What to do when Dianthus gets pests? Control methods for 2 pests and 2 diseases

When growing Dianthus, if there is one problem people least want to encounter, it is surely pests and diseases. Such problems are extremely harmful to the plant, and if not dealt with in time, they can easily cause the plant to wither and die. So what should you do when Dianthus gets pests? And how should pest and disease control for Dianthus be carried out? Below, the editor will walk you through it.

I. What to do when Dianthus gets pests

II. Pest and disease control for Dianthus

Pests

1. Aphids

Aphids are a very small pest, generally only 1.5-4.9mm in body length. This pest mainly feeds on the sap in the Dianthus plant, causing the Dianthus to lose nutrients severely and wither. Generally, many dead spots appear where this pest has sucked, and you can use this to tell them apart.

Control method: The peak period for this pest is every summer, so you must pay extra attention at this time. When dealing with this pest, we can choose to use a 1000-fold dilution of 50% malathion emulsion for control.

2. Red spider mites

In pest and disease control for Dianthus, red spider mites are a relatively common pest. This pest is red in appearance and is a very small plant pest. This pest mainly feeds on the leaves of Dianthus, causing many pitted small holes to appear on the leaves, which greatly affects their appearance.

Control method: When controlling this pest, we can use a 2000-fold dilution of 20% mite-killing wettable powder to spray and kill red spider mites.

Diseases

1. Rust disease

Rust disease is a disease caused by fungi. On the parts of Dianthus infected by this disease, many blister-like objects appear, and over time they gradually spread, causing the leaves of Dianthus to continuously drop and the plant to gradually wither and die.

Control method: When dealing with this disease, we can use a 1500-2000-fold dilution of 25% triadimefon to spray the plant for treatment, generally spraying once every 7-10 days, and after 2-3 times it can basically be cured.

2. Anthracnose

In pest and disease control for Dianthus, anthracnose is a relatively common disease. It mainly harms the leaves of Dianthus. When it occurs, many yellow disease spots appear on the leaves, and over time the color of the disease spots gradually deepens, causing the plant to suffer from malnutrition and wither.

Control method: When dealing with this disease, we can use a 600-800-fold dilution of 50% amobam to spray the diseased plants, generally spraying once every 10-15 days, and after 1-2 times it can basically be cured.

The complete home flower-growing technique set, teaching you step by step "watering, fertilizing, pest and disease control"

The complete home flower-growing technique set, teaching you step by step "watering, fertilizing, pest and disease control"

Appreciating flowers and growing flowers have now become a fashion, and home flower growing is generally mainly potted flowers. To grow flowers well, you must master care and management knowledge, especially the three key techniques of watering, fertilizing, and pest and disease control. Brother Dadi has compiled a complete home flower-growing guide for everyone today. Flower friends, remember to save it well!!

1. Choosing water quality for watering

Home flower growing mostly uses tap water for watering, but tap water contains the disinfectant bleaching powder, and the chloride ions in it easily damage the tender root hairs of potted flowers. It must be stored for 1~2 days, and only after the chlorine gas has evaporated and the water temperature is close to the soil temperature can it be used to water flowers. Because the natural arrangement of water molecules in magnetized water has been disrupted by the magnetic field, it is similar to the water molecules in plant cells and is easily absorbed and used by plants, so potted flowers are best watered with magnetized water.

Watering amount

The principle of watering is "water thoroughly when you water, and water thoroughly without letting it leak out," that is, each time water until water seeps out from the saucer under the pot. In addition, it should also be determined according to the size, depth, and texture of the flower pot. Small pots are shallow, so watering should be less and more frequent; clay pots have good water permeability, and the potting soil dries easily, so water frequently; stone pots and glazed pots do not easily permeate water, and with long-term water accumulation, flowers will rot at the roots.

Different flowers and trees have different watering periods. The first is the "prefer wet over dry" type, referring to flowers and trees that will be damaged and die after the potting soil completely dries out. Such flowers and trees should be watered sufficiently when the potting soil is slightly dry, such as maidenhair fern and brake fern; the second is the "prefer dry over wet" type, referring to flowers and trees that should be watered after the potting soil dries completely, such as cactus and aloe; the third is the "alternately dry and wet" type, referring to flowers and trees that should be watered immediately when the surface of the potting soil is dry to about 3cm, such as monstera and pothos.

