1 Causes of balcony flower diseases and pests

Due to the special ecological environment of the balcony, many diseases that flowers are susceptible to are not easy to occur when planted on the balcony. For example, without the scouring of rainwater, the probability of flower leaves being infected by bacteria attached to the mud splashed by raindrops is greatly reduced. In addition, due to the high ambient temperature, root rot and other diseases that flowers are susceptible to are not easy to occur. However, the high temperature environment has a role in promoting the harm of some viral diseases. For example, the viral disease of Salvia miltiorrhiza is particularly prone to occur under high temperature conditions.

Like the courtyard, the flowers and plants on the high-rise balcony will also be susceptible to diseases and insect pests. The sources of these diseases are as follows: first, they are brought by the plants themselves and the soil; second, aphids, leaf flies, and beetles will be blown in by the wind, and caterpillars will crawl along the wall to the fifth or sixth floor balcony. However, no matter how well-ventilated and windproof the balcony is, the incidence of diseases and insect pests is much less than that in the courtyard.

Balconies are prone to dryness and large temperature differences, which are often the cause of spider mites and powdery mildew. If flowers and plants are placed too closely and ventilation conditions are poor, the probability of scale insects will increase. When buying potted flowers, check them carefully, including the back of the leaves and the bottom of the pot, and do not introduce pests such as greenhouse whiteflies and sticky slugs.

2. Try not to spray pesticides

If you spray pesticides on the balcony, the pesticides will often drift into the room or spread to the neighbors with the wind, causing harm, so try to avoid spraying pesticides on the balcony. Use liquid pesticides to soak or rub the plants, or use solid granular pesticides to let the plants absorb them from the roots.

3 Simple methods to prevent and control pests and diseases

Aphids hate light. Based on this characteristic, you can lay aluminum foil around the plants, or cut it into small pieces and hang it on branches and leaves. Spray milk or soapy water on sunny days. When the damage caused by leaf flies is still relatively light, you can spray water on the leaves. If you fail to find leaf flies in time, they will often cause great harm. You can try to rub the back of the leaves with white paper to see if there is red juice on it. You can use a toothbrush to remove various scale insects. You can use a brush to apply pesticides to places where scale insects are prone to grow, such as leaf bases, petioles, and roots. Greenhouse whiteflies are often more difficult to deal with. You can use plastic bags to cover the plants and spray pesticides to prevent the adults from flying around. Since the pesticides have no effect on eggs and pupae, remove the branches and leaves where the eggs and pupae grow. In early summer or autumn, there are often night thieves and geometrid moths. You can catch the larvae based on the insect feces.

From early spring, in order to prevent the occurrence of the disease of grape spores, which causes petal rot in pansies, the leaves with spots or rot should be removed in time. Due to excessive fertilization, the leaves grow weakly, which often leads to powdery mildew. Splashing water on the flowers and leaves can easily lead to the occurrence of these two diseases.

4 Precautions for spraying pesticides

When preparing the medicine, you only need to prepare the dosage that can be used up on the same day. Use a beaker with a scale to dilute it according to the regulations. Avoid applying it at noon when the temperature is high and on sunny days. It is best to spray it when it is cloudy or in the evening. Note that if the potting soil is too dry, it is easy to cause pesticide damage.

A spray bottle with a long and narrow mouth that can be operated with one hand. Aerosol sprayers that put the medicine in a can are more suitable for use in Yanghe. If you spray too close to the plant, it is easy to cause pesticide damage. You must be more than 30 cm away from the plant and be careful not to let the mist fly.

