There are a wide variety of green onion diseases, and the quality and benefits of the harvest will depend on their proper treatment. The fight against fungal and viral infections is long and difficult, so it is better to take time to prevent diseases. Knowing the first signs of the onset of the disease, you can prevent the mass spread of the pathogen.
A popular type of onion grown for feathers is the batun (Ural family, Seryozha, Semiletka, Maisky). It has a fairly well developed ground part, the feather is thin and can reach 1 meter in length. There are much more useful substances in greens than in onions.
You can plant bulbs or sow seeds. Planting begins in early May. The bulbs are planted to a depth of 3 cm. In July, you can cut the greens, and after a while they will grow again. Since the trumpet grows in one place for several years, next year the first harvest can be collected within a month.
Chives are also grown for greenery. Long narrow leaves with a strong odor can grow up to 50 cm. A small bulb can also form, which is also used for food. Such varieties are known as Bohemia, Lilac ringing, Chemal, Honey plant.
Leeks form delicate and fragrant feathers, flat like garlic leaves, that grow in a fan. There is no bulb, but there is a thick, white stem. Popular varieties include: Vesta, Columbus, Elephant, Casimir, Alligator.
Shallots allow you to cut the greens several times throughout the season. Recommended varieties include Afonya, Aristocratic, Starorussky, Leader, Green, and Karlik.
You can also get greens from onions. For this purpose, small turnips are selected. The following varieties are better suited for these purposes: Soyuz, Strigunovsky, Rostovsky, Bessonovsky.
Planting turnips or onion seeds on greens begins at the end of April, but provided that the soil has warmed up to +12 degrees. Already in mid-summer you can harvest the first harvest. If you plan to collect fresh greens in the spring, then the seeds can be sown in mid-summer.
How to grow onions for greens in open soil?
Green onions can be grown both from sets and from seeds. The vegetable can be planted close to each other or keeping a distance of 3 cm. Tight planting prevents the bulb from forming, and all efforts are directed to forcing the green feather.
The process of growing onions for feathers begins with the proper preparation of planting material. The most commonly used is onion. Choose medium-sized bulbs (3 cm in diameter and weight no more than 45 g). Selected healthy planting material is dense, without damage, stains or dents. Excess husks are removed from them.
The process of heating and disinfection will help protect the future harvest from viruses. It is recommended to warm the bulbs at a temperature of +40 degrees for 8 hours. After this, keep it in a weak solution of potassium permanganate or salt.
What should you be wary of?
When planting onions on feathers, you need to be prepared for the possibility of diseases and pests. They often cause complete loss of crops. To prevent this from happening, you need to know the main signs of a problem and try to prevent further development.
Green feathers of plants affected by the fungus cannot be cut for use as food. If individual bulbs with signs of damage appear in the garden bed, they need to be removed, and the rest of the greenery should be cut off and dried at temperatures above 50 degrees. This will destroy pathogenic microorganisms.
Diseases
Growing green onions begins with preparatory work, which is aimed at destroying pathogenic flora. Under favorable conditions, fungi become active and lead to the death of the crop.
The most common infections of green onions include rust, downy mildew, and mosaic. Each disease has its own distinctive signs.
Onion rust is a fungal disease that can affect all types of onions. Oval, slightly convex yellow spots form on the leaves. As the disease progresses, feather growth stops, they dry out and die. The development of rust is promoted by wet weather and excessive watering, as well as excess nitrogen.
Powdery mildew (downy mildew) is a fungal disease. This disease spreads very quickly and destroys the entire crop. Yellow spots appear on the leaves, and a little later gray-violet spores appear. The plaque is especially noticeable in the morning, after dew. Over time, the spots increase, and all the feathers turn yellow and dry out.
Downy mildew develops in conditions of high humidity, lack of fresh air due to too dense plantings, insufficient solar heat and light.
The disease is treated with folk remedies based on wood ash and whey. After using chemicals, you should not eat greens. It is necessary to reduce the number of waterings and remove nitrogen fertilizing. At the same time, they provide the plant with a sufficient amount of potassium and phosphorus. It is these components that help fight diseases.
The causative agent of Onion Mosaic is a virus. Light yellow spots appear on green leaves. Over time, the spots grow, the feathers begin to curl and dry out at the tips. The reason may be dense planting or pest invasion.
Green onion mosaic disease can be treated with folk remedies. A tincture made from wood ash has proven itself well. 300 g of ash is diluted in 10 liters of water and boiled for 30 minutes. After the solution has cooled, add 35 ml of liquid soap. The green part of the plant is sprayed with the prepared composition.
Another fungal disease that affects onions is neck rot. The infection destroys the onion head. The neck of the bulb becomes thinner, dries and rots. A gray coating appears, which, as the disease progresses, turns into large black dots. If diseased bulbs are planted the next year, the feathers will be weak, sluggish, and pale green with a coating.
