Onions are invariably included in the list of the most common crops grown in amateur gardens. At the same time, to obtain stable yields of this vegetable, both certain knowledge and some practical experience are required. Next, we will consider the main diseases of onions and methods of combating these diseases.
Neck rot of onions
Onion neck rot is a fungal disease that affects turnips and sets. It appears mainly during storage. During storage, the upper part of the onion softens, is pressed in, and looks baked when cut. The tissue turns brown, a gray fluffy coating forms under the coverts and between the juicy fleshy scales.
Photo of onion neck fungus
The source of infection is mainly planting material, as well as infected residues remaining in the beds. The development of the disease and its spread are enhanced in cool, humid weather.
Control measures . Sowing and planting onions in the early stages; applying nitrogen fertilizers in the initial period (how to do it), and phosphorus and potassium fertilizers in the second half of the growing season; Harvesting onions after the leaves have completely yellowed. Onions and garlic are harvested in dry, sunny weather and dried in air at a temperature of 25-26 °C for 12 days, then 5 days at a temperature of 30-35 °C. While pouring the heads, feed the onions with granular fertilizer “Angricola for onions and garlic”: 10 liters. water is diluted in 50 g, consumption - 2 l. per 1 m2.
Downy mildew
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Downy mildew (peronosporosis) is a fungal disease. Initially, pale green spots appear on the leaves of the onion. Later they turn into a grayish-purple coating. The upper part of the leaves (the tip of the feather) turns yellow and dies. The disease develops strongly in humid, warm weather. The mushroom overwinters in the soil, on old unharvested plants and in bulbs during storage.
Photo of damage to onion stems
Control measures. The bed for planting onions should be directed from north to south so that it is well lit by the sun. Make sure that sowing seeds and planting seedlings are not thickened and clogged with weeds.
Before planting, the seedlings must be heated at a temperature of 30-35 °C for 8-10 hours. When the onion leaves are 10-12 cm high, they must be sprayed with a solution of the drug “Hom”: 10 liters. water is diluted with 40 g. powder and spray onions at the first signs of disease. For prevention, spray with a solution of 1% Bordeaux mixture 100 g. for 10 liters of water plus 1 teaspoon of tar soap for adhesion. Solution consumption is up to 1-2 liters per 10 m2. If this disease is detected, it is necessary to exclude watering and fertilizing with nitrogen fertilizers. You should try to do the harvesting when the leaves are still green and the bulbs have already formed. The leaves are immediately cut off and burned, and the bulbs themselves are well dried in the sun for 12-14 days.
Onion rust
Onion and garlic rust is a fungal disease. The disease affects the leaves: light yellow, slightly convex pads are formed, later they turn black. The infection persists on plant debris and on perennial onions.
Photo of onion greens affected by the disease
Control measures. Maintaining crop rotation, as well as warming up planting material before storing. Before planting, onion sets are heated for 8-12 hours at a temperature of 30-40 °C.
To prevent the spread of the disease during the period of massive growth of onions, it must be sprinkled with a solution of 1% Bordeaux mixture 100 g per 10 liters of water. The second spraying is carried out another week with a solution of the drug “Hom”: 40 g of powder per 10 liters of water, consuming 1 liter of solution per 10 m2.
Black mold
Photo of black mold on onions
Black mold is a fungal disease that occurs when onions and garlic are stored at elevated temperatures. The upper juicy scales of the affected bulbs dry out, and the sets and garlic dry out completely. This disease primarily affects unripened and poorly dried onions and garlic.
Control measures. Good drying of onions and garlic, as well as their proper storage. In case of disease, the heads need to be additionally dried and powdered with chalk.
Fusarium
Fusarium is a fungal disease.
Photo of onion affected by fusarium
Initially, there is a softening of the bottom, pinking and death of the roots, the appearance of brownishness on the leaves, their gradual death and drying out of the plant, as well as the bulbs.
Control measures. Use healthy material for planting and observe crop rotation; before planting, use a solution of copper sulfate (take 1 tablespoon per 10 liters of water). Destruction of diseased plants. Spraying with Hom (40 grams per 10 liters of water) when brownish spots appear on the leaves.
Bacterial disease of garlic
Photo of garlic affected by fungus
Bacterial disease of garlic. It affects the succulent tissue of winter garlic, resulting in brown and brown sores appearing on the bare cloves. The affected cloves take root poorly and do not overwinter well, and the garlic plantings become sparse, the yield decreases, and the ends of the leaves turn yellow.
Control measures. Pickling the cloves before planting (1 teaspoon per 1 liter of water), and then in a solution of the Energen preparation, carefully selecting planting material. Quick drying of the heads immediately after harvesting - in the sun or by heat under a canopy. During fruiting, fertilize the garlic with Agricola-2 granular fertilizer for garlic: 50 g per 10 liters of water.
