What is the disease of white spots on leek leaves? How to prevent it?

White spots on leek leaves are white spot leaf blight, also known as leek gray mold, which is one of the main diseases of leeks cultivated in sheds.

Prevention and control method 1, temperature control, humidity reduction, timely ventilation and humidity reduction, to prevent excessive humidity in the shed. According to the weather changes, open a certain amount of greenhouse film for ventilation at noon to reduce the humidity and make the relative humidity in the shed.

Keep it below 75, but it is strictly forbidden to let the bottom wind go.

2. Clean the shed after the leek is harvested, remove the diseased residue in time, and bring the diseased leaves and plants out of the shed to bury or burn them to prevent the spread of germs.

3. Pharmaceutical prevention and control.

Spray. Spray leeks 1 time before each soil cultivation, and 50 carbendazim can be used.

or 70 carbendazim wettable powder 500 times liquid, or 50 solkelin wettable powder, 50 nonlilin wettable powder 1000-1500 times liquid. Spray 40-50 kg of liquid medicine per mu each time, focusing on spraying the soil surface around the new leaves, and spray 2 times in a row.

Fumes. In the early stage of the shed, the smoke method or dust method can be used, and 10 sulfonyl smoke agent can be used, 200-250 grams per mu, or 45 chlorothalonil.

The smoke agent is 250 grams per mu, divided into 6-8 points, ignited with a dark fire, closed in the shed, and smoked for 3-4 hours.

Dust. The dust method is sprayed with 10 mildew dust agent or 5 chlorothalonil dust agent in the evening, 1000 grams per mu each time, 1 time in 9-11 days, 2-3 times continuously or alternately with other control methods.

The use of fertile leaf water-soluble fertilizer to improve the resistance of leeks to diseases and pests.

You can take a **, is it a single plant or a large area, and what medicine have you used? There are no insects, whether it affects the growth, whether there are new leaves or old leaves or the whole plant.

Causes of white spots on the leaves of green onions and leeks: The causes of white spots on the leaves of leeks and green onions are mainly caused by gray mold, thrips, and spotted loon. Especially when thrips harm the green onion leaves seriously, there are many irregularly shaped white spots on the whole leaf, and many vegetable farmers think it is a disease.

Here, experts list the main field symptoms of the above three hazards as follows, so as to facilitate symptomatic medication. Symptoms: (1) The main symptoms of gray mold damage to green onion leaves are white spot type.

It mainly occurs from the tip of the leaf, with round or oval white spots, and after continuous patches, the green onion leaves are dry and gray hairs are born when the humidity is high.

Cool and high humidity is conducive to the occurrence of green onion gray mold. (2) Thrips harm the green onion leaves to form many fine and long yellow-white spots, which are concave and shiny. Adult thrips are afraid of light, mainly at night, and are generally in the backlight during the day.

3) The spotted fly feeds on the mesophyll, and a winding snake tunnel can be seen on the leaf surface.

After the mesophyll is eaten, only two layers of white transparent leaf epidermis remain. If it has just started, many white spots can be seen, which are easy to be confused with thrips, and this situation needs to be carefully identified by the majority of vegetable farmers.

Dear, hello, I am happy to answer for you, the white spots on the leaves of leeks are edible, belonging to a kind of orange ridge of dryland leeks, the humidity is too high or the temperature is too high, because the evaporation of water will appear white spots, if not watered the white spots continue to expand, the water continues to flow, and finally dry up, yellow leaves. White dots are a natural phenomenon. If the white spot phenomenon is forcibly controlled with drugs, due to the rapid growth of leeks, most of them will have pesticide residues, and those with white spots can be determined as a sign of pollution-free leeks.

As long as it is a pure natural grown, leeks have white spots 100%, and there are absolutely no pesticides in those with white spots, which is for sure. Dryland leeks are also known as small-leaf leeks, which are more flavorful, delicious and more nutritious. It is an indispensable dish for healthy food.