5. Prevention and control methods of common diseases and pests of balcony flowers

5 1. Powdery mildew

Powdery mildew is a disease caused by powdery fungi of the subphylum Eumycotina. The pathogen usually parasitizes on the surface of plants and uses haustoria to penetrate deep into epidermal cells to absorb nutrients. Its main feature is that the surface of the affected plant is covered with a layer of white powdery mold, which makes the surface of the plant look like it is covered with a layer of white powder. Therefore, it is relatively easy to identify. Powdery mildew mainly occurs in areas with large temperature differences between day and night, high air humidity, and poor ventilation. It mainly harms the leaves, flowers, fruits and other parts of the plant. The leaves and flower organs of the affected plants are covered with a layer or pieces of white powder, which seriously affects the growth and development of the plant. Because it develops quickly, it is difficult to restore the flowers to their original state even with prevention and control. Therefore, it often brings great trouble to management and has a great impact on the ornamental value. Therefore, we should take precautions before it happens and strive to avoid the occurrence of this disease.

Prevention and control methods: Do not spray water on plants during the period of vigorous disease; avoid excessive application of nitrogen fertilizer, and appropriately increase the application of phosphorus fertilizer and potassium fertilizer; immediately remove the diseased organs and burn them in a centralized manner. In the early stage of the disease, 25% fenadimefon wettable powder 2000 times solution, 70% thiophanate-methyl wettable powder 1000 times solution, 65% mancozeb wettable powder 500 times solution can be sprayed once every 10 days, and a total of 3 or 4 times can achieve significant results.

5.2. Spot disease

Spot disease is a disease caused by fungi of the order Sphaerosporales and the order Sphaerosporales. It mainly includes spot disease, black spot disease, red spot disease, gray spot disease, etc. The pathogens mainly harm the leaves of flowers. The disease occurs widely and causes serious damage. It is very common in both the north and south. It mainly occurs in summer and autumn, when the weather is rainy and humid and the temperature is 24-28℃, and is more serious in July-September. The plant mainly starts to get sick from the base leaves, and the top leaves are generally not infected by the disease. In the early stage of the disease, green needle-like dots appear on the back of the new leaves, which then expand into 3-5 mm nearly circular to irregular spots of color. The middle part is gray, the edges are slightly raised, and it is dark brown. There are not very obvious dark green spots on both sides of the leaves, which directly affect the growth and development of the plant and its ornamental value. When the disease is serious, the scattered spots often gather into pieces, which eventually cause the leaves to scorch and die. The disease is mainly spread by the remnants of the infected plants.

Prevention and control methods: implement crop rotation; disinfect the soil; sterilize seeds before sowing; take breeding materials from disease-free plants; do a good job of waterlogging prevention; apply fertilizers reasonably; provide adequate sunshine; ventilate the environment; prune appropriately; remove fallen leaves from the cultivation site in time in winter and bury them deeply; when the plants unfold their leaves in spring, spray 50% carbendazim wettable powder 1000 times diluted once for protection; spray 75% thiophanate-methyl wettable powder 500 times diluted once on the middle and lower leaves of the plants every 10 days during the disease season, for a total of 3 or 4 sprays.

5.3. Viral diseases

Viral diseases are diseases caused by plant viruses. This disease can occur from the seedling stage to the flowering stage. Since plant viruses do not have the ability to actively invade the body of flower plants, they can usually only invade through mechanical action and wound surfaces. For example, when pruning flowers, cross-infection of plant body fluids and when flower pests such as aphids use their mouthparts to suck flower body fluids can also cause the spread of this disease. In addition, viral diseases can also be spread through propagation materials such as seeds, cuttings, bulbs, and scions. Its symptoms are most obvious during the high temperature stage in summer. Yellow spots appear on the leaves of the affected plants, showing a yellow-green mosaic state. The plants are obviously dwarfed and flowering is affected, but the plants usually do not have symptoms of rotting or wilting. When the disease is severe, the plants are also prone to death. Since there is no drug that can effectively kill viruses without damaging the plant body, it is relatively difficult to prevent this disease.

Prevention and control methods: When introducing species, pay attention to introducing seedlings that do not carry the virus; when pruning flowers, cross infection should be prevented, and pruning tools should be sterilized at high temperature or disinfected with medical alcohol; do a good job of preventing and controlling pests such as aphids that spread flower viruses; remove diseased plants in time and bury them deeply. Since diseased plants are basically impossible to recover, it is best to disinfect the knives with a 1% sodium hypochlorite aqueous solution after each pruning. During the cultivation period, spray the plants once every 10 to 15 days with 2.5% cypermethrin emulsifiable concentrate 1000 times diluted to kill thrips, aphids, leafhoppers and other pests that spread the disease.