Pests
The main pests of green onions are onion flies or moths, thrips and nematodes. The plant develops slowly, the feathers begin to turn yellow and dry out, despite proper care and timely application of fertilizing.
The main methods of pest control include proper soil preparation in the fall. The site is dug up deeply and cleared of weeds. Next year, it is advisable to plant other vegetables in this place, for example, carrots, corn, herbs. Fighting methods:
- If a problem occurs, you can water the rows with a saline solution, avoiding getting it on the greens. Dissolve 20 g of table salt in a bucket of water.
- Periodically, you can sprinkle the beds with a mixture of wood ash, ground pepper and tobacco dust.
- A tincture of tobacco and ground pepper helps. First, 300 g of tobacco is poured with water for several days. Pour 5 g of ground pepper and 20 ml of liquid soap into the finished infusion. Before spraying, the concentrate is diluted again with water.
They are very attentive to the preparation of planting material. Seeds or sets must first be warmed and disinfected.
Top dressing
There are many formulations for feeding onions for greens. It is especially important to fertilize the soil during the period of active feather growth. You can treat the beds with a solution of Agricola 2, Effecton-O, Vegata.
Wood ash, which is sprinkled between rows, is of great benefit. You can prepare an ash infusion. To do this, pour 200 g of ash with hot water, leave for a day, and then water the beds.
For intensive green growth, the soil must have sufficient nitrogen content. In order to prevent fungal diseases, beds with green onions are fed with potassium salt.
The first fertilizing is carried out after the first thinning. You can make an infusion from cow dung or bird droppings. Organic matter can be replaced with a mineral composition. A mixture of ammonium nitrate, potassium salt and superphosphate is suitable.
The second feeding of onions for greens is carried out after another two weeks. Feedings based on phosphorus and potassium are suitable. A mixture of 35 g of superphosphate and 15 g of potassium chloride is scattered on the beds where the onions grow.
Additional fertilization may be required when pests, diseases appear, or changes in the appearance of plants. For example, with a lack of nitrogen, leaves grow slowly and yellow spots appear on them. Phosphorus deficiency is indicated by the appearance of large brown spots.
Proper watering
When growing onions, you need to set the watering regime. Any varieties of onions selected for greens need to be watered once every 10. If the weather is dry, then the frequency of watering is increased. It is advisable to water with warm, settled water early in the morning or in the evening, after sunset. While the feather is growing, it is better to pour water at the root. You can water the onions on the greens until harvest.
A lack or excess of moisture can cause the green onions in the garden to begin to turn yellow. If there is a lack of moisture, the soil can become loose, and if there is too much moisture, the risk of rotting will increase. What to do in this case? If the cause is a lack of moisture, then you need to resume watering. You can check the soil moisture by digging a wooden stick deeper. If it remains wet by 10 cm, then watering is postponed for 2-3 days. It is best to organize a drip irrigation system; it is also recommended to mulch the soil.
Onion crops are characterized by good germination and rapid growth. However, the yield may decrease or even die due to diseases and pests. Timely prevention and compliance with planting technology significantly reduces risks. In this article we will examine the main questions of most gardeners: why the tips of the feathers of onions can turn yellow, what pests can spoil the harvest in spring or autumn. And also what to do and how to deal with adversity.
It is not difficult to plant and grow onions in a small plot or on a huge plantation., if you adhere to the technological process. However, in addition to the planned activities, there may be a need to treat the crop from pests and insects. You should not ignore signs of plant damage, because in just a few days the beds can thin out significantly. But it is quite difficult to cope with an advanced form of the disease or a mass infestation of insects; you cannot do without the use of chemistry. Therefore, it is recommended to include preventive procedures in your onion care schedule to prevent serious problems.
Downy mildew
Downy mildew is one of the types of fungal infection; the pathogen survives well on onion peels and seeds. The transition of bacteria to the active phase occurs when favorable conditions are created, which are characterized by high humidity and positive temperature conditions. The disease can be recognized by the following signs:
- the formation of yellowish-green oily spots on the surface of the leaves;
- a gray-violet coating settles under the feathers;
- increase in spot parameters;
- dying of leaves.
Control methods involve treating the crop and the soil underneath it with special or homemade solutions. Among the drugs that have proven themselves well are:
- Fitosporin-M for onions and garlic;
- Gamair;
- Planriz;
- Alirin-B;
- Glyocladin.
2-3 weeks before harvesting root crops, treatment with chemicals should be stopped. To protect plants from powdery mildew, it is recommended to continue spraying, but using folk remedies.
There are also traditional methods that most gardeners prefer:
- a solution of 9 liters of water, 1 liter of low-fat milk, 10 drops of iodine;
- a weak solution (slightly pink) of potassium permanganate;
- infusion of onion peel;
- a mixture of water (9 l) and whey (1 l);
- infusion of ash (half a bucket of ash for 8 liters of boiling water).
Powdery mildew on onions What does gray rot look like?
