Handbook for the Prevention and Control of Flower Diseases and Pests

Table of contents

★Pest and Disease Control
★Pest and Disease Control Tips
★Control Two Small Pests ★Pest and Disease
Control for Foliage Plants ★
Symptoms of Viral Diseases in Flowers ★Knowledge of Typical Diseases and Control for Houseplants ★What to Do When Potted Plants Have Insects? ★How to Treat Diseases in Potted Plants by Examining Leaves ★Eliminating Earthworms from Potting Soil ★ Many Causes of Yellowing Leaves in Potted Plants★Prevention and Control of Rot Disease in Succulent Flowers ★How to Deal with Ants in Flower Pots ★Trunk Injection Can Prevent Pests and Diseases ★Tips for Preventing Flower Diseases ★Preparation and Use of Wound Protectants for Flowers and Trees ★Four Methods for Making Your Own Insecticide

[Pest and Disease Control]

When growing plants at home, the last thing you want to see is pests and diseases. However, plants are living things and can get sick and infected. Therefore, homeowners should adopt the concept of "prevention is better than cure" to ensure their plants grow quickly and healthily. Understanding how to avoid and prevent pests and diseases is therefore very important!

Choose healthy, disease-free plants: When purchasing plant bulbs and seedlings at the flower market, carefully check for signs of rot or pests. Examine the undersides of the leaves for any moving organisms. Of course, a robust plant is more resistant to disease and less prone to infection.

Separate from the original plants: Do not move newly brought plants indoors immediately. You can spray some insecticides and fungicides on the outside of the window to check if the plants are healthy and to prevent pests and diseases from being introduced into the original plant population or home environment.

Proper water control is essential: too much moisture can easily cause the plant to rot and mold, while too little moisture can attract insects that prefer dry environments, such as spider mites. The amount of water should be adjusted according to the plant's characteristics and the temperature and humidity of the environment. It is best to wait until the top 2-3 cm of soil is dry before thoroughly watering the medium, continuing until water flows out.

Do not plant too many similar plant groups at once or too close together: for example, mites that harm Africa can also harm plants like sagebrush and gloxinia. If they are placed together or in large groups, the pests will have abundant hosts to live and shelter from, and their reproduction rate will be very fast. In addition, the plants should be spaced sufficiently apart; overcrowding and close proximity make them more susceptible to disease.

Treat diseased plants immediately upon discovery: If the disease is on the leaves, remove and clean them immediately. Otherwise, if the pest population spreads, it will harm the entire plant and even nearby similar hosts. Some pests can jump to other plants, so diseased plants must be completely destroyed and discarded to prevent the disease from spreading.

【Pest and Disease Control Tips】

▲Follicular Fertilizer Mixed with Pesticides: A Two-in-One Effect. Experiments have shown that spraying Chinese locust, black locust, and ash trees with 0.5% urea and 0.3% dimethoate can achieve the dual effects of fertilization and pest control. Urea is easily absorbed and has strong penetrating power, enhancing the efficacy of the pesticide. After foliar spraying, the tree leaves turn green, the tree vigor is strengthened, and aphids and other pests are effectively controlled.

▲The systemic insecticide applied in a ring is effective in controlling aphids. Dimethoate concentrate was applied to the trunk at a height of 1.2 meters, forming a 20cm ring. After three days, the results were checked. In the control group of 6 trees treated with plain water, there were over 50 aphids within 1cm of the branch. However, in the control group of 16 trees treated with the ring, only 2 aphids were observed. The leaves of the poplar trees treated with dimethoate were bright and the effect lasted for a month.

▲Experience in controlling trunk-boring pests by plugging holes with pesticides. The main trunk-boring pests in Dezhou City include the shoulder-tailed longhorn beetle, the Mongolian wood-boring moth, and the oriental wood-boring moth. Other pests include the spiny-horned longhorn beetle, the poplar clearwing moth, the cloud-patterned longhorn beetle, and the Chinese longhorn beetle. A simultaneous test was conducted using cotton balls soaked in undiluted phosmet and undiluted dimethoate to plug holes in willow trees on both sides of the road. The mortality rate for larvae was 95% with phosmet and 92% with dimethoate.

▲ Soil irrigation with systemic insecticides for aphid control: Observations of root irrigation with pesticide solutions on Sophora japonica showed that 10-20 ml of phorate per plant was effective in controlling aphids, while trunk application was ineffective. 10 ml of dimethoate per plant was recommended for root irrigation, resulting in better aphid control. Both of these systemic insecticides have a residual effect of over one month, and the insect population reduction rate is over 80%.

