What are the more common pests and diseases in the process of growing lettuce? How to prevent it?

Lettuce is a common vegetable, there will be some pests and diseases in the process of planting lettuce, so it is necessary to control it, this vegetable is nutritious and delicious, so in the process of planting, we should also pay attention to some ways and means to improve the quality of lettuce.

In the process of planting lettuce, it is easy to appear cabbage insects or aphids, these two pests need to be controlled in advance, otherwise it will affect the growth of lettuce, if the control is too late, the leaves will be polluted, so that the quality of lettuce will be reduced, and it can be controlled by pesticides and sprayed in advance. There will also be a pest that is more powerful, it needs to be found as soon as possible, it can be prevented as soon as possible, it can be controlled with avermectin EC, sprayed once a week, such pesticides can be used for two weeks, not only for this pest, but also for aphids, generally only need to spray pesticides on the surface of lettuce, you can trap and kill pests.

Downy mildew may also occur, mainly because the humidity in the field is relatively high or poorly ventilated, and the leaves close to the ground are prone to downy mildew. When this kind of vegetable is in the early stage of the disease, it can be sprayed with the solution of double enzyme carbirf, which has a prevention and control effect.

Soft rot may also occur, especially in the early stage of the disease, thiophanate-methyl can be prevented and controlled, sprayed every 10 days, and in severe cases, it can be sprayed twice or three times in 10 days. Botrytis also needs to be prevented and controlled in advance, if it is not prevented in advance, it will affect the overall growth of the ecology, and some dust agents need to be sprayed in advance to have a preventive effect. It is a common pest and disease in the planting of lettuce, and it is necessary to master the control skills, so that the lettuce will grow tender and green, the taste will become better, and the yield will also increase, so in the process of planting vegetables, scientific methods are needed.

Lettuce is prone to soft rot, downy mildew, etc. in the growth, can be sprayed with agricultural streptomycin or Pulik liquid agent to control, such as aphids, etc., can be used imidacloprid or yellow plate trapping. Lettuce has powdery mildew, brown spot disease, aphids, green worms, comprehensive drug control. Lettuce mainly has aphids, cabbage worms, and is controlled by chemical methods.

Planting lettuce, the prevention and control of pests and diseases is also the key, so what are the common pests and diseases of lettuce, and how to prevent and control common pests and diseases of lettuce? Soft rot, downy mildew, sclerotinia sclerotinia and aphids are common pests and diseases of lettuce.

Downy mildew, soft rot, sclerotinia disease, aphid. Be sure to spray the fungicide in time. The land is then exposed to the sun, which kills most of the bacteria.

Usually the leaves are spotted or the leaves are falling, or the lettuce is growing too slowly, you can choose to water more water and disinfect it with some potassium permanganate.

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.

After the planting site is tidied up, directly plant garlic or leeks, after the young leaves grow, use human urine to match the appropriate amount of water to drench garlic or leeks, sprinkle plant ash on the compartment to control pests and diseases, or soak the plant ash with water, and spray the leaves with appropriate water to prevent pests and diseases. It is to fight pesticides and insecticides, which is harmful to the body, and some people choose to plant their own, but there are too many pests or the roots are rotten and die. How can we grow healthy vegetables without pesticides?

There are two methods, 1, when planting vegetables, farmhouse fertilizer is indispensable, often grow and develop in farmhouse fertilizer, on the other hand, it will increase pesticide residues on agricultural products, reduce the quality of agricultural products, and it is very unhealthy to eat, in addition, if the field is not well managed, the incidence of crop diseases and insect pests is high, and it needs to be used many times, and it will increase the planting cost to take 5 kg of peach trees, 100 grams of lime, soak it in 3 times the water for 5 hours, squeeze the peach leaves and remove the slag, add 10 kg of water per kilogram, spray, It can control cotton aphid, corn borer and rice insect. It can also be boiled with peach leaves and filtered.

The <> foundation is intact, the vigorous vitality of the vegetable seedlings can improve the ability to resist pests and diseases, in the planting of organic vegetables and ordinary vegetables of the plot to be distinguished, ordinary vegetable land to pass a certain number of years of transformation and certification to plant, to reasonably choose the type of fertilizer, the animal spring weather gradually warms, fruit trees begin to sprout and flower, pests and diseases become more sensitive after winter dormancy, this period of prevention of pests and diseases can achieve twice the result with half the effort, to the later stage, if the pests and diseases have experienced a variety of insecticides and fungicides, In principle, the emphasis is on prevention, as well as the early stage. Then, if it is to prevent, it should be divided into various models, such as open field mode and protected land model, and there are many kinds of protected land models, soilless cultivation mode, nutrient hydropoculture mode and so on. In terms of insect control and disease prevention alone, the general cause of downy mildew is that the air permeability of the soil is not very good, if it catches up with the cloudy day and rains for a long time, it will also cause diseases, and too much nitrogen fertilizer is also an important cause of disease.

Soft rot mainly occurs in the late growth stage of lettuce or bulbous stage, and its pathogen is mainly latent overwintering on the soil or diseased plants, and the infection is transmitted through watering and fertilization. Prevention and control methods: plough the land, use the sun to sterilize, remove diseased plants, reduce pathogens, strengthen fertilizer and water management, apply organic fertilizer, improve disease resistance, pay attention to drainage after rain, so as to avoid root damage caused by water accumulation in the field.

