The killer of scientifically raising orchids rotted and dried up.

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The so-called soil infectious disease means that most of the germs spread and infect from the matrix materials. these diseases have one of the biggest characteristics. They are devastating and catastrophic for orchids. In most cases, there is no life or death. It is preventable and difficult to treat. The general non-soil infectious diseases are normally only traumatic, such as damaged leaves, spots, damage to plant integrity and aesthetic appearance, this kind of disease can not only be prevented but also treated.

The pathogen of Phytophthora blight is flagellum subphylum Phytophthora and Phytophthora Phytophthora. The typical symptoms of the former are that the upper part of the leaf is mostly green in the early stage, the leaf base turns yellow, and the leaf base is broken when the environment is dry; in the latter, there are wrinkles, black spots, necrosis, rot, green withering and atrophy of leaves in the middle stage, and stem base rot in the later stage, similar to soft rot, which is basically difficult to distinguish from soft rot in hot and humid conditions. The former is common in ink orchids.

The pathogen of Rhizoctonia solanacearum is Rhizoctonia solani. The typical symptoms are rotten roots, yellow leaves, and then withered leaves. Under normal circumstances, the roots rot first, and finally the leaves wither and die. Sometimes in the early stage, it can be observed that most of the leaves are green and atrophied. In most cases, it takes several weeks from root rot to leaf death, and some take months to one or two years. It is consistent with Fusarium wilt in the later stage, and the main difference lies in the early stage, because Rhizoctonia solani is rotten roots first and then yellow leaves, so in the early stage, the leaves can sometimes be observed in the early stage, the leaves atrophy in the green, the leaf edges curl, the leaves wither and yellow, from the leaf tip to the leaf base withered, the overall leaf performance is from the leaf tip to the leaf base. It is withered while it is yellow, and most of the new buds have long been necrotic, rotten, or do not sprout.

When the humidity is high, the "non -" white mycelium or sclerotia can be observed (I understand it as brown), "non-white" is mainly to distinguish it from white silk disease. The sclerotia and hyphae of Rhizoctonia solani overwintering in materials and diseased tissues are highly saprophytic, and generally can survive in the soil for two to three years. Under suitable conditions, the pathogen invades the root directly from the wound and expression, and the pathogen can invade by water, utensils, organic fertilizer, and immature materials. High temperature and humidity are beneficial to the spread of hyphae. When selecting preventive and therapeutic agents, we must be targeted at hyphae and sclerotia. Otherwise, it is difficult to prevent and treat.

Fusarium wilt is caused by Fusarium oxysporum. The typical symptoms are first yellow leaves, then rotten roots, serious root withering and corm rot. Plants can die quickly in a short time, some for a day or two, and some for a few weeks. Fusarium infection destroys vascular bundles and causes dehydration and lack of nutrition, which is a kind of necrosis from the inside to the outside, which leads to the loss of water and nutrition, and the leaf surface is yellow at first. after the leaves turn yellow at the initial stage, we can see that there are purplish red necrotic areas on the yellow leaves, mostly on one side of the main vein, rather than whole leaves, this is because the vascular bundles in the leaves are necrotic. Most of this phenomenon starts from the lateral leaves, and when the whole vascular bundle is necrotic, the leaves will wither and die. The difference between Fusarium oxysporum and Rhizoctonia solanacearum on the leaf surface, Rhizoctonia solanacearum is yellow on one side, withered on the other, from the tip of the leaf to leaf disease, mostly from the central leaf; Fusarium is first yellow, then purplish red at the same time, and then the whole leaf is withered without obvious gradual death, mostly from the side leaves.

Second, Fusarium wilt is from the first bad root, and then to the leaf surface; Fusarium is the first bad aboveground part, and then rotten root; finally, Fusarium wilt basically will lead to the necrosis of new buds, do not send, basically when the leaves are dry, can not see new buds; Fusarium basically will not show from the new buds, a lot of time when the disease seedlings withered and necrotic, can also see new buds snow-white, clean green, the surface is healthy. In addition, the incubation period to the expression period to the necrotic period is a very slow process. In many cases, when we see that the leaves are scorched, we cut them while withering, and they are gone at the end; Fusarium is a quick process from leaves yellowing to death, especially from the appearance of purplish red on the leaves, which will dry in a day or two.

