Radical cure of burnt tip and cultivation of strong seedling

Figure 1: Cheng Mei who won the gold medal Figure 2: Physiological scorched tip symptoms Figure 3: Brown spot symptoms Figure 4: Anthracnose symptoms Figure 5: Black spot symptoms Figure 6: Black spot symptoms Figure 7: Dry tip symptoms Figure 8: Black spot on the leaf blight Figure 9: Anthracnose and black spot damage at the same time Figure 10: Black stripes at the junction of diseased leaves Figure 11: Physiological scorched tip, brown spot, anthracnose, dry tip, leaf blight and black spot Figure 12: Remove the diseased leaves to cure the scorched tip and cultivate strong seedlings

Lu Mingxiang

In 2006, China's first Cymbidium Expo was held in Xuanwu Lake, Nanjing. The diecai and Cheng Mei presented by the author both won gold medals. After Cheng Mei won the gold medal, a debate on "Should this pot of Cheng Mei win the gold medal" was triggered in "China Orchid Net." The main focus of the debate is that some Lan friends think that this pot of Cheng Mei is a native species, the orchid grass is healthy, the flower quality is good, and it deserves the gold medal; there are also some Lan friends who think that although this pot of Cheng Mei is good, the orchid grass is healthy, but the orchid grass is burnt and sharp, and it should not win the gold medal. (Photo 1: Cheng Mei, Gold Award winner) I used to think that it was not surprising for orchids (especially cymbidium) to have some scorched tips when cultivated in a natural environment, so I never paid much attention to it. This spring, Shandong a Lan you to my garden to buy orchid grass, insisted on a pot of not a little coke sharp Xie Peimei. This argument and Shandong Lan You purchase orchid matter touched me very much, it told me: although orchid grows strong, but if the head is burnt, it is still not a healthy good grass. This incident also prompted me to calm down to study, think, explore and solve the focal point problem of Lan Ye.

(1) The main reason for the burning tip of the orchid leaf

There are many reasons for causing scorched tip of orchid leaves, some are caused by natural factors, some are caused by improper management, and some are caused by diseases. Among them, the scorch tip caused by disease is the most serious.

1. Focal point caused by natural factors

1) The humidity is too low. The scorched tip of orchid leaves is closely related to water supply, especially if the leaves of cymbidium are longer, if water supply is not sufficient, it will inevitably cause scorched tip of orchid leaves. The water supply of orchid leaves is transported by roots and absorbed from the air. Therefore, the reason for the scorched tip of orchids, in addition to the excessive dryness of the pot soil, has a lot to do with the low humidity of the air. If the humidity in the air is too low and too dry, it will cause the transpiration of orchid plants to strengthen, and the imbalance between water supply and demand of orchid leaves will cause the tip of orchid leaves to be burnt. Generally speaking, indoor orchid air humidity is larger, blue leaf coke tip situation is not serious, and outdoor orchid because of air humidity is difficult to control, blue leaf coke tip situation is more serious.

2) Climate change. Take 2007 as an example, people just moved orchids out of the orchid house with high humidity, that is, they encountered a drought once in decades, the river dried up and the air humidity was extremely low, so the orchids were more severely scorched. Although the plum rain season comes late, but the time is very long, up to 50 days or so, the orchid leaves that have not seen the sun for a long time are thin and soft, just out of the plum rain season immediately encounter high temperature and scorching sun, so the situation of coke tip becomes more serious. The author visited several outdoor orchids, and the coke tip of cymbidium is more serious.

3) Air pollution. Lanyuan is close to sewage area, industrial area, or someone burns harmful substances near Lanyuan, causing harmful gases to pervade the air and harm orchid leaves and cause coke tip.

2. Focus caused by improper management

(1) The light is too strong. Summer lack of shade or shade intensity is not enough, resulting in too strong light, resulting in blue leaf coke tip.

(2) Long-term maintenance. Orchids in the growth process of excessive shade, too weak light, long-term shade, resulting in thin and weak orchid leaf quality, if suddenly let orchids see strong light, easy to cause orchids coke head shrink leaves.

(3) Water damage to seedlings. Watering too often causes rotten roots and leads to burnt tips. Sunlight spray, water gathered leaf tip, by strong light irradiation and coke tip. Water quality pollution, or orchids drenched in acid rain can also cause scorched leaves.

(4), fertilizer damage leaves. Root fertilization fertilizer concentration is too large, too frequent, resulting in blackened roots, and then cause blue-leaf coke tip.

(5) The application is too concentrated. Pesticide ratio has a certain proportion, if the concentration exceeds the standard, spraying too much, resulting in pesticide accumulation orchid leaf tip, causing leaf tip damage caused by coke tip.

