Cucumber downy mildew is the main disease of cucumber, what medicine is good for cucumber downy mild

Downy mildew overwinters in plants, fruit disease residues and soil, germinates in the second year, spreads with wind and rain, and infects the disease through the stomata on the surface of the plant. The most important key is to control the humidity in the greenhouse, and ventilate the greenhouse when the humidity is too large to reduce the moisture in the greenhouse. Pay attention to the balance of various fertilizers, too much nitrogen fertilizer will accelerate the spread of disease.

Seedling cultivation is to do a good job of disinfection and treatment of chemicals.

High temperature and high humidity, insufficient light, poor ventilation, lack of phosphorus fertilizer, poor root system are the main conditions for inducing downy mildew, downy mildew can be treated with silver farry + enoylmorpholine plus potassium dihydrogen phosphate, and can also be prevented and controlled by Zengwei Yinglu or Kaitega Bosa, while paying attention to ventilation and humidity, the main control measures are: first, select disease-resistant varieties. Generally, Jinyou series Jinlu series has good downy mildew resistance and is also suitable for planting at low temperatures, such as Jinyou 20.

Second, to cultivate sterile seedlings, it is best to use electric heating to raise seedlings, and the seedling time is short, and the seedlings are ***.

1. Select excellent disease-resistant varieties to cultivate seedlings, and choose robust and vigorous seedlings for cultivation when planting. Control: Choose disease-resistant varieties.

2: crop rotation, 3 seed treatment, you can choose 50% of the seed weight of Fumei double wettable powder or 75% chlorothalonil wettable powder seed dressing. 4：

Reasonable dense planting, moisture drainage, and reasonable fertilization. 2.The land in the shed can be leveled, drainage ditches can be dug to prevent water accumulation, reasonable fertilization, sufficient base fertilizer, top application of phosphorus and potassium fertilizer, and less nitrogen fertilizer.

The planting environment and high humidity in the shed are the main factors that induce downy mildew, so rainy weather is easy to get sick, the temperature is too high, and the large temperature difference between day and night is also easy to cause downy mildew. Improper selection of varieties, early maturing varieties are prone to downy mildew. Improving cultivation management

Pay attention to crop rotation and stubble, choose plots with high terrain and good drainage for planting in greenhouses, and pay attention to controlling watering in disease-prone seasons to prevent flooding. Apply plantar fertilizer, increase phosphorus and potassium fertilizer and organic fertilizer to promote good plant development. The greenhouse should be ventilated frequently.

You can use Anker, Fenke, Amicida, Enoylmorpholine, and Suppression These drugs are very good, and the effect is very obvious, but it is still necessary to keep the cucumber ventilated, so that the cucumber is not easy to get sick.

Mepaian, Pycogen, Kinredomir, Enomorpholine, Pyretha, Manganese Zinc, Amicida, Anker, etc., are several pesticides that help to help remove downy mildew.

To spray sugar on cucumbers, it is to use edible sugar and urea spray with water. Edible sugar can be white sugar or brown sugar, and the effect is good to prevent and control cucumber downy mildew through this spray.

Huang Heng Zen melon downy mildew is best with Anker, Fenke, Suppression Kuaijing, Jinlei Domir, Mepaian and Amicida.

Cucumber downy mildew, also known as dew fungus, commonly known as running horse, black hair, pestilence, etc., is a disease caused by the infection of Cuban pseudodowny mildew and occurs on cucumbers. It mainly harms leaves, stems and inflorescences, and can be diseased from seedling stage to adult plant stage, especially when cucumber enters the melon harvesting stage.

Cucumber downy mildew is the most serious epidemic disease in cucumber production in solar greenhouses, which can cause most of the leaves of cucumbers to die within a week or two after the onset of the disease, and the cucumber fields are yellow.

Cucumber downy mildew occurs all over China. The peak incidence of cucumber downy mildew in Shanghai area of China was cultivated in protected areas from March to June in spring, April to June in open field, late August to October in autumn, and September to November in protected areas.

Agricultural control methods for cucumber downy mildew

1. Choose disease-resistant varieties

The resistance of cucumber varieties to cucumber downy mildew varies greatly, and the more resistant varieties should be selected. to prevent seedlings from growing and aging. Apply more fertilizer with dust collector to promote the growth of seedlings. Enhance light exposure and disease resistance.

2. Soak seeds to promote germination and cultivate strong seedlings

First, soak seeds in 5 warm water, which can reduce the source of disease; the second is to use nutrient bowls to cultivate strong seedlings and enhance disease resistance; Third, the use of wild pumpkin grafting seedlings can reduce the occurrence of cucumber downy mildew; Fourth, the seedling site and the production site must be isolated, and the diseased seedlings must be eliminated when planting; Fifth, diseased leaves should be removed in time; Sixth, completely remove and properly dispose of diseased and residual leaves after harvesting.