Watering changes with the seasons. In early spring when it turns warm, the weather is changeable. At this time, potted flowers begin to sprout and take root and need a large amount of water, so the potting soil should be kept moist; summer is dry and evaporation is fast, so watering should be doubled; in autumn, watering should be appropriately reduced to avoid excessive growth of flower branches, which would affect flowering the 2nd year; in winter, most flowers and trees are in a dormant state, so keeping the potting soil slightly dry is enough.

The complete home flower-growing technique set, teaching you step by step "watering, fertilizing, pest and disease control"

Watering time

The daily time for watering flowers differs in spring, summer, autumn, and winter. As the flower proverb says, "Morning water is sweet dew, noon water is arsenic, evening water is a life-saving soup." This means that in spring and autumn, around 10 a.m. and after 4 p.m. are suitable times to water flowers, while in summer never water flowers at noon. At noon in midsummer, the temperature is highest and the difference between the potting soil and water temperature is greatest. Watering flowers at this time can easily block the normal physiological activities of the root system, weaken the root system's absorption of water, cause physiological drought, and make the branches and leaves wilt. By the same reasoning, in winter it is better to water flowers at noon. In short, "water at noon in spring, morning and evening in summer, every other day in autumn, and check frequently in winter."

Watering methods

Before watering potted flowers, the compacted potting soil must be loosened so that the water can be absorbed in time and will not overflow from the edge of the pot. It is best to use a fine-hole watering can to water evenly and thoroughly. For small potted flowers, the best watering method is the pot-soaking method, that is, placing the flower pot into a larger water basin so that water seeps into the potting soil from the drainage holes, and after the surface of the potting soil is slightly wet, taking it out. This can prevent the potting soil from compacting due to watering and is beneficial to the root respiration of potted flowers. Generally, shade-loving foliage potted flowers, under the special environment of a dry room and covered with dust, often find it difficult to show their bright true colors. In addition to regular watering, the leaf-surface irrigation method of sprinkling water to wash off dust and spraying water to moisten leaves should also be adopted. This method can also lower the temperature and relieve heat for potted flowers at noon in summer, and help semi-dormant flowers break dormancy and continue to bloom well.

The complete home flower-growing technique set, teaching you step by step "watering, fertilizing, pest and disease control"

2. Fertilizing

Organic fertilizer. Organic fertilizer is fertilizer formed from the seeds, organs, remains, or excrement of various plants and animals after processing and decomposition, such as human and animal manure and urine, livestock and poultry manure, oilseed meal, distiller's grains, and weed green manure. Organic fertilizer is a slow-release fertilizer with complete nutrients and long-lasting effects. It must be fermented and decomposed before use.

Inorganic fertilizer. Inorganic fertilizer is fertilizer made by chemical synthesis or processing of natural minerals, such as urea, superphosphate, and potassium dihydrogen phosphate. Inorganic fertilizer has quick effects, but its nutrients are simple and its effects do not last long. Its nutrient components are single, and if used alone for a long time, it will make the potting soil compact, so it is better to use it together with organic fertilizer.

The complete home flower-growing technique set, teaching you step by step "watering, fertilizing, pest and disease control"

Rational fertilization

The principle of fertilization is timely and appropriate amounts. Timely means applying it when the flowers need it, such as applying fertilizer when the flower leaf color becomes lighter or the plant grows thin and weak. No matter when, the amount should be appropriate. Excessive fertilization will affect the growth and development of flowers. Too much nitrogen fertilizer makes the plant prone to excessive growth, with weak stems and leaves, affecting flowering and fruiting, and making it more susceptible to pests and diseases; too much phosphorus fertilizer will hinder flower growth and development and affect flowering and fruiting; too much potassium fertilizer makes the plant short, with wrinkled brown leaves, and even withering.

Change fertilization according to the growth stage of the flower seedlings. During the seedling stage, growth is rapid, so more nitrogen and potassium fertilizer should be applied to make the stems and branches sturdy and the root system well developed; before flowering and at bud formation, apply more phosphorus fertilizer to promote large flowers, beautiful colors, and full buds; spraying potassium dihydrogen phosphate during color change and after flowers fade can prevent flower and bud drop; during the flowering period and early fruit set, fertilizer and water should be controlled, otherwise flowers and fruits are prone to drop.