The infection persists well on planting material, infecting the soil and, accordingly, the entire crop through loosely closed scales. When you press on the turnip, the skin bends in the neck area, and a gray coating is visible on the surface.
The fight against the disease consists of the following measures:
- disinfection of seedlings before planting;
- soil enrichment with phosphorus-potassium fertilizer;
- timely removal of damaged plants from the plantation;
- moderate watering and control of soil moisture levels;
- proper collection of root crops;
- airing and drying the onions after assembly;
- creating conditions for storing crops;
- periodic bulkheading to remove rotten turnips.
Bacteriosis and its treatment with chemical and folk remedies
At high humidity, and in warm weather, putrefactive bacteria penetrate through the onion scales and infect a healthy fruit.
Rotting can occur directly in the soil, but most often bacteriosis occurs during crop storage. The fruits can be identified simply by their characteristic smell and swollen skin.
Remnants of last year’s fruits can provoke the appearance of harmful bacteria in the soil, so the beds must be dug up after harvesting. Onions are planted in an infected area no earlier than after 4 years.
Fusarium rot and how to get rid of it in spring and autumn
The disease is infectious; the pathogen is located in the soil, where infection occurs. During the development period, the bottoms of the turnips are affected by rot, as a result of which first the greenery dies, then the root part. Among the reasons that provoke the formation of a pathogen in the soil:
- waterlogging during irrigation;
- harvesting in rainy weather;
- late fruit harvesting;
- drought during turnip ripening.
- before planting, the seedlings must be disinfected;
- when choosing seeds, preference should be given to early and mid-ripening species (they are less susceptible to infection);
- observe watering norms, avoid waterlogging of the soil;
- Root crops should be collected in dry weather.
If an affected onion is identified, it should be removed from the garden bed and the soil should be treated with Bordeaux solution (1%).
Bacterial rot of onion seed
Rot often affects turnips when there is excess moisture in the soil. The reason is prolonged rains and the type of soil that prevents the rapid absorption of precipitation. Initially, mold forms in the neck area of the onion, descending over time through the seeds. Such a crop cannot be stored for a long time; the rotting process cannot be stopped.
Turnips are usually not used even for obtaining seeds; such material is affected by a fungus and is not capable of producing good seedlings.
- before planting, the seedlings must be disinfected;
- Irrigation should be carried out under constant control of the degree of soil moisture;
- regularly clean the beds of affected plants;
- Harvesting should only be done in dry weather;
- ensure proper storage conditions with a temperature range from +5° to +8° and ventilation.
The main pests of onions and protection against them
Not only diseases, but also various pests that prefer to colonize onions can reduce yields.
- Before planting, the sets should be prepared: warmed for several days at a temperature of 23-25°, soaked in a saline solution (1 liter of water per 1 tablespoon of salt) - 3 hours, then repeat the procedure, but in a manganese bath - 2 hours.
- Choose a well-ventilated place for the beds. It is recommended to place onions and carrots next to each other. For both crops, this will provide additional protection from pests.
- Change the location for planting onions every year. In late autumn, when frost sets in, you need to dig up the ground well so that harmful bacteria and larvae die.
If there is a massive invasion of flies on a plantation, it is unlikely that it will be possible to do without chemicals. Among the popular ones: Bazudin, Aktara, Muhoed.
In order not to use chemicals, many gardeners use traditional methods. The most effective are considered:
- a solution based on ammonia (for 10 liters of water take 3 drops of iodine, a tablespoon of ammonia, several crystals of potassium permanganate);
- tincture of fragrant herbs (add several branches of valerian, wormwood, mint to 10 liters of boiling water);
- pine decoction (half a bucket of spruce or pine needles is brewed in 10 liters of water);
- wood ash powder;
- powder of ash, red hot pepper, tobacco leaves.
In addition to the above methods, you can treat the bed with salt at the rate of 300 g of salt per bucket of water. The main thing that should not be forgotten when using this method is to spray the onions with clean water to wash off the salt from the feathers. If the treatment is successful, the flies will stop flying over the onions and will not lay eggs in the beds.
In addition, piperazine helps to cope well with the pest. Used at the rate of 1 package per bucket of water. It is necessary to spray all affected areas.
Pre-sowing treatment of onion sets against onion fly is carried out in early spring. You need to spray the entire garden bed. The zemlyan preparation also helps well in the fight against pests; you can always find out how to apply it in the instructions.
Onion mite and treatment against it
Before planting onions, the soil is fertilized. This is exactly the environment the tick chooses for itself. You can identify an insidious pest in a garden bed by its characteristic features:
- deformation of feathers with the formation of a white coating on them;
- wrinkling of the plant due to loss of moisture;
- formation of mold and mildew.
You should not use pesticides in the fight against ticks. The product is addictive to insects, so the treatment will be ineffective.
For pest prevention purposes, the following methods are used:
- careful sorting of seed during storage;
- preparing seedlings for planting (sorting and warming);
- carrying out disinfection procedures;
- regular treatment of beds with herbal decoctions and nettle infusion.