(6) Plant material is too dry. Lazy watering causes the plant material in the pot to be too dry, unable to meet the water demand of the orchid plant, forming empty roots, the orchid leaves cannot get normal water supply, and the orchid leaves are scorched because of water loss.

The above-mentioned several kinds of blue leaf coke tip caused by natural factors or improper management are usually called physiological coke tip, which is usually black, and there is no black striation at the edge of the disease, so it will not advance rapidly, the course of disease is relatively slow, and the degree of harm is not large. (Fig. 2: Physiological burn tip symptoms) As long as the cause is found out and symptomatic management is carried out, the harm caused by orchid leaves can be controlled.

2, the focus caused by bacteria

(1) Bacterial brown spot disease. Orchid brown spot disease is caused by bacterial infection of orchid leaves, it is the most ferocious burning tip disease in orchid leaf disease, easy to identify, its disease spot is brown, its leaves in the early stage of the disease have water-like discoloration spots, and quickly connected to a piece forward, causing the whole leaf to die, it is highly infectious, rapid spread, great harm. (Figure 3: Symptoms of brown spot disease)

(2) Anthrax. Anthracnose of orchid is caused by fungi, it is the most common scorch tip disease of orchid leaves, it is easy to identify, its remarkable characteristic is that there are several wavy transverse black bands after the leaf tip is damaged and dried, if the scorched tip leaves are cut off, they will continue to advance, it is a serious scorch tip disease. (Figure 4: Anthrax symptoms)

(3) Black spot disease. Orchid black spot disease is caused by fungi, is one of the most common orchid leaf scorch tip disease, easy to identify, its remarkable characteristic is that the disease spot is round, scattered on the leaf surface and leaf edge, serious can also be connected into a piece, resulting in the whole orchid leaf lost ornamental value. (Figure 5: Symptoms of black spot disease)

(4) leaf blight. Orchid leaf blight is caused by fungi, is one of the more ferocious scorched tip disease, easy to identify, its remarkable characteristics are late leaf tip turn gray whole section dead, sick leaf junction is dark brown, and constantly advance, even make the whole leaf quickly dry, great harm. (Figure 6: Symptoms of leaf blight)

5. Dry tip disease. Orchid blight is caused by fungi, is the most common scorched tip disease, easy to identify, its prominent characteristics are dead part of the grayish yellow, no banded traces (and anthracnose difference), the junction has black-brown stripes. (Figure 7: Symptoms of dry tip disease)

These diseases sometimes occur singly, and sometimes several diseases occur simultaneously. For example, orchids not only suffer from leaf blight but also suffer from black spot, and black spots still exist after leaves die. (Fig. 8: Black spot disease on leaf blight) Another example is that blue leaves suffer from both anthracnose and black spot disease. After the leaves die, both diseases exist at the same time. (Figure 9: Anthracnose and black spot simultaneously harm)

The damage caused by the fungus is generally serious. There are usually black stripes at the disease edge, and this black stripe disease spot keeps advancing (Figure 10: black stripes at the junction of diseased leaves). In severe cases, the whole leaf will be scorched and withered. Even if it is cut off, it will continue to be scorched and scorched again until it is bald. Even the life of the orchid plant constitutes a deterrent, must not be underestimated.

(2) Accurate diagnosis of blue leaf scorched tip disease

Although the symptoms of all kinds of focal point disease have been clearly explained in the front, it is difficult to distinguish what causes the focal point of Lan You in general. In fact, it can be identified as long as you pay attention to observation. (Fig. 11: Physiological scorched tip, brown spot, anthracnose, withered tip, leaf blight and black spot) From this picture we can clearly see their remarkable differences:

1. Physiological scorched tip (water injury, fertilizer injury, phytotoxicity, etc.) is completely black at the injured place, and there is no black stripe at the junction; pathological scorched tip leaves are not black after withering, and there are black stripe disease spots at the junction.

2. The disease spots caused by bacteria have brown spots with boiling water in the early stage; while the dead tips caused by fungi have no yellow-brown patches.

3. Diseases caused by fungi generally have black horizontal spots at the junction. Anthracnose damaged dead tip, there are several horizontal wavy black stripes, other diseases do not have such wavy stripes; leaf blight damage is gray; leaf blight damage is gray yellow.

