Vegetable greenhouse planting is most afraid of pests and diseases, how to prevent and control it?

1. Garden soil disinfection: 3-5 grams of carbendazim or methyl bromide per square meter of bed soil are treated to kill pathogenic bacteria in the soil and prevent the occurrence of soil-borne diseases.

2. Double-layer coverage: cover the greenhouse with plastic film or add a small arch shed. Mulching film can increase the temperature of the soil surface soil 2, and the addition of small arches can keep the temperature of the vegetable growing environment above 15.

3. Improve the way of racking film: using iron wire instead of bamboo pole and bamboo sheet film, and replacing bamboo pole with plastic rope as climbing object, which can reduce shading and improve photosynthetic efficiency.

Out-of-season cultivation of vegetables is not in accordance with the natural growth law of plants for crop production, but according to the needs of the market, the use of various means, can produce a method at any time, artificially create an environment conducive to the growth of plants and meet the conditions for plant growth, the use of greenhouses or greenhouses to regulate temperature and humidity, promote plant growth, development, fruit, so as to meet the market demand of a planting method, off-season cultivation of vegetable pests and diseases is the main biological disaster, affecting the yield and quality of vegetables, in addition, In the process of pest control, the use of chemical pesticides is unreasonable, and it will also affect the environment and the safety of the use of products, so strengthen the control of vegetable pests and diseases in sheds and produce pollution-free vegetable products in order to ensure the needs of the market and the income of farmers.

You can apply more pesticides to vegetables, and no less pesticides for insecticides, so that you can refuse insects to eat indiscriminately.

Spray pesticides in advance before the aphid season, which not only sprays less in quantity, but also can nip the pest in the bud.

Cataplexy

It occurs from sowing to leaf stage, and the peak period of disease is from the first leaf to the first heart stage, and the diseased seedlings appear to form acute lodging, which is the main feature of cataplexy. Before the seedlings are unearthed, the disease causes rotten seeds, and after the emergence of the seedlings, the disease occurs at the base of the stem, and the lesions are around the stem for 1 week, and then become soft, the epidermis falls off, the diseased part is shrunk, and the stem is linear. The onset of the disease is rapid, and the upper part of the lesion collapses before it can manifest symptoms.

When the seedlings are not unearthed or just unearthed, there is more disease, and the disease of large seedlings is less. When the humidity is high, white cotton wool-like mold will grow on the soil surface of the diseased area or its surroundings. Caused by fungal infestation such as Pythium.

Blight

It is similar to cataplexy, but the symptoms are different, the development of blight is slow, the duration is long, and it is mostly harmful to large seedlings. Newly unearthed seedlings will also be damaged, the seedlings are seriously ill in the middle and late stages, and the base of the stem of the diseased seedlings produces oval dark brown depression lesions, and the lesions extend to the ring stem for 1 week in severe cases. Seedlings wilt during the day, and can recover sooner or later, resulting in shrinkage of the base of the seedling stem, wilting and dying of stems and leaves on the ground, and cataplexy disease is that the diseased seedlings are upright and do not lodging, such as pulling up the diseased seedlings, sometimes the diseased part can be seen in the ring pattern or light brown spider silk mold.

The diseased area does not have distinct white hyphae, which can be distinguished from cataplexy.

Roots

After the seedlings are unearthed, they do not grow new roots or adventitious roots, and the surface of the young roots begins to be rusty brown, and then rots, resulting in wilting and scorching of the aboveground parts, and the seedlings are easy to be pulled up.

Common pest species at the seedling stage of vegetables

Aphids

Cruciferous vegetables: peach aphid, radish aphid and cabbage aphid, collectively known as vegetable aphid.

Peach aphid (Aphid fumigatus): polyphagous, more than 350 species of hosts.

Radish aphid (cabbage tube aphid, vegetable aphid): oligophagous, mainly for cruciferous vegetables.

Fabaceae: Phaseolus vulgaris.

Cucurbitaceae: melon aphid (cotton aphid).

Apiaceae: Celery aphid.

Characteristics of aphid damage

Homoptera, mainly adults and nymphs are concentrated in vegetable seedlings, young leaves, stems and the back of leaves near the ground, stinging and sucking sap. Due to the large amount of reproduction, intensive damage, resulting in serious loss of water and nutrients of the affected vegetables, the formation of leaf shrinkage, yellowing, serious causes the leaves to "collapse", in addition to the transmission of viral diseases.

How to reduce disease in greenhouse vegetables

According to the agricultural technology extension doctor, when it continues to be polluted by rain or haze, do not water and spray to prevent tomato gray mold to avoid the humidity in the greenhouse to increase again, and at the same time ensure the temperature in the greenhouse, moderate ventilation; After the tomato bears fruit, the stigma should be cut off immediately to avoid infecting the fruit. To prevent deformed fruits, it is most important to control the sunlight exposure and temperature and humidity in the greenhouse, and the temperature in the greenhouse should be maintained at 20-25 during the day and 10-17 at night. At the same time, improve the cultivation technology to prevent the incidence of deformed fruits due to more nitrogen and more water in the soil layer, and it is necessary to control the amount of basal fertilizer and fertilizer application at the seedling stage.