5.4. Cataplexy

Damping-off disease is a disease caused by pathogens such as Pythium aphanidermatum and Pythium debari. The pathogen mainly harms the seeds and roots of balcony flowers. It overwinters on the residual branches and leaves and in the cultivation soil. The zoospore germ tubes germinated in the spring of the following year will directly invade the base of the host seedlings to complete the initial infection. After that, sporangia are generated in the affected part, and the zoospores germinated will infect the plants again. This cycle is repeatedly spread with the process of flower management and watering operations. Damping-off disease mainly occurs when the air temperature is high from May to July, and the most serious damage is when the soil temperature is 12 to 23°C. The affected plants are mainly flower seedlings. When the seedlings are sick, water-soaked lesions will appear on the roots and the base of the stems, and can extend up and down the plants. Damping-off disease develops rapidly, and the affected seedlings wilt and fall over in a very short time, and finally die.

Prevention and control methods: Avoid continuous cropping; do not use culture soil that has been used to grow Solanaceae plants; disinfect the potting soil; sterilize the seeds, which is an important way to prevent the spread of sudden case disease; reduce watering when the temperature is low; do not use organic fertilizers that have not been decomposed at high temperature; pull out the diseased plants when the disease occurs, burn them in a centralized manner, and then spray the plants with 1000 times diluted 25% carbendazim wettable powder once.

5.5. Root rot

Root rot is a disease caused by the fungus Pythium. This disease is particularly prone to occur when the ambient temperature is low and the root system is damaged. The diseased plants usually rot at the root first, and then the disease often spreads further. The result can be mild weakness of plant growth, or even rot and death of the plant. For balcony flowers, this disease can occur throughout the year, especially from January to August when the disease is more serious.

Prevention and control methods: First, choose potting soil suitable for flower growth, and do not make it too sticky. Second, watering should follow the principle that the lower the ambient temperature, the less watering. For most succulent plants and cacti, if the ambient temperature is between 5 and 10°C, watering can be done once every 3 to 4 weeks; if it is between 0 and 5°C, watering can be done once every 5 to 6 weeks. If watering is too frequent under low temperatures, succulent plants or cacti are particularly susceptible to this disease. Cultivation experience shows that even if succulent plants and cacti are watered once every few weeks during the low temperature season in winter and spring, it will not affect their normal growth, because drought resistance is a common feature of succulent plants and cacti. Third, if the fertilizer management is strong, if the plant tissue is full, its resistance to root rot is also strong. Fourth, placing balcony flowers under appropriate sunlight, especially in the low temperature season in winter and spring, so that they can receive appropriate sunlight, is very helpful in reducing the occurrence of root rot. Too low or too high an ambient temperature can easily lead to root rot. Therefore, care should be taken to keep the plant in a humidity range suitable for its growth. Fifth, be careful to burn the remains of diseased plants and do not use them as fertilizer, otherwise it will make the disease difficult to control. The potting soil used can also be sterilized before reuse.

5.6 Sunburn

Sunburn is a physiological disease. The main cause of the disease is that strong sunlight damages the young and tender tissues of the plant. This disease often occurs in the high temperature seasons of summer and autumn. The high temperature generated by strong sunlight damages the cells of the stems and leaves of flowers, causing the young leaves to lose their green color and the tender stems to turn yellow, causing irreparable damage. In addition, even if the balcony flowers that have not seen strong light for a long time are suddenly exposed to strong sunlight in the low temperature seasons of winter and spring, sunburn will occur. This disease may occur throughout the year. Since the surface cells of the affected part of the plant have died, even if the diseased flowers are treated, the existing symptoms cannot be eliminated. Therefore, the damage caused by sunburn is often difficult to repair. It is not until the affected leaves, stems and other parts are cut off from the plant that it is possible to restore the original appearance of the plant. Sunburn has a great impact on some slow-growing plants, such as Clivia. If its young leaves are burned by sunlight, due to its morphological characteristics, it is difficult to use the method of cutting off the damaged young leaves to compensate for the decline in ornamental value, which will naturally make the whole plant look very ugly. Because if you wait until the damaged leaves naturally age and die, it usually takes 2 to 3 years. It can be seen that although sunburn generally does not cause fatal damage to balcony flowers, it has a great impact on the ornamental value of balcony flowers, so it must be strictly prevented.

