What to do if the leaves of hibiscus flowers are yellow? there are five ways to improve the leaf yellow phenomenon / prescribe the right medicine.

Hibiscus is a perennial shrub, so its leaves should be evergreen, but some flower friends will also encounter the phenomenon of yellowing leaves when planting, which not only does not look good, but may also affect growth and flowering, so what if the leaves of hibiscus flowers turn yellow? The editor will tell you how.

What if the leaves of hibiscus are yellow?

If we want to solve the problem of yellowing leaves, we must find out the causes of the problems. according to the summary of flower friends, the main reasons for hibiscus leaves yellowing are: improper watering, less fertilization, too strong light, wrong time to change pots, diseases and insect pests, and the solutions are as follows.

1. Improper watering

Hibiscus flower needs enough water to grow, but it does not require much water, and if it is watered too little, it will be dry and yellow, while if it is watered too much, it will appear yellow, so improper watering should be avoided in planting.

[solution]: when watering, as long as you ensure that the soil is not dry, do not let stagnant water around the roots, and do not be watered for a long time. Specific watering methods can refer to the detailed introduction of how to teach hibiscus flowers in water.

2. Less fertilization

Too little fertilization or lack of nitrogen fertilizer will lead to yellowing of leaves, and if the concentration is too high or too many times, it will also cause the same situation, so thin fertilizer should be applied frequently.

[solution]: what if the leaves of hibiscus flowers turn yellow due to insufficient fertilization? Top application of nitrogen fertilizer, every 15-20 days, after fertilization should be appropriate watering, nitrogen fertilizer can promote the growth of leaves, can make the leaves more green.

3. The light is too strong

Hibiscus can not only grow in full light, but also more shade-tolerant, but if it is not shaded in summer when the light is too strong, the leaves will just be burned and yellowed.

[solution]: move the hibiscus flower back to the shade for maintenance, or slightly shade it, block more than 50% of the light, and then spray water properly to the leaf surface to prevent other leaves from continuing to yellowing.

4. the time to change the basin is not right.

When planting hibiscus flowers, we stressed that the pot soil should be changed every 1-2 years, but the time to change the pot should be before sprouting in spring, not in flowering or winter, otherwise the leaves would turn yellow due to sudden changes in the environment.

[solution]: know the correct time to change the hibiscus flower pot, make sure that there is no damage to the root when changing the basin, pour water thoroughly after changing the basin, and maintain it in a suitable environment so that it can pass through the slow seedling stage smoothly.

5. Diseases and insect pests

Diseases and insect pests usually occur on branches and leaves, because many pests feed on mesophyll and sap, so when diseases and insect pests occur, leaf yellowing is the most prominent feature.

[solution]: preventive measures should be taken when planting, such as keeping the environment clean and ventilated, which can reduce the occurrence of diseases and insect pests, and should be treated with chemical spraying when diseases and insect pests occur.

How to prevent diseases and pests in flower maintenance

How to prevent diseases and pests in flower maintenance

Flowers can get sick just like people, such as poor adaptation to the environment, more or less water and fertilizer, high or low temperature, and the presence of bacteria or viruses.

Only by understanding the symptoms can we prescribe the right medicine to the case. Let's first take a look at common flower diseases:

1. Classification and Control measures of Flower Diseases

Flower diseases are generally divided into two categories: infectious diseases and non-infectious diseases.

The main results are as follows: (1) Infectious diseases: infectious diseases are caused by pathogens and are contagious, and there are the most kinds of infectious diseases in flower diseases. According to the types of pathogens, they can be divided into the following categories:

① fungal diseases: most of them are caused by fungi. The main diseases caused by fungi are as follows.

a. Powdery mildew: bacteria grow on buds or shoots, the injured leaves and shoots will gradually curl and atrophy, buds deformed rickets, can not open normally. The spores will spread with the wind. When the light is insufficient, the ventilation is poor, the humidity is high, and the temperature difference between day and night is in HTC, the pathogen will break out in a large area quickly. Such as rose, inverted golden bell, plum blossom, impatiens, melon leaf chrysanthemum, dahlia and so on are easy to suffer from powdery mildew. This kind of pathogen is usually easy to appear in spring or autumn. Pay attention to the ventilation of flowers. If the branches and leaves of flowers are too dense, they should be thinned to ensure that they are well ventilated. Keep the temperature difference from being too large. Of course, you can also spray flowers before the disease, for example, you can spray 1000 times of thiophanate, 50% carbendazim or 500 times of trimethoprim, and spray medicine every 10 days or so when it is easy to occur.