Onion thrips
To prevent thrips from settling in onion beds, it is recommended to carry out the following measures:
- change the location of planting onions in the garden annually;
- store planting material under proper conditions;
- follow the rules for preparing and planting seedlings;
- removal of all crops and tops from the garden bed;
- digging the soil in late autumn.
How to process onions?
In case of large-scale damage to the plantation, special preparations are used:
- Aktara;
- Fitoverm;
- Karate;
- Spark Gold;
- Zeon et al.
When using chemicals, you should not eat greens.
You can also try traditional methods:
- placing sticky tape for flies between the beds as traps;
- planting a nearby onion plantation of fragrant herbs and marigold flowers;
- spraying with infusion of tobacco leaves (leaf for 3 hours);
- treatment of plants with infusion of celandine leaves (leave for 48 hours).
Reasons why onions turn yellow in the garden and what can be done
Yellow spots on winter onions do not always indicate the presence of diseases or pests. Sometimes the cause may be a lack of nitrogen in the soil. To correct the situation is quite simple - introduce nitrogen-containing fertilizers into the soil. For these purposes, organic and mineral baits can be used. You can also feed green vegetables with ammonia. It is an excellent fertilizer and also helps get rid of flies and other pests.
Watering with ammonium nitrate should be done with caution according to the instructions. In addition, you can water and spray the onions with kerosene. It allows you to protect the crop from onion flies. You need to process the bed using 2 tbsp. kerosene to a bucket of water. This measure will help preserve the harvest and there is no fear of re-infection.
Yellow feathers may also indicate insufficient crop care. Each variety has its own growing characteristics. When planting different species, few people are interested in the intricacies of growing a particular hybrid. Experienced gardeners recommend that during the selection process you familiarize yourself with the description of the plant and the rules of care.
Unfavorable weather conditions can provoke the formation of yellowness on the batun. As a result of prolonged rains, feathers change color and become deformed. Or, due to too hot summers under the influence of intense sunlight, feathers begin to dry out prematurely. In such cases, plants can be helped by covering them with film or agrofibre. Treatment in this case is not required. You need to fertilize the vegetable as usual.
Early diagnosis of the problem will help save not only the crop, but also prevent soil infection. There is no point in delaying treatment, because pests and diseases destroy plants very intensively.
This valuable vegetable crop is susceptible to a lot of infections. About fifty species of fungi and pests cause all kinds of onion diseases. Moreover, they affect it both in open ground and in greenhouses. To combat this, you need to approach the problem comprehensively, including treating plantings with special means and accurately implementing agricultural technologies. Very often, onions get sick on waterlogged clay soils, saturated with mineral fertilizers and rotted manure, containing large amounts of nitrogen.
Treatment of onion diseases
Until now, scientists have not found those reliable mechanisms that would prevent the development of epidemics, although the search for ways to destroy or at least weaken the activity of microorganisms that infect onions is ongoing. During the growing season, at the first signs of infection, fungicides are used. The effectiveness of the pesticides used, their doses and the number of treatments depend on how the disease develops. The most rational and popular way to use pesticides is to treat or treat planting material. How is it processed? Until now, as in the 20s of the last century, the use of Bordeaux mixture is relevant, especially in private households. Today there are its substitutes - contact zinc-containing fungicides. Previously, contact fungicides that were effective at high application rates were used to protect onions. Later, systemic drugs began to be used, showing high efficiency at high consumption rates at the initial stage of their use.
When growing onions in greenhouses, the risk of contracting certain infections is reduced. In such rooms it is easier to regulate humidity and maintain the required temperature. With ventilation and constant air circulation, mold and mildew will not appear. However, it is not possible to completely get rid of diseases here. For example, downy mildew can cause damage in the greenhouse as well as in the field.
For general aspects of growing onions (including onions), see the infographic.
(click to enlarge) Main diseases of onions
- Powdery mildew. This bacterial infection is also called peronosporosis. It manifests itself in a change in the shape of the bulbs and the cessation of their development. The causative agent of peronosporosis is a fungus that infects the leaves of the plant, on which a yellow coating appears, after which they gradually begin to die.
Treatment:
- Fertilizers made from phosphorus and potassium. Thanks to them, the vegetable will increase resistance to infection and increase protection against disease.
- Preventive treatment with fugicides.
- It is inadmissible to thicken the planting when growing onions. Weeds should also not be allowed to grow.
- When the first signs of powdery mildew appear, you must stop watering the crop and feeding the soil with nitrogen fertilizers. Remove the bulbs that have formed by that time and dry them in the sun for two weeks. Peronosporosis develops under bad weather conditions.
- The following drugs are effective against this disease: “Ordan”, “Alirin-B”, “Quadris”, “Abiga-Pik”, “Bravo”, “Revus”, etc.