Bacterial rot of onions
Photo of rotten onion
Bacterial rot of onions is detected when cutting into ripe onions, in which a dark layer of softened tissue is visible between the healthy, juicy scales. During storage, such bulbs gradually rot. The infection is carried by insects (onion fly, mites, thrips, etc.).
In the spring, when planting diseased bulbs, the growing seeds look depressed, the leaves turn yellow, and the flower stalks dry out.
Control measures . Before planting, the bulbs are carefully selected, cutting off their neck and base by 0.5-1 cm so that all scales are visible.
Before planting onion sets or turnips, treat the soil with the preparation “Hom” - dilute 40 grams in 10 liters of water, using 1 liter per 10 square meters.
Green mold rot
Green mold rot of onions is often found on onions and garlic during storage.
Initially, brownish watery spots appear on the bottom or outer scales of the bulbs. In garlic, individual cloves become slightly sluggish, and sunken yellowish spots appear on the juicy tissue. Later, the bulbs feel empty to the touch, a musty smell appears, and the garlic cloves soften, wrinkle, darken and begin to crumble.
A green or bluish-green coating forms on the spots and under dry scales. This is the mycelium of the mushroom. They are stored in the soil on plant debris.
Strong development of the disease is observed two to three months after the start of storage. Various damage, freezing and high air humidity in storage areas contribute to damage.
Control measures. Thoroughly dry the bulbs before storing them. Optimal storage mode. 5 days before storing onions and other vegetables, a sulfur smoke bomb is burned in the vegetable storage.
Black mold rot
Black, moldy rot affects onions during storage at poor ventilation and high temperatures.
Diseased bulbs soften, later their scales dry out, and sometimes the bulb mummifies. A black, dusty mass forms between the scales.
Photo of onions affected by black rot
The infection reaches the bulbs through direct contact and through the air. In storage areas, spores persist for a very long time. In dry conditions, at low temperatures, the disease develops slowly.
The most susceptible to black mold rot are unripe, thick-necked, poorly dried bulbs. Varieties with colored scales are less resistant than those with white scales.
Control measures. Optimal storage mode. Drying onions and garlic before storing. Planting onions and garlic at the optimal time.
Numerous diseases and pests of onions can significantly reduce the yield of this extremely useful healing vegetable. Powdery mildew, various types of rot, insect pests, and bacterial infections affect the leaves, fruit, and roots of the plant. Often “spot” control measures are ineffective - a set of measures is required, including not only treating plantings with special means, but also strict adherence to agricultural technologies.
Invisible danger
Let's look at the main diseases of onions and their treatment. Onions are damaged by about 50 species of fungi, insects and microorganisms. Most often, plants get sick on clayey, floodplain, and waterlogged soils. Saturation of the soil with rotted manure and mineral fertilizers, which contain a lot of nitrogen, also leads to loss of production due to the accumulation of diseases.
Downy mildew
The onion disease downy mildew (downy mildew) has been known for a long time. The causative agent, the fungus Peronospora destructor Casp, was first discovered and described in England in 1841. Decades later, it struck Europe and the vast British colonies, from America to Australia.
For a long time, the harmful microorganism was encountered sporadically in eastern Europe, until an “epidemic” of the disease occurred in 1965-66. At that time, downy mildew affected half of all onion plantings in Ukraine and Kuban. A new wave of distribution swept in the 70s. Now downy mildew is observed annually in all growing areas, especially in the southern regions.
All types of vegetables are susceptible to this onion disease: onion, family, and trumpet are regularly affected. Chives, Altai and Beijing - only in the years of epiphytotics (epidemics). Powdery mildew has become not only a common, but also the most harmful disease. It leads to a reduction in the size of the affected heads and delays their maturation. Attempts to develop varieties that are not susceptible to downy mildew were unsuccessful. Among the fairly stable ones, experts note “Skvirsky”.
Description
In addition to bulbs, fungal spores can overwinter in plant debris, germinating under conditions unfavorable for the fungus. Bulgarian scientists have found that one diseased specimen infects 90% of plants within a radius of 2 meters, and 30-35% of plants within a radius of 6 meters. Phenomenal: in just four incubation periods (1 period is 11-15 days), a single outbreak can spread 2 kilometers!
Downy mildew also causes losses in onion storage areas. Scientists' experiments have shown that affected bulbs are poorly stored and germinate prematurely, and losses reach 50-60%.
Course of the disease
The spread of this onion disease in the garden is rapid. After planting infected bulbs, the appearance of the conidial stage (spread of spores) under favorable conditions can occur after a short period of time. At a humidity of 90-95% and a temperature of 15-18°C, after 4-9 days the infection reaches 40-50%, and after two weeks all the plants on the plantation are infected. This period shortens or increases depending on temperature and humidity. The formation of conidial sporulation occurs only at low temperatures and high humidity. During the growing season, the mushroom can produce 4-7 generations.