B. black spot, brown spot: this virus is a common disease of flowers. The pathogen lurks in the soil for a long time. In the season of high temperature and high humidity, with Rain Water or water splashing, the pathogen will invade the lower leaves and spread upward rapidly. The damaged leaves will appear small black spots, and gradually expand into a round, oval, fused into a piece. The diseased leaves turn yellow until they wither. The disease usually occurs rapidly during the rainy season from July to August. Rose, chrysanthemum, peony, geranium and other flowers often suffer from this disease.

Brown spot is similar to black spot, it is oval or irregular brown or dark brown spot, the outline is not obvious. The pathogenesis is the same as that of black spot.

Spot diseases such as black spot and brown spot should be prevented as soon as possible. For example, when configuring the culture soil, we can mix human-suitable fl ammonium and other sterilized pesticides to disinfect the soil. In daily life, the delicate and complicated branches and leaves close to the soil should be cut off in time, keep the branches and leaves ventilated and transparent, and spray topiramate and other pesticides to the leaf surface and back. In the rainy season, 1000 times of Dysenamine solution can be sprayed on the lower part of the plant and on the potted soil surface. Soil stains appear in the lower leaves, which should be cleaned in time and sprayed with pesticides.

C. Botrytis cinerea: the damaged petals will show water-burst spots and continue to expand soft rot. When the pathogen falls on the leaves, it will immediately cause the leaves to get sick and the leaves will gradually rot. The temperature difference between day and night is on the large side.

Excessive humidity, poor ventilation and lack of light are all easy to cause this disease. In particular, Fusang, geranium, chrysanthemum, cyclamen and other flowers are vulnerable to this disease.

It is necessary to cut branches and leaves in time, help flowers to be ventilated, and often let them be exposed to sunlight. It is also necessary to spray 75% chlorothalonil 500 times liquid and other pesticides during the high incidence period.

D. blight disease: this disease often breaks out in the flower seedling stage, and the infected seedlings will wither and die. This pathogen often lives on the surface of the soil and infects from the root neck of seedlings. The disease of seedlings is often characterized by rot, quenching and blight. Usually the seedlings are unearthed for about 20 days, which is the most susceptible period. Flower blight often occurs in a variety of pine and cypress seedlings, chrysanthemum, carnation, gladiolus, four seasons begonia, Scutellaria barbata and so on.

If you want to prevent flowers from suffering from this disease, you should mainly disinfect the soil. Pentachloronitrobenzene and formalin can be used for disinfection. Each square meter can be made into medicinal soil with 8 grams of pentachloronitrobenzene, covering the soil surface of about 1 cm, and 40% formalin, 50 grams of water, 10 kg of water, watering 1 square meter of substrate, and then covered with grass for 10 days, so that seedlings can be raised. A small amount of pot sowing seedlings, you can choose plain sand and new tile basin. Before loading the soil into the basin, the soil is exposed to the sun or watered with boiling water to disinfect the soil.

When the seedlings are unearthed for about 20 days, watering should be strictly controlled. in general, sufficient water should be irrigated on the cultivated soil before sowing, and no irrigation should be given temporarily after sowing. In case of excessive dampness, it is easy to get sick. Then give more ventilation to the seedlings, seedlings unearthed, can be sprayed 0.5% ferrous sulfate, 1% Bordeaux solution or 50% benzoylammonium 200 times solution, in order to eliminate soil surface bacteria and protect seedlings.

If individual seedlings are found to be sick, they should be removed immediately and protected by spraying to prevent the spread of germs.

e. White leprosy. The disease often occurs at the root neck of the plant near the ground. At the initial stage, the disease department will produce water-routed purple-brown spots, then spread, the leaf base will gradually rot, a clear white mycelium layer will appear on the disease part and the surrounding soil, and there will be a lot of sclerotia the size of rapeseed, which will turn white at first, and then gradually turn yellow and brown, and the plant will die slowly. Such as orchids, orchids, peonies, peonies and other flowers often get this disease.

This pathogen can survive in the soil for a long time. When the conditions are right, the hyphae of the pathogen will invade people from the root neck or root of flowers and trees, and the disease will occur in about a week. High temperature and humidity, stagnant water in soil, poor ventilation and light transmission will cause this disease and spread easily.

