Why are greenhouse vegetables prone to pests and diseases? How to control pests and diseases in gree

Pay attention to preventive work, and the humidity in the shed should not be too high. Due to the high humidity and suitable temperature in the greenhouse, it is conducive to the occurrence of pests and diseases. It is necessary to pay attention to covering plastic film, using water and fertilizer integration technology, strengthening ventilation and other measures to reduce air humidity.

Symptomatic treatment of pests and diseases that occur.

<> is mainly due to the high temperature and humidity of the greenhouse, which is suitable for the occurrence of pests and diseases, and the ventilation should be strengthened and the temperature should be strictly controlled. In terms of vegetable health care, non-toxic protective agents and health care agents should be sprayed. Spraying 400-500 times of Panacea oil on the foliar surface of vegetables can form a polymer non-toxic lipid film on the foliar surface, which has the effect of antifouling.

Foliar spraying of plant-based factors can improve the plant's ability to resist insect pests, and it is non-corrosive, non-polluting, safe and convenient.

In short, the daily management measures of greenhouse vegetable pest control are very important agricultural environmental control methods, on the basis of comprehensive agricultural control of different pests and diseases, different vegetables, we should take targeted biological and chemical measures to ensure that vegetables grow vigorously, high quality and high yield. Prevention first, comprehensive prevention and control, do a good job in environmental disinfection and soil disinfection before planting, reasonable fertilizer and water management, control the temperature and humidity in the shed, healthy cultivation of plants, enhance plant resistance, and timely use of drugs to prevent the disease in the early stage.

The humidity and temperature in the greenhouse should adapt to the survival of pests and diseases, before covering the greenhouse film, it is necessary to thoroughly clean up the weeds and branches or unrotted organic fertilizer, resulting in the breeding of diseases and insects, and carry out prevention and control measures for the greenhouse film, clean up the sundries and weeds and then use the rotten fertilizer, reasonably adjust the temperature and humidity, and strengthen field management. In terms of anti-freezing measures, greenhouses should pay attention to preventing physiological freezing damage of vegetables. The main purpose of greenhouse planting vegetables is to provide suitable temperature conditions for the growth of vegetables and realize the off-season production of vegetables.

Therefore, the key to technical management is to control the temperature and prevent frost damage. In terms of preventing frost damage, the thermal insulation effect of greenhouses is improved by thickening the wall, covering with double-layer film, and reducing holes with film pressing lines, so as to reduce the occurrence of vegetable frost damage and physiological diseases.

There are high humidity, weak light, poor ventilation and a single cultivar in the greenhouse.

First, the soil salinization and other problems, greenhouse vegetable pest control to the optimization of varieties and breeding as the core, strengthen the introduction of management and quarantine.

It is because the humidity is not well managed, and it is not well kept dry and exposed to sunlight; We let it bask in the sun regularly, don't water it too much, spray some insecticidal ones, tidy it up more, and clean up some bad leaves.

Because the temperature of the greenhouse is not only suitable for the growth of crops, but also for the growth and reproduction of diseases and insects. At present, the prevention of greenhouse diseases and insect pests mainly depends on spraying.

How to prevent and control diseases in the seedling stage of greenhouse and greenhouse vegetables? With the rapid development of today's social economy, China's science and technology are constantly improving, and the rapid update of products is a very good phenomenon. But it also has a negative impact, namely environmental pollution, which is now often referred to.

Environmental pollution includes air pollution and water pollution.

and soil pollution, the most serious of which is soil pollution. China is a big producer of agricultural products, but at present, the soil on which agricultural products depend is suffering from huge pollution, which directly affects the quality of China's agricultural products. Almost all of the food we eat grows out of the soil.

<> if the soil is heavily contaminated, it will directly threaten the safety of the food we eat. From the above discussion, it can be seen that the prevention and control of soil pollution and the development of pollution-free agricultural products are very important to our daily lives. Soil is the basic resource on which human beings depend for survival and an important foundation for agricultural development.

For crop growth, there is often an imbalance between supply and demand, and attention must be paid to adjustment, especially when people intentionally or unintentionally add various "harmful" elements to the soil that are not conducive to growth, so that the soil and water bodies are polluted, which will lead to the deterioration of agricultural quality and affect human health. Therefore, soil quality is directly related to the quality of life of humans.

Soil-borne diseases have long been considered to be one of the most common diseases in plant communities, and are the most prevalent and most harmful in greenhouses, greenhouses and open fields. Soil-borne diseases are mainly related to the temperature and humidity of the local soil, and are affected by tillage and management methods.

impact. Constant temperature and humidity continuous cropping vegetable greenhouses are more prone to soil-borne diseases, which have a great impact on the yield and quality of crops.