The development of onion disease occurs mainly at night and in the morning, when raindrops remain on the plants, or dew falls, and the air temperature decreases. In field conditions, two wet nights are required for a complete infection cycle. This is facilitated by condensation of water on the leaves, whose temperature is lower than the air. Damage does not always occur, but only on critical days, when moisture on the leaves remains until noon. Conditions are very favorable for the epiphytosis of peronosporosis when cool nights alternate with relatively warm days - the fungus is spread by wind and heavy rains.
Signs of powdery mildew
The disease is accompanied by stages, which can be distinguished by characteristic symptoms:
- The first sign of green onion disease is the appearance of a brownish-purple velvety coating on healthy leaves.
- Over time, the spots increase in size and first become pale yellow and later brown.
- Over time, the spots become necrotic, which leads to the death of leaf tissue. The affected shoots have a yellowish-pale color and, like the leaves, are often colonized by other fungi Alternaria, Stemphilium, etc.
Fusarium rot
Fusarium onion blight is less common than downy mildew. It appears both during the growing season and in storage. During the growth period, fusarium wilting of onion leaves occurs, and during storage, characteristic rot of the bottom of the bulbs occurs. The disease is most often recorded at the end of the growing season. Characteristic features:
- Premature yellowing, curling and dying of leaves, starting at the crown.
- Subsequently, the disease spreads to the entire leaf blade, the leaves wither and rot. Infected parts of the bulb turn brown.
- Sometimes, due to a lateral lesion, the healthy half grows, and the infected half curls and is pressed in - the disease gives the bulb a concave-convex shape.
Cervical or gray rot
One of the most dangerous diseases of onions during storage, and sometimes during the period of growth and harvesting. The disease begins soon after harvest - with softening of the scale tissue, usually at the neck of the bulb, especially in places of mechanical damage. The affected areas look like depressed “cooked” spots and gradually cover the surface of one or more scales. They are brown, watery, and over time such areas die off and become porous, like a sponge. A gray mass appears on the infected tissue (between the scales), and a black mass of small sclerotia may form on the outer tissue (around the neck). The area of infected tissue enlarges, spreading down the scales.
The bulb is affected only through damaged areas, almost always at the neck, which is why this disease is also called neck rot. Most often, rot penetrates the tissue during harvesting, when the leaves of unripe and poorly dried bulbs are cut too low. Specimens that are infected with downy mildew are more susceptible to gray mold.
Bacterial rot of onion seed
The causative agent of onion disease is most often the bacterium Erwinia carotovora Bergey, which can cause vascular and parenchymal lesions. The source of infection is contaminated soil and affected post-harvest onion residues. Bacteria are spread by splashing raindrops, irrigation water and insect pests. Sometimes other bacteria also cause bulb rot: Pseudomonas aeruginosa, Pseudomonas gladioli and others.
Microorganisms cause soft rot diseases of various organs. In affected bulbs, a large light or slightly pink spot forms around the stem end. The tissue softens and becomes covered with mucus. In such heads, the first outer layer of scales is healthy, and the next ones become yellow-brown. When severely damaged, the tissues soften, emitting an unpleasant odor.
Onion diseases and their treatment
Unfortunately, today there are no reliable mechanisms to prevent the development of epiphytoties (epidemics). Scientists are constantly searching for means to suppress the activity of microorganisms in order to obtain full onion yields. During the growing season, fungicides are applied at the first signs of infection. The effectiveness of any pesticide used, its application rates and frequency of treatments largely depend on the development of the disease. In plant protection practice, the most common and rational way to use pesticides is to treat or treat seeds and planting material.
How to treat onions against diseases? In the 20s, Bordeaux mixture was used (it is still relevant now, especially in private farms), and then substitutes appeared - zinc-containing contact fungicides. Based on them, a system of chemical protection measures against peronosporosis has been developed. Contact fungicides, effective at high application rates, were previously used to protect onions. In the 80s, they began to use systemic drugs that were highly effective at the initial stage of use.
- For powdery mildew: “Quadris”, “Ordan”, “Alirin-B”, “Revus”, “Bravo”, “Abiga-Pik” and others (according to the instructions).
- For gray and cervical rot: “Quadris”, “Bravo”, “Ridomil Gold”, “Switch” and others.
However, constant treatment of vegetative plants with systemic fungicides can lead to the emergence of resistant strains of pathogens and reduce the effectiveness of the drugs.
Many gardeners refuse to grow onions on their own plot and prefer to buy them in the store. Onions are inexpensive, but when you grow your own, there are a lot of problems with them. One of the main reasons is illness. But you can fight for the harvest if you know how.