In order to prevent the outbreak of this pathogen, we should pay attention to proper watering, reasonable fertilization, and not too deep planting in the daily flower management; disinfect the soil, and disinfect the seedlings with formalin before planting; remove the disease part in time when discovering the diseased plant, and then replant it.

② bacterial diseases: most bacterial diseases invade people from stomata, lenticels or wounds of plants. The main symptoms are as follows:

A. soft rot. The damage to the plant is not due to the phenomenon of soft rot, and the rotten tissue is sticky and smelly. Cyclamen, magnolia and other flowers are often infected by this disease.

This pathogen has a wide host range and strong saprophytic ability. it survives for a long time in diseased and residual plants, soil and compost, and spreads by contact with soil, water, tools, insects, diseased plants and so on. Bacteria mostly invade people from the wound and get sick rapidly, and it is most likely to break out from July to August when it is hot and humid.

In order to prevent the occurrence of this disease, we should pay attention to the ventilation of the flowers in the high temperature season, and avoid dripping, do not water to the top of the tuber, transplant, move to prevent artificial trauma, and avoid the occurrence of insect pests. Diseased leaves and diseased plants should be removed and burned in time, and the soil should be replaced, and other healthy plants should be disinfected. At the initial stage of the disease, 400 micrograms of streptomycin or oxytetracycline can be sprayed or irrigated immediately.

B. Cancer. The plant infected with bacteria will produce lumps of different sizes in its root neck, stem and so on. The color is elastic at first, then it becomes hard and woody gradually, and its appearance becomes rough. The disease often occurs on flowers and trees such as rose, cherry blossoms, green peaches, plum blossoms and so on.

This pathogen will survive the winter in the diseased tumor or soil and invade the plant through grafting interface, insect injury and so on. The incidence is relatively high in moist and alkaline soil.

In order to prevent this disease, the soil can be disinfected when planting. The diseased tumor of the plant should be removed immediately after the disease, and the wound should be sterilized with alcohol. ③ root knot nematode disease. When the plant is infected with this disease, it will produce round nodule-like root knot on its branch root or lateral root, solitary or serial, the root knot begins to be yellow-white, then gradually turns brown, the surface is rough or even broken, and there are white granular female adults in the nodule. After the disease, the growth of the plant is slow or stopped, and the plant is short, and the leaves turn yellow or even wither. Cyclamen, dahlia, goldfish grass, impatiens, a bunch of red and other vulnerable to this bacterial infection.

Root-knot nematodes overwintered in soil, and diseased soil and diseased plants were the main sources of infection. After invading the young roots, the larvae will fix and parasitize to form the root knot, and the larvae will mature in the root knot, and the adults will mate and lay eggs. Generally, one generation is completed in 30-50 days, and many generations occur in a year. Plants growing in high-temperature and humid sandy loam are most likely to be infected with the disease.

In order to prevent and cure this disease, it is necessary to clean and disinfect the soil, and the basin soil can also be disinfected with 3% carbofuran granules, 15% iron mifenac granules, Mianlong, Kexidan and so on.

④ virus disease. The diseased plants will show many symptoms such as mosaic, chlorosis, streak, ring spot, necrosis, broken color, dwarf, deformity and so on. Carnation, canna, chrysanthemum, lilies, tulips and other flowers are easily infected.

Most viruses are transmitted by aphids, leafhoppers and planthoppers, and grafting and cuttings are also effective ways of transmission. In addition, the contact between diseased plants and healthy plants is also prone to cross-infection.

Diseased plants should be removed and burned in time, and attention should be paid to pest control.

(2) non-infectious diseases: non-infectious diseases are called physiological diseases, which are mainly caused by flowers not adapting to the surrounding environmental conditions. The main non-infectious diseases are as follows:

① is caused by plant disease due to the lack of certain nutrients during plant growth. Such as iron deficiency chlorosis.

In the early stage of iron deficiency chlorosis, the mesophyll will fade and turn yellow, and the leaf vein will remain green, forming a reticular vein. As the disease becomes more and more serious, the whole leaf will turn yellow and fall off, affecting the growth. Such as rhododendron, camellia, Milan, orchid, jasmine, Jiaozi and other flowers are easy to suffer from this disease.

