What is the cause of yellow leaves and how to deal with it

In addition to the normal growth physiological law, the general leaf survival time on the plant is about 3 years, and the old leaves turn yellow and age and fall off naturally, which is the natural process of the growth metabolism of the orchid, but the new leaves are not normal in time.

The main symptom of leaf spot disease is the appearance of small yellow or brown dots on the leaf surface, and then the color of the spots gradually deepens, and the area of spot ulceration gradually expands, so that the leaves or the whole plant rot.

The main reasons for leaf spot are: first, the application of fertilizer that is not fermented. Allow germs to multiply in the potting soil.

Second, the potting soil has not been changed for a long time, and there are pathogenic bacteria in the old soil. The third is that the new soil is relatively raw and has not been fully fermented. Secondary fermentation in pots.

Fourth, the imbalance of nitrogen, phosphorus and potassium of fertilizers, especially caused by less potassium fertilizer or direct fertilizer contact with roots during fertilization. Different approaches to prevention and prevention are needed to address specific causes. The fertilizer applied must be fully fermented, the fertilization concentration should be small, nitrogen, phosphorus and potassium should be balanced, and the fully fermented nutrient soil should be replaced twice a year in spring and autumn, without raw soil.

In this way, leaf spots can be eliminated.

The main symptom of xanthophyllosis is that one leaf turns yellow locally, the yellow leaf part is irregular, and the end of the second leaf turns yellow first and gradually spreads to the pseudobulb. The three pseudobulbs first turn yellow and gradually spread to the leaf end, and the fourth is the whole leaf turns yellow from the bottom to the end at the same time. The first situation is caused by the surface of the leaf being burned by sunlight exposure, cold wind, local slug, snail and other pest bites where the germs spread, or the wound expands after trauma.

The reason why the leaf end turns yellow first is mainly that the rotten roots interrupt the leaf nutrition**, and the leaf begins to turn yellow from the tip of the leaf to the pseudobulb. or hypertrophy and thickness, the use of raw soil or poor soil quality can cause this phenomenon. The third condition may be caused by insect bites that gradually expand the leaves of the pseudobulb to the tip, or water accumulation at the pseudobulb in summer, and bacterial breeding of local yellow leaves.

And gradually spread. It is more common for the whole leaf to turn yellow at the same time, and the cause is more complex, mainly due to improper management. For example, poor ventilation in summer, large amounts of water, excessive fertilization, and root problems may cause the leaves to turn yellow as a whole.

Preventive measures, first of all, to prevent plant rot roots, so that the leaves can get sufficient nutrition, and then to eliminate trauma, to prevent the spread of wounds, the amount of fertilizer must be controlled, do not hypertrophy, summer adult flowers do not water to the false bulb, summer to pay attention to ventilation, cooling to strengthen management, regular spraying of carbendazim, chlorothalonil, methyl tobu, agricultural streptomycin and other sterilization drugs for prevention and control, that is, can reduce the occurrence of leaf spot, chlorophyllosis.

There are generally several cases of yellowing of the leaves of the orchid, if the bottom leaves grow new roots from the axils of the leaves, the yellowing of the leaves is a normal metabolism. One situation is that the leaf axils do not grow new roots and the leaves turn yellow, which is mostly due to soil quality, poor air permeability, too much fertilizer or poor watering and humidity control of the roots, which may make the leaves of the Junzi orchid yellow. Water can not be watered, the root tip lacks water, it will make the leaf tip turn yellow and dry tip, in this case, it must be watered thoroughly, in summer, every 7 10 days at the bottom of the pot can sit a small pot of water, so that you can ensure that the water is watered, this is called the water immersion method.

Another condition is the appearance of yellow spots of varying sizes on both sides of the leaves, called brown spots. This is mainly due to the fact that the soil is relatively grown, and the amount of fertilizer applied is too large. Generally speaking, the potting soil should be made of humus, with good air permeability, especially in summer fertilization, thin fertilizer should be applied frequently, and fertilizer water should not be dripped onto the leaves, so as to prevent the occurrence of spot removal.

In another case, due to the abundant sunshine and high temperature in summer, if the orchid is exposed to the sun, solar fever will also occur, and the leaves will turn yellow and wilt in the heavy. In summer, shading should be taken, a ventilated place should be placed, and the shade should be avoided.

50 As a good thing, the south window of the home can be shaded with a layer of gauze.

The yellow spot of the leaves of the orchid is caused by the brown spot and leaf spot of the plant, as well as too much light and improper fertilization. If it is caused by excessive light and improper fertilization, the plants should be moved to a suitable position and given appropriate light and fertilizer.