General information about onion diseases
There are many onion diseases that can deprive us of our harvest. All of them are divided into fungal and viral. Fungal spores live in the soil, bulbs, and plant debris. They manifest themselves in different ways, but have the same nature, reproduce in conditions of high humidity, and are treated with the same methods. Viruses live only in living tissues, cannot be treated, and are spread by insects. This means that their occurrence can be prevented by carrying out pest control.
You cannot get both greens and heads from the same plant at the same time. When growing turnips, do not pluck out the feathers; each leaf forms the scale of the head. In addition, at the point where the onion is picked or cut, it becomes vulnerable to disease.
Fungal leaf diseases
Fungi overwinter safely in the soil or on onion sets. After planting in open ground, when favorable conditions are created, fungi begin to actively multiply. Their spores grow inside the tissues, which leads to necrosis (death) of the leaves. In addition, they are transferred by wind and rain from diseased plants to healthy ones. In a matter of days, the entire onion plantation can become sick.
Downy mildew
Another name is downy mildew. The disease appears approximately 3 weeks after the start of the growing season. Favorable conditions: rainy weather, heavy dew in the morning, excessive watering against a cool background. Downy mildew also develops well in dense plantings, beds overgrown with weeds, when onions are poorly lit and ventilated.
Signs:
- In the initial stage, green feathers are covered with a powdery coating with a gray or purple tint.
- In affected areas, tissues die, turn brown, leaves become deformed and dry out.
One plant infects the entire garden bed. Downy mildew affects almost all crops: vegetables, berry bushes, fruit trees.
All stages of peronosporosis are visible on onions: powdery coating, tissue necrosis, feather death
Signs:
- White spots with a watery outline appear on the leaves. They grow and become concentric, reminiscent of growth rings on a cut tree.
- The color turns to brown with a burgundy tint.
- In places where the spots merge, the feather breaks and dries out.
- In conditions of high humidity, a gray-black coating appears - these are myceliums with spores.
Alternaria fungi often settle on old feathers, as well as those affected by downy mildew, on top of necrotic spots. In this case, the leaves turn black. The disease spreads to the bulb. It becomes watery, and a brown coating appears between the juicy layers.
Signs of Alternaria: some spots are still small and white, others have already grown, become concentric and turn brown with a red tint.
Rust
Signs:
- Onion feathers are covered with many convex red spots, similar to rust. Later they turn black.
- The leaves dry out.
- The spores overwinter on perennial onions and plant debris.
Rust also affects garlic and fruit trees. Favorable conditions for the growth of fungi are high humidity (97%) and cool or moderate heat (+15… +20⁰C).
Rust often affects weakened plants under stress conditions, for example, frequent watering with cold water, lack or excess of nutrition, attack by pests, etc.
Fungal diseases of the bulb
Symptoms of these diseases are found on onions during storage. But infection occurs in the beds; fungi spread to the bulbs from the ground or from diseased leaves.
The development of fungal diseases is promoted by:
- wet weather during the ripening period;
- early or late harvest;
- poor drying;
- violation of storage conditions.
Onions are dried with ventilated air at a temperature of +25 ⁰C... +30 ⁰C. In winter, it can be stored cold - in the basement at a temperature of -3 ⁰C... 0 ⁰C and a humidity of 75–90%, and warm - in an apartment at +18 ⁰C... +22 ⁰C and a humidity of 50–70%. When purchasing seeds, you should check whether the onions are suitable for winter storage. There are varieties only for summer consumption.
Cervical rot
The fungus gets inside the bulb if rainy weather occurs after the leaves have fallen. In this case, the feathers rot, and spores penetrate through them into the head. Obvious symptoms can be observed after 1–1.5 months of storage.
Signs:
- The bulb at the neck becomes wet and turns brown inside.
- Rot spreads from top to bottom.
- Gray mold appears on the covering scales (shirt).
- The spores move to neighboring healthy heads.
Cervical rot is clearly visible on the cut, it spreads from top to bottom
Another disease that develops due to rainy weather during the ripening period of the bulb or due to late harvesting, when the onion is left in damp soil for a long time. Fusarium fungi live in the soil and settle on the bottom of the bulb.
Signs:
- Rot spreads from below to the neck.
- The head becomes watery.
Plants weakened by other diseases and pests are at risk.
Fusarium rot spreads from the bottom upward, the bulb becomes watery
Green moldy rot
Signs:
- The upper juicy scales become transparent and brown.
- A bluish-green coating similar to dust appears under the shirt.
The disease affects damaged or frozen bulbs.
When affected by green rot, the head becomes empty, and a dusty coating is found under the covering scales.
Aspergillosis
And this disease affects unripe bulbs harvested early from the garden. Spores settle in thick and undried necks. They develop especially actively during storage at high temperatures and poor ventilation.
Signs:
- The bulbs become soft and then mummify.
- A black dusty layer forms under the shirt.
Another name for aspergillosis is black rot of onions.