To sum up, all the affected parts of physiological scorched tip are black, and there are no black stripes at the junction of diseased leaves; the affected parts of bacterial brown spot disease begin to have brown patches, and the later diseased spots are black, and there are black stripes at the junction of diseased leaves; there are several horizontal wavy black stripes on the affected leaves of anthracnose disease, and there are black stripes at the junction of diseased leaves; the affected parts of leaf blight are gray white, and there are black stripes at the junction of diseased leaves; the affected parts of dry tip disease are gray yellow, and there are black stripes at the junction of diseased leaves.

Only when we accurately grasp the symptoms of all kinds of Jiaojian disease, can we know and target when treating Jiaojian disease, so we must make great efforts to study it, and really do the right medicine when treating it.

(3) Measures to eradicate focal point disease

It is indeed difficult to eliminate the blue leaf scorched tip disease caused by the disease fundamentally, but as long as we actively treat it, seriously manage it and comprehensively control it, we will certainly achieve remarkable results.

1. The diseased leaves should be cut off. Since the leaves are already sharp, it is not enough to cut them off. They must be resolutely cut off. There is no need to linger. Cut off the diseased leaves thoroughly, cut the mouth to be more than 1 cm away from the diseased spot, if the old plant is seriously ill, you can cut off the whole plant mercilessly. (Fig. 12: Cutting off diseased leaves) Several years ago, I bought several clumps of mountain grass, which had serious black spots on the tip. At that time, the new grass was not infected. I immediately cut off all the old plants and sprayed them with thiophane methyl. Later, the new plants did not become infected. The diseased leaves should be burned or buried deeply after being cut off. Never leave the cut diseased leaves in the orchid garden. The diseased leaves dropped on the ground during pruning should also be picked up to prevent them from becoming the source of disease again.

2, medication should be symptomatic. Orchid leaves have been scorched tip, to find out what is the cause? If it is caused by improper management of physiological focal point, then symptomatic strengthen management. If it is caused by disease, it is first distinguished whether it is caused by bacteria or fungi. This is a good distinction, that is, the brown spot disease caused by bacteria has an obvious symptom: the early stage of the disease is like boiling water. The diseases caused by bacteria were controlled by streptomycin, chlorothalonil and chlorpyrifos, while the diseases caused by fungi were controlled by thiophanate methyl, chlorothalonil and other chemicals. If it is difficult to distinguish what kind of disease it is at the moment, the mixture of bactericidal and fungicidal agents can also achieve twice the result with half the effort.

3. Treatment should be timely. Once the disease is discovered, it is necessary to use drugs in time for treatment. Do not have the paralytic thought of "Lan Ye Jiao Jian has nothing to do with it", let alone the wrong thought of "Lan Ye Jiao Jian is normal", and delay treatment will cause the disease to worsen and expand the scope. It is necessary to clearly realize that the speed of infection of orchid leaf disease is very fast, although it is not fatal, but it loses its ornamental value. Moreover, it is impossible for orchid leaf to become a commodity when it is bald.

4. Prevention should be constantly grasped. "Prevention is more important than cure", prevention work should be constantly grasped, to spray liquid medicine regularly, preventive medicine should start from early spring, killing bacteria, fungicidal medicine should be together, every 7~10 days, even if no disease is found, medicine should be used, prevention before it occurs, disease should be eliminated in the bud.

5. Water spraying is strictly prohibited. Once the orchid leaves appear scorched tip caused by bacteria, it must be strictly prohibited to spray water. Because spraying water will make the leaves wet and accelerate the propagation of germs, while spraying water will accelerate the spread of germs, causing malignant transmission. If there is too much dust on the leaves, which affects the photosynthesis and respiration of orchids, it can be sprayed immediately after spraying when the leaves are dry to prevent the spread of germs.

6. Management should be strengthened. Not only the physiological burning tip of orchid leaves is related to management, but also the burning tip caused by bacteria has a great relationship with management in the final analysis. Therefore, we should think more and study more in management, do a good job in managing orchids, and try our best to eliminate the burning tip of orchid leaves caused by man-made.

7. Be careful when buying grass. Because of growing in high temperature and humidity environment all the year round, the seedlings of returning grass and greenhouse grow almost soaked in liquid medicine. Once transplanted into natural environment, due to increased light and reduced humidity, they will quickly cause scorched head and shrinking leaves.

8. Pesticides should be rotated. Any pesticide used for a long time will produce resistance, so must not use a pesticide for a long time to control diseases. Pesticides should be rotated frequently. Generally speaking, each pesticide can be replaced by three consecutive uses, so that better control effects can be achieved.

"It is difficult to raise orchids, and it is more difficult to seal the tips of orchids leaves," especially for orchids cultivated in natural environments. "Let the orchid seal tip" is an important topic that every orchid keeper needs to study, and it is also the highest level that every orchid artist wants to pursue!