[Control of Two Small Pests]

Potted plants are frequently damaged by aphids and spider mites. Both pests are notorious for their small size, large numbers, and rapid reproduction. They primarily affect many flowers, including those in the Asteraceae, Rosaceae, Crassulaceae, Asclepiadaceae, Theaceae, and Cactaceae families. The method of elimination is spraying pesticides. However, the application of pesticides requires careful consideration. For example, dichlorvos is ineffective in eradicating the pests and often causes yellowing leaves in cherry blossoms and peach blossoms; methamidophos often causes blackening of the leaves of dwarf coconut palms; and dimethoate causes leaf drop in plum blossoms, fragrant clover, and coral flowers. Through years of practical experience, I have found that the most effective pesticides for eradicating these two small pests are dicofol and fenvalerate. The method of application is compound spraying and continuous application. The specific operation procedure is as follows: After filling a 15 kg container with clean water, add half a packet of "One-Way Cleaner", three bottle caps of dicofol, two vials of "Insecticide King", and an appropriate amount of dissolved carbendazim (topazin and zineb are also acceptable and can be used alternately). You can also add two vials of "Spray Treasure" or one vial of "Green Smoke" (both are foliar fertilizers). The aphid and acar control rates of the above-mentioned pesticides are 100%, and there is absolutely no phytotoxicity. Apply from April to December. Spray once every 45 days to ensure that aphids are eradicated from potted plants, spider mites are killed, and stem borers are also killed, and diseases such as sooty mold, black spot, and powdery mildew are treated.

[Pest and Disease Control for Foliage Plants]

Foliage plants are susceptible to pests and diseases during their growth. Affected plants not only suffer from impaired growth but also lose or even their ornamental value. Therefore, pest and disease control for indoor foliage plants is essential and a fundamental skill for all plant enthusiasts; otherwise, the true purpose of foliage plants—beautifying and purifying the environment—is lost.
　　While there are many types of indoor foliage plants, the number used in each unit or household is relatively small, requiring meticulous management. Although pests and diseases may not easily spread to other plants, they often develop rapidly on affected plants. Therefore, the main methods for controlling pests and diseases in these plants are prevention, integrated pest management, and strengthening cultivation management; creating a good plant ecological environment to promote healthy plant growth and enhance their own resistance are also effective cultivation measures.

　　Before bringing any indoor foliage plants indoors, they should be thoroughly inspected. Select adaptable, disease-resistant varieties or healthy plants and arrange them appropriately. If minor diseased leaves or a small number of aphids, mites, or scale insects are found, treat them promptly using physical methods such as manual pruning to remove diseased leaves, washing with soapy water followed by rinsing with clean water, or wiping with a soft, damp cloth. Scale insects can also be gently scraped off with a bamboo skewer. If the infestation is severe, remove the plant from the indoor environment.

　　Indoor foliage plants should not be treated with pesticides indoors, as pesticides are generally toxic substances. Allowing these toxic substances to remain in or be introduced into the indoor air circulation system will lead to various adverse consequences. Indoor foliage plants, as decorative items, often attract people to admire their various characteristics; some may smell them, while others may touch their leaves. To maintain a healthy public interest, regulations should stipulate that indoor decorative plants should not be treated with pesticides for pests and diseases. If some plants are infested with pests or diseases, and physical methods are ineffective, they must be moved outdoors to isolate them from healthy indoor plants before further treatment, such as chemical control or destruction. Indoor plants must be inspected regularly, and timely treatment and prevention are essential to reduce the extent of damage and prevent future problems. Maintaining cleanliness, ventilation, and light in the indoor environment will keep foliage plants green, fresh, and retain their high ornamental value.

[Symptoms of Floricultural Viral Diseases]

Floricultural viral diseases are a special type of disease caused by viruses that harm flowering plants. These diseases differ significantly from common diseases in terms of symptom characteristics, occurrence patterns, and control measures. With the development of domestic and international flower trade, the circulation of seedlings, and self-propagation of seedlings, viral diseases have become a very prominent problem. In recent years, they have risen to the second most prevalent status after fungal diseases, and this trend is gradually worsening. They affect the yield and quality of flowers, as well as their export earnings.

　　I. Symptoms of Flora Viral Diseases

　　Viruses are a tiny type of parasite that can harm many precious flowers, such as daffodils, orchids, carnations, lilies, dahlias, tulips, peonies, herbaceous peonies, chrysanthemums, gladioli, and gerberas.

　　The morphological characteristics that plants gradually exhibit after being damaged by viruses are called external symptoms. External symptoms can be divided into local symptoms and systemic symptoms based on their distribution on tissues such as leaves. Local symptoms refer to the spots that appear around the infection point after the virus is inoculated into plant leaves; these can be categorized as chlorotic spots, necrotic spots, or ring spots. Systemic symptoms refer to the symptoms that occur in tissues such as leaves, stems, and fruits after the virus infects the host and can transport throughout the entire plant.

　　1. Color change

　　There are three types of mosaic symptoms: variegated, mottled, and fragmented. Uneven chlorosis caused by viral infection is called mosaic symptom; mottled refers to large, indistinct, and unevenly distributed chlorotic spots on diseased leaves; fragmented discoloration occurs when the color appears on petals or fruits. Camellia virus infection causes yellow mottled or chlorotic spots on leaves, creating a yellow-green mosaic pattern. When rose leaves are affected by the virus, the leaves become smaller, and ring-shaped and wavy pale yellow patterns appear along the midrib. Mottled foliage is a major cause of yield and quality loss in flowering plants.

