What causes the cucumber ash streak phenomenon? How to improve?

The gray streak phenomenon of cucumbers is caused by low temperature, less light, and large temperature differences.

Foliar spraying of natural brassinin + potassium dihydrogen phosphate of fertile leaves or liquid fertilizer should be remedied in time, once every 7 10 days, 2 3 times in a row, to speed up the return to normal growth.

What causes the cucumber ash streak phenomenon? How to improve? Cucumbers are out of tune, which may be caused by the virus being infected. Can you go to the plant hospital and prescribe some of that antiviral medication and see if the effect will improve after spraying?

The cucumber ash streak phenomenon can be caused by a number of reasons:

1.Low temperature: gray mold is a low temperature and high humidity type of disease, when the night temperature is too low, especially when the night temperature is lower than 15, the root growth is hindered, the absorption capacity is reduced, resulting in leaf malnutrition, leaf edge yellowing, etc., the deficiency of nutrients is obvious, and the bacteria take the opportunity to infect.

2.Excessive humidity in the shed: excessive watering or unreasonable watering methods, and dripping water in the shed will cause the humidity in the shed to increase, and the leaves or melon strips will be dewed for too long, creating favorable conditions for the occurrence of gray mold.

3.Poor ventilation of the shed: In the case of continuous rainy weather, especially in the late winter, the outside temperature is low, and some farmers are afraid of trouble and do not remove the quilt and do not ventilate, so that the seedlings grow in a still air and low temperature environment, the plant resistance is reduced, and the germs take the opportunity to infect.

4.Wounds: Artificially caused wounds, such as pruning, beating old leaves, dotting flowers, picking melons, spraying and other agricultural operations, as well as insect bites, pesticide damage, fertilizer damage, etc., will cause wounds and create opportunities for germs to invade.

5.The seedlings are vigorous, lacking potassium and calcium, and the leaves are senescent.

To improve the cucumber ash streak phenomenon, the following measures can be taken:

1.Reasonable fertilization: increase the application rate of organic fertilizer and phosphorus and potassium fertilizer, and supplement trace elements in an appropriate amount to improve the disease resistance of plants.

2.Control watering: avoid excessive watering or unreasonable watering methods, especially in winter, pay attention to water control to prevent excessive humidity in the shed.

3.Strengthen ventilation: On the premise of ensuring the temperature, try to open the window for ventilation to reduce the humidity in the shed and increase the light, and improve the disease resistance of the plants.

4.Prevent wound infection: When carrying out agricultural operations, it is necessary to pay attention to reducing the damage to plants, avoiding artificially caused wounds, and at the same time paying attention to the prevention and control of insect pests and pesticide damages.

5.Control the growth of the plant: Reasonably control the amount of nitrogen fertilizer and the number of watering, adjust the plant in time, and maintain the appropriate growth rate and nutrient balance.

If gray streaks have already appeared, the following measures can be taken to improve them:

1.Remove diseased leaves and melons in time and destroy them in a centralized manner to reduce the source of disease.

2.Use a special agent for gray mold for spraying, and pay attention to the rotation of different types of agents to reduce the resistance of the pathogen.

3.Appropriately increase the night temperature and increase the light to promote plant growth and recovery.

4.Control watering and maintain proper soil moisture to promote root growth and nutrient uptake.

In short, through reasonable planting management measures and timely measures, the phenomenon of cucumber ash can be effectively improved.

3. The pathogen and pathogenesis of all cucumber gray mold: (1) pathogen.

Cucumber gray mold is caused by infection by the subphylum Semi-known bacteria, Botrytis cinerea.

2) Infection cycle.

The pathogen overwinters in the soil with hyphae, conidia or sclerotia with diseased residues, and is the first infestation of the second year**. When conditions are right, the pathogen begins to germinate and invade from the wound and parenchyma, causing the plant to develop disease and the diseased part to produce conidia. The germs are spread and reinfected through natural scattering of airflow, rainwater, irrigation water and diseased tissues.

3) Onset conditions.

The suitable temperature for the development of the pathogen is 18 23 degrees Celsius, the appropriate temperature for the onset of the disease is about 20 degrees Celsius, the relative humidity is more than 90%, when the light is insufficient, the low temperature and high humidity, the management is extensive, the plant growth is weak, the disease resistance is poor, the watering is excessive, the shed is poorly ventilated, and it is easy to induce gray mold.

What causes cucumber gray mold? How can it be prevented? Here's what the experts say.

In order to infect the fallen flowers, the flowers rot, grow a light gray-brown mold layer, and then further infect the young melons, the damaged melons quickly become soft, shrank and rot, and the gray-white mold layer is dense on them. The leaves are mostly round, nearly round to irregular lesions, with a diameter of 20 50 mm, the edges of the lesions are obvious, the surface is light reddish-brown, and a small amount of gray mold is born. The stem and vine are damaged and cause local rot, and in severe cases, the diseased stem is broken and the whole plant dies.

How to control cucumber gray mold?