- Gray (cervical) rot. Signs of this dangerous onion disease are gradual damage to the scales near the neck. This occurs through the soil or after harvesting in a garden bed or greenhouse. The infection spreads after rains or when infested by pests.
Treatment:
- Use of exclusively healthy material when growing; choice for sowing early varieties.
- Fertilizing the soil with nitrogen fertilizers, and at the end of maturation, using potassium and phosphorus.
- The use of drugs “Bravo”, “Quadris”, “Ridomil Gold”, “Switch”, etc.
It should be remembered: if during the growing season of plants they are subjected to constant treatment with systemic fungicides, then resistant strains of pathogens may arise and the effectiveness of the drugs will decrease.
- Fusarium. This is a fungal disease in which the bottom of the bulb softens and the root system dies. The leaves turn yellow and the bulb gradually dies. Fusarium is provoked by the onion fly, which damages the bulb, and during storage it begins to rot.
Treatment:
Before sowing onions, it is necessary to till the soil. Only high quality planting material should be used.Affected plants must be destroyed immediately, and the rest must be treated with a special preparation.
Before planting, onion sets must be treated by immersing them in a three percent suspension of TMDT fungicide for 20 minutes.It is important to follow the rules of crop rotation: onions can be replanted on former beds only after 3-4 years. It’s good if its predecessors are grain crops.You can lim the soil with chalk and feed it with dolomite flour. To protect against fusarium, potassium permanganate with the addition of boric acid, this non-concentrated solution can be watered generously at the roots of the plants. Horsetail decoction and ash infusion help well.
Before putting the onions into storage, the bulbs are cleaned of scales. If there were sick people among them, spray the remaining ones with Fitosporin and dry. Methods of struggle.Before planting, the seedlings need to be warmed up. And before storing for storage, keep it at a temperature of +45°C for 18 hours.
- You should not plant different varieties of onions nearby. Be sure to promptly remove all weeds on the site. Follow the rules of crop rotation. Mosaic of a bow.
Before putting the onions into storage, the bulbs are cleaned of scales. If there were sick people among them, spray the remaining ones with Fitosporin and dry. This disease is caused by a virus. Signs: small yellow-white spots in the form of stripes appear on the leaves. Then the leaves change their appearance, indicating a lack of nutrients, and then begin to wither and dry out. The inflorescences on the testes are sharply deformed. Small bulbs appear instead of flowers. Bulbs affected by mosaic have an elongated shape; they do not reach maturity, and begin to germinate in the fall. The carriers of this virus are ticks, nematodes, and aphids living in the soil.
- It is necessary to isolate perennial onions and seeds from onions. Regularly remove plants affected by mosaic. After harvesting, warm the bulbs for 10 hours at a temperature of 40-42°C. Onion jaundice.
- The leaves of onions affected by this viral disease become spotted, and the arrows of onions turn yellow. Jaundice cannot be treated. The fight against it consists of regularly removing diseased specimens, and at the same time all weeds. Plants are sprayed.Stemphylliosis of onion.
Fungal disease. It begins with small light yellow or brown watery spots appearing on the leaves, gradually developing into elongated tubercles. Then they darken along the edges and stick together over time, affecting the entire leaf. Compliance with agrotechnical practices, combating pests and causes leading to the death of onion leaves.
- White rot of the bottom of the onion. This disease affects onions both in the soil and especially during storage. The leaves of young plants begin to turn yellow and die. Seedlings often die. On onions, dieback occurs from the tips of the leaves downwards. A white cottony coating and soft rot appear on the scales and roots of young onions, on the surface of which tiny black rounded sclerotia form. Sometimes the disease can only be detected during cleaning.
Protection measures:
- alternate crops;
- remove diseased bulbs and plant debris during harvesting and storage;
- maintain the necessary soil moisture;
- use high-quality planting material, disinfect it with preparations containing copper.
- Gray cervical rot. Fungal disease. This is especially noticeable when storing onions. Sometimes during harvesting and growth of testes. Sign: the neck of the onion softens and weakens, a fluffy gray coating forms on it, which turns into a powdery mass. Later, tiny black sclerotia appear in it. If the disease develops, the entire bulb becomes covered with plaque. Onions become infected before or during harvesting (when cutting leaves).
Protection measures:
- removal of plant residues;
- sorting onion seedlings with signs of disease;
- compliance with crop rotation (onions can be planted in their old place only after 3 years);
- isolation of areas with onions of different ages;
- suitable storage conditions.
Video “On onion diseases”
An indicative video that will answer many questions about onion diseases.
Other fungal diseases of onions
| Anthracnose | Cercospora | Aspargillosis |
| Appears at the end of the growing season. Brown spots with a dark border appear on the leaves. On the shoots there are light brown spots with a brown rim. The causative agent is a phytopathogenic fungus Colletotrichum capsici. It affects legumes, tomatoes, berries, and grapes. |
Onion leaves appear
chlorotic spots with a yellow rim. In humid weather, the affected tissues become covered with an olive coating. The causative agent is a fungus Cercospora duddiae Welles. Found on soybeans, beets, and grapes. |
This disease is also called “black rot of onions.” Onions are damaged if stored improperly. The bulbs gradually soften and mummify. Pathogen mold
genus Aspergillus. Found on garlic. |
How to protect onions from fungal diseases
- Thorough destruction of plant residues.
