Cucumber downy mildew is a disease caused by fungi. It is endangered in greenhouses, greenhouses, and cucumbers in Daejeon throughout the year. It mainly depends on air currents and rainwater, and it is heavy in high humidity conditions. Traditional methods of prevention and control use pesticides. Here is a method for preventing cucumber downy mildew without pesticides.
The basic symptoms mainly damage the leaves. Mostly after the flowering result, the disease begins from the lower old leaf. At the early stage of disease, water-stained and light green spots appear on the back of the leaves. After being expanded, the veins are limited by polygons. The color of the lesions changes to green and yellow and eventually turns to brown. On the back of the leaves, the smuts grow on the surface of the leaves. Floor.
Cucumber downy mildew caused by the pathogen is caused by the flagellum submucosa, Pseudopercodium genus fungal disease, the spore sacs of the bacteria spread by air currents and rain.
Diseases caused by regular fungal diseases occur in greenhouses, greenhouses, and Daejeon cucumbers throughout the year, and are mainly transmitted by air currents and rainwater. Heavy onset under high humidity conditions. Precocious and good quality disease is heavy. In the greenhouse, people's production activities are the main source of infection for downy mildew. The most suitable temperature for cucumber downy mildew disease is 16-24°C, which is lower than 10°C or higher than 28°C. It is more difficult to attack, lower than 5°C or higher than 30°C, and basically does not cause disease. Appropriate incidence of humidity is 85% or more, especially in the leaves with water film, the most vulnerable to the incidence of infestation. When the humidity is lower than 70%, the spores of the pathogenic bacteria are difficult to germinate and infect, and less than 60%, spores of the pathogen cannot be produced.
Prevention and control method of variable temperature management In the morning, after pulling open grasshoppers, the air is discharged for half an hour, and then the greenhouse is closed. The temperature of the greenhouse is quickly raised to 28°C or more. When the temperature rises to 30°C, a small breeze is started. In the morning, the temperature is controlled at 28°C-32°C. If the temperature of the shelf continues to rise in the afternoon, the amount of air leakage can be increased and the temperature can be lowered to 20°C-25°C. After the night, the temperature was controlled between 18°C ​​and 20°C in the middle of the night and the temperature was kept below 14°C in the late night.
Timely watering watered according to the weather, soil moisture and seedlings. Watering time should be selected in the sunny morning, can be poured water, avoid flooding irrigation. Immediately after the watering, close the greenhouse, raise the temperature to 32°C, maintain at this temperature for 1 hour, and then release the air.
Improve cultivation conditions greenhouses should try to use non-drip membrane. The drop-free film has good light transmission, which can prevent the condensation of the film on the shelf, increase the temperature in the shelf, and reduce the humidity in the shelf. It is also possible to hang a light curtain on the back wall of the shed to enhance the light in the shed and increase the temperature inside the shed. In addition, hay can be spread between rows to prevent evaporation of soil moisture and reduce the humidity in the shed.
After the high-temperature stuffy shed enters the autumn, if a diseased plant is found, the shelter can be closed on sunny days in the morning. The temperature is raised to 45° C. and maintained for 2 hours to kill the bacterium in the shed. In order to prevent the occurrence of downy mildew, a boring shed may be used once a week, and after the sheds are properly released, the amount of bleed air is small and large. It should be noted that the day before the dungeon must be watered.
After the nutrient control cucumbers enter the growth stage, the growth of the cucumbers is obviously weakened, and the nitrogen sugar content of the plant sap is reduced. In this case, the plants are most susceptible to downy mildew. At this time, the nitrogenous sugar liquid can be sprayed on the leaves to supplement the nutrition. . The nitrogen sugar solution can be prepared with white sugar, urea, and water in a ratio of 1:0.5:100, sprayed once every 5 days, and sprayed 5 times.
It is best to use wild pumpkin grafting to cultivate seedlings. The roots of cucumber grafted with this pumpkin seedling are well developed and highly resistant to downy mildew.