Onion viral diseases
Viruses are transmitted by sucking pests. They feed on juices, and to do this they pierce the most vulnerable (soft and juicy) tissues of the onion. The insects then move to another plant. By piercing its feather or head, they bring the juice of the previous one inside. This is how diseases spread. Viruses do not live in the soil, but only inside living plants and organisms.
Mosaic bow
Signs:
- The leaves become flat and corrugated, covered with light streaks and spots of various shapes.
- On seed plants, the peduncle becomes bent and the inflorescences change.
- Instead of pistils and stamens, long leaves grow and aerial bulbs are formed.
- There are either few seeds or no seeds at all.
- The heads in the ground elongate, do not ripen, and without entering the dormant stage they can begin to grow again.
Symptoms of mosaic: the surface of some feathers is flat, corrugated, covered with light strokes, on others yellow spots of various shapes are visible
Yellow dwarfism
Signs:
- Bright yellow stripes appear at the base, the leaves bend and curl.
- The feathers turn completely yellow and their tips droop.
- Sick plants appear dwarf.
- The bulb does not grow to the required size.
- The testes do not bear fruit or there are few of them.
The disease can destroy the entire crop. The onion dries while standing, without lodging the tops. Yellow dwarfism, in addition to onions and garlic, affects cereals and some varieties of daffodils. The virus persists in the bulbs.
Yellow dwarfism: leaves are bright yellow, twisted, bulb is small, does not grow
Ways to combat and prevent onion diseases
Onions grown for their production are not treated with chemicals, otherwise they cannot be eaten. Onions also have a short growing season, and diseases often develop in the second half, when the bulb is filled, and the waiting period for fungicides is 20–60 days. In order not to fight diseases with radical methods, it is necessary to carry out prevention.
Agrotechnical techniques
- Maintain crop rotation. Return the onions to their old place no earlier than after 3–4 years. The best predecessors: pumpkin, zucchini, potatoes, beans, peas, early cabbage, tomatoes. Do not compact plantings with carrots. It may drive away the onion fly, but it grows quickly and begins to shade the onion with its lush bushes, inhibiting its growth.
- Provide good nutrition. With its deficiency, immunity decreases, fungi and viruses settle on weakened plants. Please note that onions love neutral or slightly alkaline soil fertilized with organic matter.
- Place the bed in a suitable place: sunny, without stagnant water, well ventilated.
- Weed out weeds, remove plant debris from the garden bed, and loosen the soil between waterings.
- Water your plantings according to the climate of your region. If it rains frequently, plant onions in raised beds to avoid excess moisture. In dry regions, place plants on level ground. Water the onions on the greens 1-2 times a week at the rate of 10 liters per 1 m². When growing onions, water in the first half of summer, and then let the heads ripen. If the weather is rainy during this period, then fungal diseases cannot be avoided. There is a way out, but it is labor-intensive - cover the beds with film, make canopies, etc.
- Carry out pre-sowing treatment of onion sets in the spring and harvest on time, dry it well in the fall.
Video: how to grow healthy onions
Pre-planting treatment of the site and seeds
- For spring planting, select a site in the fall and clear it of weeds and plant debris.
- You can sow the area with green manure, for example mustard, which has a phytosanitary effect on the soil and prevents the accumulation of pathogenic fungi and pests.
- You can also spray the soil in future onion beds with a solution of copper sulfate - 40–50 g per 10 liters of water, consumption - 1 liter per 1 m², or water with a solution of the biological product Fitosporin - 2 tbsp. l. paste concentrate into a bucket of water.
- It is recommended to add phytosporin to the water for watering onions during the growing process: 1–2 tbsp. l. on the watering can every 7–10 days.
Fitosporin contains beneficial bacteria, which, when they enter the soil, begin to compete for food and space with pathogens and leave them no chance to survive.
Onion sets, even in a specialized store, can be stored in poor conditions and become affected by fungi
Methods for disinfecting onion sets before planting:
- Thermal: pour onion sets for 10–15 minutes with hot water: +45 ⁰C... +50 ⁰C, then put them in cold water for 10 minutes.
- Chemical: soak the onion for 20 minutes in a solution of copper sulfate - 3 g per 1 liter of water.
- Folk: place the bulbs in salt water for 3–5 minutes (1 tablespoon per 1 liter of water), or 5–7 minutes in an ash solution (250 g per 5 liters), or 20–30 minutes in a purple solution of potassium permanganate. Then rinse the onions with clean water.
- Modern: treat planting material with growth stimulants that help strengthen the immune system and protect against diseases: Zircon, Cytovit, Biostin, etc.
Video: processing onions before planting
There is no point in treating black onions for diseases, since fungi and viruses are not transmitted through the seeds. It is by growing from seeds that many agricultural crops are made healthier: potatoes, onions, strawberries, etc.
