How to control cucumber downy mildew 20

I have been growing cucumbers for about 15 years and lilies for 10 years. Talk about the feelings of downy mildew with cucumbers, downy mildew is caused by excessive humidity, first of all, ventilation, exposure to the sun, high temperature spraying, tobacco agent =, delay disease. Recommended drugs [Prik, Dyson Mengsen, Fenke, etc.] Do not spray the opposite side of the leaf, at least 3-4 times, once every 5-7 days.

Don't trust the pharmacy, it's very dark, ask the older melon farmer. Cucumber downy mildew is directly related to the environment, my family is Lingyuan, if you are from Shandong, the climate can be different, grasp the scale yourself.

1.At the seedling stage, the cotyledons initially appear greenish spots, gradually appear yellow irregular spots, and the back of the cotyledons produces gray-black mold layer when wet, and with the development of the disease, the cotyledons quickly turn yellow and dry up. At the onset of the adult plant stage, light green water-soaked spots appear on the leaves at the beginning, which are limited by the leaf veins after expansion, and are polygonal, yellow-green to light brown, and the disease spots are merged into pieces in the later stage, the whole leaf is dried up, and the gray-black mold layer is born on the disease spots on the back of the leaf when wet, and the whole plant leaves die when it is severe.

Disease-resistant varieties have few and small lesions, and the mold layer on the back of the leaves is also sparse.

2.Prevention and control of cucumber downy mildew is recommended to engage in agricultural activities from the following aspects and precautions:

The prevention and control of cucumber downy mildew should be based on prevention, and the prevention period is determined according to the temperature and humidity conditions. Prevention is usually carried out before the arrival of rainy days and in the case of continuous rain. Methods can be sprayed with protective agents.

Once downy mildew occurs, it should be controlled with chemicals. The agent is mainly water-based, and the spraying should be uniform and thoughtful, and the front and back of the leaves should be sprayed evenly, focusing on the leaf back mold layer of the diseased leaves, and spraying the upper healthy leaves for protection. In addition, attention should be paid to the selection of downy mildew resistant varieties; Strengthen cultivation management, appropriate sparse planting, and use high furrow cultivation:

Watering small water, it is strictly forbidden to flood irrigation, pay attention to leakage prevention in rainy days, and use drip irrigation technology in conditional areas to better control diseases; After harvesting, the diseased and fallen leaves should be completely removed, and brought to the shed and outdoors for proper disposal.

3. To prevent and control cucumber downy mildew, we must conscientiously implement the plant protection policy of "prevention first, comprehensive prevention and control", and focus on ecological prevention and chemical prevention and control on the basis of comprehensively doing a good job in the comprehensive prevention and control measures of pollution-free and comprehensive pest control of energy-saving greenhouse vegetable cultivation.

First of all, it is necessary to regulate the temperature and humidity in the greenhouse, and use the closed characteristics of the greenhouse to create a high temperature and low humidity ecological environment conditions to control the occurrence and development of downy mildew.

Pesticide prevention and control: pay attention to timely spraying protection and prevention. When preventing, before the occurrence of the disease, Frost Bell is sprayed with 500 times dilution solution, once every 5-7 days, sprayed 2-3 times, **, 50ml of Frost Bell plus 15ml of garlic oil mixed with 15 kg of water for spraying.

2 times a day, spray 2-3 times in a row.

Pharmaceutical fumigation: In the early stage of the disease, use 200 300 grams of 45 chlorothalonil fog agent (safe type) per mu, close fumigation for 1 night, and open the window for ventilation in the next morning. Smoke once every 7 days.

Pharmaceutical prevention and control of seedbed disease should be used in a timely manner, before transplanting to the field, the field should be taken with medicine, and the field disease should be used in a timely manner. The commonly used agents are: 25 Methyl Frost Powder WP 800 times liquid; 40. 300 times of aluminum ethyl phosphorus water-soluble powder; 64 500 times of alum wettable powder; 70 mancozeb wettable powder 800 times liquid; 80% Dasheng WP 600 times liquid; 72 Double dew wettable powder 500 750 times liquid.

