How to prevent irregular mildew on onion leaves?

1. Select disease-resistant varieties, implement crop rotation, increase organic fertilizer, phosphorus and potassium fertilizer and micro fertilizer, turn the soil deep for more than 40 days, improve the soil, try to eliminate and reduce the residual pathogens in the soil, and reduce the source of infection.

2. Strengthen fertilizer and water management, especially pay attention to timely spraying Tianda 2116 to improve the disease resistance and adaptability of plants.

3. Scientific medication, downy mildew, in the early stage of the disease, use 80% ethylphosphine aluminum 500 times liquid + 64% alum 500 times liquid or 70% methacrylen manganese zinc or ethyl phosphorus aluminum manganese zinc 500 times solution, or 72% DuPont Cryo 600-800 times solution, or Pulik 700 times solution, or green milk copper 800 times solution, or Trico 800 times solution, or gram frost cyanide 600 times solution, or 75% chlorothalonil 800 times solution, etc. Purpura is prevented and treated with 78% Kebo wettable powder 500 times, or parachloride 1500 times, or 75% chlorothalonil wettable powder 600 times, or 64% alum wettable powder 500 times, or 50% iprodione (pomulonic) wettable powder 1000 times. In the early stage of the disease, use 1000 times of 25% prochloraz emulsifiable concentrate, or 1200 times of Shijiale suspension, or 3000 times of Suclin, or 1500 times of 50% pampin wettable powder.

Anthrax should be prevented and treated with 1500-2000 times of 10% Shigao water-dispersible granules at the initial stage of the disease, or 1000 times of 25% prochloraz (100 grams) emulsifiable concentrate, or 500-800 times of 50% anthrax Fumei wettable powder. The above disease prevention solutions need to be mixed with 800 times of neutral soap powder and 600 times a day at intervals up to 2116 alternate spraying, 1 time every 7-10 days, 2-3 times in a row. can achieve good prevention and control effects.

I will introduce the onion pests and diseases and control methods to you here, I hope you will have something to gain after reading it, and master the methods to eat healthy and green vegetables. <>

Estimated to be gray mold. Onion gray mold, also known as white spot leaf blight, mainly damages leaves, peduncles and bulb necks. At the beginning, there are dirty white depression spots on the seedling leaves, round or oval, 1-3 mm in diameter, and the edge is obvious, and then the lesions expand to spindle or irregular shape, mostly developed downward by the leaf tips, and gradually connected into pieces, so that the green onion leaves curl and die.

Under high humidity, a gray-brown mold layer is densely formed on the dead leaves.

Prevention and control methods: choose 1000-1500 times of 50 Pythium wettable powder, or 600 times of 75 chlorothalonil wettable powder, 1000 times of 70 thiophanate-methyl wettable powder, 1000 times of 50 ethylene sclerotia wettable powder, 1500 times of 50 iprodione wettable powder, 800 times of 40 carbendazim suspension, 600-900 times of 3 spinomycin aqueous solution, 300 times of amino-oligosaccharides aqueous solution, 25 prochloraz emulsifiable concentrate 2000 times and 40 Azimethamine suspension 1200 times liquid and other spray control. Spray 1 time every 7-10 days, a total of 3-4 sprays.

Agricultural measures Choose high-lying plots with easy drainage and implement 2 to 3 year rotation with crops other than onions. Disease-resistant varieties are selected, and generally red-skinned and yellow-skinned varieties are more disease-resistant. At harvest time, the diseased and residual plants are cleaned up and taken out of the field to be buried or burned.

Seed sterilization Mix seeds with 35 redomir weights of seeds, or soak seeds in 50 warm water for 25 minutes, then soak them in cold water, remove them to dry, and sow seeds.

Pharmaceutical prevention and control spray 90 ethyl phosphorus aluminum wettable powder 400 500 times liquid, or 75 chlorothalonil wettable powder 600 times liquid, or 50 methyl copper wettable powder 800 1000 times liquid, 64 alum wettable powder 500 times liquid, or Pulik water agent 800 times liquid, or 70 ethyl manganese wettable powder 500 times liquid, or 60 amber ethonium aluminum wettable powder 500 times liquid and other agents, once every 7 10 days, continuous prevention and control 2 3 times.