- Maintaining crop rotation.
- Rejection of planting material with symptoms of rot.
- Early planting.
- Fertilize the crop subject to the dose and timing.
- Harvesting onions in dry weather.
- Mandatory drying of onions before storage.
Diseases caused by pests
- Onion fly. It penetrates the fruits in the form of larvae. As a result, the onion stops growing and begins to rot. Feathers turn yellow and dry out.
Fighting methods:
- Spray the soil around the onion with a salt solution (300 g per 10 liters of water). Repeat the procedure every 10 days. You need to water at the roots, but do not touch the leaves.
- Plant onions far from the place where you grew them before.
- Root mite. When infected, the onion begins to rot and a fungus appears. Therefore, you will have to fight both the pest and the fungus.
Fighting methods:
- You should not grow onions in a mite-infested area for 3 years;
- the onion should be thermally treated;
- spray the plants with a 0.2 percent keltan solution.
- Onion moth
The butterfly chews out the leaf, creating tunnels in the tissue, which causes the leaves to die.
Control measures:
- onions must be sprayed;
- remove plant debris;
- deeply loosen and dig up the soil.
- Stem nematode:
This is a small thread-like worm 1-1.5 millimeters long that lays eggs in the roots of the onion, after which its heads crack. Onion leaves become deformed.
Control measures:
- select uninfected seed material;
- heal onion sets in hot (+45-46°C) water for 10 minutes, in water at a temperature of 50-52°C - 5-10 minutes, at a temperature of 55-57°C - 3-5 minutes. Or soak the onion for 3 days in water at a temperature of 16-18°C.
- Onion thrips . It is a light yellow or dark brown small insect with fringed wings and a narrow oblong body. Thrips, together with its larvae, suck the juice from the inflorescences and leaves, after which they become deformed, turn yellow and dry out.
Fighting methods:
- it is necessary to alternate cultures;
- before planting, disinfect the bulbs in hot (45°C) water for 10 hours, then cool in cold water;
- soak the bulbs for 24 hours in a 2% solution of sodium nitrate;
- After harvesting, dry the onions for 5-7 days at a temperature of 35-37°C.
- In the fall, carefully destroy plant debris and dig up the soil.
- Onion secretive proboscis. A black beetle with white scales, 2-2.5 millimeters long. It gnaws small holes out of leaves. Females lay eggs inside the leaf. The larvae emerge after 5-16 days and feed on leaves. Then they pupate and in early July beetles emerge from them, feeding on onions.
Control measures:
It is necessary to trim and destroy the leaves affected by the larvae, while simultaneously feeding and watering the onions. During the period of mass pupation of larvae, the soil should be loosened.
- And timely collection and subsequent destruction of plant debris. Onion hoverfly.
Greenish-bronze fly 6.5 -9 millimeters long. She eats the pulp of the onion. From July to September, two generations of hoverflies live, causing damage to onions.
You need to fight it in the same way as with the onion fly.
- Prevention of onion diseases
- Before you start growing onions, you should prepare a greenhouse or disinfect the soil in your garden.
- Maintain crop rotation. After harvesting, ensure comfortable storage conditions for onions.
Harvest when fully ripe. The harvested onions should be thoroughly dried before storing them.
Video “Folk way of fighting insects and diseases”
Demonstrative video with a clear example of the use of a folk method to combat pests and diseases of onions.
- Question answer
What can you plant in the garden after onions?
- Experts advise: If you mean a complete annual crop rotation, then after the onions you can plant cucumbers, zucchini, beets, and carrots. And after harvesting the onions in August, it is good to sow lettuce, Chinese cabbage, and spinach. And in September - radishes, which do not like “long days”. So, it will still have time to ripen and give you a new harvest.
For what diseases are onions contraindicated?
For diseases of the kidneys, liver, as well as acute gastrointestinal diseases. If you have cardiovascular diseases, you should not abuse onions in large quantities.
Pathogens that have settled in your garden can negate all the efforts made and destroy the harvest. To prevent this from happening, you need to know the “enemy” by sight and try to prevent possible infection of plants. Well, if you notice characteristic signs of the disease on onion shoots, then you will need tips on how to cope with the scourge.
Before talking directly about onion diseases, it is worth noting that one of the basic rules of cultivation is to observe crop rotation: onions and other crops of the lily family can be returned to their original beds only after 4-5 years, not earlier. Additionally, the room in which the harvested onions will be stored is treated with a bleach solution one and a half to two months before harvesting. It is recommended to keep onion sets for planting at a temperature of about 40 degrees for 10-12 hours.
