What are the causes of cucumber spot disease? What are the pesticides for cucumber spot disease cont

Causes of cucumber spot disease: The pathogen of cucumber spot disease is mainly mycelium and conidia overwintering in the soil with the diseased residues. Conidia were used for primary and re-infection.

Pathogens are spread by rainwater splashing. In warm and humid climatic conditions, it is conducive to the onset of cucumber spot disease. Cucumber spot disease mainly affects leaves, and mostly occurs on lower leaves in the late growth stage.

The leaves are water-soaked, gradually light brown, the middle part is lighter, there is a water-soaked light green halo around the lesions, and the middle part of the lesions is thin paper-like, pale yellow or gray-white, easy to break. There are a few small black spots on the lesions that are not obvious.

Cucumber spot disease prevention.

1. It is better to rotate with non-nightshade melons and vegetables, and it is better to rotate water and drought.

2. Strengthen the middle and late management of melon fields. Before transplanting and after harvesting, clean up the weeds in the field and around it in time, and burn them in a centralized manner; Plough the land deeply, promote the decomposition of diseased and residual bodies, and reduce the source of disease and insects.

3. Prevention and control of pesticides.

During the flowering and fruiting period of cucumbers, watering is not timely, and field management is not done well, resulting in serious pest and disease disasters and bacterial infections. Pesticide control involves surfactants, which are diluted and then sprayed regularly after rain or in the morning.

It may be that the humidity in the greenhouse is too high, it may be that the soil is too wet, it may be that the leaves are too wet. Be sure to disperse pesticides in time, enhance permeability, and don't plant too densely.

<> For cucumber white spot disease, each mu can be sprayed with 1000 times of Wei WP or 1500 times of 50% Benmyl WP with 50L of water, and sprayed once every 10 days, a total of 2-3 times; You can also spray Manhattan Hou Master No. 8 fungicide control, spray once every 5-7 days, a total of 3-4 times, mainly spray the base of the cucumber vine and close to the ground when spraying the drug.

1. What drugs are used to prevent and control cucumber white spot disease?For cucumber white spot disease, 1000 times of Wei WP or 1500 times of 50% Benmyl WP can be mixed with 50L of water per mu and sprayed, sprayed once every 10 days, a total of 2-3 times; Or you can spray Manhattan Hou Master No. 8 fungicide, generally every 5-7 days, a total of 3-4 sprays, spraying mainly at the base of the cucumber vine and close to the ground. In addition to drug control, when selecting seeds, we should choose excellent seeds without pathogens and strong disease resistance, and before sowing, the seeds can be soaked in warm water of 55 for 15min, so as to reduce the probability of infection, and when the infected leaves are found, remove them in time to prevent the spread of pathogens to the surrounding cucumber vines, so as to increase the ventilation of the rattan trellis.

Second, what are the symptoms?Cucumber white spot disease, also known as scab, is caused by fungi, at first the fungus attaches to the seeds, after the seeds germinate, the spores are transmitted by rain and air, enter from the stomata of plant leaves, and then continue to produce spores to infect cucumbers. In the early stages of the disease, cucumber leaves will develop some white, moist spots that will slowly turn yellowish-white over time, then grayish-white or yellowish-brown, and the edges of the leaves will turn purple to dark brown. The spots on the top are generally between in size and slowly change from round to irregular shapes, and in severe cases, the leaves will die.

Hello, horn spot disease mainly affects the leaves, but also the fruits and stems. At the time of leaf disease, small water-soaked transparent spots the size of pinheads are initially produced on the young leaves, and then enlarged to become pale yellow lesions with yellow halos, and brown in the middle. Later, it is grayish-white, and as the leaves grow, the diseased part breaks into irregular perforations.

On old leaves, water-soaked spots are also produced at first, which are more pronounced when wet, and when they enlarge, they become yellow-brown angular spots due to the restriction of leaf veins.

The middle of the lesion is grayish-brown or grayish-white, and gradually yellow, dry, brown, and mixed with white. When the air is humid, the back of the leaf is overflowing with fine-grained, milky white bacterial pus, and then it is white powdery, and when it rains, there is a white spot on the top of the water particles falling on the lesion, and the old lesions are brittle and easy to crack or perforate and fall off. Germs are generally spread by wind, rain and insects.

The onset of the disease begins at the end of May and early June, and the peak period is July.