　　2. Fading green, yellowing

　　The entire plant or parts of its organs may turn light green or yellow, but the yellowing is not as widespread as in mosaic disease. For example, chrysanthemum mosaic disease manifests as indistinct, pale green mottling on the leaves.

　　3. Spots, stripes

　　It commonly occurs on leaves, stems, and fruits, manifesting as necrotic spots, necrotic streaks, chlorotic spots, or chlorotic streaks. Peony virus type 1 causes annular and linear spots on leaves and stems, damaging peonies through various necrotic spots. Narcissus pattern virus causes pale or yellow streaks and patches on leaves and stems.

　　4. Ring spots, oak leaves, and etched patterns

　　These three conditions mostly appear on leaves. Concentric spots are called "ring spots." Discoloration along the veins resembling oak leaves is called "oak leaf." Irregular linear markings on the leaves are called etch marks. For example, tobacco ring spot virus produces ring spots, while tobacco etch mark virus produces etch marks.

　　5. Clear pulse, yellow pulse, pulse belt

　　Clear veins and yellow veins are the early stages of mosaic symptoms. First, the veins become transparent, which is called "clear veins," and then the veins turn yellow, which is called "yellow veins." "Vein bands" refer to the dark green color along the veins. For example, chrysanthemum vein mottle disease manifests as fading of green along the veins, showing the symptoms of clear veins.

　　6. Wrinkled leaves, curled leaves

　　Deformation of local tissues or organs. Vein growth is inhibited, while leaf tissue continues to grow, resulting in wrinkled leaves and upward or downward curling of leaf edges. For example, in canna mosaic virus, yellow streaks appear along the veins, gradually turning brown and tearing at the affected areas. In severe cases, the central leaves become deformed, curling inward into a trumpet shape, and the plant becomes stunted, failing to flower or producing very few flowers. Similarly, in lily clump disease, leaves turn yellow at the base of the clump, flower stalks fail to form, leaves become smaller, twisted, and drooping, resulting in deformed flowers or no flowers at all.

　　7. Clumping, dwarfing

　　In diseased plants, the terminal bud is suppressed, while lateral buds sprout in large numbers, resulting in bushy branches, a condition known as "clumping" or "bush branching." Shortened internodes and a uniformly stunted plant are termed "dwarfing." Viral infection often causes plants to become smaller, exhibiting symptoms such as stunting, bushing, and twisting. Sometimes, viral infection does not show obvious symptoms; this is called latent infection. Plant dwarfing often reduces leaf size, internode spacing, and the number of leaves, and may also cause smaller fruits and seeds due to reduced cell division and slowed growth.

　　8. Deformity

　　Viral infection can cause abnormal development in the host, a condition known as malformation. For example, when WTV infects white clover, it produces tumor-like growths on the stem; pea auricle mosaic virus (PEWV) infects cowpea and produces auricles.

　　9. Necrosis

　　Necrosis refers to the death of tissues, organs, or the entire plant, such as tobacco necrosis virus. PVX and PVY can also cause necrosis. When the virus infects the host, necrosis quickly spreads to the growing point cells and is killed, followed by the wilting and death of the entire leaf. When tomatoes are mixed-infected with TMV and CMV, the plant tip necroses, and the leaves become smaller.

　　Dahlia virus disease causes pale green ring spots on leaves, mosaic malformation, shortened internodes, and lateral branch growth, resulting in bushy growth, dwarfing, and very few or no flower buds.

　　II. Distinguishing symptoms of viral diseases from those of other diseases

　　Viral diseases are easily confused with non-infectious diseases, especially those caused by nutrient deficiencies or air pollution, due to their symptom characteristics. Viral-infected plants are often scattered in the field, with healthy plants nearby. Once infected, these plants often cannot recover. Non-infectious diseases, on the other hand, usually spread in patches and can be managed by increasing nutrition and improving environmental conditions. Floriculture viruses only show obvious symptoms without actual disease manifestations. Viral disease symptoms are often mosaic and yellowing, and they frequently present as systemic infections, with less rot and wilting. Of course, viral symptoms can also change; different viruses may exhibit different symptoms on different host species and varieties, and some viral diseases may develop latent symptoms due to changes in temperature, etc.

　　It should be noted that many phenomena on garden plants that resemble variegated leaf symptoms (viral diseases) are not actually viral diseases, but rather a special type of plant with high ornamental value. Examples include variegated lily, golden-edged large-leaved boxwood, variegated galangal, variegated clivia, and variegated orchids. Therefore, they should not be confused.

[Typical Diseases and Prevention Knowledge for Houseplants]

　 The basic principle for preventing diseases in houseplants is prevention first, followed by targeted treatment. The following aspects should be considered when caring for plants:
　　1. Strengthen plant quarantine: Harmful seedlings and propagation materials should be strictly prohibited from entering the home to prevent the spread of disease.

　　2. Directly eliminate diseases: When diseases occur, treat them with pesticides in a timely manner and try to kill the diseases in a short period of time.