Prevention and control methods: In the hot summer and autumn seasons, shade should be provided for flowers that prefer semi-shaded or shaded environments. If the temperature at noon is too high, water can be sprayed to cool down. However, it should be noted that sometimes water droplets adhere to the surface of the leaves, which will produce a lens-like effect and burn the plants, but this phenomenon is relatively rare. For balcony flowers that have been placed in a shaded environment for a long time, they should avoid being suddenly exposed to strong sunlight, but should gradually extend the time they receive direct sunlight. You can use the light-adding method of 10 minutes on the first day, and then extend the sunlight by 10 minutes every day.

5.7. Anthrax

Anthracnose is a disease caused by the fungi of the order Melanodisperales. Under warm conditions, the pathogen can cause anthracnose symptoms on the leaves, stems, flowers, etc. of plants, i.e., stripes or circular spots with clear boundaries and slight depressions. One of the important characteristics of anthracnose is that obvious black spots grow in the middle of the lesions, arranged in concentric rings. The disease is most likely to occur when the plant is weak in growth, in the rainy seasons of spring and autumn, and the temperature is around 23°C. The affected plants often first develop circular to irregular lesions on the leaf margins. In the early stage, they are yellow-brown, slightly raised, and have yellow halos on the edges. Later, the lesions will expand day by day, and black spots will grow on the surface.

Prevention and control methods: remove the source of the disease, remove the diseased leaves in time, and destroy them in a centralized manner; since anthracnose is mostly spread through propagation materials, materials should be selected from disease-free plants; pay attention to applying less nitrogen fertilizer and more phosphorus and potassium fertilizers; before or in the early stage of the disease, spray 75% chlorothalonil WP 500 times liquid, 50% thiophanate WP 500 times liquid, 70% thiophanate methyl WP 1000 times liquid for prevention and control. Usually spray the medicine once every 10 days or so, and use the medicine 3 or 4 times in total to achieve significant results.

5.8. Whitefly

Whitefly is also called greenhouse whitefly. Its adult is 1 to 1.5 mm long, with a pale yellow body and white wax on its wings. This insect likes warmth and can have several generations throughout the year. It likes to feed on tender tissues, mainly harming leaves. It often gathers on the back of leaves, sucking sap, and eventually turning the leaves yellow; the honeydew it secretes will clog the stomata, thus affecting the smooth progress of photosynthesis; its piercing and sucking mouthparts can also spread plant viruses. Since the adult whitefly can fly, it is difficult to control it, because when the spray encounters vibration, the adult will fly away from the plant, and when the pesticide evaporates, they will return again and continue to harm the plant, so the effect of the spray is very poor.

Prevention and control methods: When introducing species, be careful not to buy balcony flowers that are infested with this insect; use spraying as little as possible, and use the yellow tendency of the adult insects, that is, the biological characteristics that they like yellow objects to kill them. The specific method is to hang a few yellow color plates next to the flower pots, and then apply a layer of colorless vaseline on these plates. When whiteflies stay on the color plates, they will be stuck and unable to leave. If possible, you can also use a small vacuum cleaner to catch them. This method is effective in sucking and catching adults. During the operation, you can move the plants while sucking. This method is more effective in killing whiteflies and will not cause chemical pollution to the environment.