Change the fertilization concentration according to seasonal changes. In winter, the temperature is low and plant growth is slow. Most flowers are in a dormant or semi-dormant state, so generally no fertilizer is applied. Spring and autumn are peak growth seasons, so more topdressing should be applied appropriately. In summer, the temperature is high, water evaporates quickly, and flowers grow vigorously, so adhere to the principle of light fertilizer applied frequently. Organic fertilizer must be fully decomposed before application. The concentration of chemical fertilizer applied must not be too high, to prevent flowers from being "burned to death."

In different seasons, the fertilization time is different. Generally, in summer it is better to fertilize in the evening, and in winter it is better to fertilize around noon. Generally, fertilization can be done on sunny days when the climate is dry or before rain, and should not be done after rain or during continuous rainy days; apply more when the climate is warm and suitable for growth, and do not apply when the climate is hot or cold and the plant is semi-dormant or dormant; apply when the potting soil is dry, and do not apply when it is wet; apply more to old potting soil and less to newly changed potting soil; apply less when base fertilizer is sufficient, and apply more when there is no base fertilizer or it is insufficient.

Fertilize according to the characteristics of the flowers. For foliage-oriented flowers, such as pine, bamboo, and spider plant, nitrogen fertilizer is mainly used, which can promote the growth of branches and leaves and make the color deep green. For flowers mainly grown for their blooms and fruits, more fertilizer is needed. When growing branches and leaves, apply 1~2 times fertilizer mainly based on nitrogen fertilizer; at the growth stage of flower bud differentiation, flower bud formation, and before flowering, fertilizer mainly based on phosphorus fertilizer should be applied, which can make the flowers abundant and the fruits plentiful. Generally, for diseased or newly transplanted flowers, do not fertilize for the time being; for flowers in the flowering period, it is best not to fertilize, so as to avoid causing buds and flowers to drop.

The complete home flower-growing technique set, teaching you step by step "watering, fertilizing, pest and disease control"

Fertilization methods

Base fertilizer. There are generally 2 methods for applying base fertilizer: first, mix the fertilizer uniformly with the growing medium in a certain proportion (about 1:9) and then cultivate the flowers, which can both improve the physical properties of the soil and supply the nutritional needs of the flowers throughout the whole growth period. Second, when potting, repotting, or changing the soil of flowers, place a small amount of fertilizer at the bottom of the pot, generally not exceeding 1/10 of the potting soil, and cover it with 1 layer of soil above before planting the flowers.

Topdressing. There are generally 2 methods for topdressing: first, soil application, that is, applying fertilizer directly into the soil. For liquid topdressing, first dilute it and spray it onto the potting soil; for solid topdressing, it can be evenly scattered on the surface of the potting soil and then covered with 1 layer of soil. Note that after fertilizing, water should be applied to aid absorption. Second, leaf-surface spraying, also called foliar feeding, which has the advantages of saving fertilizer and taking effect quickly. It is usually used during the vigorous growth period of flowers or when they lack a certain element. Generally, inorganic fertilizer is prepared into a concentration of 0.1%~0.5% and sprayed in the morning or evening when there is no wind, so that the leaf surface is moistened. The most commonly used are urea, potassium dihydrogen phosphate, superphosphate, ferrous sulfate, etc.

The complete home flower-growing technique set, teaching you step by step "watering, fertilizing, pest and disease control"

3. Control of common pests and diseases

① Powdery mildew. Diagnosis of powdery mildew: small yellow transparent spots appear on the leaf surface, then gradually spread to the entire leaf, with white powdery spots appearing, and in the later stage the disease spots turn gray. It mainly harms many flowers such as Chinese rose, rose, dahlia, chrysanthemum, peony, cineraria, garden balsam, and banksia rose.