In addition to selecting the above measures to prevent downy mildew, every morning should also be carefully examined in the field, immediately after the diseased leaves are found and removed, and preventive measures are taken to eliminate the disease in the bud.
The basic symptoms mainly damage the leaves. Mostly after the flowering result, the disease begins from the lower old leaf. At the early stage of disease, water-stained and light green spots appear on the back of the leaves. After being expanded, the veins are limited by polygons. The color of the lesions changes to green and yellow and eventually turns to brown. On the back of the leaves, the smuts grow on the surface of the leaves. Floor.
Cucumber downy mildew caused by the pathogen is caused by the flagellum submucosa, Pseudopercodium genus fungal disease, the spore sacs of the bacteria spread by air currents and rain.
Diseases caused by regular fungal diseases occur in greenhouses, greenhouses, and Daejeon cucumbers throughout the year, and are mainly transmitted by air currents and rainwater. Heavy onset under high humidity conditions. Precocious and good quality disease is heavy. In the greenhouse, people's production activities are the main source of infection for downy mildew. The most suitable temperature for cucumber downy mildew disease is 16-24°C, which is lower than 10°C or higher than 28°C. It is more difficult to attack, lower than 5°C or higher than 30°C, and basically does not cause disease. Appropriate incidence of humidity is 85% or more, especially in the leaves with water film, the most vulnerable to the incidence of infestation. When the humidity is lower than 70%, the spores of the pathogenic bacteria are difficult to germinate and infect, and less than 60%, spores of the pathogen cannot be produced.
Prevention and control method of variable temperature management In the morning, after pulling open grasshoppers, the air is discharged for half an hour, and then the greenhouse is closed. The temperature of the greenhouse is quickly raised to 28°C or more. When the temperature rises to 30°C, a small breeze is started. In the morning, the temperature is controlled at 28°C-32°C. If the temperature of the shelf continues to rise in the afternoon, the amount of air leakage can be increased and the temperature can be lowered to 20°C-25°C. After the night, the temperature was controlled between 18°C ​​and 20°C in the middle of the night and the temperature was kept below 14°C in the late night.
Timely watering watered according to the weather, soil moisture and seedlings. Watering time should be selected in the sunny morning, can be poured water, avoid flooding irrigation. Immediately after the watering, close the greenhouse, raise the temperature to 32°C, maintain at this temperature for 1 hour, and then release the air.
Improve cultivation conditions greenhouses should try to use non-drip membrane. The drop-free film has good light transmission, which can prevent the condensation of the film on the shelf, increase the temperature in the shelf, and reduce the humidity in the shelf. It is also possible to hang a light curtain on the back wall of the shed to enhance the light in the shed and increase the temperature inside the shed. In addition, hay can be spread between rows to prevent evaporation of soil moisture and reduce the humidity in the shed.
After the high-temperature stuffy shed enters the autumn, if a diseased plant is found, the shelter can be closed on sunny days in the morning. The temperature is raised to 45° C. and maintained for 2 hours to kill the bacterium in the shed. In order to prevent the occurrence of downy mildew, a boring shed may be used once a week, and after the sheds are properly released, the amount of bleed air is small and large. It should be noted that the day before the dungeon must be watered.
After the nutrient control cucumbers enter the growth stage, the growth of the cucumbers is obviously weakened, and the nitrogen sugar content of the plant sap is reduced. In this case, the plants are most susceptible to downy mildew. At this time, the nitrogenous sugar liquid can be sprayed on the leaves to supplement the nutrition. . The nitrogen sugar solution can be prepared with white sugar, urea, and water in a ratio of 1:0.5:100, sprayed once every 5 days, and sprayed 5 times.
It is best to use wild pumpkin grafting to cultivate seedlings. The roots of cucumber grafted with this pumpkin seedling are well developed and highly resistant to downy mildew.
In addition to selecting the above measures to prevent downy mildew, every morning should also be carefully examined in the field, immediately after the diseased leaves are found and removed, and preventive measures are taken to eliminate the disease in the bud.
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