When choosing a vegetable type, which vegetables are less susceptible to pests and diseases?

Lettuce, leeks, coriander, garlic sprouts, spinach, fennel, green onions, these vegetables have a unique smell that keeps pests away, so they are not easy to provoke pests, and they will grow well even if they are not sprayed.

Spinach, lettuce, kale, cucumber, loofah, these are high-yielding, vigorous vegetables, they are not susceptible to pests and diseases during the growth process, easy to manage, but also allow people to obtain higher economic benefits.

Vegetables that are not suitable for pests and diseases include lettuce, leeks, coriander, garlic sprouts, spinach, bitter gourd, fennel, green onions, etc. Because the unique smell of these vegetables will keep insect pests away, they will not be easy to attract insect infestations, and they will grow well even if they are not sprayed.

The environmental conditions of vegetables and other crops cultivated in greenhouses are very different from those in open fields, resulting in large differences in the occurrence of vegetable diseases and pests compared with those in open fields.

1) Physiological diseases are common.

Greenhouse vegetable cultivation is based on the artificial control of the environment, manual intervention is very strong, and the cultivation of protected land often occurs due to improper "protection" and fertilizer damage, high temperature injury, harmful gas poisoning, etc. In addition, the soil in the greenhouse from late autumn to spring, up to more than 5 months of time the ground temperature is low, 20 cm below the soil temperature can generally only be maintained at 12 14, the crop root system is shallow, the activity is poor, the absorption capacity is weak, thus inducing the physiological disease of deficiency.

2) Long duration of harm.

Greenhouse with its unique environmental conditions not only to ensure the normal growth of vegetables annually, but also for the breeding and reproduction of vegetable pests and diseases provides very favorable conditions, pests no longer need to hibernate for winter, the occurrence period and the effective damage period is extended, and even the annual harm, no longer shows seasonal changes.

3) Small pests are seriously harmful.

Due to the high intensity of greenhouse cultivation management and good isolation conditions, large pests are not easy to occur in large quantities. Small pests such as aphids, thrips, whiteflies, mites, spotted loons, etc. can not only overwinter in the open field, but also continue to grow and reproduce in greenhouses, causing frequent harm.

4) Rapid development and easy to erupt.

The humidity in the greenhouse is high, which is very suitable for the reproduction of germs. Especially in winter and spring, after the foliar dew of the plant, the fungus infects quickly, and it is easy to spread quickly under poor ventilation conditions. Pests are not harmed by wind and rain and natural enemies, have superior conditions, reproduce rapidly, and are also prone to outbreaks.

5) Soil-borne diseases occur severely.

Due to the small cultivated area and single planting variety, the facility cultivation does not pay attention to crop rotation and stubble change for many years, and the soil-borne pathogens and pests accumulate in large quantities in the soil, which is very easy to cause the epidemic of pests and diseases.

6) Heavy occurrence of moisture-loving bacteria and pests.

The relative humidity of the air in the greenhouse is large, often reaching 90% 100%, and the surface of the plant is condensed, therefore, gray mold, blight, soft rot, sclerotinia disease, downy mildew, bacterial spot disease and other moisture-loving diseases occur seriously. At the same time, the harm of moisture-loving pests such as snails and slugs is gradually increasing.

7) Some minor pests and diseases gradually rise to major pests and diseases.

Botrytis cinerea, powdery mildew, powdery mildew, cucumber scab, as well as cucumber downy mildew, tomato blight, bacterial spot disease, etc., have begun to seriously harm greenhouse vegetables.

The controllability of the greenhouse environment is strong, and the production should be based on the types of vegetables and their growth characteristics, to create an environmental condition that is conducive to the growth of vegetables and is not conducive to the occurrence of pests and diseases, so as to reduce the occurrence of pests and diseases and improve the quality of vegetables.

(1) There are many types of pests and diseases, and the occurrence law is complex.

The occurrence of vegetable diseases and pests is closely related to the cultivation system and cultivation environment of vegetables. The vegetable crop production system has the characteristics of many varieties, complex stubble, various forms of intercropping, and extremely complex cultivation system. These characteristics lead to the complexity of the types and occurrence patterns of pests and diseases.

2) The occurrence and harm of pests and diseases are serious.

Sparse vegetables have relatively high economic value, fine tillage and management, good plant nutritional conditions, and the occurrence and harm of pests and diseases are also serious. At the same time, because many vegetable disease pathogens often survive in the soil with the diseased residues after the host plant is harvested. The vegetable field has a high multiple cropping index, which provides good environmental conditions for the mass propagation and accumulation of pathogens, and also aggravates the harm of vegetable diseases.

3) The spread and prevalence of diseases are fast.

At present, vegetable varieties are constantly being upgraded, and seed exchanges in different regions are becoming more and more frequent, which accelerates the spread and epidemic of many vegetable diseases transmitted by seeds. At the same time, vegetables have higher water requirements than other crops in the process of growth and development, and vegetable fields are often watered to maintain moist environmental conditions, which are also conducive to the occurrence and epidemic of diseases.

