How to do orchid white silk disease? Symptoms and Control methods of White Silk Disease of Orchid

Orchid white silk disease is one of the main diseases of orchids, also known as white silk disease, Sclerotinia sclerotiorum and so on, which is second only to anthrax. Once it occurs, the harm and loss will far exceed anthrax. Usually, the infection begins from April to May, and the disease occurs rapidly during the peak period from June to August, resulting in the rot and death of the injured orchid plants. Let's take a look at the prevention and control methods of orchid white silk disease.

Develop symptoms

White silk disease began from the stem of the orchid plant near the ground, showed yellow to light brown running water disease spots at first, then browned to black brown rot, and spread on the surface of the rhizosphere soil and at the base of the stem, destroying the stem and infecting young leaves and roots, and white hyphae were produced in leaf sheaths and roots. The injured part was waterlogged, decayed and softened, blackened, until the leaves withered, the bacteria spread to the pseudobulb, the sclerotia changed from white to reddish brown to brown necrosis, and in severe cases, the whole plant withered.

Characteristics of the disease

The pathogen of orchid white silk disease is a subphylum fungus, which overwinters with sclerotia in soil or fertilizer and on undecayed remains. In areas with high winter temperature, hyphae can also overwinter on undecayed remains. Sclerotia germinated the following year, spread in the soil and invaded from the base of orchid leaves. Bacteria check has strong resistance to adverse environment and can survive in the soil for several years. It can be spread by running water, irrigation water, Rain Water sputtering and fertilization. The soil is sour and the disease is the most serious, and the disease is easy to be induced in high temperature and humid weather. The infection began from April to May, and the disease occurred rapidly during the peak period from June to August, resulting in the rot and death of the injured orchid plants.

Prevention and cure method

1. Orchid white silk disease is easy to occur when the substrate is sour (pH less than 5.3), so mixing plant ash with a volume ratio of 10 in the substrate, or pouring 0.3% lime water to increase the pH value to about 6.5, can reduce the occurrence of white silk disease, and the effect is obvious.

2. The orchid matrix soil is disinfected with 0.2% pentachloronitrobenzene 500 times solution and 50% carbendazim wettable powder 600 times solution, or the rhizosphere and soil can be sprayed with pentachloronitrobenzene 500 times solution or 70% methyl thiophanate 800 times solution, or 50 grams of pentachloronitrobenzene powder mixed with 4 to 5 kilograms of semi-dry and wet fine sand, sprinkled on the rhizome of diseased plants to inhibit the spread of the disease.

3. In the rainy season from May to June in the south, the soil moisture is high, and white silk disease is easy to occur on the basin surface. We should quickly move out of the orchid field to "isolate", remove the substrate infected with mycelium, cut off the diseased root, spray 1000-fold solution of potassium mongolate, and spray 1500-fold solution of methyl topiramate on the roots and wounds, sprinkle fresh plant ash around the orchid root, then cover with the substrate to protect the root, and water the root after 2 to 3 days. If the matrix is wet, the rewatering can be postponed for 5 to 7 days, and the control effect is good.

4. During the occurrence of orchid white silk disease, 2000 times aqueous solution of medical chloramphenicol injection was used to sprinkle the diseased plants once a day for 3 times. Once the disease occurs, the diseased leaves should be cut off, the ventilation conditions should be improved, and the whole orchid should be soaked in 10% copper sulfate solution for disinfection. To the nearby orchid plant, also want to spray comprehensively, wet the base, basin surface, spray once a day, apply twice in succession, can control the disease, the control effect is good.

5. After the new buds of orchids grow out of the soil, 0.05% chloramphenicol is sprayed once a week for 2 to 3 times. If the potted soil is dry, this medicine can be used to prevent bacterial infection. It can also be sprayed with 1500 times aspirin solution, which can enhance the immunity of the orchid plant and prevent the invasion and spread of bacteria.

6. during the period of new bud extension and leaf expansion of orchid, medical penicillin, streptomycin, chloramphenicol or penicillin can be diluted to 2000 times, sprinkle the diseased plant, and spray comprehensively, once every 3 to 4 days, twice in succession, the control effect is good.

7. After the orchid attack, spray 50% benzoate wettable powder 1000 times, or 50% carbendazim wettable powder 500x, or 50% thiophanate wettable powder 500x liquid or 70% chlorothalonil wettable powder liquid 1000 times, every 7 to 10 days, spray 2 to 3 times, the control effect is good.

