensitive to light, but it likes sufficient sunlight. When cultivated in a greenhouse, adding 2~3 layers of plastic film in winter allows it to overwinter safely. Before the first frost in late October, cover with one layer of plastic film; around November, small tunnels should be built over each bed for insulation. From June to September, 50% shade nets can be used for cooling.
(8) Removal of withered leaves. The rosette leaves at the base of Gerbera easily turn yellow and age, and should be removed promptly; this not only benefits the sprouting of new leaves and new flower buds, but also benefits 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 promptly to ensure the retained flower stems have sufficient nutrition 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. When the outermost two layers of ray florets of the Gerbera head are perpendicular to the flower stem and show the color characteristic of the variety, it can be picked; the best time is in the morning and evening when temperatures are low, when picking is easy and does not damage the plant. The method is to hold the lower half of the flower stem with the hand and shake it side to side, and it can then be picked. Remove flowers with disease spots, insect spots or deformities, cover the flowers with a No. 12~15 funnel-shaped plastic bag, then grade by variety and length, tie 20 stems as a bunch with a rubber band and they are ready for sale. If not sold immediately, insert them upright in a bucket or other container with clean water for water preservation, with the water depth preferably covering 5~10 cm of the base of the flower stem.
Cultivation protocol: soil preparation
1. Soil tillage and base fertilizer: plow deeply once before planting (30-40 cm), apply chemical fertilizer and barnyard manure (apply 2000 kg of decomposed barnyard manure, 5 m3 of humus soil, 65 kg of superphosphate, and 50 kg of compound fertilizer per mu) into the soil, then plow deeply (15-25 cm).
2. Bed preparation: dig drainage ditches 70-100 cm deep nearby (depending on the water table level), form high beds of 45 cm, with bed width 1.0 m and furrow width 40 cm.
3. Soil disinfection: use formaldehyde disinfection and chemical agents such as Vapam (tentative), taking 40% industrial formaldehyde disinfection as an example: dilute to a concentration of 1%, spray evenly on the soil, and immediately after spraying cover tightly with plastic film for sealed fumigation; after 2-3 days remove the film, air-dry the soil for two weeks, then rinse with water, and only after another two weeks can planting be done. Different disinfectant agents are determined according to instructions and trials. Soil planted for the first time need not be disinfected.
Seedling selection
Select seedlings 11-15 cm tall with 4-5 true leaves for planting. Quality seedling standards: robust seedlings, oily green leaves, well-developed root system, many fibrous roots, white in color, leaves free of disease spots, insect bite notches and mechanical damage.
Planting
Planting time: planting can be done year-round, but from the perspective of production and sales, April to June is ideal.
Planting method: plant 3 rows per bed, with the middle row staggered from the side rows, plant spacing 30 cm, 9-10 plants per square meter, and over 1100 plants can be planted per greenhouse.
Planting method: 2-3 days before planting, water the soil thoroughly; planting time is on cloudy days or in the morning and evening of sunny days; when planting, make a deep hole and plant shallowly, with the root crown exposed 1-1.5 cm above the soil surface, otherwise the plant is prone to fungal infection; if the plant is planted too shallowly, the plant is easily loosened or pulled out when harvesting flowers; after planting, water thoroughly in time.
Cultivation management
1. Management during the seedling stage: after planting, shade with 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 day temperature at 22-25 °C and the night temperature at 20-22 °C for 1 month; during this period use sprinkler watering, preferably in the morning. Make a small hole beside the plant to indicate soil moisture; water should be neither too dry nor too wet, with watering frequency once every 5 days, but this is not fixed and should be determined specifically according to soil structure, weather conditions, etc.; inspect plant by plant every day, promptly remove diseased plants, and fill in with robust small seedlings.
2. Management during the mature seedling stage: about 1 month after planting, Gerbera enters a vigorous growth period, and when light is too strong it needs appropriate shading; adjust the temperature to 14-16 °C at night and a minimum of 18-25 °C during the day; apply 0.1% compound fertilizer (N:P:K = 15:15:15) once every week, and spray 0.1% monopotassium phosphate as foliar fertilizer once every 2 weeks; spray broad-spectrum fungicides, such as 800-**** times solution 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 week. Use foliar spraying of trace element fertilizers, generally once every 25 days, each time with 0.1-0.2% Ca(NO3)2.4H2O, 0.1-0.2% chelated iron plus 0.1-0.2% borax plus 5-10 ppm sodium molybdate for alternating foliar spraying; use drip irrigation for watering, with the watering principle of "do not water if not dry, and water thoroughly when watering", and never water from the center of the leaf rosette. Keep the relative humidity in the greenhouse at 80%-85%; promptly pull weeds, remove diseased leaves and withered leaves, pull out diseased plants and disinfect the soil in the planting holes with quicklime; during the summer flowering period, pay attention to shading and ventilation for cooling; during the winter flowering period, pay attention to insulation and heating, especially preventing too large a day-night temperature difference to reduce the occurrence 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; in a growing environment not exceeding 26C during the day it can flower year-round. The suitable temperature during the winter dormant period is 12C-15C, and it stops growing below 7C. It is insensitive to photoperiod, and the length of natural daylight has no effect on flower count or flower quality. Gerbera requires loose, fertile, well-drained, humus-rich, deep, slightly acidic sandy loam soil.
II. Propagation
Gerbera is mostly propagated by tissue culture for rapid propagation, and can also be propagated by division, with each mother plant divisible into 5~6 small plants; seed propagation is used for dwarf potted varieties or breeding; single buds or short lateral buds occurring at the base of the neck can be cut and used for cuttings.
