How to prevent and cure the white silk disease of peony

Peony white silk disease mainly occurs at the base of the stem near the ground. Soil and fertilizer are the sources of infection of the disease, especially when sweet potato and soybean are used as previous crops. The disease is easy to occur before and after flowering and in the hot and rainy season. In the initial stage, the aboveground part had no obvious symptoms, and with the increase of temperature and humidity, the hyphae spread from the rhizome to the soil surface, which was densely distributed around the rhizome, and finally formed a brown millet-like sclerotia. The top of the diseased plant withered, the leaves withered and drooped, and finally the whole plant died.

Prevention and control methods:

1. Rotation with gramineous crops is not suitable for rotation with rhizome medicinal materials, sweet potatoes, peanuts, broad beans and other crops.

2. Select the disease-free seedlings and disinfect the healthy seedlings. The disinfectant can be soaked in 50% methamphetamine or 70% methyl topiramate or carbendazim 800-1000 times for 10-30 minutes.

3. In order to prevent the disease at the seedling stage, 70% pentachloronitrobenzene powder can treat the soil with 2.5 kg per mu and 50 kg of dry fine soil, mix evenly, sprinkle it in the sowing or cutting ditch, and then sow or cut. After planting, the new high-fat membrane was sprayed to isolate diseases and insect pests and protect the healthy growth of plants.

4. The diseased plants were dug up and burned in time, and the diseased holes were disinfected with lime.

5. In the early stage of the disease, sprinkle 2.5 kg of 70% pentachloronitrobenzene powder per mu in the nursery and loosen the soil after application, so that the powder can be evenly mixed into the soil; the seedling root can also be irrigated with 500 times of 50% carbendazim wettable powder or 1% copper sulfate solution.

How to prevent and cure the white silk disease of peony

Peony white silk disease mainly occurs at the stem base of seedlings near the ground. Soil and fertilizer are the sources of infection of the disease, especially when sweet potatoes and soybeans are used as previous crops. The disease is easy to occur before and after flowering and in the hot and rainy season. In the initial stage, the aboveground part had no obvious symptoms, and with the increase of temperature and humidity, the hyphae spread from the rhizome to the soil surface, which was densely distributed around the rhizome, and finally formed a brown millet-like sclerotia. The top of the diseased plant withered, the leaves withered and drooped, and finally the whole plant died.

Prevention and control methods:

1. Rotation with Gramineae crops is not suitable for rotation with rhizome medicinal materials, sweet potatoes, peanuts, broad beans and other crops.

2. Select the disease-free seedlings and disinfect the healthy seedlings. The disinfectant can be soaked in 50% methamphetamine or 70% methyl topiramate or carbendazim 800 times solution for 10-30 minutes.

3. In order to prevent the disease at the seedling stage, 70% pentachloronitrobenzene powder can be used to treat the soil, 2.5 kg per mu and 50 kg of dry fine soil, mix evenly, sprinkle it in the sowing or cutting ditch, and then sow or cut. After planting, the new high-fat membrane was sprayed to isolate diseases and insect pests and protect the healthy growth of plants.

4. The diseased plants were dug up and burned in time, and the diseased holes were disinfected with lime.

5. In the early stage of the disease, 2.5 kg of 70% pentachloronitrobenzene powder was applied in the nursery. After application, the soil was loosened and the powder was evenly mixed into the soil. The seedling root can also be irrigated with 50% carbendazim wettable powder 500 times or 1% copper sulfate solution.

How to prevent and cure the white silk disease of peony

Symptoms: the symptoms of various susceptible plants are similar. The disease mainly occurs at the stem base of the seedling near the ground. At the beginning, the epidermis of the diseased part turned brown, gradually developed around, and produced white silk-like hyphae in the diseased part, which fanned and spread to the nearby soil surface, and later formed a rapeseed-like tea-brown sclerotia on the basal surface of the diseased seedlings or on the mycelium layer of the soil surface. After the disease of the seedling, the cortex of the stem base and root decayed, the transport of water and nutrients of the plant was cut off, the leaves turned yellow and withered, and the whole plant withered.

Pathogen; Sclerotium rolfsii Sacc. Sclerotinia sclerotiorum belongs to semi-Yamen subphylum, Trichospora, non-spore order. This strain does not produce asexual spores and rarely produces sexual spores. the hyphae are white at first and brownish later, with a diameter of 3-9 microns. In the later stage, the hyphae can gather together to form rapeseed sclerotia.

The route of transmission; the pathogen usually overwinters with mature sclerotia on the soil, killed weeds or the remains of diseased plants. Spread through Rain Water. Sclerotia can survive in soil for 4-5 years. Under suitable conditions of temperature and humidity, sclerotia germinated to produce hyphae and invaded plants. In the Yangtze River basin, the disease generally began to occur in the first ten days of June, was the peak period from July to August, and basically stopped after September. Under the condition of 18-28 ℃ and high humidity, it took only 8-9 days from sclerotia germination to supreme new sclerotia formation, and about 9 days from sclerotia formation to maturity.

The disease condition: the pathogen liked high temperature and humidity, and the development stopped when the optimum growth temperature was 30 ~ 35 ℃ and higher than 40 ℃. Soil PH5~7 is suitable for disease occurrence, but it is rare in alkaline soil. The soil is rich in humus, high in nitrogen content, heavy soil viscosity and relatively sour garden, and the incidence is high.

Prevention and control methods:

1. In order to prevent the disease at the seedling stage, 70% pentachloronitrobenzene powder can be used to treat the soil, 250 grams per 67 square meters, add 5 kilograms of dry fine soil, mix evenly, sprinkle it in the sowing or cutting ditch, and then sow or cut.

2. In the early stage of the disease, 70% pentachloronitrobenzene powder can be sprinkled on the soil surface in the nursery and 250 grams per 67 square meters. Loosen the soil after application, so that the powder can be evenly mixed into the soil. It can also be used to irrigate the roots of seedlings with 800 times of carbendazim, 500 times of 50% carbendazim wettable powder, or 500 times of 50% topazine wettable powder, or 1% copper sulfate solution, or verapamil 10ppm, or chlorpromazine 25ppm, to control the spread of disease.

3. After the symptoms appear in the aboveground part of the tree body in spring and autumn, the soil near the main root of the trunk can be removed to dry, which can restrain the development of the disease. The time of root drying can be carried out from early spring to March to autumn until the leaves fall, and the tree holes can be filled before the rainy season to prevent adverse effects. When drying the roots, we should also pay attention to building a ridge around the hole to prevent water from flowing into the hole.

4. When selecting disease-free seedlings and transporting seedlings, strict inspection should be carried out, disinfecting healthy seedlings and removing diseased seedlings. Disinfectants can be soaked in 200-300 times of carbendazim, 70% methyl topiramate or carbendazim 800-1000 times, 2% lime water, 0.5% cupric sulfate solution for 10 minutes, and then planted. It can also be soaked in 45 ℃ warm water for 20 to 30 minutes to kill root germs.

5. After the diseased tree treatment determines that the root is sick according to the symptoms of the aboveground part of the tree, peel off the soil at the base of the tree trunk to look for the disease site. After the disease is diagnosed as white silk disease, scrape off the disease spot of the root neck thoroughly with a knife, and disinfect the wound with 50 times of the antibacterial agent 401 or 1% sulfuric acid, then apply Bordeaux paste and other protective agents, and then cover the new soil.

6. Dig the isolation ditch around the diseased plant, dig the isolation ditch and seal off the ward.