Generally speaking, this disease is most likely to occur in the flowers raised in the south and north, because the soil in the north is alkaline, the pH is between 7.5 and 8.5, there is a lack of soluble divalent iron in the soil, and the plant can not synthesize chlorophyll because of iron deficiency. The water quality in the northern area is relatively alkaline, and even if the cultivation substrate is acidic, it is easy to yellowing after a long time.

Change the disease.

In order to prevent and cure this disease, we can apply alum fertilizer water, choose 2.5 kilograms of black alum, 5 kilograms of cake fertilizer, 5 kilograms of feces, 200 kilograms of water and 250 kilograms of water. Take out some and water the flowers with 1 times dilution. It can also be retted to a certain amount according to this proportion. It can also be sprayed with vinegar, which can be sprayed at the ratio of 1: 250 to 1: 300, every 10 days for 3 times.

② is caused by diseases such as sunburn caused by plants that are not adapted to light. Some Xiyin flowers often suffer from the disease because they are exposed to the sun and the tissue of the tender leaves is killed by the sun. For example, orchids, orchids, camellia, ferns, Camellia oleifera and other foliage plants are easy to suffer from this disease.

After the disease, the leaves of the plants will lose their luster and become rough. sometimes the leaves will form faded yellow-brown or yellow-white withered spots to the light surface, and in severe cases, the leaf tip of the leaf edge will become white and scorched.

To understand the floral nature of all kinds of flowers, the shade-loving plants should be moved frequently and placed in a shady place to avoid exposure to the sun.

③ is poisoned by multi-salt. Also known as alkali damage, is the damage to plants when there are too many salts in the soil, especially soluble salts, such as sodium chloride, sodium carbonate and sodium sulfate. After being injured, the sprouting is blocked and slowed down, the growth of young plants is slender and morbid, the leaves fade, and the mature state of flowering and fruiting can not be achieved.

Rinse the salt in the soil with fresh water to dilute it. The purpose of ploughing and loosening the soil and increasing the application of organic fertilizer to improve soil structure and accelerate soil desalination.

④ is affected by temperature, and some flowers will get sick because they do not adapt to the temperature. For example, when the temperature is too high, the photosynthesis of some plants will be hindered, chlorophyll will be destroyed, dead spots will appear on the leaves, the leaves will turn brown and yellow, and there will be premature senility and abnormal gametes. abnormal physiological phenomena such as inflorescence or ovary shedding. There are also some plants will appear stem base heat ulcer, plant root rot or aboveground wilting and other phenomena. If the temperature is too low, it is easy to cause freezing damage to flowers. After freezing, woody plants show bud withering, top withering, withering, broken skin, glue flow and fallen leaves from the top down; the tender stems or young leaves of some plants will appear water-like disease spots on the injured parts, and then turn brown and finally the tissue dies; and some whole plants will turn black, dry and die.

Attention should be paid to keeping plants warm in autumn and winter, and if frost injury occurs, the frozen tissue should be removed in time so as not to rot in the frozen place and affect other good tissues.

⑤ drug damage. The improper use of chemicals has caused drug damage to flowers. If you spray too much arsenic preparation, Bordeaux liquid, lime-sulfur mixture. Plants will appear burn spots or stripes on the leaf surface or petiole stem 2-5 days after spraying, and the leaves turn yellow, deformed, wither, fall off and other symptoms. Therefore, when spraying pesticides to the plant, we must pay attention to the concentration, try not to be too concentrated, can be low concentration, spray several times.

⑥ environmental pollution. For example, if there is a lot of sulfur dioxide in the air, it will destroy the chloroplast of plant palisade cells, and then destroy the cellular structure of sponge tissue, causing the cells to shrink and disintegrate, and flowers will wilt; there are also dark green water collapse spots that further develop into necrotic spots. There are also plants that are sensitive to fluoride. Fluoride and calcium combine to form insoluble substances, resulting in calcium deficiency in plants. Reddish-brown patches or streaks will appear on the leaf tip and edge of the plant, and the leaf veins will also be reddish brown, which will gradually necrosis, break and wither in the end. When plants have some symptoms, think about whether it is caused by serious air pollution, based on which you can judge the air quality, take the initiative to cultivate other plants or use other means to improve the air at home.

two。 Insect pests of flowers and their control

There are two main types of insect pests:

(1) chewable pests: such as green insects, diamondback moths, longicorn beetles, crabs (beetle larvae), etc., all belong to this category. This pest can scratch or perforate the roots, stems, leaves, flowers, fruits and other parts of the plant.