The yellow spot on the leaves of the orchid is due to brown spot disease, which is mainly caused by fungal infection. In the early stages, it will change color from the tip of the leaf, showing oval-shaped brown spots on the leaf that will gradually extend to the petiole. In the later stage, the patches will dry up and turn yellow, and eventually fall off.

The residual leaves can be cut off and the relevant agents can be used**.

Leaf spot disease can also cause yellow spots on the leaves of the orchid, and in a dark and humid closed environment, high temperature, and poor ventilation, it will cause the plant to suffer from leaf spot. Yellow spots will grow on the reverse side of the leaves in the early stage, and large areas will grow in the later stage. After the plant gets sick, it is necessary to prune the diseased leaves in time, and wipe the spot with carbendazim or potassium permanganate solution and other fungicides.

Strong sunlight exposure will also make the leaves of the orchid grow yellow spots, the orchid likes light and is afraid of the sun, the plant needs sufficient sunlight for photosynthesis, but can not be exposed to the scorching sun, especially in summer, need shade. If the plant is exposed to strong sunlight in summer, the leaves will lose moisture and will shrink and dry out, slowly grow yellow spots, and then wilt and fall off.

Improper fertilization is also an important reason for the yellow spot of the leaves of Monarch Orchid, to fertilize reasonably, more nitrogen fertilizer needs to be applied during the growth of the plant, and more phosphorus and potassium fertilizer should be applied before the flowering period. Too little potassium fertilizer will cause rust spots to grow on the leaves. It should be noted that in summer, the temperature is high, the growth of plants is slow, and if you apply fertilizer frequently, it will cause the roots of the plants to be burned out, which will affect the growth of leaves.

It is brown spot disease, is a typical fungal disease, the initial symptoms start from the lower leaves, gradually spread to the upper part, the initial is round or oval, purple-brown, the later stage is brown spot black, the diameter is 5-10mm, the boundary is clear, the disease spots can be connected into a piece in severe cases, so that the leaves are yellow and fall off, affecting flowering.

The pathogen overwinters in dead leaves or soil with mycelium or conidia, and begins to occur in early summer with the help of wind and rain, and in autumn, the harm is serious, high temperature and humidity, insufficient light, poor ventilation, continuous cropping, etc. are conducive to the occurrence of diseases.

Prevention and control methods of brown spot disease:

Before or when the high temperature and humidity weather comes, it is necessary to apply less or no nitrogen fertilizer, maintain a certain amount of phosphorus and potassium fertilizer, avoid string irrigation and flood irrigation, especially try to avoid evening irrigation.

When dead spots appear, the dew should be removed as soon as possible in the morning to help alleviate the condition. Properly pruned residual branches should be removed in time, and timely and effective chemical control should be carried out.

First of all, it is necessary to prevent the plant from rotting roots, so that the leaves can get sufficient nutrition, and then it is necessary to eliminate external injuries and prevent the spread of wounds.

In summer, it is necessary to pay attention to ventilation, strengthen the management of cooling, and regularly spray carbendazim, chlorothalonil, methyl tobu, agricultural streptomycin and other sterilizing drugs for prevention and control, which can reduce and eliminate the occurrence of leaf spot and chloromycosis.

In general, this phenomenon can occur due to over-watering, over-fertilization, or too much sunlight, but in addition to this, it is also possible that the plant has developed leaf spot.

In general, this phenomenon can occur due to over-watering, over-fertilization, or too much sunlight, but in addition to this, it is also possible that the plant has developed leaf spot. Therefore, in the daily maintenance, we need to do as much as possible reasonable watering, scientific fertilization, moderate light, if leaf spot disease occurs, do a good job of pruning diseased leaves, replacing potting soil, spraying prevention and control.

Workaround:

1.Cut off diseased leaves. Yellow spots on the leaves of Junzi orchid are often due to leaf spot disease, and the diseased leaves and branches must be cut off in time to prevent the spread of the disease.

2.Replace the potting soil. After destroying the diseased leaves, replace the potted plants with new potting soil. Before changing the soil, the roots of the orchid need to be cleaned and disinfected, and the rotten part can be cut off directly. After all the disinfection and pruning treatment, plant it in the new potting soil.

3.Spraying control. If leaf spot disease occurs in Junzi orchid, it can be appropriately sprayed with 50% dycenum 1000 times liquid for prevention and control, sprayed once every 6 days, and sprayed four times in a row.