Downy mildew is a high incidence of cucumbers, use this method to prevent and control, no pesticides, save money and practical!

Hello! In the early stage of cucumber downy mildew, the agent can choose mancozeb, acetophine phosphorus and aluminum, and methafen mixture, which has a good effect; If the downy mildew of cucumber is severe, the agent can be changed to downy mildew, silver farry, azoxystrobin, copper quinoline, enoylmorpholine + frost urea cyanide control effect is good, and amino-oligosaccharides can improve the control effect.

The symptom of cucumber downy mildew is that most of the cucumber leaves die within a week or two after the onset of the disease, and the cucumber field is yellow. The prevention and control methods of cucumber downy mildew include scientific fertilization, fumigation and other methods.

1. Symptoms of cucumber downy mildew.

Cotyledons are infected at the seedling stage, first produce irregular greenish and yellow spots on the reverse side of the cotyledons, and gray-black mold layer on the dorsal lesions when wet, and when the disease gradually develops, the cotyledons quickly turn yellow and dry up.

2. Prevention and control methods of cucumber downy mildew.

Scientific fertilization: apply sufficient basal fertilizer, and do not apply too much nitrogen fertilizer during the growth period to improve the disease resistance of plants. The disease of plants is often related to the imbalance of "carbon and nitrogen ratio" in the body, and the disease is easy when the carbon content is relatively low.

According to this principle, the disease resistance of cucumbers can be improved by increasing the proportion of carbon through foliar fertilizer spraying. Experience has shown that from the time after colonization, urea:glucose (or white sugar):

The ratio of water (:1:100 is prepared into a solution, sprayed once every 5-7 days, sprayed 4 times in a row, and the control effect can reach about 90%.

Fumigation method: use 45% chlorothalonil tobacco agent kilogram hectares evenly distributed in 75 places, use a dark fire to ignite from the inside to the outside, and close the shed. It is advisable to take the medicine in the evening, ventilate the next morning, and smoke once every 7-10 days. It is also effective for powdery mildew and gray mildew.

Cucumber downy mildew**

Cultivation is also directly related to fertilizer and water management and disease occurrence, and low-lying terrain, poor soil texture, insufficient fertilizer, over-dense cultivation, poor ventilation or excessive watering can all lead to aggravation of diseases. After the cucumber enters the vegetative growth stage, the number of watering should not be too much, and the brother should be ventilated and transmitted to the light in time during the day to enhance the disease resistance of the plant. Organic fertilizers should be increased.

Because the organic fertilizer has complete nutrients, stable properties and long fertilizer efficiency, it can continuously meet the needs of cucumber growth at all stages and enhance the ability to resist disease.

At the same time, it is necessary to pay attention to the application of phosphorus and potassium fertilizers, which play an important role in promoting root development and the formation of mechanical tissues, and can improve the disease resistance of cucumbers. Dense planting should be determined according to different varieties, not too dense, high density, poor ventilation, affecting the light effect, but also the main reason for the occurrence of downy mildew.

1. The method of cucumber prevention and control of downy mildew, in addition to the large source, it is recommended that everyone cultivate strong seedlings, pay attention to the appropriate density when planting, avoid over-density to avoid partial nitrogen fertilizer, and increase phosphorus and potassium fertilizer. In order to prevent premature plant senescence after the full melon period, foliar topdressing should be carried out regularly to supplement nutrition and improve plant disease resistance.

2. Cover with plastic film and use dark irrigation under the film, and control watering before melon formation; In case of rainy days, we should pay more attention to ventilation and chemical control, and now many people will recommend that we take nutritional control methods to prevent and control downy mildew.

