In the last picture and text, "The cork known as the "golden tree", in the May harvest season, how much can the bark of a 20-year-old tree be sold for", we shared the relevant knowledge of professional planting of cork trees, see the space limitations, we did not explain in detail when we briefly described the comprehensive prevention and control of pests and diseases of cork trees.
Picture 01~02): Inflorescence of a cork tree
Some netizens consulted Qingjianghe in the background, hoping to supplement and share this part of the content. Based on this, this picture and text Qingjiang Crane will continue to pay attention to and chat with all of you and teachers about the related topics of yellow cyk brown spot disease, aiming to identify the symptoms of yellow cyk brown spot disease in the field? To explore the incidence of brown spot disease in the field? What are the commonly used chemicals and their concentrations? In order to provide scientific and effective prevention and control methods for pharmaceutical farmers. I hope you like it, and actively participate in the interactive comments, forward and share the pictures and texts of this issue.
Symptoms of "brown spot disease" of cork trees in the field:
In the cultivation and production of medicinal plants, the healthy growth and development of Phellodendron phellodendron is very important to ensure the quality and yield of medicinal materials.
Picture 03~04): Inflorescence of the cork tree
However, brown spot is a common fungal disease in the cultivation and planting process of Phellodendron chinensis, which often brings great challenges and hazards to the planting of Phellodendron trees.
Brown spot disease of cork trees mainly affects its leaves, and in the early stage of the disease, small yellow-brown polygonal or irregular spots appear on the leaves, which are round or irregular in shape and have clear edges.
As the disease worsens, the brown spots gradually expand in all directions, darkening in color, and the central part may appear grayish-brown with small black dots (actually gray mold), which are the conidia or conidia of the pathogenic bacteria. When the disease is severe, multiple lesions are connected to each other, resulting in a large area of leaf death, which seriously affects the photosynthesis of plants, thereby reducing the yield and quality of medicinal materials, and weakening the tree.
Picture 05~06): Freshly processed cork bark
To explore the pathogenesis and conditions of brown spot disease in Phellodendron chinensis:
The pathogen of brown spot disease in Phellodendron phellodendron is "Cercospora spp., which is a fungus of the subphylum Semi-Telltellaria Bacteria. The fungus uses mycelium to safely overwinter on diseased residues such as diseased branches and leaves of cork trees.
In the spring of the following year, the pathogenic bacteria produced conidia under suitable conditions for initial infection and re-infection, which caused the recurrence of Phellodendron brown spot disease in the field.
In the high mountains and two high mountains of Qingjiang Crane Residence, the onset time of brown spot disease of Phellodendron tree is at the end of April and early May, and reaches the peak of incidence in mid-June, and then the disease gradually declines, and when the conditions are suitable, it shows a high incidence trend again, until the end of September and the beginning of October, the brown spot disease of Phellodendron is basically "stopped" and "ended". According to the incidence of phellodendron brown spot disease in the field, we know when it is time to spray the phellodendron ground plants.
Picture 07~08): Cork bark in drying
The incidence of brown spot disease in Phellodendron is closely related to climatic conditions, cultivation management and other factors.
Generally, the disease is easy to occur in high temperature and humidity environments, such as when it is rainy in summer and the field humidity is high, and the incidence of the disease will increase significantly when the tree is weak.
In addition, factors such as overcrowded plants, poor ventilation, and insufficient nutrition can also increase the risk of brown spot disease. The pathogenic bacteria mainly overwinter in the diseased residue or soil with mycelium, and produce conidia under suitable conditions in the following spring, which are spread by wind and rain to infect the leaves of the cork tree. In this way, "spread and expand" in the field "over and over again" and "continuously".
Picture 09~10): Harvesting fresh wet cork bark
"4 key points" of effective prevention and control measures for yellow cyk brown spot disease:
According to the characteristics and patterns of brown spot disease in Phellodendron chinensis, we can take the following effective prevention and control measures:
01) Choose disease-resistant varieties suitable for local climatic conditions:
The cork tree is divided into varieties such as "Guan cork" and "Sichuan cork". There are also many "mutated" varieties of cork in various places. Therefore, before planting Phellodendron trees, it is necessary to choose Phellodendron varieties with strong disease resistance and suitable for local climatic characteristics, which is the basis for improving the effect of preventing and controlling Phellodendron brown spot. The "fit" is the best.
Picture 11~12): Conventional fungicide pyraclostrobin
02) Improve the planting technology of cork and strengthen cultivation management:
In order to make full use of temperature and light resources and improve the land multiple cropping index, the intercropping mode of Phellodendron chinensis can be considered. For example, the intercropping of cork and Coptis chinensis, the intercropping of Coptis chinensis and Rehmannia and so on.
In addition, it is necessary to fully consider the reasonable dense planting of cork and maintain the ventilation and light transmission of the field. Leaf pruning can be done appropriately. Scientific fertilization to enhance the disease resistance of plants; Remove the sick and residual bodies in time and reduce the overwintering places for germs.
03) Comprehensive chemical prevention and control measures are indispensable in key links:
In the early stage of the onset of Phellodendron brown spot, suitable fungicides can be used for spray control, such as difenoconazole, pyraclostrobin, etc., and attention should be paid to alternate use to avoid the development of drug resistance of the bacteria.
Picture 13~14): conventional fungicide chlorothalonil
In the early stage of cork brown spot disease, you can also use 800~1000 times of 40% chlorothalonil methyl frost suspension suspension, or 800~1000 times of 50% chlorothalonil suspension, or 800~1000 times of 40% chlorothalonil diynylomid suspension, 500~600 times of 65% zeb zinc wettable powder, or 800~1000 times of 70% thiophanate-methyl wettable powder, or 20% syringoxystrobin suspension 2500~3000 times. Or 25% oxidoxystrobin suspension 2500~3000 times liquid, or 70% dysenlian water dispersible granules 500~800 times liquid, or 70% mancozeb wettable powder 500~800 times liquid spray stem and leaf treatment.
04) Biological control of cork brown spot disease:
Biological resources such as antagonistic bacteria and biological pesticides were used to carry out biological control of brown spot pathogens, so as to reduce the pressure of chemical pesticide prevention and control in the field. For example, Bacillus subtilis and so on.
Picture 15~16): Conventional fungicide Daisenlian
Words written at the end of cork brown spot:
The prevention and control of brown spot disease of cork trees requires us to start from many aspects, including the selection of disease-resistant varieties, the strengthening of cultivation management, and the adoption of appropriate chemical and biological control measures. Only by comprehensively using various prevention and control methods can we effectively curb the occurrence and spread of brown spot disease, ensure the healthy growth and development of Phellodendron chinensis and the yield and quality of medicinal materials.