Tomato late blight can be impregnated with tomato stems, leaves and fruits, tomato late blight should prevent the humidity in the greenhouse from being too high for a long time, moderate ventilation, and immediately eliminate the main stem with disease in the early stage of the disease, and immediately use medicine to prevent it. When the seedlings grow steeply after transplanting, ventilation should be improved, moisture control should be effectively controlled, plant naphthalene acetic acid should be sprayed moderately, and naphthalene acetic acid should be prevented from being accidentally sprayed into the main stem buds when spraying flowers.

Farmyard manure can improve soil organic matter through a variety of elements and trace elements, so it is widely used in the planting industry, and the application of farmhouse manure for vegetables in plastic greenhouses must be fully mature. If the farmhouse fertilizer is not mature enough to enter directly, it contains a large number of germs and insect eggs, fertilize after fertilization, maintain the spread, and a large amount of ammonia and seedlings can be burned in the process of fermentation and maturity. The whole fertilizer method is divided into base fertilizer, autumn fertilizer, leaf fertilizer, the bottom fertilizer is generally tasted a week before the formal meal, mainly organic fertilizer and farmhouse fertilizer, and the taste should be evenly mixed with the soil.

Autumn rain is generally based on fast-acting fertilizers to promote the rapid growth of vegetables, chase ditches or holes at a distance of 7-10 cm from plants, cover soil and water in time after autumn rain, and can not directly contact plants. To prevent the fertilizer from volatilizing or burning the vegetables.

Foliar fertilizer is generally placed in the peak season and late growth period when fertilizer is needed, and is carried out on cloudy days or in the evening, and the mixed fertilizer solution is sprinkled on the leaves to allow vegetables to absorb. If there is too much fertilizer and the salt concentration in the soil is too high, the soil can be controlled by chlorination and nitrogen fertilizer application, and phosphorus, potassium fertilizer**, nitrate, nitrogen fertilizer fertilizer is prohibited. In the management of the house, it is necessary to increase the ventilation time, strengthen the work, reduce the nitrate content, give some fertilizer, improve the soil structure, improve the quality of vegetables.

The trial of incomplete materials is an appropriate amount, and the demand for trace elements for vegetables is small, but it has a great effect on vegetables, which can greatly improve the quality of vegetables.

The amount used must be reasonable, in order to avoid the loss of fertilizer, the good use of plant growth regulators can play a role in increasing yield, but it is necessary to control the time and concentration of use. Otherwise, it will not only fail to increase production, but also affect human health. Temperature control should be based on the principle that plants do not freeze, and the temperature should not rise too high, especially the water temperature should be properly controlled.

The method of covering the mulch film with the cultivation line, covering the wheat straw with the operation line, or covering the plastic film with the whole film can reduce the evaporation of soil moisture and reduce the humidity in the warehouse. Field management of vegetables in winter sheds is multifaceted, but the most important are water, fertilizer, temperature, light, pest and disease management. Temperature control is the key to the management of winter greenhouse vegetables.

It is necessary not only to take ultra-small warming measures across the board, but also to prevent crops from flourishing due to excessive temperature and humidity.

Before planting, put an appropriate amount of organic fertilizer or manure into the key, add trace elements to the soil, use pesticides to prevent insects in vegetables, and regularly sterilize vegetables.

1. Before planting, be sure to apply a sufficient amount of well-rotted organic fertilizer or manure to supplement the soil with healthy and nutritious organic matter and other nutrients.

2. If conditions permit, the application of organic fertilizer is accompanied by the application of medium and trace element fertilizer and EM microbial fertilizer or medium and trace element fertilizer containing biological bacteria to supplement the soil with medium and trace elements and beneficial bacteria.

3. If there are many harmful pathogens in the soil and the heavy stubble is serious, the self-trophic biological bacteria that can eliminate the harmful bacteria of the soil can be flushed and fertilized after applying the bottom fertilizer, which contains the nutrients that the plant quickly absorbs and solves the harmful bacteria of the soil, purifies and activates the soil, improves the permeability of the soil, and can nutrientically take root, let the plant grow healthily, and improve the absorption and utilization of fertilizer.

4. Regarding fertilization, it is good to balance water-soluble fertilizer, but try to choose potassium nitrate and potassium dihydrogen phosphate, so that the soil sulfate ion is less, which is relatively high for reducing soil acidity and alkalinization, and the absorption and utilization of this kind of fertilizer is also relatively high, and the amount of fertilizer is reasonably grasped according to the growth of the plant.

Deep fertilization. Chemical fertilizers should be applied deeply or dissolved in water.

2. Appropriate amount of fertilization. Due to the low loss of fertilizer in the greenhouse, its application rate should be lower than that of open-field vegetables.

3. Organic fertilizer is applied cooked. In particular, pen fertilizer and human and animal manure must be fully decomposed and fermented before application.