Causes and Control measures of Root Rot of Oil Peony

How to prevent and cure root rot of oil peony? What are the specific prevention and control measures? In recent years, the occurrence of root rot of oil peony is serious, especially in rainy years, which often causes the whole plant or even a piece of death. Xiaowen Huinong Xiaobian summarized the occurrence law and control of root rot of oil peony.

1 occurrence regularity

The pathogen of root rot of oil peony is Fusarium solanum, which is a subphylum fungus. It often occurs in the rainy season, which is caused by poor drainage in the field, water accumulation for a long time and humid environment, which is related to the pests in the soil and the continuous cropping land. The peony root has a sweet taste, and the pests in the soil bite the peony root to form a wound, resulting in the invasion of germs. In addition, improper fertilization, poor fertilizer quality, large particles or unfermented into the soil, resulting in an increase in the number of bacteria in the soil, causing harm to the roots of peony.

2 main symptoms

Root rot is mainly harmful to the root. After part of the root system is infected, irregular black spots are produced on the root bark, which causes the root to blacken and spread to the main root, resulting in the blackening and decay of all the roots. The growth of the aboveground part is weak, the leaves are yellow, part of the mesophyll turns yellow, and when the leaves and branches die seriously, if it is not controlled in time, the whole plant will die.

3 Prevention and control measures

3.1 soil disinfection

Soil disinfection was carried out when the soil was turned over, and phoxim or methyl isofenphos granule 3~5kg was applied per mu to control underground pests.

3.2 Root soaking in solution

Before planting seedlings, the roots of seedlings were soaked in 600 × 800-fold methyl topiramate solution for 2-3 minutes, then dried and planted.

3.3 drainage rotation

Drainage should be carried out in time in the rainy season to reduce stagnant water in the fields. Avoid continuous cropping and implement crop rotation to reduce the long-term accumulation of germs.

3.4 Pesticide control

Nutrition bowl was used to raise seedlings and transplant to prevent root trauma. In the early stage of the disease, the root was irrigated with 150 times diluted solution of root rot, and used continuously for 3 times every half a month. Diseased plants should be dug up in time, incinerated and disinfected with lime.

That's all for today. Now more and more people begin to plant oil peonies, because it is of special significance for farmers to adjust their planting structure and shake off poverty and become rich. If you also have ideas, first pay attention to Huinong Network to learn planting techniques.

Control measures of purple stripe feather disease of tree peony

Peony purple feather disease, commonly known as purple or black root rot or root rot, is a common fungal disease of peony. The incidence of old plants and continuous cropping for many years is higher, which not only harms forest fruit trees and crops, but also harms trees and crops.

The symptoms were mainly harmful to the root system and root neck of the plant. first, the young root was infected and gradually extended to the lateral root, main root and root neck. at the initial stage of the disease, it appeared yellow-brown wet rot in the diseased part, and in severe cases it became dark purple or black. a layer of cotton-like mycelium was produced on the surface of the diseased root, and in the later stage, the surface layer of the diseased root rotted completely and partially separated from the wood. The disease has a long critical period, and it usually takes 3 to 5 years or more for diseased plants to die. The growth potential of the damaged plant weakened, yellowed, and the leaves became smaller, blooming in large and small years, and in severe cases, some branches or the whole plant withered. Once the cotton-like mycelium appeared in the root neck of the plant, it was proved that most of the underground parts had rotted, and the plant would die quickly.

The pathogen is basidiomycetes Helicobasidium purpureum (Tul.) Pat. , belonging to basidiomycetes subphylum fungi. Fruiting body membranous, purple or purplish red. The subsolid layer is upward and smooth. Basidium curly, basidiospore unicellular, kidney-shaped, colorless.

The pathogens overwintered with fungal cord or sclerotia in the soil or mycelium in the disease residue, and the pathogens in the soil could survive for 3 to 5 years. When the conditions are suitable, the pathogen germinates and grows vegetative hyphae, invades the host young root, and then spreads to the main root or lateral root. Basidiospores and basidiospores were produced from May to June, and basidiospores germinated to produce hyphae. Pathogens spread in the field through irrigation water or Rain Water, farm tools and so on. Soil permeability is good, water holding capacity is 60% to 70%, pH5.2~6.4 is the most suitable for the growth and development of bacteria. The land with low-lying terrain, poor drainage, viscous weight of soil and high content of soil organic matter occurred seriously, and the incidence of soil drought was also serious. There are more Rain Water from July to August every year, and the disease is more serious.

Prevention and cure measures

1. Strictly disinfect seedlings and soil

The seedlings soaked the roots in 20% lime water for half an hour, or 100 times or Bordeaux solution for 1 hour, and then soaked the roots in 1% copper sulfate solution for 3 hours. Then wash it with clean water and plant it. For soil disinfection, 2.5% Sailisan powder or 2.5kg pentachloronitrobenzene powder or 10Mel 20kg sulfur powder can be applied per mu before turning the soil. Small area planting, can carry out seedbed or tree hole disinfection, with 30% liquid agent "soil bacteria elimination" 500 times liquid spray, the dosage is 3 liters per square meter.

two。 Strengthen the management of soil water and fertilizer

The main cause of root rot disease is caused by soil infection by the application of organic fertilizers such as human manure and urine which are not fully mature and fermented. Therefore, the main measures to strengthen soil water and fertilizer management are as follows:

① increased application of potassium fertilizer to promote the growth of new roots. During the growing period, 0.1 per cent potassium dihydrogen phosphate can be used for foliar spraying, or potassium sulfate or potassium chloride (not used in saline-alkali land) can be added during fertilization, with a dosage of 5ml 7.5 kg per mu.