Leeks have white leaves, which may be caused by the damage of gray mold in leeks:

1) Onset of symptoms.

Leek gray mold, also known as leek white spot leaf blight, mainly damages leaves. At the initial onset, small white to light grayish-brown dots appear on the affected leaves, usually more on the front than on the back, and then as the disease progresses, the spots gradually expand and merge with each other to form oval-shaped eye-shaped prismatic spots until half or all of the leaves rot. When the humidity is high, the lesions can be densely covered with gray-brown villous mold layer or mildew, sticky and black.

The knife cut stubble is susceptible to disease, and after infection, it decays downward, and at first it is a water-soaked pale green lesion, the shape is semicircular or "V" shaped, and the diseased tissue is yellow-brown, and there is a gray-brown to gray-green villous mold layer on the surface.

(2) Prevention and control measures.

Choose disease-resistant varieties. Pingke No. 1, Yingxue, Yu Leek No. 1 (Ping Leek No. 2), Ping Leek No. 4, Ping Leek No. 6, etc.

Strengthen field management. First of all, attention should be paid to reasonable watering to prevent excessive soil moisture. Secondly, after each harvest, a thin layer of plant ash can be sprinkled on the moisture surface, which can play the role of heat absorption, moisture absorption and warming, and can increase the content of potassium fertilizer in the soil, which is conducive to the steady growth of plants and enhances disease resistance.

Thirdly, if the shed is cultivated, attention should be paid to the ventilation and moisture drainage in the shed to reduce foliar condensation. In addition, the diseased leaves and old leaves that have been cleaned up should be buried deeply each time to reduce the source of reinfection. After harvesting, it should be applied in time with phosphorus and potassium as the main water-soluble fertilizer of fertile leaves, and excessive application of nitrogen fertilizer is strictly prohibited.

Fumigation control. For every 667 square meters, use 350 grams of 3 trianphazim smoke agent, or 1 kg of 5 milfazin dust agent, or 250 grams of 10 sulfazalin smoke agent, divide 6-8 points, smoke with dark fire for 3-4 hours, and smoke 5-6 times in a row. Chemical control.

Chemical control should generally be carried out in the early stage of the disease, with 10% propathazole 800-1000 times solution, or 50 sulfamine or 50 methyl tobuzine 1000 times solution, or 40 grams of milfin wettable powder 600 times liquid spray control, focusing on spraying on the newly germinated leaves and surrounding soil, once every 7 days, spraying 3-4 times.

<> white spots on the leaves of leeks are generally caused by diseases, which are likely to be gray mold of leeks, which is also one of the more common diseases of leeks. In the early stages of the disease, white or light brown spots will form on the leaves of leeks, and as they grow, they will continue to expand until they affect the health of the entire leaf.

You can choose to use 1000 times of 70% methyl tobuzin wettable powder and 500 times of 50% carbendazim wettable powder; 50% Suclin, 50% Nonrylin 1000 times, 70% mancozeb wettable powder 400 times liquid. The above agents are sprayed once every 7 days, and sprayed 2-3 times in a row.

When planting, try to choose varieties with strong disease resistance, and pay attention to the supplement of nutrients during the growth period, such as using trim water-soluble fertilizer, which can improve its disease resistance.

There are a lot of white spots on the leaves of leeks because they have gray mold.

The disease is a low-temperature and high-humidity disease, and the incidence is closely related to temperature and humidity. Temperature 15 21, air relative humidity above 85% severe disease, relative humidity below 60% mild incidence or no disease. Leeks are frozen at night, and the high temperature and humidity during the day make the disease serious.

In early spring or late autumn and early winter, the disease is prone to epidemic when the relative humidity is above 95%.

**Measures: Timely ventilation and humidity reduction to prevent excessive humidity is the key to early prevention and treatment of the disease. Depending on the weather conditions, it can be ventilated around noon and humidified.

For greenhouses that have been diseased, they can be treated with drugs in the early stage of the disease. Diseases that have occurred can be sprayed twice with Trichoderma harzianum (fungus clearing). When the leeks are not sick, smoke the medicine once every 7 days to prevent the onset of the disease.