III. Planting
Cultivating Gerbera with artificial potting soil can significantly increase yield and quality; please refer to the formula: 5 parts humus; 2 parts perlite; 3 parts peat, self-mixed potting soil for planting, but this method has relatively high production costs. Field planting is also possible; choose loam soil suitable for Gerbera growth with at least 25 cm of deep soil layer for planting. Before planting, apply sufficient base fertilizer; generally apply 5 tonnes 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, forming a ridge-and-furrow layout with ridges 40 cm wide and furrows 30 cm wide; plants are planted on the ridges in double rows in a staggered arrangement. Spacing between plants is 25 cm. When planting, care should be taken to leave the root crown slightly exposed above the soil to prevent root crown rot. After planting, irrigate in the furrows.
IV. Post-planting management
1. Temperature
Use cultivation facilities to meet as much as possible the temperature requirements of Gerbera during the seedling, growing and flowering stages, so as to facilitate normal growth and flowering. In South China, it cannot overwinter in the open field and requires greenhouse cultivation; outside the Yangtze River basin, unheated plastic tunnel cultivation can be used. In summer, shade nets need to be covered on top of the greenhouse, and the plastic film on both sides of the greenhouse should be opened for cooling. In winter, when the outside night temperature approaches 0C, seal the plastic film tightly for cooling, 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 attention should be paid to appropriate shading and enhanced ventilation to lower the temperature and prevent high temperatures from causing dormancy.
3. Irrigation
After planting, during the seedling stage, keep appropriately moist and control the seedlings to promote root development and rapid establishment. During vigorous growth, maintain an adequate water supply; water 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, watering can be combined with fertilization.
4. Topdressing
Gerbera is a fertilizer-loving perennial flower with a high fertilizer demand; the ratio of nitrogen, phosphorus and potassium applied is 15:18:25. When topdressing, special attention should be paid to supplementing potassium fertilizer. Generally apply 2.5 kg of potassium nitrate, 1.2 kg of ammonium nitrate or ammonium phosphate per mu, once every 5-6 days in spring and autumn, and once every 10 days in winter and summer. If high temperatures or relatively low temperatures cause the plant to enter a semi-dormant state, stop fertilizing.
5. Removal of withered leaves
The lower leaves of the basal leaf rosette of Gerbera easily turn yellow and age, and should be removed promptly; this not only benefits the sprouting of new leaves and new flower buds, but also benefits ventilation and enhances plant vigor.
6. Pest and disease control
The main diseases of Gerbera include leaf spot, powdery mildew and viral disease. For leaf spot, spray 70% thiophanate-methyl wettable powder at 800-**** times or 50% carbendazim wettable powder at 500 times solution. For powdery mildew, use 70% thiophanate-methyl at 1500 times solution or 75% triadimefon wettable powder at 1000-1200 times solution for control, once every 7-10 days, spraying two to three times consecutively. For viral disease control, the seedling entry gate should be strictly controlled, and aphids should be controlled promptly to reduce virus transmission vectors; diseased plants found should be promptly removed and destroyed. The main insect pests of Gerbera include tarsonemid mites, cotton bollworm, tobacco budworm, beet armyworm, aphids, etc. Tarsonemid mites can be controlled with 40% dicofol at 1000 times solution.
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 the vase life of cut flowers; never cut flower stems when the plant is wilting or when the flowers are half-closed at night. After harvesting, carry out grading, preservation treatment and packaging for market.
Most of the professional production bases for Gerbera seedlings in China are concentrated in the Yunnan area, and a large number of emerging professional flower seedling producers, represented by the Yunnan Luxin 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, chemoorganotrophic. This pathogen mainly infects various cruciferous plants such as chicory, lettuce, pea, melon and cabbage, and can also harm tomato, clover, etc. The pathogen mainly overwinters in diseased field soil and diseased plant residues, and spreads by means of rain, agricultural operations, insect carriage, etc.
2 Gerbera viral diseases
2.1 Gerbera spotted wilt
After being affected, Gerbera shows symptoms such as fading, necrosis and stunting, and flowers are deformed. This disease occurs on cultivated Gerbera 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, inactivation temperature 40~46 °C, survival period in vitro less than 5 h, dilution endpoint 10-3. It is transmitted by mechanical inoculation, and the insect vector thrips transmits it in a persistent manner. This disease has a wide host range and is an important pathogen of many crops such as tobacco, tomato and potato.
2.2 Gerbera mosaic disease
Diseased plants show leaf chlorosis, deformed leaves, and formation of patches; growth weakens, the number of cut flowers drops sharply, and with continued development the diseased plant dies. It can infect other crops such as common tobacco and Nicotiana glutinosa, producing mosaic symptoms, and infecting zucchini causing chlorotic yellow spots and mosaic symptoms. The pathogen is Cucumber mosaic virus (CMV); the virus particles are spherical, 30 nm in diameter, with three types of particles similar in morphology; it is transmitted by mechanical inoculation, and aphids transmit it in a non-persistent manner. Inactivation temperature 70 °C, survival in vitro 4 days, dilution endpoint 10-3. This disease has a wide host range, and is mainly transmitted by sap and aphids.
2.3 Gerbera mottle disease
Chlorotic ringspots appear on leaves, some chlorotic spots appear as oak-leaf patterns, and individual tissues bordering the spots become necrotic. When the disease is severe, leaves become smaller, shrunken 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, inactivation temperature 90~95 °C. This disease has a wide host range, and 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 round or long elliptical yellowish-white lesions. The lesions are covered with a white substance; when severe, the entire leaf is covered with white powder, and later the powder layer turns grayish-white and the leaves scorch and wither. The pathogen is (Oidium sp.); the mycelium is white, epiphytic, and penetrates deep into the host epidermal cells with haustoria to absorb nutrients. The conidiophores are erect, unbranched, and produce conidia in a holoblastic manner. The conidia are oblong, single-celled, colorless, produced in chains, maturing from top to bottom in sequence. This disease is more likely to occur when temperatures are high, relative humidity is 80%~90%, and ventilation in the greenhouse is poor.