　　3. Improve environmental conditions to inhibit the growth and reproduction of harmful bacteria: High temperature and formalin can be used to disinfect the soil. At the same time, a good environment should be created, such as reasonable fertilization and watering, timely loosening of soil and weeding, pruning and trimming of branches and leaves, removal of diseased branches and leaves, improvement of light, and maintenance of ventilation, so that the flowers can grow and develop healthily and improve their disease resistance.

　　Most flower enthusiasts should know that there are many causes of plant diseases, each with different harms, and they cannot be generalized. Various diseases are frequently encountered during flower cultivation. The causes of plant diseases are numerous, mainly due to infection by harmful organisms such as fungi, bacteria, viruses, mycoplasma, nematodes, algae, and parasitic seed plants, as well as the influence of adverse environments. These mainly include the following:

　　I. Physiological Diseases: These are caused by abiotic factors such as unsuitable environmental conditions like temperature, humidity, soil, and fertilizer, leading to physiological abnormalities and diseases in flowers. Common symptoms include leaf discoloration, yellowing, scorching of leaf tips and edges, leaf drop, and flower and fruit drop. These symptoms will usually subside if the environmental factors are changed, and the flowers will gradually grow stronger. In this case, no chemical treatment is needed.

　　II. Invasive Diseases:

　　1. Control of fungal diseases: Fungi are multicellular lower plants without chlorophyll. They can parasitize flowers and also saprophytically live on dead bodies. Their spores are spread by wind, rain, and insect bodies, such as powdery mildew, rust, black spot, damping-off, sooty mold, white mold, sclerotinia rot, etc. Prevention and control of fungal diseases (1) Powdery mildew, anthracnose, black spot, brown spot, leaf spot, gray mold and other diseases: First, reasonable fertilization and watering, pay attention to ventilation and light, excessive or frequent watering, water accumulation after rain or poor drainage of the bottom hole of the pot, poor soil quality and long-term lack of repotting and soil replacement, etc., can also cause fungal flower diseases, which often start from the roots turning black. Because the vascular tissues of leaves and roots are connected, if the roots have problems, it will inevitably be reflected on the branches and leaves. Therefore, attention should also be paid to soil quality, water and drainage performance. In addition, the application of uncomposted organic fertilizer can also easily cause diseases. When using domestic organic waste to make fertilizer, you can add Jinbaobei biological fermentation agent (Jinbaobei organic material composting agent). It can accelerate composting and also kill the pathogens in it. Second, remove dead branches and fallen leaves in early spring or late autumn and prune and burn diseased branches and leaves in time; third, spray 65% zineb at 600 times dilution for prevention; fourth, spray 50% carbendazim or 50% thiophanate-methyl at 500 to 600 times dilution, or 75% chlorothalonil at 600 to 800 times dilution in the early stage of disease. (2) Sooty mold: First, wipe the diseased branches and leaves with clean water and spray 50% carbendazim at 500 to 800 times dilution after the disease occurs; second, avoid water accumulation. (3) Rust: In addition to the above methods, spray 97% sodium chlorate at 250 to 300 times dilution (with 0.1% laundry detergent) or 25% triadimefon at 1500 to 2500 times dilution after the disease occurs. (4) White rot and sclerotinia: First, treat the soil with 1% formalin solution or 70% pentachloronitrobenzene, about 5 to 8 grams of pentachloronitrobenzene per square meter, mixed with 30 times the amount of fine soil and applied to the soil; second, select disease-free seedlings or soak them in 500 times the amount of 70% carbendazim solution for 10 minutes before planting; third, water properly and avoid waterlogging. (5) Damping-off and root rot: First, disinfect the soil by treating it with 1% formalin or steaming the potting soil in a pot for 1 hour; second, avoid waterlogging; third, at the early stage of the disease, irrigate the root zone with 300 to 400 times the amount of 50% mancozeb solution, using 2 to 4 kg of the solution per square meter.

　　2. Prevention and control of bacterial diseases: Bacteria are single-celled microorganisms that often spread through flowing water, rainwater, insects, seed bacteria, soil and diseased plant residues. They invade the plant through stomata or wounds, causing diseases such as soft rot, bacterial wilt, crown gall, and bacterial spot disease. (1) Methods for preventing and controlling soft rot: First, potted plants should be replaced with new potting soil once a year; second, after the disease occurs, the soil around the roots of the diseased plant should be irrigated with 600-800 times diluted dichlorvos solution. (2) Bacterial spot disease: First, spray 65% zineb at 600 times dilution before the disease occurs for prevention; second, remove and burn the affected parts in time; third, spray 50% thiophanate-methyl at 800-1000 times dilution at the initial stage of the disease. (3) Crown gall disease: First, select disease-free seedlings or treat the soil with pentachloronitrobenzene when planting; second, cut off the gall immediately after the disease occurs and disinfect with 0.1% mercury solution.