1.Removal of diseased residues: In the later stage of harvesting, the diseased plant residues are completely removed, the soil is turned deeper than 20 centimeters, the diseased residues left on the soil surface are turned into the bottom layer, and the soil is disinfected by spraying disinfectants and new high-fat films, so as to reduce the initial infection source in the shed.

Remove diseased flowers, diseased melons and diseased leaves in time before seedling stage and melon expansion, and bring them out of greenhouses and greenhouses to bury them deep outside to reduce the source of reinfection.

2.Strengthen cultivation management: strengthen ventilation, watering appropriately, avoid watering on cloudy days, and prevent the temperature from being too high; Pay attention to heat preservation to prevent cold snaps.

In the high temperature season, deep irrigation in greenhouses and greenhouses, and fish out floating objects on the water surface, bury or burn them in a concentrated manner, and keep greenhouses and greenhouses clean. Spray strong guarillin at the bud stage to thicken the fruit pedicle, promote fruit development and improve the quality of cucumber.

3.Pharmaceutical control: In the early stage of greenhouse and greenhouse, smoke method, dust method and biological control method can be used to prevent and control the disease.

4.Smoke method: use 20% Sukelin tobacco, 200-250 grams per mu each time, or use 50% Nongliling tobacco, 250 grams per mu each time. Smoke for 3-4 hours. Generally, it can be smoked in the evening, and the doors and windows can be opened for ventilation in the next morning;

5.Dust method: spray 10% quick-extinguishing dust agent, or 5% chlorothalonil dust agent, or 10% mildehyde dust agent in the evening, 1 kg per mu each time, spray once every 7-10 days, and spray 2-3 times on the border or alternately.

The preventive effect of the above-mentioned fungicides is better than the first effect, and the dosage should be appropriately increased after the onset of the disease. In order to prevent the emergence of drug resistance and improve the efficacy, it is recommended to rotate or compound the use of several drugs.

6.Biological control: dilute 300-500 times of Olik-mildew, spray before or at the beginning of the disease, spray once every 5-7 days, and the number of sprays depends on the condition.

When the condition is severe, dilute it with 300 times of Olik-mold and spray once every 3 days. The application should avoid the high temperature period, and the optimal application temperature is 20-30.

7.Drug prevention and control: 50% Nonliling wettable powder 1500 times liquid spray; 40% clomycoline wettable powder; 65% anti-milfocarb wettable powder 1000 1500 times liquid; 1500 times of 50% promethane wettable powder; 40% dimethylpyrimidine (sclerotinia net) suspension 500 700 times; 10% Polyann WP 500 700 times liquid.

When the above liquid medicine is prevented, spray once every 5 or 7 days. At the onset of the disease, it is necessary to increase the dose, reduce the interval between medications, and spray 2 or 3 times in a row, and pay attention to spraying on the young fruits. The pathogen of the disease has developed resistance to Suclin.

3. Botrytis is an important disease of cucumber in the protected area. With the development of solar greenhouses, gray mold is becoming more and more serious. The disease also harms tomatoes, eggplants, peppers, leeks, lettuce, scorch, beans, etc.

Symptoms of gray mold are mainly harmful melon strips, resulting in rotten melons. The pathogen mostly infects from the flower part and gradually develops to the melon strips, causing the top flowers of the melon strips to become soft and rotten, and produce a gray mold layer (color version 15, 84). The leaf is infected, mostly starting from the leaf margin, expanding into the leaf in a "V" shape, and a gray mold layer grows out of the disease.

Infection at the seedling stage often causes wet rot and gray mold.

The pathogen belongs to the subphylum Hemimycetes, Botrytis cinerea, the fungus (see Botrytis cinerea).

Pathogenesis. The disease is a low-temperature, high-humidity disease. Poor management, over-dense planting, untimely winding, large temperature difference between day and night, long condensation time and large water flooding are all conducive to the occurrence and epidemic of this disease.

Prevention and control methods. 1) Disinfection and sterilization of sheds. Nursery sheds or production sheds should be smoked for 24 hours with 5% Sukelin smoke agent per 667 square meters per 1 kg before planting; or 50% promethine 800 times liquid or 70% Fumei double 300 times liquid sprayed in all directions.

2) Control temperature and humidity. That is, increasing temperature, controlling water, ventilating and reducing humidity.

3) Spraying control (see tomato gray mold control for details).

What causes cucumber gray mold? How can it be prevented? Here's what the experts say.

Cucumber gray mold mostly invades from the female flowers that open and fail, and initially produces water-stained lesions on the flower pedicle, and gradually grows a gray-brown mold layer, causing the flower to soften, shrink and rot, and gradually expand to the young melon. The leaves are infected, and the lesions are water-stained at first, and then turn into irregularly shaped light brown lesions with obvious edges, and sometimes a small gray-brown mold layer grows on the lesions. Under high humidity conditions, the lesions expand rapidly, forming large lesions with a diameter of 15-20 mm.

After the blind chain stem vine is infected, the stem rots, and the melon vine is broken, causing seedling rot.