3.2 Gerbera leaf spot
There are mainly two types of Gerbera leaf spot: (1) Phyllosticta leaf spot. Initially small purplish-brown to tea-brown spots appear on the leaves, gradually expanding into round or nearly round 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. The conidiogenous cells are cylindrical, colorless, smooth, and produce conidia holoblastically; the conidia are elliptical, single-celled, colorless, with a truncate base. It grows very quickly on artificial culture medium, with more aerial mycelium, and the pycnidia are formed relatively sparsely, with a membranous wall. The pathogen overwinters as mycelium and pycnidia in diseased fallen leaves. Old leaves are more severely affected than young leaves. (2) Cercospora leaf spot. Initially small purplish-brown dots appear on infected leaves, gradually expanding into round or nearly round lesions, with a dark gray center, edges with slightly raised brown line markings, and a purplish-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; the conidiophores are thick, of the mycelial type, olive-brown or brown, lighter in color at the top, unbranched or occasionally branched, growing in clusters on the stromatic tissue; the conidia are whip-shaped, straight or slightly curved, colorless, with 3~12 septa. The conidiogenous cells are mostly blastic, with sympodial extension, cylindrical, with obvious conidial scars. The conidia are solitary, with a scar at the base, having multiple septa, with a smooth surface. This disease mostly overwinters on diseased residues and diseased leaves, and generally occurs severely in environments that are shaded and damp with insufficient light, heavy clay soil, and poor drainage.
3.3 Gerbera gray mold
Water-soaked round or irregular lesions appear on the stem near the ground of diseased plants, later turning grayish-brown to brown; the diseased part becomes soft and rotten, 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 rot, 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; the conidiophores are straight or flexuous, 960~1 200 μm x 16~22 μm in size, growing in clusters of several, brown, smooth, with 1~2 branchings at the top. The ends of the branches often swell markedly, forming colorless or pale flask-shaped conidiogenous cells; the 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 stem base, causing the stem to rot. In the early stage of the disease, the diseased part shows water-soaked soft rot, brown, gradually spreading to the stem and petiole. Later, black mouse-dropping-shaped sclerotia can be seen both inside and outside the stem. The typical symptom of this disease is rapid soft rot at the diseased part, densely covered with white flocculent material, or with black mouse-dropping-shaped sclerotia; each sclerotium can produce 1~9 apothecia. This disease is caused by the fungus Sclerotinia sclerotiorum Fuck. The apothecia are produced on the sclerotia, disc-shaped, with long stalks. The asci are arranged in parallel, with persistent paraphyses between the asci. The asci are club-shaped or elliptical, colorless; the ascospores are single-celled, elliptical, arranged in a single row. The pathogen has a very wide host range; it overwinters as sclerotia in diseased residues and soil, and produces ascospores the following year to infect and cause damage. Fields 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, with a wide occurrence area and great damage; the plant is affected throughout its entire growth period, and is most severely affected during the flowering period. The pathogen infects from the stem base at ground level; the affected part becomes soft, water-soaked, and light black; the plant leaves suddenly wilt and turn purplish-red. When the diseased plant is pulled out, the diseased part at the stem base breaks easily, and when moist, white mold spots can grow on the surface. This disease is mainly caused by Phytophthora cryptogea. Phytophthora cryptogea belongs to the kingdom Chromista, phylum Oomycota, order Peronosporales, family Pythiaceae, genus Phytophthora; its vegetative body is non-septate, multinucleate mycelium, with hyphal swellings produced, and asexual reproduction produces zoosporangia. The sporangia are pear-shaped or elliptical, without papillae, large, averaging 46 μm x 27 μm in size, with a wide host range. Heterothallic, sexual reproduction produces oogonia, oospores and antheridia; the oogonia are spherical, containing one spherical thick-walled oospore; the antheridia are single-celled, colorless and transparent, amphigynous. The pathogen overwinters on residues or in soil, and the overwintering pathogen is the main primary infection source of this disease. Sudden alternating dry and wet soil or frequent intertillage and loosening of the soil causes many wounds on the plant roots; the pathogen invades from the wounds, and under suitable conditions spreads through irrigation water or rainwater, causing a major outbreak of the disease. Fields with poor drainage and continuous cropping are severely affected. 3.6 Gerbera Fusarium wilt
The symptoms of this disease are similar to Gerbera root rot; it occurs throughout the entire growth period of Gerbera; the root system of diseased plants is dark brown, the cortex of the diseased roots peels off, there are few fibrous roots, and the plant is easily pulled up. When the disease develops slowly, the leaves of the diseased plant turn purplish-red or dark brown and gradually wither; when severely affected, the plant dies in a green wilt state. This disease occurs in Italy, Australia, China and other countries. Because Gerbera is basically cultivated under protected conditions, this disease can occur year-round, with April to August each year being the period when the disease is more severe. The pathogen overwinters in the soil or in diseased plant residues; infected soil and affected plants are the main sources of infection of this disease; high temperature and high humidity weather and heavy clay soil all promote the proliferation and spread of the pathogen. This disease is mainly caused by Fusarium oxysporum; on artificial culture medium it produces dense mycelium, loose cotton-like; the conidiophores are colorless; the conidiogenous cells produce conidia in an enteroblastic phialidic manner, producing two types of spores; the microconidia are oval to elliptical, 5~12 μm x 2.5~3.5 μm in size; the macroconidia are 27~46 μm x 3~4.5 μm in size, spindle-shaped to sickle-shaped, with a hooked apex and a small pedicel at the base, with 3~5 septa, most with 3 septa. Chlamydospores are usually formed in large numbers, intercalary or terminal, solitary, occasionally in chains, with a smooth or rough wall.
In addition, Gerbera diseases also include downy mildew (caused by Bremia lactucae), white rust (caused by A. tragopogonis), and ringspot mosaic disease (caused by TBRV), etc.