　　3. Viral Disease Control: Viruses are tiny, cell-free parasites that infect plants through mechanical damage such as insects, grafting, cuttings, and pruning. Symptoms in infected flowers include mosaic patterns, necrotic spots, yellowing leaves, deformities, and bushy growth. These viruses overwinter in seeds, diseased plant debris, soil, and insects. Prevention is key to controlling viral diseases, and a comprehensive approach is essential. Methods for controlling diseases and pests include: First, soil disinfection. Burnt soil or formalin (40%) diluted 50-300 times can be sprayed onto the soil, then covered with plastic film. After 5 days, the soil should be turned over, and after 3 days, it can be used as potting soil. Second, heat treatment is necessary; for example, seeds can be soaked in 50℃-55℃ warm water for 10-15 minutes. Third, selecting disease-resistant and superior varieties is the fundamental way to control viral diseases. Strictly select non-toxic propagation materials; fourth, spray 40% dimethoate emulsion at appropriate times (1000-1500 times dilution) to eliminate aphids, whiteflies, and other virus-transmitting insects; fifth, promptly remove and burn diseased plants, and wash hands and tools that have come into contact with diseased plants with soapy water to prevent human-to-human transmission; sixth, remove weeds to reduce sources of virus infection, and pay attention to ventilation and light penetration, and apply fertilizer and water appropriately to promote healthy flower growth, all of which can reduce viral diseases.

　　4. Nematode Disease Control: Nematodes are tiny roundworms that parasitize the roots of plants. They pierce root cells with their spear-shaped proboscis, causing nodular growths known as nematode disease. Control methods mainly include: First, soil disinfection: steam the potting soil for about 2 hours. Second, hot water treatment: soak the infected parts used for propagation in hot water (10 minutes at 50°C; 5 minutes at 55°C) to kill nematodes without harming the host. Third, turning and sun-drying the soil several times during the hottest days of summer can eliminate a large number of pathogenic nematodes. Fourth, removing diseased plants, plant debris, and wild host plants. Fifth, proper fertilization and watering to promote healthy plant growth can also significantly reduce nematode infestation.

[What to do if potted plants have worms?] **

Soapy water for aphid control:** Add a small amount of laundry detergent or soap (preferably medicated soap) to a basin halfway filled with water. After stirring to create lather, press the branches of potted plants into the soapy water to rinse them, or use a soft brush to apply the soapy water to the branches and leaves. After a few days, aphids, scale insects, spider mites, and other pests will be eliminated. **Cigarette butt water for whitefly control:** Spraying a solution of soaked cigarette butts to create a brown nicotine solution onto the branches and leaves is very effective in controlling whiteflies. Whiteflies hatch larvae year-round, emerging as adults with white waxy wings. They can fly short distances, reproduce rapidly, and are highly damaging to flowers, especially hibiscus, roses, and hydrangeas. **Garlic for rodent control:** Crush a head of garlic, preferably with a tablespoon of pepper, and mix it in a liter of water. Let it sit for an hour, then spray the leaves and branches of your plants. Rats and other animals will avoid the smell of garlic, preventing them from damaging the leaves.

Beer to repel snails: Place a small, shallow dish on the soil of potted plants, pour beer into the dish, and the snails will crawl into the dish and drown. Milk to repel ticks: Mix half a cup of whole milk with four cups of flour and 20 liters of water, strain the liquid through cheesecloth, and spray it on the leaves and branches to kill most ticks and their eggs. These methods for protecting potted plants are simple, easy to implement, do not affect the growth of the plants, and do not pollute the air.　

How to treat diseases in potted plants by examining their leaves

If potted plants are not properly cared for, their leaves will turn yellow, wither, and curl. Observing changes in the leaves can help identify problems in the care process and allow for appropriate measures to be taken.

　　Yellowing of young leaves, curling and withering of lower leaves, and continuous leaf drop are generally caused by overwatering. Potted plants should be watered only when the soil is dry to the touch; if water accumulates in the pot, it should not remain for more than half an hour, otherwise root health will be affected. Sometimes, yellowing of young leaves in potted plants is due to a lack of certain nutrients. If the leaves are yellow but the veins are still green, it is caused by iron deficiency. In this case, ferrous sulfate can be applied. A mixture of 3 parts silty sand and 1 part commercially available well-rotted nitrogen and phosphorus fertilizer can also be effective.　

　　Old leaves turning yellow and new leaves growing very small indicates a lack of nitrogen, phosphorus, or potassium in the potting soil. You can apply some well-rotted organic fertilizer or commercially available fertilizer tablets to supplement these nutrients.

　　If the tips of young leaves are scorched, check if the potting soil is too dry, or if the light is too strong or the temperature is too high, which may scorch the plant.

　　Shrinking of new shoot tips, pale yellowing of young leaves, and dark yellowing of older leaves are mostly caused by waterlogging and lack of oxygen in the potting soil, as well as root rot. The soil should be loosened immediately, fertilization stopped, and watering reduced. If the new leaves at the top are normal in color, but the lower leaves gradually dry out, turn yellow, fall off, or wither and scorch upwards, then it indicates a lack of water.