Common diseases of lettuce are soft rot, sclerotinia sclerotinia and downy mildew, once it is found that lettuce has soft rot should be pulled out immediately, before planting, the soil should be disinfected, sprayed with some fungicides.

The function of potassium dihydrogen phosphate is mainly for the reproductive growth of crops, but potassium dihydrogen phosphate can also be used in the vegetative growth period of crops to supplement the lack of phosphorus and potassium elements in crop growth. The nutrients of potassium dihydrogen phosphate are 52% phosphorus and 34% potassium, which have a certain effect on supplementing the phosphorus and potassium elements required for the reproductive growth of crops. Because of the effect of phosphorus in promoting flowering and potassium fruit expansion, spraying potassium dihydrogen phosphate in the reproductive growth period has a certain effect on promoting flower bud differentiation, prolonging flowering period, promoting early maturity, increasing yield and improving quality of crops.

The leaves will be particularly wilted, and there will also be some black spots, which are the consequences of pests and diseases, and we should spray some pesticides to prevent pests and diseases.

Lettuce sclerotinia sclerotinia disease, which harms the base of lettuce stems, at the beginning of the onset of lettuce stems will appear yellow-brown water stains, slowly turn brown, and finally extend to the entire stem, resulting in the phenomenon of stem wear and rot, serious will spread to the leaves and other parts, and finally slowly die. Prevention and control methods: Once lettuce sclerotinia occurs, it has a great impact on the yield of lettuce.

To prevent this disease, after the lettuce is harvested, the leaves are thoroughly removed and then deeply turned. The second round of planting should be reasonably densely planted, so as to reduce the humidity in the field and reduce the conditions for the occurrence of diseases.

Lettuce downy mildew, lettuce downy mildew occurs first to damage the leaves, especially the lower leaves, and then slowly spread upwards. In the early stages of the disease, yellowish round spots or polygonal spots appear on the leaves. When the humidity is too high, white mildew spots will appear on the back of the leaves, and serious ones will appear on the front of the lettuce leaves, and the whole lettuce will wither if the disease is too severe.

Prevention and control methods: After the lettuce is harvested, carefully clean up the fallen leaves in the soil, carry out reasonable dense planting, and remember not to water too much. If there is a lot of precipitation, it is necessary to drain the excess water in the ditch in time to avoid too much humidity in the field.

Lettuce has bulb lettuce and leaf lettuce, which prefers to grow in a neutral soil quality with fresh and moist, fertile soil and loose material. It is more resistant to low temperature and disease. In the case of more routine soil, fertilizer and water management, it is generally not easy to be susceptible.

When the management method is backward and extensive, or it is more susceptible to disease in a poor growth environment. Common diseases in lettuce include downy mildew, sclerotinia sclerotinia disease, brown spot and verticillium wilt. The key pests and diseases are bud worms, jumping beetles, soil silkworms, slugs, and cabbage butterflies (larvae).

The leaves of lettuce are light yellow and nearly round from the bottom leaf upwards.

When the gas is wet and cold, a milky white frosty mold layer emerges on the body of the leaves, and sometimes there is also a layer of mold on the front face of the leaves. When the milky mold layer is more severe and the lesions are fused with each other, the leaves will turn yellow and wilt. At this time, downy mildew has already reached the peak of the disease.

The key injury stage of downy mildew downy mildew is the most likely to occur in autumn and spring, accompanied by a warmer ambient temperature, all kinds of ambush insect pests can not be tolerated, they gradually enter from small seedlings, and immediately continue to complete the adult plant, if the prevention is negligent, it will cause more serious property losses to the planters. In order to better prevent the formation of downy mildew bacteria.

In order to effectively plough and scientifically arrange crop rotation, it is best to use plastic film to cover planting on commercial land with high furrow cultivation. In the case of planting, the seeds should be cleaned and disinfected, and the farmyard manure should be applied to irrigate the farmyard as base fertilizer. Diseased plants should be removed immediately and incinerated or buried.

Sclerotinia sclerotinia sclerotinia sclerotinia is the key to sclerotinia sclerotiorum, when it is found that the stem has brown water traces, it is necessary to cut off the diseased plants without fear of danger, and carry out disinfection and sterilization in the application of quicklime powder to carry out disinfection and sterilization, and cover it with plastic film to erase the germination of pathogenic bacteria.

Pests and diseases: Pests and diseases are dominated by leaves. Since the key food source of oilseed wheat cabbage is leaves, the leaves are tender and crisp green, and the taste is particularly delicious. However, insect pests seem to be more sensitive to body tea, and they also like the tender taste, especially the bud insects are also the culprits, they often gather together, and many inhale the leaf juice until the leaves dry up and turn yellow and die.

When pests and diseases are discovered, certain effective measures must be taken to solve them urgently. There are many diseases of vegetables and fruits, and it is necessary to observe the growth and development status in time, and to prevent diseases and pests and diseases in time to prevent large-scale spread to the infection and suffer serious losses.