4 Pest: whitefly
Key control techniques: thoroughly remove weeds, insert yellow sticky boards for monitoring at any time, and once pests are found, take measures promptly. Choose good pesticides and use them correctly: whitefly easily develops resistance to pesticides, so pesticides must be rotated. Pesticides with good effects include beta-cypermethrin, abamectin, imidacloprid, etc. Choose dawn for spraying; after spraying, seal the greenhouse for 4-5 hours, and spray once more continuously the next morning. Keep the greenhouse ventilated and low in humidity; promptly remove diseased leaves; when the disease occurs, spray 70% thiophanate-methyl at 1500 times solution, or use 20% Junke smoke for fumigation control, once every 7 days, for 2-3 consecutive treatments. In addition, use the sulfur fumigation method for control: place 20-30 g of sulfur powder in each fumigator, and 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 fumigating for 15 days. During the onset period of powdery mildew, fumigate 8-10 h every day, and powdery mildew can be eliminated in about 10 days.
Thrips
Key control techniques: promptly cut off flowers with insects, thereby reducing the insect source in the greenhouse (room). Fumigating pesticides in the greenhouse is the best control method; fumigate with 300-400 ml of 80% dichlorvos for 1 hour, or spray with 5% imidacloprid at 1500-2000 times solution and then close the greenhouse for 8-10 hours; fumigation can be carried out at around 10 a.m. or 5 p.m. when the temperature is slightly higher, to achieve good efficacy.
Cabbage caterpillar
Key control techniques: for larvae, spray with 10% Chuchujin at 2000-2500 times solution for control; for older larvae, beta-cypermethrin at 1000 times can be used for control, once every 7 days, for 3 consecutive times.
Note: The above pesticides are determined after testing according to the reference formula provided by the Resource and Environment Institute.
Phytophthora blight
Key control techniques: soil for continuous cropping must be disinfected with Vapam and formaldehyde, etc.; see the instructions for usage and dosage; plant shallowly, with the root crown exposed 1 cm above the surface; prevent the soil from being too wet; if soil below 10 cm of topsoil does not form a ball when placed in the palm and squeezed hard, then it can be watered; in the early stage of the disease, when part of the leaves turn red and begin to wilt, drench the roots with 58% phosethyl-Al and mancozeb at 400 times solution, then after 7 days drench the roots with 64% sandofan powder at 500 times solution; apply the pesticide in the morning and evening when temperatures are low, stop applying when the temperature is above 28 degrees, apply once every 7 days, for 3 consecutive times.
Spot disease
Key control techniques: promptly remove diseased leaves when found and destroy them in a centralized manner; in the early stage of the disease, spray 2.5% myclobutanil emulsifiable concentrate at 300 times solution or 70% thiophanate-methyl wettable powder at 800-**** times solution, once every 7 days, for 2-3 consecutive sprays.
Gray mold
Key control techniques: controlling humidity is the key to controlling gray mold. Thin out densely planted and overgrown leaves; increase ventilation and air permeability, keeping air humidity at 75-85%; water from below the plant rosette; to prevent water vapor from condensing on the flowers, after 10 a.m. on sunny days, gradually open the side greenhouse, avoiding a sharp rise in temperature inside the greenhouse; in the early stage of the disease, spray 70% thiophanate-methyl at 1500 times solution on the leaves, combined with smoke agents for control.
5 Physiological diseases
1. Symptoms: dark green spots appear on young leaves; when severe, the young leaves and growing point die first, while the old leaves can still remain normal.
Solution: judging from the symptoms, it may be caused by calcium deficiency. Spray 0.15% Ca(NO3)2.4H2O on the leaves, once every 25 days.
2. Symptoms: "mosaic" appears in the mesophyll of old leaves, and an inverted "V"-shaped green part forms at the leaf base, and its top can also extend to near the leaf tip. Leaves become brittle, curved, 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 2 times. Solution: judging from the symptoms, it may be caused by magnesium deficiency.
3. Symptoms: 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 curl, 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, the other side does not, and the leaf curves sideways.
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; in severe cases the flower stem breaks, and the cracks look like cuts.
Solution: use 1~2‰ calcium nitrate, spray once a week.
2. Leaf margin scorch: the leaf tips or the tips of pinnate lobes suddenly scorch.
Solution: caused by too high a fertilizer concentration; immediately spray clean water to dilute or rinse off the fertilizer liquid adhering to the leaves; extend the fertilization interval and reduce the fertilization 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 70% thiophanate-methyl wettable powder at 800-**** times or 50% carbendazim wettable powder at 500 times solution. For powdery mildew, use 70% thiophanate-methyl at 1500 times solution or 75% triadimefon wettable powder at 1000-1200 times solution for control, once every 7-10 days, spraying two to three times consecutively. For viral disease control, the seedling entry gate should be strictly controlled, aphids should be controlled promptly to reduce virus transmission vectors, and diseased plants should be promptly removed and destroyed. The main insect pests of Gerbera include tarsonemid mites, cotton bollworm, tobacco budworm, beet armyworm and aphids. Tarsonemid mites can be controlled with 40% dicofol at 1000 times solution. Other pests can be controlled with 2.5% deltamethrin or 40% omethoate at 1000-1500 times solution, once every eight to nine days; spraying has an adverse effect on flower color and should not be used during the flowering period.
Spot disease
When Gerbera is cultivated in protected facilities year after year, the warm, humid and poorly ventilated environment 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 purplish-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 grayish-brown dusty fungal filaments on it.
Disease pattern: generally the lower leaves are affected first. Excessive nitrogen fertilizer easily triggers the disease. Heavy soil and poor drainage are also important conditions that induce the disease.