② Anthracnose. Diagnosis of anthracnose: yellow-brown sunken spots appear on the leaves and spread outward into dark brown round spots, or irregular patches appear on the leaves, and the leaf tips dry up and continuously spread downward. In the later stage, small black dots form on the disease spots, often arranged in concentric rings, and when the disease is severe, the leaves wither and die. It mainly harms many flowers such as orchid, rubber tree, Rosa species, cactus species, peony, jasmine, Dianthus, and fishtail palm.

③ Black spot disease. Diagnosis of black spot disease: nearly round or irregular black disease spots appear on the affected leaves and gradually expand. When severe, the leaves turn yellow and fall off, and even cause the plant to die. It mainly harms flowers such as Chinese rose, azalea, camellia, cherry, and elm-leaved spirea.

The complete home flower-growing technique set, teaching you step by step "watering, fertilizing, pest and disease control"

Control methods:

① Agricultural control. Strengthen cultivation management, appropriately apply more phosphorus and potassium fertilizer to enhance the disease resistance of the plant, and promptly remove diseased and fallen leaves and burn them, clean the environment, and reduce transmission vectors; pay attention to ventilation and light transmission.

② Chemical control. Spray 1:1:100 Bordeaux mixture at the early stage of disease for protection, to prevent the occurrence and development of the disease; at the early stage of disease, spray fungicides such as 50% carbendazim, 50% tecloftalam, 65% zineb, 75% chlorothalonil, 50% thiophanate at 500-fold dilution, and 50% benomyl at 1000-fold dilution.

Pests

① Aphids. Aphids, also known as greasy insects, can occur throughout the year and mainly harm bougainvillea, chrysanthemum, pomegranate, etc. The leaves of the affected plant curl, and the branches and leaves turn yellow, causing a large number of leaves and flowers to drop, and in severe cases causing the plant to die quickly.

Control method: Use 50g of red chili pepper, add 30~50g of water and soak for 24 hours, and spray the filtrate on the affected plant. The control effect is very good. Or spray 40% dimethoate emulsion at 2000~3000-fold dilution, 50% menazon emulsion at 1000~1500-fold dilution, or 80% dichlorvos emulsion at 3000-fold dilution.

② Red spider mites. Red spider mites, also called fire dragon insects, occur in multiple generations per year. They mainly harm the leaves and petals of wild elm, Japanese bush cherry, five-needle pine, etc. The body of the red spider mite is about the size of a needle tip, dark red or purple, and the naked eye can only see small red dots. The leaves of the affected plant lose their green color, and the leaf margins curl upward, so that they scorch and fall off, causing early shrinkage of flower buds, and in severe cases the plant dies.

Control method: Use 50g of citrus peel, add 0.5kg of water and soak for 24 hours, then filter and spray the plant, or spray dicofol at 1500-fold dilution or 40% omethoate at 2000-fold dilution for control. When spraying, spray both the front and back of the leaves for a better effect.

The complete home flower-growing encyclopedia, home flower-growing techniques and tips knowledge

Growing and raising flowers is one of the ways modern people entertain themselves. Growing flowers nourishes the spirit, and raising flowers calms the mind. Through the ages, there have been countless famous poems and lines praising flowers. Without having planted and raised them, one cannot understand this natural pleasure. However, what should be noted when growing and raising flowers?

First, you should grow suitable flowers. Some flowers are not only beautiful in appearance but can also absorb harmful gases indoors. For example, spider plant and aloe can absorb formaldehyde in newly decorated houses; wintersweet and Dianthus can absorb sulfur dioxide in the air; narcissus and chrysanthemum can absorb nitrogen oxides. Most flowers carry out photosynthesis during the day and release oxygen, while cactus is just the opposite. If they are grown together, the oxygen output can be maintained, which is good for body and mind.

Second, do not grow flowers with a strong fragrance or irritating or even toxic odors. Roses, lilies, and others have rich fragrances, but if too many are placed, they easily stimulate the brain and cause insomnia at night; the fragrance of tulips can cause diseases such as skin allergies; the stems, leaves, and petals of oleander are toxic, and if accidentally eaten, they can cause poisoning. Also, if there are too many flowers, they release a lot of carbon dioxide at night, which is also harmful to the human body.