8. Orchids can be sprayed before and after overcast rain or before and after rain. 500 times of 50% Sukeling powder or 500 times of 50% Nongliling powder, 500 to 600 times of detoxification alum and 300 times of Jinggangmycin water can be sprayed on stems, leaves and pots, and the control effect is significant.

Symptoms and control methods of white silk disease of orchids (scientific name: Cymbidium ssp.) Orchid (scientific name: orchid): epiphytic or terrestrial herbs, with several to many leaves, usually born on the base or lower nodes of pseudobulbs, distichous, banded or rarely oblanceolate to narrowly elliptic, base generally with broad sheaths and enclosing pseudobulbs, articulated. Racemes with several or many flowers, the colors are white, pure white, white-green, yellowish green, yellowish brown, yellow, red, cyan, purple.

White silk disease is one of the most common plant diseases, with more than 500 species in 100 families, such as Cucurbitaceae and Caryophyllaceae. Although white silk disease is not as common as Botrytis cinerea and anthracnose in orchids, it is also one of the more common diseases in orchids and is a worldwide disease. Cymbidium, Magnolia, Jian Orchid, Oncidium, Phalaenopsis, Wandai Orchid, Cymbidium, Dendrobium and Cymbidium can all be infected with the disease, often causing certain losses. Now take Oncidium as an example to explain the cause of the disease and the methods of prevention and treatment. Symptoms: if the condition is suitable, it can infect any part, such as root, bulb, leaf and so on. The diseased part is often flooded, sometimes accompanied by yellow liquid exudation. The white silk-like substance grew in the injured part, sometimes radiating, and the sclerotia the size of rapeseed was produced on the hyphae, which was white at first and brown in the later stage, with a diameter of 2mm~4mm. When the false bulb is infected, it finally leads to the lodging and death of the plant. Disease conditions: sclerotia is the residual tissue of bacteria, is an important source of infection, no dormant period, has a strong resistance to adverse environment. The pathogen overwintered with mature sclerotia in the disease part or with the disease residue into the soil, and the warm area could overwinter with mycelium on the organism. It can spread with the spread of water, and it is easy to occur under the conditions of high temperature and high humidity. generally, the temperature reaches 25 ℃ ~ 35 ℃ from May to June, and the sclerotia begins to germinate and spread in the soil when the humidity reaches more than 90%. The main factors affecting its germination are temperature and humidity. The lower limit of pathogen development is 8 ℃, the upper limit is 40 ℃, the most suitable value is 25 ℃ ~ 33 ℃, and the most suitable pH value is 5.9. Sclerotia can survive for 10 years under indoor conditions, 5-6 years under natural conditions, and only 3-4 months in water. The high temperature and humidity in the rainy season in southern China, coupled with the wet substrate and poor ventilation, can easily lead to the occurrence of the disease. Anti-metallurgical methods: physical prevention and control: 1. In the rainy season, the substrate should be prevented from getting too wet, the air humidity should be too high, and attention should be paid to ventilation, and watering should master the principle of "no dry, no watering". 2. The culture medium and flowerpot can be treated at high temperature before use, the sclerotia can be killed when the temperature reaches 100℃, and the hyphae are easy to die when exposed to the hot sun. 3. When diseased plants are found, they should be isolated immediately, destroyed immediately if they are serious, and the diseased plants, diseased leaves and cultivation substrates should be cleaned up to block the source of infection. Chemical control: 1. The lightly diseased plants immediately change pots, remove the diseased plants, and soak the orchid plants in the same basin in 1% copper sulfate solution for disinfection. And spray chemical control to the surrounding plants, the drug control can use Jinggangmycin 500 times 700 times liquid, direct spray gonorrhoeae plants 2 times 3 times, can basically be completely removed. Jinggangmycin is one of the most effective drugs to control white silk disease at present. You can also use 15% pink rust rather than wettable powder mixed with fine dry soil to spread 200 parts on the rhizome of the diseased plant. 2. Before use, the matrix can also be treated with chemicals in addition to high-temperature disinfection. 40% pentachloronitrobenzene powder can be used, 0.2-0.3% of the weight of the matrix can be mixed into the matrix, or 500 times diluted with water. Prevention and Control of White Silk Disease of Orchid

Orchid white silk disease is one of the main diseases of orchids, also known as white silk disease, Sclerotinia sclerotiorum and so on, which is second only to anthrax. Once it occurs, the harm and loss will far exceed anthrax. Usually, the infection begins from April to May, and the disease occurs rapidly during the peak period from June to August, resulting in the rot and death of the injured orchid plants. Let's take a look at the prevention and control methods of orchid white silk disease.

