Lettuce pests and diseases? What are the hazards of lettuce leaves?

1. Occurrence hazards and symptoms of diseases 1Downy mildew main hazards: The disease can occur throughout the growth process, and the disease is more severe in the adult plant stage, often leading to patches of disease, resulting in serious yield reduction.

Harmful symptoms: lettuce downy mildew mainly harms the leaves, starting from the lower old leaves or mature leaves of the plant, and gradually expanding to the upper leaves, the initial appearance of faded green spots, the edge continues to expand after being limited by the leaf veins to be nearly round or irregular light yellow spots, the back of the leaves produces a white mold layer when wet, and when the occurrence is severe, a number of lesions limited by the leaf veins are connected into a piece, so that the leaves dry up and die. Pattern of occurrence:

The main onset period of lettuce downy mildew is in March to May, and autumn is in October-November.

Lettuce is a relatively common vegetable, its young leaves, stems are edible parts, containing a large number of nutrients needed by the human body, so now the market demand for lettuce is still very good, but when planting lettuce, it is prone to various pests and diseases, how to prevent it? Let's find out!

1. Downy mildew.

It is mainly harmful to leaves. Yellow-green lesions appear on the leaves, and then the lesions expand into irregularities, and white mold grows on the back of the leaves, and the leaves wilt directly in the later stage.

Prevention and control methods: strengthen cultivation management, through reasonable dense planting, timely ditch cleaning and drainage, can effectively reduce the source of disease, increase the application of available phosphorus and potassium fertilizer, and promote the growth of plants.

2. Sclerotinia sclerotiorum.

The disease mainly affects the base of the stem, first appears water-stained lesions, rapidly expands to the upper part of the stem, petioles, and appears soft rot and white mold, and later turns black. It will cause the leaves of lettuce to wilt and die quickly.

Control method: select disease-resistant varieties, and select seedling age 6 8 leaf stage zone * planting. Seedlings can be raised in a nutrient bowl or nutrient * block, and transplanted with * to improve the seedling rate and disease resistance. It can also be mixed with fungicides*, which can effectively improve the disease resistance of lettuce.

3. Soft rot.

The disease mainly harms the leaves and petioles, which are water-stained at first, and the outer leaves wilt at noon on sunny days, and can recover in the morning and evening, and the tissues of the leaves, petioles and stems at the base of the leaves are rotten in the later stage, full of white and yellow-brown viscous, and the smell is overflowing. Continuous cropping and low-lying areas are severely affected. Generally, the epidemic period is from mid-October to late November.

Prevention and control methods: pay attention to timely ditch cleaning and drainage after rain or irrigation. Combined with disease prevention, foliar sprays such as potassium dihydrogen phosphate and boron fertilizer were applied to improve plant stress resistance. It can play a role in disease prevention and control.

4. Botrytis cinerea.

After the onset of the disease, water-stained lesions will appear with a gray mold layer, and the lesions will expand until they will eventually be yellowish-brown. and rot and deteriorate.

Prevention and control methods: Deal with diseased and residual plants in time after harvest, burn them in a centralized manner or bury them deeply, and reduce the source of bacteria. Strengthen field ventilation, reduce humidity, prevent and control foliar dew, fully apply organic fertilizer, and increase phosphorus and potassium fertilizer. Improve plant resistance.

The above is all the introduction to the common pest control of lettuce, if farmers want to plant high-yield lettuce, we must master the scientific pest control methods, do a good job in field management, I hope you can apply what you have learned.

Not only are lettuce leaves harmless, but even the nutritional value of lettuce leaves is not lower than that of lettuce.

Lettuce is a nutritious ingredient, people generally eat its rhizome as a delicacy, but they will throw away its leaves, because most people think that lettuce leaves are not edible, in fact, lettuce young leaves are also a good food, it contains nutrients even richer than lettuce rhizomes.

The content of vitamins in lettuce leaves is generally higher than that of stems, the content of carotene in leaves is dozens of times higher than that in stems, vitamin B1 is twice that of leaves, vitamin B2 is 5 times, and vitamin C is 3 times. Not only is the content of niacin in the leaves higher than in the stems, but its antioxidant effect is also better. In addition, the leaves contain a lot of calcium, which is a pity if you discard it.

How to eat lettuce leaves:Cold salad: with sesame sauce and garlic paste, the taste is very refreshing.

Dipping sauce: You can dip it in yellow sauce, sweet noodle sauce, hot sauce, etc., and it is delicious to eat.

Hot stir-fry: You can stir-fry lettuce together, and it tastes good.

Make soup: Put some in the egg soup, you can also do it.

The above content reference: People's Health Network - Can you eat lettuce leaves? Lettuce leaves are high in vitamins.