5.9. Red Spider

Red spiders are also called fire spiders. They are not actually insects, but crustaceans, because they have eight legs, while insects have only six legs. However, many flower growers and plant protection workers often discuss them as flower pests, and I also use this method. Red spiders are shaped like spiders, but their bodies are like needle tips, and their body colors are mostly reddish brown to vermilion. They mainly harm plants by sucking the body fluids of plants with their mouthparts, causing the affected areas to turn yellow and yellow spots the size of needle tips to appear. Red spiders occur seriously from April to October each year. The leaves of the affected plants turn yellow, grow slowly, and the new shoots shrink. In severe cases, they will wither and die.

Prevention and control methods: Improve the microclimate environment of the cultivation site, spray water around the cultivation environment frequently to increase air humidity, and do a good job of indoor ventilation to keep the temperature of the environment from exceeding 30°C. Because red spiders reproduce rapidly under dry and high temperature conditions, increasing air humidity or lowering the temperature of the environment can inhibit their spread and even prevent their large-scale occurrence. Therefore, a relatively simple prevention and control method is to spray water frequently in the environment and maintain air circulation. In the case of serious damage, 40% trichlorfon emulsifiable concentrate 1000 times liquid can be sprayed once a week, and the drug can be used 2 to 3 times in total. Be sure to spray evenly, because trichlorfon is not a systemic drug. If it does not come into contact with the body of the red spider, the prevention and control effect is poor.

5.10. Scale insects

Scale insects are common pests of balcony flowers. Their adults are mostly long and oval, and their colors are light yellow, pink, dark brown, etc. depending on the species. Their body length is usually 100 mm. Its nymphs can crawl, and when they find a suitable place, they will settle down, pierce the cortex of the plant with their mouth needles, and suck its body fluids. This insect often gathers on the back of leaves, pedicels, and branches. They are active all year round, and usually occur seriously under conditions of high humidity and poor ventilation. The growth of the affected plants is affected because the adults and nymphs are densely distributed on the leaves to absorb body fluids. In addition, the non-excrement of scale insects can also induce sooty mold, which hinders the photosynthesis of the plants and affects the ornamental effect of the leaves. The prevention and control of scale insects is not as easy as other pests. Usually, several measures must be coordinated to achieve the purpose of eradication.

Prevention and control methods: Avoid introducing seedlings with this insect; ensure that the environment is well ventilated to block the growth environment of this insect; do reasonable pruning, cut off the dead branches and leaves at any time, and burn the cut branches and leaves together. If the insect is not serious, you can use a toothbrush to brush it off from the place where it grows, and then burn it together. The advantage of this method is that it does not use highly polluting pesticides, and it will not cause damage to the plants due to improper spraying. When the insect pest is more serious, you can consider the method of applying pesticides. Since the wax on the surface of the nymphs formed by scale insects in the early stage of egg formation has not yet formed well, the application of pesticides at this time usually has a good effect. During the egg formation period of nymphs, spray 1,000 times of 40% oxydemeton-methyl emulsifiable concentrate once a week, and use the medicine twice in total. When it develops into an adult, the effect of applying the medicine is poor. Therefore, it is necessary to pay attention to comprehensive prevention and control of scale insects.

5.11. Ants

Although ants mainly move on the ground, they are very active and can even climb high buildings. They often settle in the soil of pots, build nests, and then gnaw on plants and bite tender buds. In general, ants are less harmful to balcony flowers than other insects, but they often crawl around on the surface of plants, which makes people feel quite unsightly. They climb on the branches and leaves of plants mainly to eat the honeydew secreted by aphids. In many cases, ants will feed on the roots of some balcony flowers. For example, the tubers of dahlias are often eaten by ants. In addition, it sometimes builds nests in the stems of flowers, which often causes the plants to be broken.

Prevention and control methods: Do not bury unrotten skins or other fertilizers that attract mosquitoes in the potting soil to prevent mosquitoes from migrating into the potting soil. For flowers that have mosquitoes, you can immerse them in water with the pots. Due to lack of oxygen, the ants will flee, and you can take this opportunity to kill them. Be careful not to immerse flowers in water for a long time, otherwise it will cause waterlogging. Usually, the immersion time should not exceed 10 minutes. This method is not suitable for those cactus plants that do not like water. If the ant infestation is more serious, you can put chicken bones, pig entrails and other foods that ants like to eat in places where they often move. Usually, after a few hours, a large number of mosquitoes will crawl onto these baits. At this time, you can take the opportunity to scald them to death with water, or move them to other places for treatment.