Finally, your mindset for growing flowers should be well adjusted. Flowers are also life and need water and sunlight. Do not miss watering times, and do not leave them without sunlight for long periods; fertilize appropriately, and do not let flowers be bitten by mosquitoes and insects. At the same time, do not over-care for them, watering at every turn and handling them at every turn. Flowers need rest, and frequent disturbance easily makes them tired. Some people will not grow anything but rare and precious flower species, but most of these flowers have harsh growing conditions, and if these people themselves have no time or energy, it can only end in vain joy.

1.1 Choosing water quality

Home flower growing mostly uses tap water for watering, but tap water contains the disinfectant bleaching powder, and the chloride ions in it easily damage the tender root hairs of potted flowers. It must be stored for 1~2 days, and only after the chlorine gas has evaporated and the water temperature is close to the soil temperature can it be used to water flowers. Because the natural arrangement of water molecules in magnetized water has been disrupted by the magnetic field, it is similar to the water molecules in plant cells and is easily absorbed and used by plants, so potted flowers are best watered with magnetized water.

1.2 Watering amount

1.2.1 Watering principle

The principle of watering is “water thoroughly when you water, and water thoroughly without letting it leak out,” that is, each time water until water seeps out from the saucer under the pot. In addition, it should also be determined according to the size, depth, and texture of the flower pot. Small pots are shallow, so watering should be less and more frequent; clay pots have good water permeability, and the potting soil dries easily, so water frequently; stone pots and glazed pots do not easily permeate water, and with long-term water accumulation, flowers will rot at the roots.

1.2.2 Watering period

Different flowers and trees have different watering periods. The first is the "prefer wet over dry" type, referring to flowers and trees that will be damaged and die after the potting soil completely dries out. Such flowers and trees should be watered sufficiently when the potting soil is slightly dry, such as maidenhair fern and brake fern; the second is the "prefer dry over wet" type, referring to flowers and trees that should be watered after the potting soil dries completely, such as cactus and aloe; the third is the "alternately dry and wet" type, referring to flowers and trees that should be watered immediately when the surface of the potting soil is dry to about 3cm, such as monstera and pothos.

1.2.3 Watering season

In early spring when it turns warm, the weather is changeable. At this time, potted flowers begin to sprout and take root and need a large amount of water, so the potting soil should be kept moist; summer is dry and evaporation is fast, so watering should be doubled; in autumn, watering should be appropriately reduced to avoid excessive growth of flower branches, which would affect flowering the 2nd year; in winter, most flowers and trees are in a dormant state, so keeping the potting soil slightly dry is enough.

1.3 Watering time

The daily time for watering flowers differs in spring, summer, autumn, and winter. As the flower proverb says, “Morning water is sweet dew, noon water is arsenic, evening water is a life-saving soup.” This means that in spring and autumn, around 10 a.m. and after 4 p.m. are suitable times to water flowers, while in summer never water flowers at noon. At noon in midsummer, the temperature is highest and the difference between the potting soil and water temperature is greatest. Watering flowers at this time can easily block the normal physiological activities of the root system, weaken the root system's absorption of water, cause physiological drought, and make the branches and leaves wilt. By the same reasoning, in winter it is better to water flowers at noon. In short, “water at noon in spring, morning and evening in summer, every other day in autumn, and check frequently in winter.

1.4 Watering methods

Before watering potted flowers, the compacted potting soil must be loosened so that the water can be absorbed in time and will not overflow from the edge of the pot. It is best to use a fine-hole watering can to water evenly and thoroughly. For small potted flowers, the best watering method is the pot-soaking method, that is, placing the flower pot into a larger water basin so that water seeps into the potting soil from the drainage holes, and after the surface of the potting soil is slightly wet, taking it out. This can prevent the potting soil from compacting due to watering and is beneficial to the root respiration of potted flowers. Generally, shade-loving foliage potted flowers, under the special environment of a dry room and covered with dust, often find it difficult to show their bright true colors. In addition to regular watering, the leaf-surface irrigation method of sprinkling water to wash off dust and spraying water to moisten leaves should also be adopted. This method can also lower the temperature and relieve heat for potted flowers at noon in summer, and help semi-dormant flowers break dormancy and continue to bloom well.