　　Scorched leaf edges are often caused by over-fertilization or improper watering. You can rinse the potting soil several times with clean water to allow the dissolved fertilizer to drain out through the drainage holes.

　　If the edges of the leaves curl, wrinkle, and turn brownish-red, this is mostly caused by excessively dry indoor air. You should frequently spray the leaves with water at room temperature; or use a double-pot method, placing the flowerpot inside another larger pot and stuffing the space between the two pots with damp straw ash or damp old cloth strips to create a more humid microclimate around the potted plant.

Removing earthworms from potting soil

Earthworms are beneficial to outdoor garden plants, but they can hinder root growth in potted plants and cause the soil to dry out easily by burrowing too much. If earthworms are found in potted plants, the plant should be removed from the pot, the earthworms dug out, or the soil can be watered with a mustard solution. Alternatively, a few tender leaves from a thornless locust tree can be crushed, the juice extracted, and watered to force the earthworms out of the soil for removal.

                         [Many Reasons for Yellowing Leaves in Potted Plants]

      Overwatering: Prolonged waterlogging and waterlogging can suffocate and rot the roots, preventing them from absorbing water and nutrients properly, leading to yellowing and even leaf drop. If yellow leaves are observed, immediately stop watering and fertilizing, loosen the soil, and place the plant in a well-ventilated, dry place to accelerate evaporation. Watering should adhere to the principle of "watering thoroughly only when the soil is dry to the touch," avoiding sporadic watering. Furthermore, avoid

　　spraying water on the flowers during the flowering period and protect the plant from heavy rain. If a plant is dehydrated and its leaves droop, immediately spray water on the leaves to accelerate water absorption, then water the pot, but only lightly, keeping the soil moist.

　　Improper fertilization: During the growing season, insufficient or no fertilization can cause yellowing leaves. Excessive application of concentrated fertilizer can burn the roots, preventing water absorption and also causing yellowing and leaf drop. In summer, apply a diluted fertilizer once a week, avoiding concentrated fertilizer. If too much fertilizer has been applied, water thoroughly to dilute it and flush away the fertilizer from the soil. Nutrient deficiency can lead to compacted potting soil, yellowing, thin, and weak leaves, and elongated, yellowish branches. Fertilizer should be applied immediately, with effects seen within a week. Regular fertilization will promote normal growth and abundant flowering.

　　Excessive temperature in summer can easily cause leaf tips or edges to scorch in cool, shade-tolerant plants under high temperatures and strong sunlight. In such cases, move the plant to a shaded, well-ventilated location, spray with water to cool it down, and increase humidity to promote growth.

　　High alkalinity can cause salt and alkali to accumulate in the potting soil due to prolonged watering, sometimes resulting in an alkaline crust that causes leaf drop. The solution is to replace the soil or spray the leaves with a ferrous sulfate solution to neutralize the alkalinity. Using alum fertilizer solution or fermented rice water can also yield good results, but over-application should be avoided. If too much ferrous sulfate is applied, the leaves may turn yellow but not fall off; in this case, water with alkaline water to adjust the balance.

　　Dry air can also cause problems for some plants grown in northern regions that prefer humid environments. For plants like camellias and orchids, excessively dry air often leads to withered leaf tips, scorched leaf edges, or scorched spots on the leaves. Symptoms include curling, wrinkling, and browning of the edges. This is especially severe in areas with indoor heating (coal fires or central heating) during winter. In such cases, the leaves should be frequently sprayed with water at room temperature to increase humidity. In summer, when growing plants on a balcony, water can be sprinkled on the floor to create a humid environment and provide some cooling.

　　Large plants in small pots require more water and fertilizer due to their large root systems. This often results in older leaves becoming dry, yellow, and dull, while younger leaves turn yellow and thin. The plant should be repotted into a suitable pot, and the soil should contain 30% humus to promote healthy growth.

　　Overly dense foliage, especially without pruning, leads to insufficient light in the inner branches, causing yellowing and leaf drop. Pruning should be increased to improve ventilation, and appropriate fertilization should be provided.

　　Insufficient light can weaken sun-loving plants, such as roses and pomegranates. Placing them in low-light conditions for extended periods will cause the plants to gradually weaken, resulting in thin, yellow leaves and reduced or no flowering.

　　Cold damage, such as early exposure to wind and cold in spring or autumn, can cause frost damage and yellowing leaves. These plants should be brought indoors for warmth and hardened to withstand cold.

　　Pests and diseases can cause yellowing and leaf spot, resulting from fungal infections and other pathogens. Preventive measures include timely spraying with pesticides and providing ample light and ventilation. Summer's high temperatures can also lead to pests, such as aphids and spider mites, which feed on the undersides of leaves, causing yellowing and even leaf drop. Timely pest control can restore the plant's health.

　　Other flowers can suffer from physiological drought due to exposure to toxic gases in the atmosphere or sudden watering with cold water when temperatures are high. High-concentration pesticides can also cause leaf tip or leaf surface scorching, and even death of the entire plant. Therefore, it is important to eliminate sources of air pollution, plant pollution-resistant plants, and use pesticides rationally. In hot summers, watering is best done before 10 am or after 4 pm.