Develop symptoms

White silk disease began from the stem of the orchid plant near the ground, showed yellow to light brown running water disease spots at first, then browned to black brown rot, and spread on the surface of the rhizosphere soil and at the base of the stem, destroying the stem and infecting young leaves and roots, and white hyphae were produced in leaf sheaths and roots. The injured part was waterlogged, decayed and softened, blackened, until the leaves withered, the bacteria spread to the pseudobulb, the sclerotia changed from white to reddish brown to brown necrosis, and in severe cases, the whole plant withered.

Characteristics of the disease

The pathogen of orchid white silk disease is a subphylum fungus, which overwinters with sclerotia in soil or fertilizer and on undecayed remains. In areas with high winter temperature, hyphae can also overwinter on undecayed remains. Sclerotia germinated the following year, spread in the soil and invaded from the base of orchid leaves. Bacteria check has strong resistance to adverse environment and can survive in the soil for several years. It can be spread by running water, irrigation water, Rain Water sputtering and fertilization. The soil is sour and the disease is the most serious, and the disease is easy to be induced in high temperature and humid weather. The infection began from April to May, and the disease occurred rapidly during the peak period from June to August, resulting in the rot and death of the injured orchid plants.

Prevention and cure method

1. Orchid white silk disease is easy to occur when the substrate is sour (pH less than 5.3), so mixing plant ash with a volume ratio of 10 in the substrate, or pouring 0.3% lime water to increase the pH value to about 6.5, can reduce the occurrence of white silk disease, and the effect is obvious.

2. The orchid matrix soil is disinfected with 0.2% pentachloronitrobenzene 500 times solution and 50% carbendazim wettable powder 600 times solution, or the rhizosphere and soil can be sprayed with pentachloronitrobenzene 500 times solution or 70% methyl thiophanate 800 times solution, or 50 grams of pentachloronitrobenzene powder mixed with 4 to 5 kilograms of semi-dry and wet fine sand, sprinkled on the rhizome of diseased plants to inhibit the spread of the disease.

3. In the rainy season from May to June in the south, the soil moisture is high, and white silk disease is easy to occur on the basin surface. The orchid should be quickly removed, the substrate infected with mycelium should be removed, the diseased root should be cut off, and 1000 times solution of potassium hyperoxylate can be sprayed to disinfect the root and wound. 1500 times solution of methyl topiramate can also be used to spray roots and wounds, and sprinkle fresh plant ash around the orchid root, then cover with substrate to protect the root, and then water the root after 2 to 3 days. If the matrix is wet, the rewatering can be postponed for 5 to 7 days, and the control effect is good.

4. During the occurrence of orchid white silk disease, 2000 times aqueous solution of medical chloramphenicol injection was used to sprinkle the diseased plants once a day for 3 times. Once the disease occurs, the diseased leaves should be cut off, the ventilation conditions should be improved, and the whole orchid should be soaked in 10% copper sulfate solution for disinfection. To the nearby orchid plant, also want to spray comprehensively, wet the base, basin surface, spray once a day, apply twice in succession, can control the disease, the control effect is good.

5. After the new buds of orchids grow out of the soil, 0.05% chloramphenicol is sprayed once a week for 2 to 3 times. If the potted soil is dry, this medicine can be used to prevent bacterial infection. It can also be sprayed with 1500 times aspirin solution, which can enhance the immunity of the orchid plant and prevent the invasion and spread of bacteria.

6. during the period of new bud extension and leaf expansion of orchid, medical penicillin, streptomycin, chloramphenicol or penicillin can be diluted to 2000 times, sprinkle the diseased plant, and spray comprehensively, once every 3 to 4 days, twice in succession, the control effect is good.

7. After the orchid attack, spray 50% benzoate wettable powder 1000 times, or 50% carbendazim wettable powder 500x, or 50% thiophanate wettable powder 500x liquid or 70% chlorothalonil wettable powder liquid 1000 times, every 7 to 10 days, spray 2 to 3 times, the control effect is good.

8. Orchids can be sprayed before and after overcast rain or before and after rain. 500 times of 50% Sukeling powder or 500 times of 50% Nongliling powder, 500 to 600 times of detoxification alum, and 300 times of Jinggangmycin water can be sprayed on stems, leaves and pots with remarkable control effect.