Control methods
1. Soil treatment: chloropicrin fumigation can be used to effectively kill pathogenic bacteria and reduce the accumulation of inoculum in 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; disease is unlikely to occur under low temperature and low humidity conditions.
3. Spray fungicides once every 7 to 10 days, such as 75% chlorothalonil at 500 times solution, 50% captan at 500 times solution, and 70% thiophanate-methyl at 1000 times solution; the control effect is obvious.
Control of Phytophthora blight
Gerbera Phytophthora blight, also known as rhizome rot, once it occurs, causes severe damage, often causing the death of the whole plant, or even the death of the whole greenhouse, bringing serious economic losses to growers. After several years of cultivation experience, the author has summarized some effective measures and now introduces them to everyone.
1. Disease pattern: Phytophthora overwinters as chlamydospores and oospores in diseased residues or soil. When there is no host, the resting spores can survive for a long time. The pathogen is transmitted by water flow, soil, and diseased plants.
2. Symptoms: it first infects the rhizome part of the plant; the leaves of the affected plant first turn yellow, then grayish-brown, until withered and dead, and the rhizome part turns black and rots.
3. Prevention and control: (1) Select healthy, disease-free plants for cultivation.
2. Before planting, disinfect the soil in the nursery. This pathogen is mainly spread through the soil, so the nursery must be carefully disinfected before planting. The main disinfection methods are: 1) Chemical disinfection: Use a mixture of Dexon plus quintozene (3:1) at a rate of 4-6 g/sq m. During disinfection, spray the chemicals onto the soil surface, mix thoroughly with the soil, seal with plastic film, fumigate the greenhouse in a sealed state for 30 hours, then remove the covering, ventilate, re-mix the topsoil, and plant after 15 days. 2) Steam disinfection: Release steam into the soil through pipes. This method has higher investment costs but good results.
3. For Gerbera, the planting depth should follow the principle of shallow planting, requiring the root crown to be exposed about 1.5 cm above the soil surface, with slight lodging being acceptable (gently straighten it after 3 days). Because it has contractile roots, the root crown of the plant will become deeply buried in the soil, giving pathogens easy access for infection. To better promote the growth and development of seedlings, a localized substrate planting method can be used: first dig a round planting hole about 10 cm in diameter at the planting site, 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, irrigate the root zone with captan 0.1 g/l + 1% copper sulfate. 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. Through this, we call on the relevant departments to pay attention to this.
(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. However, 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, it is necessary to spray pesticide at least once every 3-4 days, for 10-12 consecutive applications. Whitefly eggs, older nymphs, and pupae have strong resistance to temperature and pesticides. Once various life stages occur simultaneously on crops, control becomes very difficult. It can be seen that whiteflies are more difficult to control than ordinary pests and are more likely to resurge, causing continuous cyclic damage.
The population density of whiteflies has the characteristic of rising exponentially. In the early stage of whitefly infestation, it occurs only in scattered spots, and the plants appear to show no damage symptoms on the surface, so it is often overlooked. However, the harm of whiteflies in transmitting viruses, weakening plant growth vigor, and seriously affecting shipment quality is already developing. Once it spreads, it may cause years of cyclic damage in the greenhouse and be difficult to completely eliminate. Therefore, in daily flower production management and the process of introducing seedlings, attention must 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, with a length of 0.2-0.25 mm, which is not easily noticeable to the naked eye and requires observation with a magnifying glass or microscope. They are mostly distributed on tender leaves. Nymphs and pupae are usually fixed on the middle and lower old leaves and are easy to find. Adults like to attach to the underside of tender leaves and mature leaves. Both adults and nymphs can secrete honeydew, which accumulates on leaves and causes sooty mold. If black-gray sooty mold caused by fungal parasitism is found on 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, salvia, dahlia, geranium, cineraria, gloxinia, fuchsia, hibiscus, clematis, abutilon, solanaceous 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 succulents.
Sometimes flower crops and vegetable crops are rotated or planted in contiguous blocks, so it is necessary to know the vegetable crops severely damaged by whiteflies, such as cucumber, tomato, lettuce, green bean, celery, melon, pumpkin, and garlic. Weeds inside and around greenhouses are breeding grounds for whiteflies. The weeds they like include chickweed, wood sorrel, nettle, dandelion, etc.
(3) Control of whiteflies
1. Focus on prevention and cultivate insect-free seedlings. Seedlings, crop residues, and weeds carrying insects are important pathways for the spread of whiteflies. Therefore, 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 infested with whiteflies, the movement of its crops in and out must be handled very carefully to prevent all greenhouses from becoming infested. Yellow boards should be placed in the greenhouse for monitoring at any time. Regular field inspections should be carried out to check growth conditions and whether pests and diseases are occurring. Hanging white or silver-white plastic strips at the greenhouse entrance can repel adult insects from entering.
2. Choose good pesticides and use them correctly. Whiteflies easily develop resistance to pesticides, so it is necessary to know more about the available pesticide types in order to select them. For pesticides to which they originally have no resistance, pest resistance will only develop in the second generation. Therefore, for pesticides with good trial results, they can be used continuously for at least one generation or more until resistance is found. Attention should be paid to correct pesticide application methods, and it is not advisable to change pesticides frequently. The table below lists pesticides with good results tried domestically and abroad, for reference.