                      [Prevention and Control of Rot in Succulent Flowers]

    Through practical experience in treating rot, my basic understanding is:
　　1. Rotten plants are caused by waterlogging due to only placing window screen at the bottom of the pot without covering it with tiles. The substrate I used was a mixture of well-rotted sawdust and river sand (7:3 ratio), placed under a tree in my outdoor yard. While the growing environment was good, it inevitably got rained on, which eventually clogged the drainage holes. If a plastic film is used to protect it from rain, there is no worry about waterlogging.
　　2. Charcoal powder is generally ineffective in treating rot. It works well for small wounds because it is highly hygroscopic, does not carry bacteria, and has a good barrier against external pathogens. However, if the wound is large, pathogens can easily invade, and charcoal powder can only prevent infection, not kill them, so it is
ineffective .
　　3. Sulfur powder is not ideal for treating rot. Although it has strong bactericidal ability, its hygroscopicity is very weak, the wound dries slowly, and it lacks penetration ability, so it cannot kill pathogens that have already invaded the plant tissue. Therefore, it is only suitable for treating mild rot.
　　4. Thiophanate-methyl is effective in treating rot. Also known as methyl thiophanate, it is a 70% wettable powder. It not only has strong bactericidal effect but also systemic properties, making it effective for both prevention and treatment.
　　5. During treatment, the wound should be left exposed and kept dry. The faster the wound dries, the better. Do not rush to cover it with soil to prevent secondary infection. Do not water for at least half a month after the diseased plant recovers to prevent recurrence. After a month or two of care, once the wound is confirmed to be healed, it can be covered with dry sand. New roots will soon sprout thereafter.

                     [How to Deal with Ants in Flowerpots]

         Termites and ants are very harmful to potted plants. They bore into the trunk and damage the root system, weakening the plant's ability to absorb and transport nutrients and water, ultimately leading to poor growth, wilting, or even death. Here are some methods to control ant infestations.
　　Eliminate the Source of Ants
　　: Keep potted plants away from ant nests. If ants are found in the soil, first follow their crawling routes to find the nest and eliminate them by flooding, burning, or spraying pesticides. Sprinkling lime on the nest and the ant crawling routes can prevent further damage.
　　Physical Control:
　　1. Apply Well-rotted Manure: When applying base fertilizer or organic fertilizer, it must be fully fermented and decomposed. Do not use raw or semi-fermented fertilizer, as this will attract ants.
　　2. Clean Leaves: Excrement from flies, moths, aphids, mites, and other insects on the leaves easily attracts ants. Therefore, frequently spray the leaves with clean water to keep them clean. Meanwhile, the ground should be cleaned frequently to keep the potted plant's growing area
clean and hygienic , so as to prevent odorous substances from attracting ants.
　　3. Soaking for insect control: Slowly place the potted plants already infested with ants into a bucket filled with water (the water should just cover the soil) and soak for 30 to 60 minutes. The ants cannot withstand the water and will all crawl out of the soil. At this time, you can remove the ants floating on the water surface and crawling on the stems and leaves of the potted plants.
　　4. Garlic for insect repellent: Peel and crush garlic, bury these pieces in the potting soil, and the ants will flee on their own because they cannot withstand the smell of garlic.
　　5. Repotting and removal: For plants that have already built nests in the roots, the most effective way is to repot them in a pool of water to kill all the ants. Then clean the roots of the plant and cultivate the potted plants with sterilized new potting soil.
　　Chemical control
　　1. 1. **Potting Soil Disinfection:** Before potting or repotting, disinfect the potting soil with agents such as 40% formalin, 65% zineb powder, or 50% carbendazim powder to kill termites, ants, and their eggs.
　　2. **Medicated Soil Application:** Mix 1 part 50% trichlorfon wettable powder with 50 parts sieved fine soil to create medicated soil. Bury this medicated soil evenly into the potting soil to eliminate ants.
　　3. **Drenching with Solution:** For plants that are not suitable for repotting in hot weather, where medicated soil application is ineffective, or where ants have already built nests in the potting soil, use 10 grams of 50% phoxim emulsifiable concentrate diluted in 500-1000 grams of water, or 5-10 grams of 40% dimethoate emulsifiable concentrate mixed with 1000 grams of water. Pour the solution into the potting soil and areas with ants, then seal the entire pot with a plastic bag for 12 hours to kill all ants.

                     Injecting pesticides into tree trunks can prevent pests and diseases.

Injecting a certain amount of pesticide into the tree trunk using external force to control pests and diseases, correct nutrient deficiencies, and regulate plant and fruit growth and development is a new chemical pesticide application technique. Key technical points are as follows:
1. Application equipment. For example, the BG305D type hole-punching and injection machine, powered by a gasoline engine, is relatively fast, capable of punching 8 to 10 holes per minute.