Summary. Hello, there are four common pest control methods for lettuce: 1. Aphid control

10% imidacloprid wettable powder 1000 times can be used for spraying control; 2. Downy mildew control: usually 58% methalene-manganese-zinc or anchor manganese-zinc and other agents are used for prevention and control; 3. Prevention and control of gray mold: 50% carbendazim 800 times solution and 28% 10% dicarcarb 600 times solution were used for alternate spraying control; 4. Prevention and control of sclerotinia sclerotiorum:

700 times of 70% thiophanate-methyl wettable powder was used and sprayed every other week or so for prevention and control;

Hello, the common pest control methods of lettuce are as follows: 1. Aphid cavity insect transport: 10% imidacloprid wettable powder 1000 times can be sprayed for control; 2. Downy mildew control

It is usually treated with agents such as 58% methalene-manganese-zinc or anchor manganese-zinc; 3. Prevention and control of gray mold: 50% carbendazim 800 times solution combined with Wu Chiliang 28% 100 percent and ethylmycocarb 600 times solution for alternate spraying control; 4. Prevention and control of sclerotinia sclerotinia disease: 700 times of 70% thiophanate-methyl wettable powder is used and sprayed every other week or so for prevention and control;

To plant lettuce, it is necessary to choose a soil with high terrain, convenient drainage and irrigation, low groundwater level, and deep and loose soil layer. Spring lettuce is a variety with late sprouting, high yield and good commerciality; Summer lettuce and autumn lettuce should choose varieties with strong heat resistance and slow response to high temperature and long sunshine. Winter lettuce is a late-maturing variety with strong cold tolerance, fast growth plum pin infiltration and hypertrophy of stems.

The main pests and diseases of lettuce are powdery mildew, spot disease, sclerotinia sclerotinia disease, lettuce armyworm, lettuce aphid, etc. The control methods mainly include the following points: 1. Reasonable fertilization

Timely fertilization to maintain the fertility of the soil and improve the plant's resistance to diseases and insects. 2. Spraying insecticides: Cypermethrin, dichlorvos and other insecticides can be used for spraying, pay attention to the dose and frequency.

3. Pharmaceutical control: For fungal diseases such as powdery mildew, sulfur powder and other agents can be used for spraying, and methyl tobuzin can be used for drug prevention and control of spot disease. 4. Plant varieties with strong resistance to pests and diseases

Choose varieties with strong resistance to pests and diseases to increase the resistance of plants to diseases and insects. 5. Strengthen field management: remove fallen leaves and diseased plants in time, keep the field clean, and reduce the environment for pests and diseases to breed.

Lettuce is a vegetable that is relatively susceptible to pests and diseases, and once infected with pests and diseases, it can easily spread to surrounding vegetables. Therefore, it is necessary to strengthen the pest control of lettuce and avoid the large-scale occurrence of pests and diseases. When using pesticides for pest control, we must use them in strict accordance with the instructions for the use of pesticides to avoid affecting the environment and human health.

At the same time, we should also pay attention to field management, maintain field hygiene, clean up fallen leaves and diseased plants in a timely manner, reduce the breeding environment of pests and diseases, and fundamentally control the occurrence of pests and diseases.

Choose disease-resistant varieties. Generally, lettuce with pointed leaves is more resistant to disease than lettuce with round leaves, such as lettuce with white pointed leaves, which are more resistant to downy mildew of lettuce.

2.Strict crop rotation and stubble, ridge cultivation. Reasonable dense planting, keep the field ventilated and light.

3.Strengthen field management. Timely tillage before ridge sealing of plants in the field, and increase the number of tillage at seedling stage. More watering in the early stage, less in the later stage, after the plant ridge sealing.

4.Observe in time, detect the disease early, and clean the countryside in time. Pick out the diseased leaves in time and burn them, especially the old leaves in the lower part to increase permeability.

Hello, lettuce leaves are harmed mainly because of the oxalic acid they contain. Oxalic acid is a toxic substance, and excessive intake can cause harm to the human body. Consuming large amounts of lettuce leaves may cause gastrointestinal discomfort, burning in the mouth, vomiting, abdominal pain, and other symptoms.

In addition, lettuce leaves may also contain pesticide residues and heavy metals, which can also cause harm to human health. Therefore, when eating lettuce leaves, you should pay attention to the appropriate amount, and it is best not to eat them alone, but to eat them with other vegetables to reduce the content of oxalic acid. In addition, when buying lettuce leaves, choose high-quality, pesticide residue-free fresh vegetables and wash them thoroughly before cooking.

In addition to lettuce leaves, there are some other vegetable leaves that also contain oxalic acid, such as spinach, beets, taro leaves, etc. Therefore, when eating these vegetables, we should also pay attention to the appropriate amount and cook them to reduce the content of oxalic acid and protect the body.