Onion diseases and their treatment leading to rotting may be a sign of infection Alternaria blight. The spots have a watery consistency; on old feathers they quickly turn brown. Whatever the size of the spots, zoning is always clearly visible in them, and a yellow outline can be seen along the border.
Alternaria - onion disease photo
The disease affects onion scales, feathers break, and the plant rots. If the disease was not detected in time, the harvested crop will not be stored. In order to minimize the risk of infection, it is necessary to avoid conditions of high humidity. If the onion was in a humid environment for more than 11 hours, then it is necessary to treat it with fungicidal preparations against Alternaria. The same measures are taken if the plants show signs of disease.
Bacteria living in the soil layer can cause bacteriosis. When infected, the feathers and scales of onions become covered with mucus, and when squeezed, they release a liquid with an unpleasant odor. Bacteria enter the plant during mechanical damage and spread in the tissues. Most often, onions become infected in the field, but signs appear when the crop is stored.
Bacteriosis - onion disease photo
Excessive moisture in plantings favors the development of bacteriosis, therefore, in the last weeks of the growing season, watering should be very moderate. In addition, it is very important not to allow the soil layer to become waterlogged in hot, dry weather.
A common disease of many crops, including onions, is white rot. It develops slowly in field conditions, but quickly affects the crop during storage. You can recognize it by its softened scales, on which a white coating appears, reminiscent of cotton wool, in which dark inclusions are clearly visible.
White rot - onion disease photo
The development of white rot is facilitated by factors such as excessive waterlogging, especially at low temperatures, non-compliance with crop rotation, excessive amounts of nitrogen fertilizers and increased soil acidity. If signs of the disease are detected early, plants must be sprayed with Sumilex.
The most dangerous disease for onions is called peronosporosis, and more popularly known as “downy mildew.” The disease is transmitted from plant to plant by moisture, wind, animals and humans. The mycelium germinates in a new place, affecting large areas.
Rapid spread is facilitated by high humidity and average air temperature. Infected bulbs intended for planting do not differ in appearance from healthy ones. The disease manifests itself after about a month, when spots appear on the leaves - yellowish or greenish, lighter than the main leaf tissue.
The development of the fungus leads to the death of the plant. But on its tissues a mycelium with spores matures in the form of purple or brown spots. The causative agents of the disease enter the bulbs, where they overwinter. In order to prevent the development of mycelium and infection of onions, the beds should be made in well-lit, sunny areas, choosing light soils with a good drainage system. Excessive watering should be avoided, especially in the evening. A good measure is to observe crop rotation. Bulbs intended for planting next year must be treated thermally: when heated to 40°C for 8 hours, the mycelium of the pathogen dies.
If small spots of a yellowish color appear on the leaves, stripes arranged in a chaotic manner, and the leaves themselves wither and lie down, then your onion plantings have become infected mosaic bow.
The inflorescences are deformed, often elongated leaves are formed instead of stamens and pistils, and the flower petals grow together. The bulbs do not develop to the required size; the causative agent of the disease remains in them. The virus is transmitted by aphids and nematodes. The virus is destroyed in the soil and when the bulbs are heated at a temperature of 40°C for 10-12 hours.
Onions may cause damage during storage bottom rot. When infected, yellowed leaves die, and a white coating forms on the bottom, the bulbs soften and begin to rot.
Onion diseases - bottom rot photo
On the white coating, small, no larger than a poppy seed, black sclerotia are clearly visible, which, when growing, give an abundant coating. Infection occurs through the soil and already infected bulbs. If there is damage on the bottom, then fungal spores penetrate through them, leading to the development of the disease, death of the roots and destruction of the bottom. Warm weather and abundant watering are excellent conditions for the development of onion bottom rot. Maintaining crop rotation, culling low-quality infected bulbs, and treating onion sets with a 3% TMTD solution for half an hour will help protect onions from this scourge.
Onion diseases and their treatment video
These small-sized bladderpods (0.8-0.9 mm) live everywhere on completely different crops. They are characterized by camouflage colors: brown, yellow. The thrips body is narrow. Wings with a characteristic delicate fringe. The larva is wingless and light-colored. The female lays eggs 0.25 mm long in depressions previously made in the pulp of the leaf plate, one at a time. In total, there are up to 100 such single clutches during a lifetime. After 3 or 5 days, “youth” appear, similar to the imago, but smaller in size and wingless.
The adult overwinters on dry plant residues in the soil layer and in bulb scales during storage. With a favorable microclimate in storage, it can reproduce all winter. With the advent of the sun, the first weeds attack. Then, in June, they move on to onions, tobacco, watermelons, cucumbers, etc. In total, the number of plants affected by the pest has exceeded 400! Continues to cause damage until the crop is completely harvested. The bulbs become wrinkled under the scaly layer. They acquire a brown tint with a silver tint. It is difficult to completely remove the pest. The harm from thrips is noticeable:
- They feed on juice, sucking it from flowers, leaves, and fruits.