2. Preparation of the injection solution. Determine the appropriate injection concentration. For the control of forest tree diseases and pests, an effective concentration of 15% to 20% is suitable, while for fruit trees, an effective concentration of 10% to 15% is appropriate. It is best to use cooled boiled water for preparation.

3. Injection Site and Dosage. Inject at a depth of 30-50 cm above the ground, with the hole at a 45-degree angle to the ground. The solution should be injected into the 2-3 year old new xylem, not under the bark. Dosage: 1-3 ml of 100% concentrate per 10 cm of diameter at breast height (DBH) (1-3 ml of diluted solution per cm DBH).

4. Injection Timing. Inject before major infestations of leaf-eating pests; do not inject fruit trees 60 days before harvest.

5. Injection Methods. Trunk injection methods include pesticide injection, micronutrient injection, and hormone injection. For forest pest control, long-lasting organophosphorus pesticides can be used first. For fruit tree control, pesticides with short-lasting effects, low toxicity, or low translocation to flowers and fruits, such as dimethoate, phosphamidon, and carbendazim, should be selected. High-residue, highly toxic pesticides are prohibited.

                       [Tips for Preventing Flower Diseases]

    In early spring, various flowers enter their vigorous growth season. At this time, you can spray the leaves and the back of the leaves with a 1% Bordeaux mixture 1-3 times to prevent diseases. The preparation method of 1% Bordeaux mixture is as follows: Crush 1 gram of copper sulfate and dissolve it in 50 ml of hot water; then use 1 gram of quicklime, add a few drops of water to make it powder, then add 50 ml of water and filter out the residue; pour both solutions into the same container and stir well. The final result is a sky-blue transparent Bordeaux mixture.
Four methods for making your own insecticide
       : ① Take 200 grams of scallions, chop them, and soak them in 10 liters of water for 24 hours. Filter the solution and use it to spray the affected plants several times a day for 5 consecutive days.
       ② Crush 200-300 grams of garlic to extract the juice, dilute it with 10 liters of water, and immediately use it to spray the plants.
      ③ Soak 400 grams of tobacco powder in 10 liters of water for two days and nights, then filter out the tobacco powder. When using, add another 10 liters of water and 20-30 grams of soap powder, stir well, and spray the affected flowers and trees. ④ Soak 10 liters of water and 3 kilograms of wood ash for three days and nights, then spray
the plants.

[Preparation and Use of Plant Wound Protectants]

When pruning flowers and trees in autumn and winter, large wounds are often left behind. To promote wound healing, after smoothing the wound with a sharp pruning knife, disinfect it with lime sulfur solution (5-10 Baume) or 1%-2% copper sulfate solution, and then apply a protective agent. The preparation methods and application techniques of commonly used wound protectants for flowers and trees are introduced below:
　　　
　　Pine oil mixture: 6 parts rosin, 2 parts alcohol, 2 parts animal oil. First, heat the rosin and animal oil in a pot until melted. Immediately after removing from heat, add the alcohol and stir thoroughly while hot. Store in a bottle for later use. When using, apply the protectant evenly to the wound with a brush or cotton ball to form a protective film and seal the wound tightly. This method is suitable for flowers and trees with large cut areas.
　　
　　Pine wax mixture: 4 parts rosin, 2 parts beeswax, 1 part animal oil. To prepare, first melt the rosin and beeswax over a low flame, then pour in the animal oil. After melting, stir thoroughly and let cool. Remove from heat and knead into a ball by hand for later use. When using, heat it to melt, then apply it to the wound with a brush.
　　
　　For the copper sulfate paste, use 1 part each of soybean oil, copper sulfate, and slaked lime. First, grind the copper sulfate and slaked lime into a fine powder. Then, pour the soybean oil into a pot and boil it. Immediately add the copper sulfate and slaked lime to the oil, stir thoroughly, and let it cool before applying. For
　　
　　the salt-lime adhesive, use 1 part cow glue, 6 parts quicklime, 2 parts salt, and 1 part 45% sulfur suspension. First, mix the quicklime, salt, and sulfur suspension with an appropriate amount of water to form a paste. Then, add the melted cow glue and stir well before use.
　　
　　For the asphalt adhesive, heat and melt the asphalt. Applying it to wounds is very effective; it not only protects the wound but also effectively prevents wood rot.
　　
　　For the clay paste, when sap flows from wounds on pruning succulent flowers, mix fine soil with glue to form a paste and apply it to the wound. Applying sulfur powder or wood ash to wounds is also very effective.

[Four Methods for Homemade Insecticides]

       ① Take 200 grams of scallions, chop them, and soak them in 10 liters of water for 24 hours. Filter the solution and spray the affected plants several times a day for 5 consecutive days.
       ② Crush 200-300 grams of garlic to extract the juice, dilute it with 10 liters of water, and spray the plants immediately.
       ③ Soak 400 grams of tobacco powder in 10 liters of water for 24 hours, filter out the tobacco powder, add another 10 liters of water and 20-30 grams of soap powder, stir well, and spray the affected plants.
       ④ Soak 10 liters of water and 3 kilograms of wood ash for 3 days and nights, then spray the plants.

Gardening