In recent years, with the expansion of high-efficiency cultivation areas of greenhouse eggplant, watermelon, cucumber, melon, etc., due to the difficulty of low-toxicity chemistry in crop rotation, soil-borne pathogens have accumulated year by year, and a variety of crop root rot, bacterial wilt, wilt, seedling wilt and wilt have appeared in a variety of crops, such as root rot, bacterial wilt, wilt, and wilt, and pathogenic nuclear disease, stem blight, brown millet disease, cotton disease, and carbon jaundice.

Bacterial canker disease, bone marrow necrosis disease, powdery mildew and gray mold, as well as various fungal and bacterial diseases and other soil-borne root diseases. Common soil-borne diseases in vegetable greenhouses include: cataplexy at seedling stage, standing blight, melon wilt, nematode disease, root rot, etc.

Due to continuous planting, repeated stubble retention and improper fertilization, crop dead trees and root rot have increased year by year. Common disinfectants have developed severe resistance to soil-borne diseases that are extremely harmful to crops.

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.

The greenhouse creates a suitable small environment for the production of off-season vegetables, and also provides convenient conditions for the occurrence and spread of pests and diseases. Because the greenhouse is a relatively closed space, the interior has formed a relatively independent microclimate, due to the high temperature and high humidity, such temperature and humidity conditions are necessary conditions for the production of vegetables out of season, and also an important condition for the occurrence and spread of various pests and diseases, so high temperature and high humidity are the main reasons why the vegetables grown in the greenhouse are prone to pests and diseases.

In the day-to-day management measures, implemented"Five changes and one increase"Measures, that is, to change the drip film to no drip film, change the open land in the shed to the full coverage of the mulch film, change the flat furrow cultivation to high ridge cultivation, change the open water irrigation to the dark tank under the film, and change the wind in the middle of the greenhouse to the high wind of the shed ridge. A waterproof ditch at the front of the shed is added to collect membrane water in the shed to prevent seepage into the ground to reduce the evaporation of water in the shed.

In the management of the shed film, it is necessary to wipe the shed film frequently, maintain the good light transmission of the shed film, increase the light, increase the temperature, and reduce the relative humidity are important conditions for disease prevention. In watering control, I carry it out"Three do not pour, three pour, three control"Technology. In the irrigation of the winter greenhouse, do not water on cloudy days and sunny days, do not water in the afternoon and water in the morning, and do not water in the open and dark water; Control watering at seedling stage, control watering on cloudy days, and control watering at low temperatures.

In the way of pesticide application, it is necessary to pay attention to the use of appropriate pesticide application methods to control pests and diseases. The greenhouse is a relatively independent closed environment, which can be controlled by fog agent and dust agent, so as to reduce the humidity in the shed and reduce the occurrence of pests and diseases.

In vegetable health care, it is necessary to spray non-toxic protective agents and health care agents. Spraying 400-500 times of Bamulan on the foliar surface of vegetables can make the foliar surface of wild exacerbation form a high-grade non-toxic lipid film, which can prevent pollution. Foliar spraying of phytobiotics can increase the plant's ability to resist insect diseases, and it is safe and convenient without corrosion and pollution.

In short, the daily agricultural comprehensive control and management of greenhouse vegetable pests and diseases is a very important environmental protection and disease prevention method, for different pests and diseases of different vegetables, on the basis of doing a good job in comprehensive agricultural control, it is necessary to take targeted biological and chemical measures to prevent and control them in combination with the actual situation, so as to ensure the healthy growth of vegetables, high quality and high yield.

There are mainly powdery mildew, gray mold, downy mildew and other diseases in the shed, and it is recommended to prevent the noisy bush by spraying the cherry blossom next to the pesticide, and the spraying is generally before 3 pm. You can choose which one to spray amicida, Kinder, Kairun, Powderrust, etc., and rotate the drugs scientifically and reasonably.

At this time, it is necessary to pay attention to the insulation work, we must dismantle and ventilate the mu in time, and it is necessary to spray the farm stove in time to take the medicine, and then we must quickly choose the right fertilizer for the jujube, and we must do a good job in water and fertilizer management, and we must weed in time.

You can use drugs to treat, or more ventilation, you can also fertilize, you must control the temperature of Shihuheng, and you should also understand the planting skills in this area, and do a good job of prevention.

It is necessary to pay attention to ventilation, to timely fertilization, but also to timely watering, to pay attention to planting density, but also to ensure the quality of the air.

In winter, the vegetables in the shed can be treated with drugs like Sun Chun, or more ventilation, or fertilizer, and the temperature must be controlled well, and at the same time, it should be called to understand the planting skills in this area and do a good job of prevention.