- are carriers of viral diseases.
The waste products of bladderpods pollute the plantings in the beds, staining the plant with small black dots. Traces of the lesion remain in the axils of the leaves in the form of light, mercury-like spots. Tobacco thrips leads a hidden lifestyle. It reminds of its presence by yellow leaves, which begin to deteriorate from the top, gradually turning yellow and dying. The plant slows down in growth, the bulbs are small. At the same time, shallots are more resistant to pests than onions. Garlic is the least susceptible to infection.
Main directions of struggle
The fight against thrips on onions is more difficult than the work to prevent their appearance. Therefore, prevention in the fight is put at the forefront.
- High air humidity is the main enemy of thrips.
- Only healthy material from proven farms is planted on the beds.
- Compliance with processing schedules. Coordination of ways to deal with adjustments to calendar weather changes.
- Direction of impact on the most vulnerable phases of insect development: egg, larva, etc.
- Don’t get hung up on one method, use a set of measures to keep the number of pests low.
- Do not neglect traditional methods of combating the repellent effect.
- Organize planting of insecticidal or repellent crops: calendula, tagetes, etc.
- Use chemicals only in extreme cases.
Prevent occurrence
- Onion thrips can be controlled by proper crop rotation. Repeated planting of bulbs is allowed in the same beds only after a four-year break.
- Regularly inspect plants for migrating thrips larvae. If they are detected, inspect the crops growing in the vicinity of the onion beds.
- There is no need for a greenhouse to plant cucumber seedlings and tomatoes with onions at an early stage.
- After harvesting, leave a clean garden in winter, removing and burning plant debris. The same is done with waste remaining in storage facilities after winter.
- Autumn digging of the soil to a depth of at least 0.15-0.25 m is required. This is due to the fact that the pest mainly overwinters at a depth of 7 cm.
- If onions are grown in greenhouses, after collecting the bulbs they are treated with Karbofos (15%).
- Weeding between rows in the summer, on the one hand, removes weeds, and on the other, destroys insect pupae.
- Before planting the affected seed, it is warmed up for 48 hours at a temperature of 40-42°C.
- You can immediately soak the bulbs in hot (50°C) water for 5 minutes before planting them in the ground and immediately dip them in cold water.
- Plantings of onions and other plants are regularly irrigated with water.
- If an insect has settled on an onion, you can wash it off with a stream of water under pressure.
- Mulching the soil will help maintain moisture.
Attention! Finding out whether there are thrips on onions is quite easy. You need to trudge the plant over a clean white sheet.
Chemical methods of control
And if thrips have already been found on onions: how to fight them?
- Fumigate the room where the seeds are stored with sulfur (sulfur gas): 60 g of sulfur is enough to treat 1 cubic meter of storage.
- A good result is obtained by systemic treatment of the crop with insecticides: Vertimek, Mospilan, Karate, Zeon, Commander Maxi.
- Thrips on onions are successfully destroyed by the natural insecticide Spintor. The drug is used in accordance with the instructions. Apply once every one and a half weeks. In general cases, repeated treatments at air temperatures of 15 to 22 degrees are carried out one and a half weeks after the first. At 22-26 degrees – in 5-8 days.
Carefully! When growing green onions, insecticides should not be used.
Other methods
Another way to deal with thrips is to place sticky traps between the beds. The base is paper tapes and cardboards, painted in colors “attractive” to insects – yellow or blue. Coated with glue to catch flies and other insects. Thrips caught in the trap will allow us to assess the real picture of the population size, as well as significantly reduce it.
Using folk remedies, you can treat onions with infusions of herbs and flowers. But these are rather deterrent measures that are practically ineffective when there is a large dominance of pests.
- Leave 1 tablespoon of chopped onion or garlic in a glass of water for 24 hours. Sprinkle the strained stock onto the culture.
- Grind dry tobacco leaves. A little water is poured. The composition is aged for 3 hours, filtered and infused for 36 hours. The strained concentrate is diluted with water 1:2 before spraying.
- Grind 200 g of dried lemon, pomegranate, tangerine and orange peels along with 80 grams of yarrow, 10 g of hot red pepper and 2 cloves of garlic. You can also add wood ash. The mixture poured with boiling water simmers over low heat for a quarter of an hour. Leave until the mixture cools down and strain.
- Use freshly picked celandine stems and flowers (400 g). Instead of fresh raw materials, dry grass (100 g) is used. Celandine is filled with water in an amount of 1 liter and infused for 48-72 hours.
Attention! Predatory mites Amblyseius degenerans, Amblyseius barken and predatory bugs Orius majusculus are also destroyers of thrips larvae. To get rid of them, it is enough to release 300 females for one infected plant. Statistics show that the effect of using entomopathogenic nematodes when applied to the soil gives an almost absolute result.
Using all of these methods or some of them will give good results in reducing the thrips population. Planting disinfected material will reduce the likelihood of future pest occurrences.