Ask in stores and buy varieties that are resistant to disease: Centurion, Sturon, Universo, Snowball, Senshui yellow, Golden Semko, etc.
Disease control during the growing season
Chemicals can only be used at the initial stage, that is, when processing planting material. For onions growing in the garden, use only techniques that are harmless to your health:
- At the first signs of disease, stop nitrogen fertilizing and apply wood ash or potash fertilizers. One of the many benefits of potassium is its ability to increase disease resistance. Nitrogen provokes active growth, large young and juicy feathers appear on the onion, their delicate surface is easily vulnerable to bacteria and pests. Onions need nitrogen only at the beginning of the growing season.
- If individual plants are affected by fungi, pull them out and burn them. Fill the remaining holes in the ground with a solution of potassium permanganate or 1% copper sulfate (100 g per 10 liters of water).
- In case of mass infection with fungal diseases, spray onion crops with HOM solution (40 g per 10 l), repeat after 7-10 days. After treatment, you cannot cut the onion into a feather for 20 days.
- In case of viral infection, remove and destroy diseased plants from the garden bed, including weeds with the same symptoms. Conduct pest control.
The tips of the leaves turn yellow - this is not a disease, or why do onions need salt?
There is one problem in the process of growing onions that worries absolutely all gardeners. The tops of the leaves turn yellow and eventually dry out completely. This is not a disease, but the result of the activity of pest larvae, mainly onion flies or nematodes. They climb to the very tops, because there the feather is softest and juiciest.
The tip is the juiciest part of the feather, so pest larvae climb into it and suck out the juices
The recipe for such a scourge came to us from the last century. When the feather grows 10 cm, dissolve a glass of salt in a bucket of water, according to other sources - 100 g, and pour over the onion. Repeat twice more with an interval of 10 days. Readers of the Garden and Vegetable Garden magazine conducted tests: part of the bed was watered with salt water, and part was not. Onions treated with salt grew better and remained green, while untreated ones grew stunted and turned yellow.
But don't overuse this recipe. Salt corrodes everything in its path, and along with the pest larvae, beneficial worms, such as earthworms, also die. But they are the ones who loosen the soil and process plant residues into humus - food for plants. In addition, with the annual use of saline solutions, salinization occurs. Salt crystals appear on the surface, plants curl their leaves, develop poorly, and the acidity of the soil increases. To reduce acidity, after watering with salt water, feed the onions with wood ash (1 glass per bucket of water), but this will not save earthworms and beneficial bacteria.
To repel pests, regularly sprinkle onion beds with tobacco. If the planting area is small, then the yellow tips with the larvae inside can be plucked off by hand and burned in the grill. After this, spray the onions with “vitamins” - stimulants that help cope with stress (Energen, Epin, Novosil, etc.).
The main causes of onion disease: damp and cool weather and pests that carry viruses. But with our help, the bow can resist them. To do this, you need to: select disease-resistant varieties, properly prepare the seed material and soil, and then provide the onions with good care. Strong and well-groomed plants suffer less often and to a lesser extent from diseases.
When growing onions, gardeners and large farms are faced with the emergence of various crop diseases that jeopardize the future harvest. To combat them, it is better to use an integrated approach, which involves treating plantings with special preparations and implementing appropriate agrotechnical practices. Onion diseases in most cases develop on excessively moist clay soils with a high content of mineral fertilizers and rotted manure, as well as a high concentration of nitrogen.
Main diseases of onions
Downy mildew
This onion disease belongs to the category of the most dangerous conditions leading to the death of the plant. Another name is downy mildew, which is transmitted from plant to plant through animals, humans, and by airborne droplets. The fungus becomes active in the spring and begins to germinate intensively in conditions of high humidity and at a temperature of 15-20 degrees Celsius. At low temperatures it does not die, but only stops development.
Onions, leeks, and spring onions are especially susceptible to downy mildew. Infected bulbs experience a change in shape, cessation of growth and development. The leaves turn yellow and begin to die.
Treatment consists of:
- application of potassium and phosphorus fertilizers. These compounds will increase the crop’s resistance to the pathogen and enhance their protection;
- carrying out preventive measures using fungicides;
- cessation of soil moistening procedures. It is also impossible to apply nitrogen fertilizers when the first symptoms of the disease are detected.
Cervical rot
Gray rot, as this onion disease is also called, appears at the end of the growing season, but most often it is discovered 1.5-2 months after harvest. Botrytis fungi progress primarily on weakened tissues. Harmful microorganisms, having settled on dying leaves, penetrate the neck of the bulb, and as a result of their vital activity, the vegetable rots.
Infection with gray rot occurs during the process of trimming the feather, when the neck has not yet had time to tighten. Symptoms of the disease are a softened neck, an unpleasant putrid odor, and gray scales in the affected area. To avoid unpleasant consequences, it is recommended to carefully select the planting material before planting it in the ground, leaving only healthy specimens. It is effective to use nitrogen fertilizers at the initial stage of the growing season, and at the end - use potassium and phosphorus.