4) There are great differences in the types and degrees of damage caused by pests.

For pests, some pests often break out in the same area and the same vegetable because they are cultivated at different times of the year.

Some are caused by natural causes, such as when it rains a lot, the air humidity is relatively high, which is easy to breed bacteria, or it may be due to human factors, such as not replenishing fertilizer or water in time.

This is due to the fact that a lot of pesticides are produced in the process of planting, and it will also cause damage to the land, so these pests will be produced.

It is due to the unsuitable pH of the soil during the planting process, or the temperature and humidity are not suitable, or it may be that there are too few natural enemies.

Natural factors: When the ambient temperature, humidity, light and other conditions are abnormal, crops are susceptible to pests and diseases. Human Factors:

Extensive management can also lead to frequent pests and diseases. Pathogen invasion: The planting plots have not been disinfected, leaving bacteria and pest eggs.

Poor stress resistance: nutrients are consumed during growth, and their own stress resistance is weakened and eroded.

1. Natural factors

During the vegetable planting period, when the environmental temperature, humidity, light and nutrition conditions are abnormal, the crops are susceptible to pests and diseases, such as when the temperature is too high or too low, it will cause harm, and during the rainy season, the air humidity is too high and bacteria breed, and the lack of light will cause poor growth.

2. Human factors

In addition to natural factors, extensive management of vegetables will also lead to frequent pests and diseases, no timely water and fertilizer supplementation of nutrients, improper cultivation and weeding, overgrown weeds in the field provide a hotbed for pests, improper harvesting causes vegetable injuries, incision infection and insect invasion.

3. Pathogen invasion

The planting plot of vegetables has not been disinfected, leaving bacteria and pest eggs, after planting, it will be infected by the root system, and the bacteria will erode from the inside after infection, so that the plant will be infected from the inside, and the pests at the bottom will also erode the stems and leaves, and the whole plant will die when the disease is serious.

4. Poor resistance to stress

The probability of infection during the growth of vegetables is mainly related to their own stress resistance, the high incidence period of general pests and diseases is incomplete in the cotyledon stage and true leaf development, at this time the root system of the crop is not fully grown, and the internal nutrients are consumed by a large amount of growth, and the stress resistance is weakened and eroded.

Common diseases in Chinese cabbage plantations are: cataplexy, mosaic disease, anthracnose, mycosis, mild rot disease, dry burn, cataplexy, also known as small foot blast, curved neck disease, mainly occurs when peony only grows 1 true leaf, after the onset of the leaf is normal, the stem appears water stains, gradually thinning and drying, resulting in sowing collapse, sudden disease spread rapidly.

Mosaic disease, also known as viral disease, occurs mainly after the growth of true leaves. After the onset of the disease, the veins gradually disappear, necrotic spots appear, the leaves fold and curl, and mosaic disease can cause the plant to be short, slow to grow, and unable to contact the heart. Mosaic disease viruses are mainly transmitted by aphids, and high temperatures and not only reduce the disease resistance of Chinese cabbage, but they also increase the activity of aphids.

Therefore, a hot and dry climate is the most effective way to prevent cabbage mosaic disease. This is done by sowing seeds after the autumn gets colder. After its appearance, water tends to "dry and wet" the soil with a small amount of water.

The anthropogenic infection of Chinese cabbage has obvious regional characteristics, which is generally more serious in the south, and the leaves, small cabbage leaves and veins will be infected. In the early stages of yeast, irregular circles appear with patches of orange water overflowing in the middle, and the edges turn brown and dry. In severe cases, the leaves will be covered with patches of disease, dense holes, and gradually wilt and die.

Fill the seeds; In terms of fertilization, the amount of nitrogen fertilizer should be strictly controlled, and the application of phosphorus and potassium fertilizers should be increased to improve the disease resistance of Chinese cabbage.

In the whole growth period of Chinese cabbage, low mildew may occur, the affected parts are mostly leaves, at the beginning of the disease, irregular soaking and light yellow spots appear on the bottom leaves, when the disease is severe, the leaves are dark brown, and there is a layer of snow or gray frozen moss on the back of the leaves. Soft rot of Chinese cabbage usually occurs in the pericardial stage, and the lesions generally spread from the base of the petiole to the tip of the heart of Chinese cabbage. The infected part is soaked in translucent water.

After a severe illness, it is grayish-brown and begins to decay, white and yellow mucus overflows, often accompanied by a foul odor.

Mosaic disease, anthracnose, mycosis, rot disease, curl neck disease, and some of the diseases that are often seen are all diseases that affect the growth of cabbage.

Mild rot disease, cataplexy, anthracnose, mosaic disease, mycosis, these are relatively common diseases.

Common diseases are mycosis, dry burn, mosaic disease, cataplexy, anthrax, mild rot, and curly neck disease.