3. Select robust and disease-free seedlings

The nursery site is isolated from the production site, and the diseased seedlings are strictly eliminated during planting.

4. Cultivation management

Cultivation is also directly related to fertilizer and water management and disease occurrence, generally poor drainage or excessive irrigation of the field, too dense planting or untimely hoeing of the field, high humidity, serious disease.

Improper fertilization, soil compaction, weakened plant growth, and decreased disease resistance. Excessive watering of the protected area, lack of timely ventilation, so that the humidity of the protected area is too high, and the foliar surface condenses water for a long time, which is conducive to the germination and invasion of sporangia and sporangia by pathogens, which can easily lead to the epidemic of diseases.

5. Scientific fertilization

Apply sufficient basal fertilizer, and do not apply too much nitrogen fertilizer during the growth period to improve the disease resistance of the plant. 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.

Cucumber downy mildew control.

1. Choose disease-resistant varietiesThe resistance of cucumber varieties to downy mildew varies greatly, and the more resistant varieties should be selected. There were differences in the incidence of cucumber varieties. Generally, the varieties with late maturity and strong heat tolerance are relatively resistant to liquid rolling disease, while the varieties with earlier maturity and low temperature tolerance are more susceptible.

2. Cultivate disease-free and strong seedlings. The nursery greenhouse is separated from the production greenhouse to reduce the infection at the seedling stage. If it is to use a hole tray or to raise seedlings in the furrow, it should be ensured that the plant row spacing of the seedlings is 10cm 10cm, and if the seedlings are raised in a nutrient bowl, the seedlings will be properly placed when the seedlings are three-leafed, so as to avoid the seedlings from growing.

Two days before planting, fungicides should be sprayed once (you can use seasonal frost, enoylmorpholine, chlorothalonil, etc.) to avoid seedlings carrying bacteria. When planting, select good seedlings and strong seedlings, and strictly eliminate diseased seedlings.

3. Adopt formula fertilization technology. Foliar sprays of light carbon, calcium and magnesium; In the middle and late stages of cucumber growth, when the nitrogen and sugar content of plant juice decreases, urea plus potassium dihydrogen phosphate or urea, wang shu glucose (or white sugar), water = 1:

100, to treat the newly ill cucumber spray season frost-free front and back spray, can improve plant disease resistance, 4-7 days spray 1 time, spray 2 times, the effect is better.

4. Ecological prevention and control. The so-called ecological control method is to use the different environmental conditions requirements for the growth and development of cucumber and downy mildew, and adopt the method that is conducive to the growth and development of cucumber and not conducive to the growth of pathogens to achieve the purpose of disease prevention.

5. 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. Spraying must be meticulous, leaf surface, leaf back should be sprayed, especially larger leaf surface should be sprayed more, the prevention and control effect is not good, not necessarily the problem of medicine, often due to the spraying is not thoughtful; When cultivating in greenhouses, be sure to spray before or after watering, which is the key; When cultivating in the open field, be sure to spray pesticides after rain to prevent it.

I myself have 10 years of experience in planting early spring cucumbers in cold sheds in Mudanjiang area, and downy mildew will occur every year, especially from mid-May to mid-to-late June. I will talk about the prevention and control methods of downy mildew in protected areas based on my own production management experience. Broad-spectrum fungicides such as carbendazim or chlorothalonil are added to it; Again, try to avoid continuous cropping with melon crops, if you can't open the ground, after the stubble vegetables are left in the garden, the residue is fully cleaned up, and then the high temperature stuffy shed, and then before the cucumber planting, use smoke agent or sulfur to sterilize the shed.

Why downy mildew occurs is induced by those factors. The occurrence of downy mildew is generally caused by high temperature and humidity, so we must avoid watering at high temperatures, followed by using pesticides to prevent and control. The following pesticides are used to prevent and control downy mildew, and ** pesticides, if downy mildew occurs, we must use drugs in time.

Cucumber downy mildew occurs mainly on leaves.

The diseased leaves are light green water-soaked spots at the beginning, limited by the leaf veins after expansion, polygonal, yellow-green to light brown, the later lesions converge into pieces, the whole leaves are dried up, and the gray-black mold layer grows on the lesions on the back of the leaves when wet, and the whole leaves die when they are serious. Cucumber downy mildew is commonly known as black hair, running horse, dry leaves, cucumber planting area is common, the disease mainly harms melon crops, such as loofah, winter melon, bitter gourd, melon, pumpkin, etc. are susceptible to blight, downy mildew will cause plant leaf death, is a common disease of cucumber planting in protected areas.