5.12. Grub

Grubs are also called ground silkworms. The adults are commonly known as scarabs. This pest is very harmful to outdoor flowers. Since scarabs have a strong tendency to attract light, they often fly to the balcony at night and lay eggs in the pot soil. The resulting grubs lurk in the soil and bite the roots of the plants, causing the leaves of the plants to be dull and their growth to be slow. This insect mainly occurs in summer and autumn. Since grubs mainly like to gnaw on the roots of balcony flowers, the affected plants often wilt when they see the sun. At this time, even watering is useless. The plants will only recover at night. As the larvae of scarabs - grubs continue to grow, the damage caused becomes more and more serious. Because sometimes there are more than a dozen grubs living in a flower pot at the same time, the result is often that the roots of potted flowers are bitten off, resulting in the death of the plants.

Prevention and control methods: Avoid burying unfermented organic fertilizers in the potting soil, as this will attract beetles to lay eggs; in areas where they are common, cover the surface of the flower pot with a layer of plastic film in the evening and remove it the next day to prevent beetles from laying eggs in the pot. If the plant is found to wilt under sunlight without lack of water during the day, and returns to normal at night, it is mostly caused by grubs in the potting soil. At this time, you can pour 1000 times of 50% dichlorvos emulsifiable concentrate into the potting soil to kill it. Grubs have poor resistance to dichlorvos, and usually one application is effective.

5.13. Aphids

Aphids are also called honey bugs and sticky bugs. They are widely distributed and very harmful flower pests. The adult body length is usually 1 to 2 mm, with a light yellow to light green body color. Some have wings and can fly, which are called winged aphids. It likes warmth and can produce several to more than ten generations in a year. It often gathers in groups on the young leaves and flower buds of plants to suck body fluids, thus affecting the growth of new shoots and the development of flower buds. The photosynthesis of the affected flowers is affected because the surface of the new leaves and tender shoots is covered with aphids. More importantly, a large amount of body fluids of the plant are sucked by them, which eventually leads to the weakening of growth.

Prevention and control methods: Try to avoid using pesticides to avoid polluting the environment. When a small amount of aphids occur, you can directly crush them to death with your hands, or use water to wash the aphids off the plants. Since aphids have a clear tendency to yellow, ecological prevention can also be carried out, using yellow plastic sheets to lure and kill them. During operation, apply motor oil or mousetrap glue to the surface to lure and stick to a large number of winged aphids. If the insect situation is very serious and it is difficult to kill them with the above methods, you can spray 1,000 times the solution of 80% omethoate emulsifiable concentrate once a week. Using the medicine once or twice will achieve significant results.

5.14, Heart Borer

The borer is the larvae of the corn borer. It is 1 to 1.5 mm long and light green in color. It likes warmth and can produce several generations in a year. The adult borers begin to lay eggs in early summer every year. The larvae begin to move in mid-June, and are most frequent in July and August. Since the borers mainly attack the bud tops and flower buds, they are extremely harmful to plants that bloom at the top of the plant, such as chrysanthemums. They often bite off the stem tips or drill into the stems to move. When you see round holes on the stems of flowers, it is most likely that the borers are at work. If there is feces next to the holes, it can basically be judged correctly that the plant has been attacked by this pest. Plants attacked by borers have weak growth potential and sometimes die. Even if they survive, their ornamental value will be greatly affected.

Prevention and control methods: When borers occur, spray 1000 times diluted 80% DDT emulsion once a week, and use the medicine 3 or 4 times in total, which can basically prevent the borers from harming the flowers. If the insects have drilled into the flower stems, use a syringe to inject 100 times diluted 80% DDT emulsion into the holes to kill the borers. Or prune the plants with borers, remove the parts above the holes, and clip the borers out of the stems. This treatment method often produces better results.