How to prevent and control black spots on the leaves of orchids

Orchid is a very fine plant in the process of planting and maintenance. if it is not managed properly, there will be certain diseases. Let me introduce to you how to prevent black spots on orchid leaves.

To prevent orchid leaves from growing black spots orchid maintenance requirements are relatively fine, a little inadvertently will occur leaf black spots and so on. If the head is drenched when watering, it is easy to splash up the basin soil and stick to the leaves, making the leaves scorched. When fertilizing, the fertilizer liquid is stained on the leaves, if you do not immediately spray clear water to remove, it will make the leaves appear black spots and scorch. If you do not pay attention to sunshade in spring and summer, it will make orchid leaves yellow and scorched in the scorching sun. Placed in an environment with more soot, orchids are blackened by smoke. In addition, orchids are damaged by anthracnose, and black spots often occur in their leaves.

Orchid anthracnose is especially easy to occur in high temperature and poorly ventilated plum rain season or autumn rain season, sometimes even more serious. The symptoms are that only semicircular or round brown spots appear in the leaves at the beginning, and then gradually develop into black-brown spots, many lesions expand into strips of dark-brown spots, and later become grayish white in the middle of the spot, with many small black spots on it. The disease is common in the middle and upper parts of the leaves.

When this disease is found, the diseased leaves should be cut off. When it is first found, in addition to improving ventilation, 50% carbendazim wettable powder can be sprayed 500 times, or topiramate wettable powder 500 times, once a week, 3 ~ 4 times in a row, can get better results. In order to prevent the infection of diseases and insect pests, orchids should not be too crowded and too dense, so as to avoid the intersecting of orchid leaves and keep a good environment of ventilation and light transmission.

The main control methods of black spot (anthracnose) are as follows: 1. Choose a place with good ventilation and no pollution to make an orchid farm. It is best to have trees, pools and small water tanks around the orchid field to improve the air temperature. Shade shed with bamboo curtain, sunshade net on the top, its shade degree had better be automatically adjusted, sooner or later open and breathable. The orchid pots should be arranged sparsely and densely so that the air is well ventilated. 2 keep it clean and hygienic. Often clean up the diseased and dead leaves of orchid, divide the pot of orchid grass or buy new orchid seedlings, disinfect and sterilize with methyl topiramate, air-dry and then plant. Plant materials (humus, pond mud, charcoal, etc.) must be disinfected at high temperature or used after sun exposure to prevent bacteria from entering the orchid basin. First, spraying method. Spray the sterilized solution (Bordeaux solution, Dysen zinc, carbendazim, tobujin, anthrax Fumei) with sprayer to orchid nursery, orchid soil, orchid pot, orchid leaf. This method is mostly used for prevention and the initial stage of the disease. After the onset of the disease, if the disease becomes more and more serious, it will enter and change the soil and basin. In order to sterilize thoroughly, the whole orchid with disease should be removed from the soil and soaked in the sterilization solution for several hours (for the "seriously ill" can be soaked for more time), then rinse the orchid plant with clean water, dry it slightly and then put it on the basin. Before putting on the new basin, spray the Langen orchid head again with carbendazim. Second, the towel method. For the leaves of bacteria suffering from anthrax, from the point of view of the whole plant and pieces, there are still preserved plants, and if you feel it is a pity to cut them, you can adopt the "towel method" of local encirclement and annihilation. The practice is: according to the size, shape and location of the disease spot, select soft toilet paper, napkins, etc., aim at the focus up and down, and then apply the sterilization solution on the paper with a pen or cotton swab. Several times a day. This method has a large amount of drug release in bud, and it is not easy to lose, so it can achieve the curative effect of winning by strength. Third, the method of division. Separate the incurable orchid leaves and orchid plants. People who raise orchids are often "loving orchids like life", but they should be willing to "give up love" to the "seriously ill". Depending on the severity of the disease, the degree of operation may be determined by cutting the adult plant or cutting the grass to remove one of its leaves. It is not a pity as long as you regard the hopeless. However, two points should be paid attention to when using the segmentation method: first, the knife should be disinfected; second, the divided "disease number" should be handled well and should not be discarded, so as not to pollute the brandy and spread the germs to other healthy orchid seedlings. Fourth, prevention. To govern orchids, we should also implement the policy of "putting prevention first". Orchid anthracnose often occurs in spring and summer when the climate is humid, and it is more serious in July and August. At this stage, sterilized liquid should be commonly used to spray orchid nursery, orchid pot, potted soil and potted leaves to make the pathogen extinguish in the budding state. Secondly, depression, high temperature and high humidity should be avoided, and climbing plants can be used as orchid protectors to block strong light and reduce the temperature of brandy. In addition, nitrogen fertilizer should be controlled and phosphorus and potassium should be increased. Pay attention to collecting leftover animal bones, shell of snail clam, etc., burn them with fire and crush them. Fifth, ventilation, humidity control, temperature control orchid cultivation to choose places with more ventilation, can greatly reduce the occurrence of anthrax. But it should not be too ventilated, because the air is too ventilated and the humidity is too small, which is not conducive to the growth of orchids. Orchid basin discharge should be appropriate, must not be too dense, lest orchid leaves crisscross, overlap, affect ventilation, so that anthrax bacteria cross-infection. When the temperature is above 22-28 ℃ and the relative humidity is above 95%, it is most likely to cause the reproduction and spread of orchid anthracnose. Therefore, the temperature and humidity must be controlled below this limit.