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The first is reasonable rotation. Thrips are found not only in onion crops but also in garlic, onions, and other crops. Because thrips eggs lurk in weeds, plants, and soil during the winter, it is best not to plant them behind crops such as garlic, onions, etc.

If the onion is dry for a long time, the incidence of thrips increases. Therefore, in the case of dry weather and little rain, timely watering and fertilization can promote the growth of onions, thereby reducing the probability of thrips.

Do a good job of physical prevention and control. Thrips have a pronounced phototaxis to yellow and blue. In the early stages of forage thrips, yellow or blue trays can be hung in the field to trap and kill forage thrips.

Green onions are grown in the countryside and have a lot of white spots on the leaves. How to prevent them is finally chemical control. When the thrips occur in a large area and the damage is serious, physical control can not prevent thrips from harming onions, and insecticides should be sprayed in time to eliminate thrips.

Commonly used thrips drugs can be sprayed 2000 times with 3% aminopyrine acetate solution, 1500 times with 10% imidacloprid wettable powder, and 1000 times with cypermethrin solution. Don't always use the same medicine. It is easy to make thrips resistant.

In order to better adsorb the drug on the green onion leaves, spray an appropriate amount of neutral laundry detergent. Timely removal of weeds and litter in the field can help reduce the source of insects, watering in case of drought, preventing soil drought, and reducing thrips damage.

3% acetamiprid EC 2000 times, 10% imidacloprid wettable powder 1500 times, or cypermethrin EC 1000 times can be sprayed on the leaves, once for 7 10 days, continuous control 2 3 times. Discontinue the medication 7 days before harvesting. Due to the smooth leaves of green onions and strong water separation, neutral laundry detergent can be added when spraying to increase adhesion and improve the spraying effect.

The leaves are covered with white spots, a typical symptom of thrips, which can be accurately identified by experienced green onion growers. Onion thrips are thrips of the order Tassels, which not only harm green onions, but also tobacco, cotton and other crops, especially liliaceae, cucurbitaceae, solanaceae, cotton, and tobacco. Rural people grow green onions with white spots and dry tips on the leaves.

What are the new precautionsIn order to completely control thrips green onions, it is necessary to understand their habits.

From a morphological point of view, thrips green onions are larger, mainly harming green onion leaves, laying eggs in the mesophyll of green onions, harming green onion leaves with mouthparts, and reproducing quickly. Eight to ten generations can occur in a year. If the green onion growers do not accurately judge and carry out targeted control, it will cause serious harmful consequences and make the green onions lose their marketability.

Generally, thrips in the Huanghuai River Basin are seriously harmed from May to June, and the climate is dry and rainy. High temperature and humidity are not conducive to the survival of thrips. In this weather, without pesticide control, thrips can die on their own due to environmental changes.

Prevention is the key to preventing green onion thrips, which means that prevention and control should be done in advance. The advantage of this is that there will be no passive situation of thrips becoming harmful, and then prevention and control will be carried out, not to mention the difficulty and high cost of prevention and control. Even if the control is successful, the damage caused to the green onion leaves will take time to recover, and serious injuries will not return to normal at all.

The best method of prevention and control is actually to share the glory, and it should be watered and fertilized regularly, so as to achieve very good results, and then the whole leaf will grow very green.

In the early stage of the disease, that is, the stage in which the green onion is currently in the question, spray the onion seedlings once every seven to ten hours, three times in a row, with chlorothalonil 500 times, or 500 times of alum, or 1500 times of promethane.

During the management period, it is necessary to pay attention to cleaning up the weeds in the plot in time to reduce the source of insects. Watering frequently when the climate is dry can also reduce thrips damage. If there are many insect infestations, it is necessary to spray drugs to treat them.

In such a situation, it is very likely that there is a lack of iron on the green onion leaves, and we only need to supplement him with a certain amount of iron, and then pour some water.

This situation can be prevented and controlled by pesticides, but Jingqin can spray some travel pesticides in the roots, or change the planting environment, more exposure to sunlight, and choose to increase the planting distance between them.

It is necessary to spray some pesticides in a timely manner, hand molds and should also be fertilized regularly, strengthen the management of water and fertilizer, ensure that the light is full of potatoes, some pesticides should be sprayed on the roots, and some residual branches should be pruned clean.

First of all, we should use some medicine, and secondly, we should also water more and fertilize more. And all these red spots should be dealt with.