Fusarium
The source of this onion disease is in the ground; it begins to become active during the growth period of the vegetable. At the beginning of the development of fusarium, brown watery spots appear on the bottom or on the outer scales. The optimal air temperature for the development of fungal disease is 10-20 degrees. In affected plants, in addition to bottom rot, leaves begin to die.
The disease occurs when there is an excess of moisture in the soil, late harvest times, and also when harvesting in rainy weather. For prevention, before planting, it is necessary to treat the soil, for example, with 3% Bordeaux mixture or Baikal.
Crop rotation gives good results. Only healthy bulbs should be used as planting material.
The source of this onion disease is a mold fungus that spreads through the air or through direct contact. Favorable conditions for the pathogen are a poor ventilation system and high temperature in the room where the culture is stored. At the initial stage of development of the disease, the bulbs become soft, the scales dry out, and eventually the vegetable becomes mummified.
Mosaic
Among the main symptoms of a viral disease are the presence of small yellow-white spots on the leaves in the form of clear stripes, which change their appearance over time, wither and dry out. The affected vegetable, not having reached full maturity in the fall, begins to germinate.
The sources of the viral disease are nematodes, mites, thrips, and small aphids. To save the plantings, it is necessary to take measures to destroy these insects.
Fungal disease is mainly observed during culture storage. Initially, watery brown spots are visible on the bottom and outer scales. Later, a white coating forms on them, which subsequently changes color to green or bluish-green. Fungal spores persist in the soil on the remains of vegetation, in places where vegetables are stored. High levels of air humidity and freezing of onions increase the risk of developing this disease.
Disease Control Measures
Unfortunately, scientists have not yet found reliable mechanisms to prevent the development of epidemics. They are constantly working to find effective means that can suppress the activity of harmful microorganisms. To increase the productivity of vegetable plantings, farmers are recommended to pay special attention to onion diseases and the features of their treatment.
During the growing season, it is recommended to use fungicides at the first signs of infection. The effectiveness of the drug used, as well as the dosage and number of treatments, is influenced by the severity of the disease and the extent of the lesion.
One of the frequently used methods of plant protection is disinfection of seed material.
Many novice gardeners do not know what to do when onions in the garden are sick, and what fungicides should be used for turnips so that the harvest can be stored longer. In practice, the following drugs show their activity against powdery mildew pathogens:
- Ordan;
- Revus;
- Quadris;
- Alirin-B;
- Abiga Peak;
- Bravo.
Use the products according to the instructions in the instructions. It is better to fight a disease such as gray cervical rot with the help of fungicides Bravo, Switch, Quadris, Ridomil Gold. Only by knowing how to deal with onion diseases and pests can you count on harvesting a high-quality harvest.
Main pests of onions
Harmful insects, like diseases, cause a lot of trouble for gardeners. To save the plantings, it is recommended to begin taking appropriate measures to combat onion pests as soon as possible, otherwise they can destroy 30-50% of the crop.
Onion fly
shallot aphid
The insect's body is ovoid and brown in color. The larvae are predominantly dark in color. As a result of the invasion of this uninvited guest, leaves wilt and become deformed. Aphids live on the outside of the leaf.
Onion hoverfly
A stocky fly with a medium-sized bronze-green body appears on plantings in the second half of the growing season. Infected plants are stunted, their leaves turn yellow and then wither. Diseased bulbs acquire an unpleasant odor. If a group of root beetles attacks one plant, it turns into a black putrid mass.
Stem nematode
This thread-like worm can destroy an entire crop if you do not react in time. The pest, using its needle-shaped stylet, sucks the juice from the plants and destroys them. It overwinters in the ground, in seeds and onions themselves. The duration of viability in dried specimens is five years.
Tobacco thrips
Onion moth
The pest has brown forewings, which makes it very noticeable in plantings. The caterpillars are green-yellow in color and covered with short hairs. Seven days pass from the moment the eggs are laid until the larvae mature. They do not touch the outside skin of the leaves, but eat the pulp. Considering that a moth can produce 2-3 generations over the entire season, if it is not destroyed, all plantings are at risk of destruction.
The bug, whose body size does not exceed 3 mm, has a proboscis bent down. The body is black, with a white stripe visible along the suprawing suture. The female lays eggs in April; after a couple of weeks, the larvae mature, capable of destroying 100% of the leaves of the crop.
The insect first attacks diseased sprouted bulbs remaining on the site after harvesting, and then attacks new plantings. The bug eats the pulp of the vegetable, which leads to the leaves drying out and the plant dying.