Leek white spots are mostly caused by thrips.

Leeks are a common vegetable on people's tables, with a delicate taste and high nutritional value, especially dishes such as sizzling leeks are deeply loved by consumers.

Due to the high market demand, leek cultivation is also very common in China. Moreover, leeks are also called lazy vegetables, which are relatively easy to manage, and many people also have leeks in their own vegetable gardens.

Leek cultivation

Leek gray mold is a common disease in the process of leek planting, which mainly damages plant leaves and has a great impact on the yield and quality of leeks. In the early stages of the disease, white or light gray spots appear on the front and back of leek leaves. As the disease progresses, the tip of the white leaf expands downward into a fusiform or oval shape.

In a humid environment, a gray-brown mold layer will also grow. The simplest and most effective measure is to choose disease-resistant varieties. For leek gray mold, the varieties with strong disease resistance include Zhong Leek No. 2, Iron Miao and other varieties.

According to the local planting conditions, it is necessary to choose the appropriate disease-resistant varieties. Leeks should be planted in rotation with cruciferous or cucurbitaceous vegetables. Do not sit with legumes, which can effectively reduce the number of pathogens.

Reasonable dense planting, timely cultivation and weeding, in order to promote the healthy growth of plants. Do a good job of reasonable fertilization and irrigation, etc., during the growth of leeks, phosphorus and potassium fertilizers need to be applied in time, and pay attention to the amount of nitrogen fertilizer.

Leeks have white spots on the leaf surface, which is called gray mold;

Agricultural control. 1) Seed ozone sterilization treatment: Before seedlings are seeded, soak the seeds with ozone water for 40-60 minutes.

2) Sterilization of high-dose ozone empty shed: Before transplanting seedlings, close the air outlet and sterilize the empty shed with high-dose ozone gas.

3) Select improved varieties and strictly control seedlings: the selection of disease-resistant varieties can improve the ability of tomato to resist gray mold. According to the cultivation test, the varieties such as Jiafen No. 1 and Shanghai 903 are more resistant to gray mold.

Seedlings should be selected disease-free new bed soil, preferably onions, garlic or grain crops that have not been planted with tomatoes for many years, and care should not take soil in the greenhouse in the sick area to raise seedlings or divide seedlings to prevent seedlings from being infected with pathogens;

4) Reasonable dense planting: according to the specific situation and the characteristics of the attack morphology, reasonable dense planting. Early-maturing cultivars, single-hole planting, generally planted 4000 5000 plants per mu, plant spacing 30 35 cm.

At the same time, the basal fertilizer based on rotting farmhouse fertilizer was applied, and phosphorus and potassium fertilizers were increased to prevent partial application of nitrogen fertilizer, which caused the plants to grow too densely and prolonged, affecting ventilation and light transmission, and reducing resistance;

5) Clean the garden: Before planting, remove the stubble and dead branches and leaves in the greenhouse, and then plough the ground. In the early stage of the disease, the diseased leaves, flowers, fruits and the lower yellow leaves and old leaves should be removed in time, and brought to the outdoors for deep burial or burning, so as to keep the greenhouse clean and reduce the source of initial infection.

When operating in the field, it is also necessary to distinguish between healthy and diseased plants to prevent the spread of germs;

Route of infection. 1) Germs invade from wounds caused by agricultural operations and mechanical damage;

2) After the bottom leaf is fertilized, it is infected with pathogens from the edge of the leaf;

3) Fungal pollen is scattered on the leaves, resulting in the invasion of pathogens;

4) Stem wounds or diseased fruits and leaves attached to stems are easy to be infected;

5) overwintering or residual pathogens in the soil invade from the base of the stem;

6) invasion of the gray mold fungus from the residual petals;

7) Botrytis numelia invades the stigma that never falls off;

8) Dead petals and leaves are pasted on the fruit surface, causing pathogens to invade from the fruit surface.