When planting, the soil should become nutritious, and pay attention to the moisture of the soil, and spray some pesticides on the soil on time.

Summary. Hello dear, you can use low-toxicity, low-residue agents for prevention and control. It can be sprayed with 3% acetamiprid emulsifiable concentrate 2000 times, 10% imidacloprid wettable powder 1500 times, cypermethrin 1000 times and other sprays, which can be used alternately to maintain the efficacy.

However, due to the waxy layer on the surface of the green onion leaves, the adhesion of the liquid medicine is poor. Therefore, in the prevention and treatment of pesticides, it is necessary to add synergistic spreaders or neutral laundry detergents to enhance the prevention and control effect.

Hello dear, you can use low-toxicity, low-residue agents for prevention and control. It can be sprayed with 3% acetamiprid emulsifiable concentrate 2000 times of Yanchen, 10% imidacloprid wettable powder 1500 times, and 1000 times of high-efficiency chlorocyanate tetrazetin and other sprays, which can be used alternately, and the wax grinding can maintain the efficacy. However, due to the waxy layer on the surface of the green onion leaves, the adhesion of the liquid medicine is poor.

Therefore, in the prevention and treatment of pesticides, it is necessary to add synergistic spreaders or neutral laundry detergents to enhance the prevention and control effect. Summary.

Hello dear, you can use low-toxicity, low-residue agents to prevent and control nurture oranges. It can be sprayed with 3% acetamiprid emulsifiable concentrate 2000 times slow large mass liquid, 10% imidacloprid wettable powder 1500 times liquid, cypermethrin 1000 times liquid and other sprays, which can be used alternately to maintain the efficacy. However, due to the waxy layer on the surface of the green onion leaves, the adhesion of the liquid medicine is poor.

Therefore, in the prevention and control of pesticides, it is necessary to add synergistic spreaders or medium imitation sail laundry detergents to enhance the prevention and control effect.

The leaves can be seen with dense white spots, the yellow-white thrips larvae can be seen on the leaves, and the black insect feces can be seen in the white spots. Therefore, the appearance of white spots in the manuscript of the green onion banquet Biye Wuxiang may be a thrips hazard.

Have a great day.

In the germination stage, the growth of buds and radicles of onions mainly depends on the nutrients stored in the endosperm, and rarely uses the nutrients in the soil. At the seedling stage of onion, the growth is slow, the growth amount is small, and the only disadvantages in the process are not much, but once the lack has an important impact on the normal growth of onions and the improvement of quality. Let's talk about the behavior of onions when they are missing various elements, as well as related management techniques.

<> but it has been planted in our country for thousands of years, and onions are prone to calcium deficiency, potassium deficiency, nitrogen deficiency, magnesium deficiency, boron deficiency and other symptoms in the planting process. The tip of the outer old leaf is grayish-yellow or light white, which falls off with the outer leaf, and the symptoms of nutrient deficiency expand inward, and the leaf is hard paper-like after drying, and the top is densely covered with hairs. Potassium deficiency during bulb enlargement makes it easy to be infected with downy mildew and reduces tolerance.

This is enough to show that onions need a certain amount of sulfur. The application of sulfate fertilizers can achieve the effect of killing two birds with one stone. Lack of copper, onion refers to the lack of copper bulbs in the Qi tribe with thin skin and light color.

Boron deficiency not only makes it susceptible to downy mildew, but also reduces shelf resistance. Generally, after the onion plant reaches the maximum height, nitrogen fertilizer should be properly controlled and potassium fertilizer should be applied to meet the needs of onion growth and development.

Occurrence rule: The pathogen causing downy mildew is fungal algae, and the suitable temperature environment is 13-25 degrees Celsius. This pathogen can overwinter and summer in the soil and diseased plant residues in the form of oospores, and can also be in the form of mycelium in the relationship between onion scales and soil, usually pathological diseases and soil types and characteristics are mostly not obvious, but related to fertility level, usually more common in fertile fields; Deficiency is closely related to soil type and characteristics, and can occur in soils with different fertility levels, but most of them are poor soils.

For onion growers, we all hope that after planting, they will not get sick, less sick, and have a good harvest in the future. But once you plant onions, what if you get sick? Then let me show you how to prevent pests and diseases!