Category English name Chinese name or trade name Notes
Organophosphate acephate has fumigant action
chlorpyrifos
etrimfos
Carbamate methomyl has a certain ovicidal effect
Pyrethroid sumicidin
Propoxur+methoxychlor
Cypermethrin
Alphamethrin
fluralinate
Acaricide mitac has fumigant action
Chitin synthesis inhibitor buprofezin
Other Tempo endosulfan
abamectin spray concentration 1000 times
Diazinon
imidacloprid
3. Application of the high-temperature sealed method. In the process of whitefly pest control, 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 leaf sap, easily creating dead corners that pesticides cannot contact, especially when plants are growing luxuriantly. When disturbed, whiteflies can fly several meters away, thereby avoiding contact with the spray solution. Therefore, even if pesticides to which resistance has not developed are used, their control efficacy is limited. The growth, development, and reproduction of whiteflies are greatly related to temperature. The developmental threshold temperature for eggs is 7.2°C, and the optimum survival temperature is 20-28°C. Above 30°C, egg and larval mortality is high, adult lifespan is shortened, egg laying is reduced, and reproduction may even stop. Whiteflies are poikilothermic animals, so above 30°C their respiratory frequency increases greatly, making it easier 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 significant control results. The method is to mix a pesticide with fumigant action and a pesticide with ovicidal action (such as chlorpyrifos + methomyl), add an appropriate amount of laundry detergent as a surfactant, and spray between 3:30 and 5:30 in the afternoon. Before spraying or while spraying, close the vents of the greenhouse to create sealed conditions, and maintain the temperature between 30-35°C for more than one hour. In summer, pull shade nets and delay the spraying time to prevent the temperature inside the greenhouse from rising excessively. In the absence of sealed conditions, spraying during the hot afternoon period is also more effective than spraying in the morning. When the temperature is high, the greenhouse can easily rise above 30°C even without sealing, so it is advisable to spray in the morning when the temperature is lower, keep the greenhouse sealed for 1-2 hours, and use shade nets to cool down if necessary, so there is no concern about excessive humidity causing disease.
4. Other methods. Very effective methods for controlling whiteflies also include fumigation, smoke fumigation, and fogging methods, which are introduced in other books. Biological control is a more scientific method and should be vigorously popularized and applied.
Mosaic disease
1. Symptoms. Leaves appear mosaic-like, and sometimes markings also appear on petals. The pathogens include cucumber mosaic virus (CMV) and tobacco mosaic virus (TMV).
2. Control methods. (1) Remove weeds in the flower garden and its surroundings at any time, and promptly use insecticides to control aphids. (2) Disinfect cutting tools such as flower shears with 10% trisodium phosphate.
Root rot
1. Symptoms. The symptoms of this disease are similar to those of wilt disease, but there is no pink spore mass at the diseased site. Water-soaked soft rot appears on stems and roots and turns black. The rotting phenomenon is significant. The pathogen includes Phytophthora cryptogea Pethy-br et Laff., belonging to Mastigomycotina. Sporangia are obpyriform, and oospores are yellow and spherical. It has both parasitic and saprophytic characteristics, and the optimum growth temperature is 25°C.
2. Control methods. (1) Breed disease-resistant varieties. (2) Before planting in flower beds where this disease occurred the previous year, first mix Dexon 1000-1500 times solution with the soil for sterilization. (3) When diseased plants are found, pull them out and burn them at any time to prevent the spread of the pathogen. The diseased soil must also be dug out and replaced with new soil.
Greenhouse diseases and pests
1. Phytophthora disease first infects the root crown. The leaves of affected plants turn yellow, then gray-brown, and eventually die. The root and stem base turn black and rot.
Control methods:
(1) Select healthy, disease-free plants for cultivation.
(2) This pathogen mainly spreads through soil, so the nursery must be carefully disinfected before planting. The chemicals can be Dexon plus quintozene (3:1), at a rate of 4-6 g/sq m. During disinfection, spray the chemicals onto the soil surface, mix thoroughly with the topsoil, seal with plastic film, and at the same time seal the greenhouse for fumigation for 30 hours, then remove the covering, ventilate, and re-mix the topsoil. Planting can be done after 15 days. Steam can also be released into the soil through pipes; this method has higher investment costs but better results.
(3) For planting, the root crown should be exposed about 1.5 cm above the soil surface, with slight lodging being acceptable. Because it has contractile roots, the root crown of the plant will become deeply buried in the soil, giving pathogens easy access for infection. To promote the growth and development of seedlings, a localized substrate cultivation method can be used: first dig a round planting hole about 15 cm in diameter at the planting site, then fill it with sun-sterilized river sand or a perlite + vermiculite (1:1) substrate, then plant the seedling on the substrate, water thoroughly, firm the roots, and then proceed with normal daily management. This can achieve immediate results.
(4) When diseased plants are found, in the early stage irrigate the roots with captan 0.1 g/l + 1% copper sulfate. In the late stage of disease, immediately pull out and burn the diseased plants, and treat the surrounding plants and soil with the above-mentioned chemicals.
2. Diseased leaves infected with virus have indistinct yellow-green spots, and new leaves become narrow. During high-temperature periods, the markings are not obvious. Growth is weakened, the number of cut flowers drops sharply, and if it continues to develop, the diseased plant will die.
Control methods:
(1) Remove diseased plants.
(2) Thoroughly eliminate aphids, the vectors that transmit the virus.
(3) When cultivated in poorly ventilated greenhouses, scale insects often occur and should be removed promptly.
3. For whiteflies, imidacloprid, dichlorvos, phoxim, and methamidophos all have good control effects. However, using a single pesticide variety easily leads to resistance, so it is best to use mixed pesticides or alternate multiple pesticides, and avoid using the same pesticide continuously multiple times. For those that have developed resistance, organophosphate pesticides can be mixed with methomyl water plus pyrethroid pesticides.
4. Leafminers have peak damage periods from April to May and October to November. They can be killed using abamectin, avermectin, or bisultap mixed with fenvalerate.
Causes of root rot
The color of gerbera in midsummer, especially under drought and water shortage conditions, becomes dark and dull; while flowers blooming during the suitable temperature period of September to October or March to June of the following year have bright colors. This indicates that gerbera is relatively sensitive to temperature and light intensity. In summer, it is necessary to keep the soil moist and not drought-stressed, cover with a shade net of 50% light transmission, and spray the leaves to increase air humidity and lower temperature.