At this time, stomach poisons, contact pesticides such as enemy killing, trichlorfon, phoxim and so on can be used to kill pests.

(2) absorptive pests: such as aphids, scale insects and red spiders (mites). These pests use mouthparts to pierce the plant to absorb juice. These pests will cause plant stems and leaves to appear spots, shrinkage, discoloration and other symptoms. At this time, contact and inhalation pesticides can be used, such as dimethoate, clenbuterol and so on.

Scale insects are common insect pests, which often damage cycads,

Loose-tailed sunflower, Magnolia, sweet-scented osmanthus, camellia, Michelia, Jiuli incense, banyan, elm, Fujian tea, palm bamboo and so on. Heavy occurrence occurs in the environment of high planting density and high shade, and it is easy to cause fallen leaves, withered branches and even plant death if it is not controlled in time. To eliminate this kind of pests, we can choose quick culling, omethoate control, and mites control with dimethoate, clenbuterol, diformamidine and so on.

There are many kinds of flowers damaged by mites, such as citrus, elm, marigold, rose, rose, cycad, bamboo and so on. Autumn is the peak of mite damage, so corresponding pesticides must be used for timely control.

When maintaining the flowers, we should pay attention to preventing insect pests in advance.

(1) for example, clean up the diseased branches and leaves of potted plants in time, keep the dish clean, and use clean water to water flowers.

(2) after the occurrence of insect pests, we should prescribe the right medicine to the case, find the insect pests in time, then buy the corresponding insecticides and spray pesticides on the plants to kill the pests. In addition, pest control can also be carried out by means of pesticide perfusion and smearing of concrete slurry.

3. Home-made pest control drugs

The following introduces some household pesticides, which can prevent and control diseases and insect pests, do not pollute the environment, and are convenient to obtain materials and easy to operate.

Ginkgo biloba L. Mash the ginkgo and then add the same amount of water to filter the original solution. When using, take the original solution, and then add twice the water dilution, install a human sprayer, spray on flowers, can control aphids.

(2) peach. Add water to the peach leaves according to the 1:6 weight ratio, cook for 30 minutes, and spray the filtrate directly to control aphids and other molluscs.

(3) mint. Mint is chopped and mashed, water is added according to the weight ratio at 1:5 and soaked for 24 hours. the filtrate can control leafhoppers and net bugs. "

(4) Pepper. Stir the pepper and water according to the 1:10 weight ratio, boil for 30 minutes, and spray the filtrate to control aphids and bugs.

(5) Tobacco. Soak tobacco and water according to the weight ratio of 10, soak for 24 hours, or boil for 1 hour, soak the filtrate through the basin soil, you can kill the ants in the basin, or take the filtrate to dilute the same amount of water and add a little soap to control aphids, red spiders, thrips and leafhoppers.

(6) Chinese prickly ash. Pepper and water according to 1:10 weight ratio mixed, boiled, divided into 5 parts of the original solution, and then according to the capacity ratio of 1:10 water diluted spray, can control whitefly, aphids.

(7) hibiscus. The filtrate can control root rot and blight by mixing hibiscus flower and water according to the weight ratio of 1:10 and soaking for 24 hours. (8) Ginger. Take ginger, mash and squeeze the juice, and then dilute the juice and water according to the volume ratio at 1:20, which can be prevented.

Rot.

(9) Chinese chives. Take leek mashed, mixed with 10 times of water diluted spray, can control rust and aphids.

(10) onions. Take green onions and mash them, add water to water according to the weight ratio of 2RU 1.5, filter and spray to prevent white disease and aphids.

11) garlic. After mashing the garlic and mixing the same amount of water, adding three times the water dilution spray can control powdery mildew, gray mold, root rot, aphids, red spiders and other molluscs.

(12) Plant ash. Plant ash and water were added according to the 3:10 weight ratio, soaked for 48 hours, clarified and sprayed on plants to control aphids and Botrytis cinerea.

(13) mosquito incense. Light the mosquito incense containing pyrethroid and put it in the flowerpot, then cover the whole pot with plastic and seal the smoke for 50 minutes for 60 minutes to kill the red spider.

(14) the essence of wind oil. Add 600 times water to the essence of wind oil to make solution spray, which can control aphids and shells.

Insects, red spiders, etc.

(15) washing powder. Pour 150 times of water into washing powder, stir evenly or spray every 5 days for 2 or 3 times in a row, which can control aphids, red spiders, shell insects, whitefly and so on.