② reasonable ploughing and winter turning, so that the mature soil layer of the peony garden, often keep at about 25 to 30 cm, prevent soil consolidation, keep the soil loose, good water permeability and air permeability.

③ avoids raw fat and heavy fertilizer. Human feces and urine are rarely used or not used as much as possible, such as the application of organic fertilizers such as human feces and urine, which must be fully ripened and fermented.

④ can control underground pests in time. The root plants bitten by grubs are easy to be infected with root rot. Therefore, every early spring, it is necessary to spray trichlorfon 800x liquid or phoxim 1000 times liquid in time.

⑤ properly grasp the watering times and water quantity of tree peony, especially in the early spring and late summer mycelium activity period, when the soil water content is not less than 60%, watering or not watering as much as possible to reduce infection.

3. Carry out root irrigation treatment

For the plants with serious disease, they can be dug up and burned, or the diseased roots can be removed, disinfected and replanted. The plants with primary or mild disease can be treated by ditching and root irrigation. The following drugs have a certain effect on root rot, and you can choose to use: Baume 1-degree stone-sulfur mixture (2.5kg-7.5kg / plant); 200-500fold copper sulfate solution (5-7.5kg / plant); Tuijitte wettable powder 500ml 800fold solution (1.5kg-2.5kg / plant); 1000-fold solution of 70% methyl topiramate (1.52.5kg / plant). In early spring or late summer, 3-5 radial trenches were dug around the trunk of the plant, which were as long as the crown, 20-30 cm wide and 30 cm deep. It was better to expose the roots and seal the soil after irrigation.

4. Exchanging soil with guest sand

Dig out the soil around the root neck of the diseased plant, replace the clean new sandy soil, and change it again half a year later.

5. Root drying and trenching isolation

The soil around the diseased plant is removed to expose the diseased root to the air, which can be carried out from early spring to the end of autumn by sunlight exposure and ventilation to reduce and inhibit the development of the disease. In addition, between diseased and healthy plants, depending on the depth of root distribution, trenches with a depth of 60-80 cm were dug to prevent and block mycelium extension from causing contact infection.

6. In order to prevent the spread and infection of peony root rot, pine and cypress should be planted around the peony garden, but poplar, willow, locust and white wax should not be planted.

Occurrence regularity and control methods of peony grub

[harm] grub is the general name of beetle larva, which is a common intractable pest in peony orchard. It lives in the soil and mainly harms the roots and stems of flowers and trees such as peony and peony, resulting in poor plant growth and affecting the ornamental effect. The peak season of grub damage is from mid-late May to late June every year. The damaged branches or plants start from the top, the leaves gradually turn reddish brown, then the leaf edges curl yellow and dry, and finally the branches and leaves dry up, and the single branch or the whole plant dies. After pulling out the dead plant, it was found that the rhizome was in the shape of a ring bite.

[morphological characteristics] the grub is nearly cylindrical in shape, milky white, and often bent into the shape of the letter "C". Densely covered with brown fine hairs in vitro, head yellowish brown, with three pairs of chest and feet.

[occurrence regularity] the overwintering larvae do great harm to the peony. In early April, grubs move from 30 to 50 cm overwintering soil layer to 10 to 20 cm surface soil layer and eat peony fleshy roots. because the wound is easy to invade Fusarium oxysporum, peony root rot occurs. The peak period of grub activity is from mid-late May to late June before the rainy season.

[control methods] 1. Strengthen plant quarantine to prevent the root of seedlings from carrying worms.

two。 Before planting peonies, treat the soil with 30% furan granules of 3 to 5 kg per mu. If the last crop in the peony garden is peanut or sweet potato, you should pay more attention to it.

3. Organic fertilizer must be fully mature before use, not fully mature organic fertilizer, especially chicken manure can easily lead to a large number of grubs and large-scale outbreaks.

4. In the early stage of the disease, the root of the plant was irrigated with medicine solution. 1500 to 2000 times of phoxim EC is often used. The amount of irrigation per plant depends on the size of the peony plant, generally speaking, 1-1.5 kg of 1-2-year-old seedlings and 2-2.5 kg of 3-5-year-old seedlings. Before filling the medicine, it is necessary to dig a small hole in the root of the peony so that the liquid is concentrated in the root soil.

5. After the grubs turned into adult beetles in autumn, the grubs were trapped and killed by black light to reduce the population density of grubs in the soil in the coming year.

6. Prevention is the most active and effective measure. Every year from March to April and September to October are the periods when grubs begin to move and larvae grow, when the effect of root irrigation is the best. If the prevention and control is in place in spring and autumn within a year, it can ensure that large-scale grub pests will not break out in the next 2 to 3 years.