In winter, sufficient warmth preservation work should be done to prevent freezing. The nighttime temperature should not be lower than 10°C, and the daytime temperature should not be lower than 15°C. These are all very beneficial for improving the brightness of gerbera. 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 entire growth period is free from mite damage is a particularly important link in guaranteeing the brilliant colors of gerbera.
The cause of gerbera root rot is mostly root rot disease occurring in the roots, and once it occurs, it is difficult to cure. The external conditions that produce root rot are excessive soil moisture around the roots, long-term water accumulation in the root zone, or long-term rainfall in open fields, which can cause the death of gerbera plants.
Gerbera potted cultivation techniques - potted production
In the daily production process of potted gerbera, the following points need attention.
1. The production greenhouse should be equipped with ventilation, shading, and heating facilities. If conditions permit, it should also be equipped with benches, ground cloth, or an irrigation system. The greenhouse should be sealed to prevent insects from entering.
2. The temperature in the greenhouse should be controlled between 15°C and 25°C, with the maximum not higher than 30°C and the minimum not lower than 13°C. Generally, the average daily production temperature is 18°C to 19°C. Above 19°C, ventilation should be provided. At the same time, the nighttime temperature should not be too high, otherwise it will affect normal flower bud differentiation. The ideal nighttime temperature should be between 15°C and 18°C.
3. Use a medium with good aeration and drainage, preferably a substrate mixed with peat and perlite. The pH value is 5.5 to 6.0, and the EC value is 0.7 to 1.0, which is beneficial for the absorption of trace elements.
4. Potted gerbera is very sensitive to water, so the correct watering time must be ensured. Water in the morning or evening, and keep the plants relatively dry at nightfall. When the plants begin to grow roots, watering must be done from below, and a bottom infiltration method can be used; during high-temperature periods, watering from above the plants can be done, but care must be taken to prevent fungal mold starting from the center of the plant.
5. Gerbera 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 supplemental lighting can be used during low light conditions. Generally, the requirement for artificial supplemental lighting is 3500 to 4000 lux per square meter. It should be noted that supplemental lighting should be carried out 4 weeks after the plants are potted.
7. From potting to flowering, gerbera requires 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 promptly when the plants have grown to a certain size.
Gerbera - post-harvest handling
Harvesting: For single-petaled varieties, the flowers can be harvested when 2-3 rounds of stamens have matured. Double-petaled varieties should be harvested when more mature; flowers harvested too early will have a shorter vase life. After harvesting, they must be immediately placed in water, and the water must be very clean. Before placing fresh flowers in water, cut off 2-5 cm of the hairy, lignified bottom flower stem so that the stem can absorb water. Vase life is one of the most important components of the commercial value of cut flowers. Post-harvest handling is very important for the vase life of gerbera. If gerbera cut flowers that have not undergone post-harvest handling flow into the market, 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 can only be harvested when one or two rounds of stamens have released pollen. Harvesting too early will shorten the vase life. This is because when harvested too early, the energy stored in the outer ray florets is not enough to complete their development. When harvesting flowers, the entire stem should be picked rather than cut, because the part left after cutting will rot and infect the sensitive roots, and will also inhibit the sprouting of new flower buds. After harvesting and sorting the flowers, cut off 2-4 cm from the bottom of the stem. Cut at an angle to avoid squeezing the xylem vessels. The bottom of the stem 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, when harvesting flowers, air may be drawn into the vessels and prevent the flowers from absorbing water. Cutting off part of the stem also removes air bubbles in the vessels.
Post-harvest pretreatment
After cut flowers are harvested, the stems should immediately be immersed in buckets and transported to a cool place. The water and buckets used should be very clean and should be cleaned and disinfected before each use to prevent bacterial growth, because bacteria will clog the vessels and prevent the flowers from absorbing water. During pretreatment, the pH of the water should be adjusted to 3.5-4.0 with chloride (bleaching powder). Too high a pH value will create ideal living conditions for bacteria. Bleaching powder can both lower the pH of the water and sterilize, and the calcium chloride in it can also help extend the life of cut flowers. Research shows that the appropriate amount of bleaching powder to add is 50-100 mg/l, and the treatment time should not exceed 4 hours. Too long a treatment time will damage the stems, shown as brown markings or bleached color on the stems. For longer 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 location should not be exposed to sunlight, otherwise the useful components of the bleaching powder will decompose and become ineffective.
Preservative solution treatment
After pretreatment is completed, immerse the stems in preservative solution for 6-24 hours. During treatment, immersing more of the stem in water helps the flowers absorb water, and the ideal length is 10-15 cm. Too high an ambient temperature will cause the flowers to lose too much water through transpiration, so 10-15°C is ideal. Loss of water will cause gerbera flowers to age, so drying and drafts should be avoided throughout the entire post-harvest handling process. It is best to raise the relative humidity of the environment to 70%. In addition, during preservative solution treatment, care should be taken to prevent cut flowers from ethylene damage. Ethylene is an aging hormone that 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. The preservative solution for gerbera consists of the following components: sucrose, 3 g/l; citric acid, 150 mg/l; dipotassium hydrogen phosphate with seven water molecules of crystallization (K2HPO4·7H2O), 75 mg/l. Sucrose provides energy for gerbera to continue opening during the process and also promotes water absorption by the flowers. Citric acid lowers the pH of the preservative solution, thereby preventing bacterial growth.
[Preservation management] Cut flowers can be stored in an environment with a relative humidity of 90%-95% and a temperature of 2-5°C. During storage and transport, gerbera can tolerate longer dry storage. However, after opening the box, they must be inserted into water as soon as possible. Commercially available preservative solutions can also be used to extend vase life.