2.1 Types of fertilizer

2.1.1 Organic fertilizer

Organic fertilizer is fertilizer formed from the seeds, organs, remains, or excrement of various plants and animals after processing and decomposition, such as human and animal manure and urine, livestock and poultry manure, oilseed meal, distiller's grains, and weed green manure. Organic fertilizer is a slow-release fertilizer with complete nutrients and long-lasting effects. It must be fermented and decomposed before use.

2.1.2 Inorganic fertilizer
Inorganic fertilizer is fertilizer made by chemical synthesis or processing of natural minerals, such as urea, superphosphate, and potassium dihydrogen phosphate. Inorganic fertilizer has quick effects, but its nutrients are simple and its effects do not last long. Its nutrient components are single, and if used alone for a long time, it will make the potting soil compact, so it is better to use it together with organic fertilizer.

2.2 Rational fertilization

2.2.1 Fertilization principle

The principle of fertilization is timely and appropriate amounts. Timely means applying it when the flowers need it, such as applying fertilizer when the flower leaf color becomes lighter or the plant grows thin and weak. No matter when, the amount should be appropriate. Excessive fertilization will affect the growth and development of flowers. Too much nitrogen fertilizer makes the plant prone to excessive growth, with weak stems and leaves, affecting flowering and fruiting, and making it more susceptible to pests and diseases; too much phosphorus fertilizer will hinder flower growth and development and affect flowering and fruiting; too much potassium fertilizer makes the plant short, with wrinkled brown leaves, and even withering.

2.2.2 Fertilization period

During the seedling stage, growth is rapid, so more nitrogen and potassium fertilizer should be applied to make the stems and branches sturdy and the root system well developed; before flowering and at bud formation, apply more phosphorus fertilizer to promote large flowers, beautiful colors, and full buds; spraying potassium dihydrogen phosphate during color change and after flowers fade can prevent flower and bud drop; during the flowering period and early fruit set, fertilizer and water should be controlled, otherwise flowers and fruits are prone to drop.

2.2.3 Fertilization season

In winter, the temperature is low and plant growth is slow. Most flowers are in a dormant or semi-dormant state, so generally no fertilizer is applied. Spring and autumn are peak growth seasons, so more topdressing should be applied appropriately. In summer, the temperature is high, water evaporates quickly, and flowers grow vigorously, so adhere to the principle of light fertilizer applied frequently. Organic fertilizer must be fully decomposed before application. The concentration of chemical fertilizer applied must not be too high, to prevent flowers from being “burned to death.”

2.2.4 Fertilization time

In different seasons, the fertilization time is different. Generally, in summer it is better to fertilize in the evening, and in winter it is better to fertilize around noon. Generally, fertilization can be done on sunny days when the climate is dry or before rain, and should not be done after rain or during continuous rainy days; apply more when the climate is warm and suitable for growth, and do not apply when the climate is hot or cold and the plant is semi-dormant or dormant; apply when the potting soil is dry, and do not apply when it is wet; apply more to old potting soil and less to newly changed potting soil; apply less when base fertilizer is sufficient, and apply more when there is no base fertilizer or it is insufficient.

2.2.5 Fertilizing according to the characteristics of the flowers

For foliage-oriented flowers, such as pine, bamboo, and spider plant, nitrogen fertilizer is mainly used, which can promote the growth of branches and leaves and make the color deep green. For flowers mainly grown for their blooms and fruits, more fertilizer is needed. When growing branches and leaves, apply 1~2 times fertilizer mainly based on nitrogen fertilizer; at the growth stage of flower bud differentiation, flower bud formation, and before flowering, fertilizer mainly based on phosphorus fertilizer should be applied, which can make the flowers abundant and the fruits plentiful. Generally, for diseased or newly transplanted flowers, do not fertilize for the time being; for flowers in the flowering period, it is best not to fertilize, so as to avoid causing buds and flowers to drop.

2.3 Fertilization methods

2.3.1 Base fertilizer

There are generally 2 methods for applying base fertilizer: first, mix the fertilizer uniformly with the growing medium in a certain proportion (about 1:9) and then cultivate the flowers, which can both improve the physical properties of the soil and supply the nutritional needs of the flowers throughout the whole growth period. Second, when potting, repotting, or changing the soil of flowers, place a small amount of fertilizer at the bottom of the pot, generally not exceeding 1/10 of the potting soil, and cover it with 1 layer of soil above before planting the flowers.