When the temperature is 28 degrees during the day, the greenhouse vent is opened, the temperature is controlled below 35 degrees, and the most suitable temperature is 32 degrees.

Cucumber downy mildew causes leaf death and slow growth, and can also spread to the roots of cucumber vines, causing cucumber vines to bloom less and fruiting melons to fall off often. Finally until the whole cucumber vine is completely dead.

In fact, this double mold disease can only cause a sharp decrease in the yield of cucumbers, because all these agricultural diseases will affect the final plant growth.

Cucumber downy mildew mainly affects leaves and stems, and tendrils and peduncles are less affected. To improve the resistance of cucumbers, on the one hand, supplement medium and trace elements, reduce temperature, and sprinkle grass and wood ash on the aisle to reduce the humidity in the shed, so as to control the occurrence and development of downy mildew.

The most important thing is that it is very harmful to the leaves, which can easily cause the leaves to turn yellow, wilt, or even fall, and also lead to the rapid death of cucumbers. It can also cause some other molds. Therefore, we must prevent and control it in time, and we must ventilate it in time, control the temperature above 35, and we must remove water and never have humidity.

The main damage site is the leaves, in addition, it can also damage the stem, peduncle, tendrils and other tissues. It can be infected at both the seedling stage and the melon setting stage. After the seedlings are infected, it can be seen that the leaves turn green and yellow unevenly, and gradually evolve into yellow spots, and when the humidity is high, the gray mold layer can be seen on the back of the leaves. According to our previous articles, it can be preliminarily judged that the diseases with mold layer at the lesions are mostly caused by fungal infection.

After further infection, the leaves turn yellow and dry up.

This is not downy mildew, but cucumber scab.

Cucumber scab is a disease that occurs in cucumbers caused by infection with melon spores. It can occur during the whole growth period of cucumber trembling, which mainly harms the growth point, young leaves, young stems and young melon. The affected leaves were light yellow-green with small round spots at first, and then the lesions became thin and brittle, easy to rupture and perforated, and there was a yellow halo around the lesions. The melon strips were injured with round or oval yellowish spots, and transparent yellow-brown gelatinous substances overflowed from the lesions.

Cucumber scab is a fungal disease, which can be infected by cucumbers cultivated in open fields and greenhouses, and the disease occurs more seriously in greenhouses. Low-lying waterlogging, poor drainage, and moist soil are prone to disease, and low temperature, high humidity, rain, long-term rain, and insufficient sunshine are prone to disease. Flood irrigation, low temperature and high humidity, large temperature difference between day and night, low temperature and cold at night are easy to get sick.

The control methods of cucumber scab are mainly agricultural control and chemical control, which first need to treat the seeds, and implement rotation with non-cucurbitaceous crops for 2-3 years. Timely removal of diseased plants, fallen fruits, diseased leaves, eggplant and diseased flowers in the field; The temperature is controlled at 28-30 during the day and 15 at night, and the relative humidity is kept below 90%; Strengthen ventilation, reduce the humidity in the shed, reduce foliar dew, and control watering from the planting stage of Huangsheng mountain melon to the fruiting stage; Finally, it is combined with chemical agents for prevention and control.

It's a pity that there is no clear reverse side of the blade**... If it is not possible to diagnose all of them, it is recommended to take more recent photos of the negative front to avoid misdiagnosis and missed diagnosis.

Just look at the front of the leaves** to determine that there is cucumber downy mildew.

First, cucumber downy mildew, the resistance is different in various places, it is recommended to choose one or two mixtures of enoylmorpholine, manganese zinc frost urea, manganese zinc of frost mildew, manganese zinc of methyl frost, manganese zinc of oxafrost, manganese zinc flumorpholine, cyanofrostazole, fluoroetheramide, oxazole ketone manganese zinc and other ingredients to choose one or two mixtures (in serious cases), and use them alternately.

If it is a protected greenhouse, pay attention to controlling the humidity, and on rainy days, it is recommended to use chlorothalonil fogging agent to control the condition. ）

Prevention first, comprehensive prevention and control (prevention of diseases, contact and Chang dosage reduction). Use pesticide ingredients alternately, and do not use the same pesticide ingredients consecutively. This is the principle of crop protection.

Second, it is recommended to mix bacterial pesticides such as mesomycin or thiamethone or chunleimycin or thiazolezinc and so on to prevent and control bacterial diseases.

Because the situation in the field is complex, we can't just look at the symptoms of a few leaves, bacterial diseases cannot be ignored, and we must prevent them before they occur.