[Grading] Harvested flower materials should be graded on the premise that they have the typical characteristics of the variety, are free from damage and contamination, and have good visual appearance: the length of grade-one cut flowers is about 60 cm; the length of grade-two cut flowers is about 55 cm; the length of grade-three cut flowers is about 50 cm. The difference in length among cut flowers of the same grade should not exceed ±2 cm of the standard.
Packaging and transport
During transport, lower the ambient temperature to 6-9°C, which slows down the life activities of the flowers and preserves energy for use when they reach consumers. Reusing 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 post-harvest handling process in order to effectively extend the vase life of gerbera. After gerbera arrives at its destination, the bottom of the stem will become dry. Use a clean knife to cut off a small part of the stem 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 higher 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 fears extreme heat. When the summer temperature is above 34°C, growth is obviously poor; it is not tolerant of frost and cold, and enters dormancy or dies when the winter temperature is below 4°C. The most suitable growth temperature is 15-25°C. Generally sown in autumn and winter to avoid high summer temperatures.
Light management
In spring, summer, and autumn, it needs to be maintained under shaded conditions. When the temperature is relatively high (daytime temperature above 25°C), if it is placed in direct sunlight for maintenance, the leaves will noticeably become smaller, the internodes of the branches will shorten, the lower leaves will turn yellow and fall off, and growth will be very slow or it will enter a semi-dormant state. In winter, because the temperature is not very high, it should be given direct sunlight to facilitate photosynthesis and the formation of flower buds, flowering, and fruiting. After maintaining it indoors for a period during the flowering stage (10-15 days), it should be moved outdoors to a place with shading (and warmth preservation) for a period (about one month), and alternated in this way to help the plant accumulate nutrients and continue flowering.
Fertilizer and water management
Like other herbaceous flowers, it has relatively high fertilizer and water requirements, but the fertilization (watering) principle of "light fertilizer applied frequently, small amounts with more applications, complete nutrition" should be followed, and after fertilizing, the leaves and flowers should be kept dry at night: Spring and autumn: These two seasons are its peak growth periods. 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 must be guaranteed each week). The interval period is approximately: 1-4 days for outdoor maintenance; shorter intervals on sunny days or during high temperatures, 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, 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 low fertilizer and water requirements, and may even need 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, 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, 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 dormant 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, 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.
Key maintenance points temperature
Cultivation facilities should meet the temperature requirements of gerbera during the seedling stage, growth stage, and flowering stage, to facilitate normal growth and flowering. Outside South China, it cannot overwinter in open fields and requires greenhouse cultivation. Outside the Yangtze River basin, unheated plastic tunnel cultivation can be used. In summer, shade nets need to be covered on top of the tunnel, and the plastic film on both sides of the tunnel should be opened to lower the temperature. In winter, when the outside nighttime temperature approaches 0°C, the plastic film should be lowered, and additional plastic film must be added inside the tunnel. In sunny and warm weather, open the film at the south end of the tunnel for ventilation for about one hour.
Light
A light-loving flower. It needs full light in winter. In summer, attention should be paid to appropriate shading, strengthening ventilation, lowering temperature, and preventing high temperatures from causing dormancy.
Irrigation
After planting, the seedling stage should maintain appropriate moisture and controlled seedling growth to promote root development and rapid establishment. During the vigorous growth period, sufficient water supply should be maintained, watering once every 3-4 days, and once every half month in winter. When watering during the flowering period, care should be taken not to let water touch the center of the leaf rosette, to prevent flower bud rot. Cultivation should also pay attention to preventing waterlogging. Fertilization can be combined with watering.
Topdressing
Gerbera is a fertilizer-loving perennial herbaceous flower with high fertilizer demand. The ratio of nitrogen, phosphorus, and potassium in fertilization is 15:18:25. Special attention should be paid to supplementing potassium fertilizer. Apply 2.5 kg of potassium sulfate 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, stop fertilizing.
Removing residual leaves
The lower leaves of the basal leaf rosette easily turn yellow and age. Removing them promptly is beneficial for the sprouting of new leaves and new flower buds, is beneficial for ventilation, and enhances plant growth vigor.
Selection of gerbera fresh cut flowers
The junction between the flower stem and the flower head of gerbera is relatively thin and soft, while the flower head is large and heavy, so it easily bends down from the neck. Therefore, when selecting, one must choose those with short and thick stems, so that the neck has more strength to support the flower head.
Only a small section at the bottom of the gerbera stem is solid; the stem above is hollow. However, gerbera mainly relies on this solid part to absorb water, so if the solid bottom has been cut off, do not choose it! After buying it and taking it home, put it 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, causing it to decline. Therefore, every possible method should be used to secure 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 directly removed, and the remaining flower center part is also quite ornamental. Because gerbera petals are very easily damaged and leave scars, they must be handled carefully.
The water level only needs to reach one third of the stem length, because the stem is soft and easily rots, so the water level should not be too high.
Preservation methods
Gerbera bought from the flower market does not need to have its roots cut, especially do not cut off the hard node at the base of the root. Just place it directly in water. Put in less water, just enough to immerse the hard bottom part. The flower bucket should be relatively tall, preferably reaching the flower head part. Gerbera that has had its roots cut easily develops stem rot, and rots especially quickly.
If newly received stock shows dehydration, first place it directly in water. If it has not recovered after a few hours, then slightly cut the base into an angled opening and place it in water.
If there is no dehydration, then it is a normal bent stem phenomenon. Straightening the flower head is actually very simple: just take it out and lay it flat, or wrap it in paper and leave it for one or two hours before putting it back in 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 enthusiasm. In the Shanghai area, people like to use gerbera flowers tied into bouquets to decorate the bridal room during wedding celebrations. Using its homophonic meaning, it conveys the idea that the newlyweds respect and love each other and that the wife supports the husband in achieving success in his career. Gerbera has a radial flower shape and is often used as the main body in flower arrangements, often configured 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