2.3.2 Topdressing

There are generally 2 methods for topdressing: first, soil application, that is, applying fertilizer directly into the soil. For liquid topdressing, first dilute it and spray it onto the potting soil; for solid topdressing, it can be evenly scattered on the surface of the potting soil and then covered with 1 layer of soil. Note that after fertilizing, water should be applied to aid absorption. Second, leaf-surface spraying, also called foliar feeding, which has the advantages of saving fertilizer and taking effect quickly. It is usually used during the vigorous growth period of flowers or when they lack a certain element. Generally, inorganic fertilizer is prepared into a concentration of 0.1%~0.5% and sprayed in the morning or evening when there is no wind, so that the leaf surface is moistened. The most commonly used are urea, potassium dihydrogen phosphate, superphosphate, ferrous sulfate, etc.

3.1 Diseases

3.1.1 Diagnosis and harm

① Powdery mildew. Diagnosis of powdery mildew: small yellow transparent spots appear on the leaf surface, then gradually spread to the entire leaf, with white powdery spots appearing, and in the later stage the disease spots turn gray. It mainly harms many flowers such as Chinese rose, rose, dahlia, chrysanthemum, peony, cineraria, garden balsam, and banksia rose.

② Anthracnose. Diagnosis of anthracnose: yellow-brown sunken spots appear on the leaves and spread outward into dark brown round spots, or irregular patches appear on the leaves, and the leaf tips dry up and continuously spread downward. In the later stage, small black dots form on the disease spots, often arranged in concentric rings, and when the disease is severe, the leaves wither and die. It mainly harms many flowers such as orchid, rubber tree, Rosa species, cactus species, peony, jasmine, Dianthus, and fishtail palm.

③ Black spot disease. Diagnosis of black spot disease: nearly round or irregular black disease spots appear on the affected leaves and gradually expand. When severe, the leaves turn yellow and fall off, and even cause the plant to die. It mainly harms flowers such as Chinese rose, azalea, camellia, cherry, and elm-leaved spirea.

3.1.2 Control

① Agricultural control. Strengthen cultivation management, appropriately apply more phosphorus and potassium fertilizer to enhance the disease resistance of the plant, and promptly remove diseased and fallen leaves and burn them, clean the environment, and reduce transmission vectors; pay attention to ventilation and light transmission.

② Chemical control. Spray 1:1:100 Bordeaux mixture at the early stage of disease for protection, to prevent the occurrence and development of the disease; at the early stage of disease, spray fungicides such as 50% carbendazim, 50% tecloftalam, 65% zineb, 75% chlorothalonil, 50% thiophanate at 500-fold dilution, and 50% benomyl at 1 000-fold dilution.

3.2 Pests

3.2.1 Aphids

Aphids, also known as greasy insects, can occur throughout the year and mainly harm bougainvillea, chrysanthemum, pomegranate, etc. The leaves of the affected plant curl, and the branches and leaves turn yellow, causing a large number of leaves and flowers to drop, and in severe cases causing the plant to die quickly.

Control method: Use 50g of red chili pepper, add 30~50g of water and soak for 24 hours, and spray the filtrate on the affected plant. The control effect is very good. Or spray 40% dimethoate emulsion at 2 000~3 000-fold dilution, 50% menazon emulsion at 1 000~1 500-fold dilution, or 80% dichlorvos emulsion at 3 000-fold dilution.

3.2.2 Red spider mites

Red spider mites, also called fire dragon insects, occur in multiple generations per year. They mainly harm the leaves and petals of wild elm, Japanese bush cherry, five-needle pine, etc. The body of the red spider mite is about the size of a needle tip, dark red or purple, and the naked eye can only see small red dots. The leaves of the affected plant lose their green color, and the leaf margins curl upward, so that they scorch and fall off, causing early shrinkage of flower buds, and in severe cases the plant dies.

Control method: Soak 50 g of citrus peel in 0.5 kg of water for 24 hours, then filter and spray the solution onto the plants, or spray with dicofol at a 1:1500 dilution or 40% omethoate at a 1:2000 dilution for control. When spraying, spray both the upper and lower leaf surfaces for a better effect.