The pathogen of white silk disease is basidiomycetes subphylum Sclerotinia in the sexual age, and the asexual generation is Sclerotinia sclerotiorum. The typical symptoms are rotting stems, then yellow leaves, and then withering from the bottom to the top, and in severe cases, the roots rot. In the early stage, the brown disease spot of running water discharge in the stem can be observed, and the dense white hyphae can be observed on the surface. The bulb gradually spreads up and down at the center. Finally, the small sclerotia of rape with large grains similar to Rhizoctonia solani can be observed. The difference between him and Rhizoctonia solani and Fusarium oxysporum is that he can see the white hyphae, which begins to rot from the stem.

Nematode disease, its pathogen is nematode, is nematode pest, not germ pest and ordinary insect pest, so the use of drugs to control germs or insect pests can be said to be basically ineffective, or can be understood as absolutely ineffective. The nematode first sucks the cell through its oral needle, then injects the liquid secreted by the base into the cell, liquefying some useful substances in the cell, and then inhaling the esophagus through the oral needle. This special way of smoking determines that the disease invaded by the nematode will show a liquefied greasy shape. In orchids, nematodes infect the roots of human beings in most cases. Due to the destruction of roots, the upper leaves of the plants show a poor state of water supply, mostly leaf tip dehydration, leaves withered and yellow. The typical symptoms are greasy roots and linear worms. Some can be seen directly in the stem, while others can only be seen by turning to the root.

The pathogen of bacterial soft rot is Eucella, the staining reaction is Gram-negative, the typical symptoms are rotting and smelly of new seedlings or new buds, and green in the upper part of leaves. Bacterial soft rot mostly occurs in new seedlings or buds, because bacteria can reproduce once in 20 to 30 seconds under favorable environmental conditions, which determines the rapid onset of bacterial soft rot, which usually takes two to three days to completely rot the base of the new seedling. In the early stage, water-immersed spots can be seen in the leaf base, and the disease spots can be seen to expand rapidly in a day or so. When the disease is serious, the contents of the rotting cells are rapidly lost and withered, and sometimes we can see that most of the upper parts are intact, and only part of the vascular bundles or fiber bundles exist in the lower veins. Most of them showed bacterial brown spot on the old leaves. The symptoms are early black spots or water-immersed spots, quickly growing in large areas, and finally perforation occurs when it dries up. Sometimes bacterial spot disease can also cause bacterial soft rot. The typical symptom of bacterial spot disease on new seedlings is that it mainly suffers from the leaf tip. In general, the leaf tip first appears a small black dehydration, and then rapidly expands into a small section of black dehydration. Disease spot and health junction to remove no yellow halo. It can turn into bacterial soft rot in hot and humid conditions. If the observation and control is not timely, it can quickly cause a large area of new bud rot.

7) the rot after fermentation mainly occurs in the deep-planted fine soil environment. The leaf center of orchid seedlings is similar to a cup-shaped one, which can show water, and can also hold part of the solution when applying fertilizer. When we water and fertilize the new buds, because the new buds are fine and tender, they are deeply buried in the fine soil. When the leaf center is water, it will isolate the air, produce a similar fermentation environment, produce a large amount of malignant gas, and make the new buds rot. At the same time, due to water evaporation, the concentration of leaf core solution will gradually increase, resulting in reverse osmosis, which will weaken the physiology of cells and accelerate decay.

The above seven diseases are often said in our orchids, such as blight, Fusarium wilt, quenching, black rot, stem rot, root rot, under normal circumstances, the above diseases must be observed and treated in time, but because of our experience and common sense, as well as the particularity of the above bacteria, most of them are very difficult, because when we observe the yellow and withered leaves, it is already late. Therefore, in my personal opinion, prevention is the first and can be said to be the most important, but now because the research on blue disease is not yet in-depth, and because quite a number of manufacturers do not formally produce orchid drugs, most of them are only part of the interests of people who tear off the packaging of some off-the-shelf medicines and change their names and exaggerate their uses to buy them to Lanmin, so it also leads to difficulties in the prevention and control of the above six germs in Orchid Industry.

The descriptions of these diseases that I see when I surf the Internet and read various orchid magazines can be said to be varied and wrong, some confuse fungal diseases with bacterial diseases, some confuse different fungal diseases, some confuse soil infectious diseases with general spot diseases, and some even confuse biological infectious diseases with physiological diseases. So write what I know and use it for reference. I hope you can make a careful diagnosis and distinguish the pathogen so as to facilitate the selection of drugs for prevention and treatment. Of course, there may be other pathogens that cause the orchid seedlings to wither and rot. Because of the limitations of the conditions, we can only combine the pathogens published by the current authoritative scientific research institutions with the results of our own observation and data investigation and examination for several years. To give you a further clear explanation, in order to facilitate the prevention and control of bacteria. Due to human factors, such as understanding, the description will cause some difference, please cool the solution.

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