Which fertilizer is better to fertilize cucumbers depends on the stage you are in. If the base fertilizer is applied, most of the organic fertilizer is selected, four or five tons of organic fertilizer per mu, and about 15 kg of compound fertilizer should be mixed. If it is found that the seedlings are thin and weak and lack fertilizer, spray potassium dihydrogen phosphate in time.

If you want to top dressing during the growing season, you should mainly choose nitrogen fertilizer, and it is recommended to use water-soluble fertilizer during the peak fruit period to promote better results.

Bacterial horn spot disease of cucumber is common in cucumber in protected areas, and the rate of diseased leaves in severely diseased sheds can reach 70%, which is one of the main diseases in the production of cucumbers in protected areas. Control methods: choose cucumber varieties that are more resistant to bacterial horn spot.

Before sowing, soak seeds in 55 warm water for 25 minutes; or soak the seeds with 600 times of haloperic acid for 30 minutes to kill the germs carried in the seeds, wash them with water and promote germination; Pay attention to the disinfection of seedbed soil, sow seeds on sterile bed soil, scientific management, and cultivate disease-free and strong seedlings; Improve the light conditions so that the plants can grow robustly; Strengthen ventilation in the early morning and evening to reduce the humidity in the shed; On a sunny morning, after the dew dries, agricultural operations such as pruning and tying vines are carried out; Remove diseased leaves and plants in time and bury them deeply. Seriously ill greenhouses and greenhouses are rotated with non-melon crops for more than 2 years. After the emergence of diseased plants in the field, 600 times of haloperic acid, or 2000 times of noromycin, or 2000 times of gentamicin solution, 300 times of 14% copper ammonia aqueous solution, 400 times of 77% killable wettable granule, 800 times of 20% phyllazole, 600 800 times of 47% Jiarui agricultural wettable powder, respectively, mixed with 600 times of 2116 liquid medicine, sprayed once every 5 7 days, sprayed 3 4 times continuously.

Pesticides should be used in rotation, and during the melon strip period, it is necessary to pay attention to the safety interval of the pesticides used.

What medicine to use for yellow spots on cucumber leaves.

Answers. 1.The yellow spots on cucumber leaves are likely to be infected with downy mildew, which can seriously harm growth and affect fruit.

2.After discovery, the diseased leaves should be cleaned up in time, and the agent should be sprayed, mainly with water.

3.When spraying, spray evenly.

4.In addition, management should be strengthened in the later stage, to ensure good ventilation, timely temperature control, and provide a suitable temperature.

5.Control the amount of watering and do not have too much humidity.

The main diseases are cataplexy, downy mildew, scab, bacterial horn spot, blight, gray mold, powdery mildew, virus disease, blight, etc., these diseases not only affect the healthy growth of cucumber plants, but also lead to a serious reduction in cucumber yield, 1. Cultivate strong seedlings and cultivate them in a timely manner.

2. Apply sufficient basal fertilizer, and appropriately increase phosphorus, potassium and biological fertilizer.

3. Reasonable watering, do a good job is to take spray-like droplets, and choose a sunny day for watering in the morning.

4. When planting cucumbers in protected areas, it is best to rotate crops in a timely manner and use high ridges to cultivate them to improve the disease resistance of plants.

Drugs**. 1) During the sowing period, the seedbed was disinfected or mixed with 95% powder of oxachlor.

2) Seed disinfection: soak seeds with 3000 times of 95% oxafen powder, and sow seeds after 2 hours; Spraying during the seedling growth period can add some foliar fertilizer to increase yield and prevent disease.

In the early stage of cucumber white spot disease, carbendazim plus vanmycoline can be sprayed, diluted 1000 times, and 60% anti-mildew Bao ultra-fine wettable powder 800 times liquid, 50% benmycephal wettable powder 1500 times Huispine liquid, 50% polysulfur suspension 600 times liquid, spraying should also pay attention to the frequency, it is best to spray once every ten days, and use it two or three times in a row to wither Huixing, and the effect will be very clear before the defeat seeps.

The main hazard is the leaf leaf pathogenic bacteria, mainly latent in the seeds, with the disease residue remaining in the land, become the second year of the pathogen spread, the fungus can have leaves to spread the melon pulp, natural invasion, the leaves through the rain pest farming operation spread, low temperature and high temperature easy to disease cucumber bacterial horn spot is caused by the bacterial infection of the genus Pseudomonas, the pathogen will overwinter in the soil in the seed or with the diseased residue, become the initial source of infection in the second year, will be infected during the seedling period, after transplanting and planting, With the continuation of low temperatures, humidity or humidity and rain in the field.

