There is a layer of powder on the leaves of the lemon tree, and the ends of the leaves are yellow an

Poor ventilation, over-watering of potting soil, and insufficient light.

Significant potassium deficiency symptoms. Foliar sprays of potassium dihydrogen phosphate can be used.

At the same time, the pot is watered.

Potted lemon trees.

The tips of the leaves begin to dry and brown, and the treatment is sufficient.

First, the yellow of drought and water is not the same as the yellow of water, the yellow of water shortage is the leaf tip or edge withered, dry, and the old leaves are withered and yellow from the bottom to the top, but the growth of new leaves is relatively normal. Pay attention to watering when watering enough, water thoroughly. Second, the lack of fertilizer yellow is manifested in the young leaves become lighter, yellow or light green, while the old leaves are more normal or gradually turn from green to yellow.

It is necessary to check the potting soil frequently, if there is a dry knot phenomenon, the soil should be replaced, and the thin fertilizer should be applied diligently, and some alum water should be poured in a timely manner to replenish iron. 3. Lack of light yellow in the shade environment for a long time, the leaves do not get enough sunlight, can not form chlorophyll.

The whole leaf turns yellow and then falls off, which can be avoided by supplementing with light. Fourth, the yellowing of flowers caused by excessive fertilization or excessive concentration of fertilizer is manifested in the dry brown appearance at the top of the new leaf, the general leaf surface is thick and dull, and the concave and convex are not stretched, and the old leaves are scorched and fall off. Fertilization should be stopped immediately, and part of the fertilizer should be washed with plenty of washing in severe cases.

Fifth, the scorching yellow strong sunlight directly shines on some shade-loving flowers (such as spider plant.

hosta, etc.), it is easy to cause the leaf tips and leaf margins of flowers to wither, and the sunny part of the leaves appears yellow spots. Move to the pubic area.

This is caused by red spiders, and if the indoor air is dry, there will be, just take some alkyne mites and thiophanate-methyl.

There are four main cases of yellowing of lemon leaves.

First, iron or nitrogen deficiency requires targeted supplementation.

Second, if the nutrients are insufficient, fertilizer needs to be supplemented, and spraying is generally required.

The third root system is caused by rot, most likely caused by stagnant water.

The rotten roots need to be cleaned, and the wound should be healed and covered with soil.

Fourth, there are insect pests, which need to be sprayed with corresponding agents.

Scale insects, copy and are very, very serious bai.

Liquor to water, the ratio is 1:2. When treating insects, water the surface layer of potting soil. DAO scale insects begin to be active at room temperature 7 in spring. It can be poured once in April, and then every half a month or so, and it is effective for 4 consecutive times.

Use 50 ml of vinegar (rice vinegar), soak a small cotton ball in vinegar, and gently rub it on the stems and leaves of the affected flowers and trees with a wet cotton ball to wipe off and kill the scale insects. This method is convenient and safe, which can not only achieve the purpose of insect control, but also make the damaged leaves green and shiny again.

Gently and repeatedly rubbing the diseased plant with alcohol can get rid of the scale insects, and it can be very clean and thorough. If you wipe the orchid leaves with alcohol, not only can you get rid of the scale insects, but also the larvae that are not clear to the naked eye, and they are completely killed, and the second year is rarely found to have scale insects as a pest, this method is simple, safe, and the effect is good.

Use diesel, laundry detergent and water to adjust the mother liquor in the ratio of :6, at this time the mother liquor contains 60%, milk-like, dilute the oil content of 30% with water, and carefully spray the scale insects on Milan, kumquat and cycad. After one week, most of the scale insects changed from fresh orange to shriveled state, indicating that this method has a good control effect on scale insects.

The above methods are good for plants that are not seriously infested, so you can try this.

The yellowing of lemon leaves is due to a lack of magnesium fertilizer.

In the later stage, the lack of magnesium fertilizer is severe, and the whole leaf will turn yellow.

Chlorophyll cannot be synthesized without magnesium fertilizer, so magnesium fertilizer supplementation is sufficient.

I gave birth to whiteflies. Just spray it with a medicated one that contains permethrin and permethrin.

Caused by incorrect watering. The principle of watering is not to dry or water; Pour it thoroughly. If the watering is not watered thoroughly, it is easy to hurt the roots, and the leaf tips will turn yellow.

There are many reasons for the yellowing of the leaves of lemon trees, if it is caused by insufficient nutrients, it needs to be fertilized appropriately to increase nutrients; If it is caused by insect infestation, it is necessary to spray pesticides to eliminate insect infestation; If it is caused by root rot, the root needs to be pruned; If it is caused by high temperature exposure, it needs to be properly shaded.

1. Increase nutrients.

1. Reason: When lemons are growing, they need a continuous supply of nutrients, and if the nutrients are insufficient, the leaves will turn yellow.

2. Solution: Don't add nutrients first when you find that the leaves turn yellow, and the process of adding them is a little slower, so that it is easier to accept. If the disease has not been alleviated after the addition of nutrients, it is necessary to consider whether it is iron deficiency and deficiency of goldenrod, in this case, it is enough to add iron-containing fertilizers.

In the lemon growth period, the foliar fertilizer of Falat amino acid can also be applied to supplement leaf nutrition.

2. Eradicate insect pests.

1. Reason: Pest pests will affect its health, and the leaves will turn yellow.

2. Solution: Spray diluted insecticides on the branches and leaves, if there are pests in the pot, you need to change the potting soil, and the potting soil should be disinfected.

3. Roots.

1. Reason: The root is rotten, most of which is caused by too much watering or too thick fertilization, which will directly affect its ability to absorb nutrients, and it is not surprising that the leaves are yellow.

2. Solution: First of all, you need to clean up the rotten roots, then apply diluent to the incision, and then cover the soil after the incision is dry and scarred. After covering the soil, try to water as little as possible to avoid re-infection.

Fourth, proper shading.

1. Reason: Lemons like the sun but do not like to be exposed to the sun, and the leaves will turn yellow after exposure.

2. Solution: If it is a pot culture, you can move it back to the house when the sun is strong, and then move it out when the strong sunlight passes; If it is farmed outdoors, it is necessary to take shade measures at noon and leave it exposed to the sun.

The lemon sapling has that sand peel on it.