3. Nutritional control: that is, in the middle and late stages of cucumber growth, urea: sugar can be used

Foliar sprays were applied with a solution of 1:2:2000 water; In addition, during the growth period, urea, sugar, and vinegar mixture can be sprayed, which can not only prevent diseases, but also help growth.

Spray every 5 days, spray 4 to 5 times in a row, and spray on the back of the leaf in the morning on a sunny day to prevent the occurrence of diseases.

1. Select suitable local disease-resistant varieties.

2. Improve cultivation conditions and apply foot fertilizer.

3. Spraying fungicide:

75 chlorothalonil wettable powder.

70 mancozeb wettable powder.

58 Redomir Manganese-Zinc WP.

72 g of dew wettable powder.

80 grams of WP.

72 Frost Plague Clear WP, spray once every 10 days or so, a total of 2-3 times.

This is a matter of professionalism. The main control methods for cucumber downy mildew are as follows:

Control methods: 1. Start from the seeds: choose high-quality varieties, and the disease resistance will be stronger. And sterilize the seeds before sowing.

2. Start with fertilization: choose well-rotted organic fertilizer, spray organic fertilizer, and reasonably increase phosphorus fertilizer to fully ensure the nutrient supply of cucumbers.

3. Start from management: reasonable dense planting, ensure field hygiene, and remove diseased leaves and old residual leaves in a timely manner. Qualified agricultural people can use plastic film to cover the whole film.

4. Physical control: biological control: according to the biological characteristics of the bacteria, reasonably control the temperature and humidity of the shed. And to achieve timely and reasonable ventilation.

Causes of downy mildew in cucumber and prevention methods.

5. Because the spread of downy mildew pathogens is very fast, it is necessary to prevent and control it in time. The drug should be sprayed once after planting, sprayed once in the early stage of flowering, sprayed as soon as possible in the early stage of the disease, and sprayed again every 7-10 fields, so 2-3 times in a row, not more than 4 times a month. It can be rotated when used to avoid the resistance of pathogenic bacteria, and can also improve the efficacy, and can also be used with fertilizer when applying pesticides.

The best agent for the prevention and control of cucumber downy mildew should be pyraclostrobin (Kairun) produced by BASF, which has a long duration and good efficacy.

Downy mildew is one of the most prevalent and serious diseases that occur on cucumbers. It has occurred in various parts of China, causing great losses to cucumber production. Downy mildew is mainly spread by dew drops and rainwater, and the disease is severe under high humidity conditions, and the suitable humidity is more than 85%, especially when the leaves have water film, they are most susceptible to infection.

Downy mildew is mainly a leaf damage. It usually occurs after flowering and fruiting, and the disease begins with the lower old leaves. At the beginning of the disease, water-stained and light green spots appear on the back of the leaves, which are polygonal after enlargement and are limited by the leaf veins, and the color of the lesions changes to green, yellow, and finally brown, and purple-black mold grows on the lesions on the back of the leaves under wet conditions.

In the later stage, the lesions are cracked or connected, causing the leaf margins to shrink and dry up, and the serious fields are yellow.

Control method: cucumber land should be selected in higher terrain and well-drained plots. Cultivate at the right time after rain to increase ground temperature and reduce air humidity.

The greenhouse is irrigated with drip irrigation or mulching. After cucumber planting and slow seedling, the plant growth rate is accelerated, downy mildew is easy to occur, during this period, spray wofonin 600 times + Liangguoan 300 times, provide the nutrients needed for plant growth, and at the same time can kill eubacteria and block the source of disease. After the cucumber flowering, the plant from the vegetative growth period to the period of reproductive growth and vegetative growth at the same time, the leaf nutrition is worse than before, the plant disease resistance is weak, should use frost bell 300 times + wofeng 600 times + garlic oil 1000 times spray.

If downy mildew occurs in the later stage, you can spray 150-200 times of Frostbell + 600 times of Wofeng + 1000 times of garlic oil + 2000 times of difenoconazole.