<> initial stage, cucumber stems and leaves should show water-soaked small spots, with the development of time and disease, water-soaked spots gradually decay, the color deepens and turns brown, and finally the lesion site is dried up, and there are white marks on the upper surface. In particular, cucumbers in winter and early spring cultivated in protected areas in northern China and cucumbers in the rainy season in East China were heavier. Moreover, cucumber bacterial horn spot is easily confused with cucumber downy mildew.

If you can't identify the condition and use the symptomatic medication, it will inevitably cause great losses.

The true leaves of cucumbers are infected with bacterial horn spot, and the water-stained shape on the damaged leaves gradually changes from light green to light brown, and when the lesions expand, they will become polygonal due to the restriction of leaf veins. In later stages, the lesions are grayish-white and can be easily perforated. Cucumber bacterial horn spot mainly affects leaves, but also causes damage to cucumbers and stems.

After the onset of cucumber seedlings, round or oval water-soaked depression lesions are produced on the cotyledons, with a slight yellow-brown color, and then brown and dry. After the true leaves of cucumbers are harmed.

The germ is bacteria, the fungus overwinters in the soil with the diseased residue in the seed, and becomes the source of infection at the beginning of the year, the seed carrier rate is 2% 3%, the germ spreads through wind, rain, insects, agricultural activities, invades tissue wounds or natural orifices to cause disease, and seeds are disinfected. Sterilize with 70 °C dry heat for 72 h. 50 Soak the seeds in warm water for 20 minutes, remove them and dry them before germination and sowing.

Streptomycin sulfate was soaked for 2 hours, rinsed and then germinated and sown.

This symptom may not be timely to the cucumber to replenish water or remove pests, etc., usually pay attention to buy some special pest sprays for spraying, more cucumber water supplement.

Cucumbers mainly damage leaves and melon strips, and stems, petioles, and tendrils are also diseased. Leaf infection: pinhead-sized water-soaked small spots, polygonal yellow-brown lesions, grayish-white, easy to perforate and rupture.

When the humidity is high, there is white pus on the lesion on the back of the leaf. 1.Choose disease-resistant varieties.

2.Crop rotation with non-melon crops for more than 2 years. 3.

Strengthen temperature and humidity management, pay attention to ventilation and humidity, and reduce humidity to below 70%. 4.Watering should be done using the technique of pouring dark water under the film, watering small water, reducing humidity, and reducing the duration of condensation in the shed to control diseases.

Some black-purple mold layer is produced on the leaves, and the leaves do not have no light transmission and so on. Therefore, we must pay attention to ventilation during the planting process, and the humidity should also be reduced to below 70%. It is best to use a spraying can when watering. You can also buy some pesticides.

Summary. The chemicals that can be used are: Bordeaux Liquid 1:

1:250 300 times liquid; 72% agricultural streptomycin soluble powder or neophytomycin 200 mg; 45% dycemonium aqueous solution 900 times; 50% copper succinate fatty acid (i.e. DT) wettable powder 1000 times liquid; 1000 times of 60% aluminum succinate ethylphosphine (i.e. DTM) wettable powder; 50% Garinone WP 500 times liquid; 77% can kill 500 times of wettable powder. If cucumber downy mildew occurs in the field at the same time, 50% Ruixin copper wettable powder 700 times can also be used for prevention and control, once every 7 days, a total of 2 3 times.

The chemicals that can be used are: Bordeaux liquid 1:1:

250 300 times liquid; 72% agricultural streptomycin soluble powder or neophytomycin 200 mg; 45% dycemonium aqueous solution 900 times; 50% copper succinate fatty acid (i.e. DT) wettable powder 1000 times liquid; 1000 times of 60% amber ethylphosphine aluminum (i.e. DTM) wettable nuclear rapid powder; 50% Garinong Qing's Bad Honorable Wet Powder 500 times liquid; 77% can kill 500 times of wettable powder. If cucumber downy mildew occurs in the field at the same time, 50% Ruixin copper wettable powder 700 times can also be used for prevention and control, once every 7 days, a total of 2 3 times.

The prevention and control of cucumber horn spot disease should also start with seed treatment. That is, use 150 times of 40% formaldehyde or 1000 mg of agricultural streptomycin and neophytomycin to soak the seeds for 90 minutes, wash them with water, and sow them.