Pest Control Methods
Treatment of plantings against onion flies, hoverflies and their larvae is carried out using the drugs Fufanon, Bazudin. Number of procedures – 2. To combat pests like onion moths, a working solution based on Iskra M is suitable. A solution of karbofos is used against caterpillars, the secretive proboscis, and its larvae. It is recommended to treat onions with a solution of colloidal sulfur against small pests. It is practically impossible to control them with standard fungicides.
Among the folk remedies for protecting culture, an infusion of tobacco and ground black pepper can be distinguished. It is prepared as follows:
- Steam 200 g of tobacco in 3 liters of water.
- After three days, add 1 tsp to the resulting infusion. black pepper and 1 tbsp. l. liquid soap.
- Add another 10 liters of water to the mixture and filter.
- The plants are sprayed.
Prevention of diseases and pest damage
Before planting, onion sets need to be treated with a weak solution of potassium permanganate (1 g of product per 1 liter of water). Disinfection of planting material significantly increases the chances of obtaining a rich harvest; it is not affected by bacterial and viral infections and various fungi. It is also recommended to immerse the bulbs for 10 minutes in a container with a solution of copper sulfate (1 tsp per 10 liters of water).
The best protection for onions from diseases and pests is to carry out preventive measures. The main thing is to know how to treat the onion before putting it in the ground. In order for the harvested crop to be stored as long as possible and not rot, it is necessary to dry it and store it in a room with good ventilation.
Those that damage onions eat the bitter inner part of the crop, and it is not always possible to notice them immediately. As a result of such “raids”, the entire harvest can be lost. Fruits damaged by insects are exposed to soil microorganisms and rot. Let's look at the main and most common pests of onions and determine what methods are best to combat them in order to preserve your harvest as much as possible.
is a dangerous pest of onions. Significant damage is caused during the years of mass flight at the beginning of development and the period of onion growth. Crops sown with seeds for sowing suffer especially badly, because the larvae in dense stems crawl from the affected to the healthy. If onions are grown from sets and there is no need for thinning, then the risk of infection is minimal.
Onions infected with stem or neck rot are especially susceptible to attack by onion and sprout fly larvae. Usually in the middle and northwestern zone, under favorable weather conditions, it produces two generations, and in the southern regions it can produce three. Main signs of damage are the wilting of the plant in groups at the cotyledon and first leaf phases: larval tunnels appear in the bulb itself, and the larvae themselves live in the leaves and bases of the cotyledons. In an older plant, the neck of the bulb and the bulb itself are damaged, which causes the crop to wither and rot, and then die.
Regardless of where exactly the fly has penetrated, the onion will still die if the growing point is damaged by even one or two larvae. Description. An adult fly is light gray in color and has a body length of 6–8 mm. Wings with a yellowish tint, legs black. The male has a dark stripe along the abdomen and a row of setae on the hind tibia.
The eggs are elongated, white, 1.2 mm. The larvae are off-white, worm-shaped; back and abdomen rounded, narrowing at the anterior end, body up to 10 mm long; hook-shaped jaws. On the posterior segment there are two dark round plates with breathing holes. The fly's pupae are contained in a brownish-yellow pseudococoon.
The primary spring invasion occurs during the flowering period. Reproduction occurs due to additional feeding with nectars during the week.
Females lay 5–20 eggs under lumps or between onion leaves. The egg laying period can last up to 1.5 months. Newly formed larvae gnaw through the neck of the leaves and penetrate into the flesh of the bulb itself, eating away its cavity, and then are able to migrate to other bulbs. Pupation of the larvae occurs after two weeks next to the damaged onion in the ground.
How to fight with onion pests in the form of flies :
Did you know? Research by scientists has proven that substances that are found in onions and can cause aroma, taste and tearing from its processing have a negative effect on cancer cells.
Description of the moth. The butterfly is small in size with brown front wings, the caterpillar is green-yellowish and covered with small short hairs. Butterflies, like pupae, overwinter on the remains of onions, in sheds, and greenhouses. Eggs are laid in June on the back of a leaf, bulb or flower arrow.
Causing harm. After seven days, the larvae mature and eat the pulp of the leaves, leaving the outside skin untouched. The caterpillar penetrates the bulb or neck and can even damage the inflorescences. Pupation of caterpillars occurs on onion leaves in the first period of June: in the soil, on plant remains. After two weeks, butterflies form. The caterpillar is capable of causing damage to the onion throughout the entire growth period, since it can produce two or even three generations over the summer.
Control measures:
Onion pests in the form of moths are very dangerous for the crop, so there are also many types of fight against them using folk remedies: - infusion - pour boiling water over 300 g of ash, set aside, strain, add 40 g of liquid soap;
- garlic infusion - mince a large amount of garlic, add water at a ratio of 1:1. Infuse in a warm place for at least a week in a tightly closed container. This infusion is called mother infusion and can be stored for a very long time. Treat with a solution: 70 g of infusion per bucket of water;
- tobacco infusion - 200 g of raw tobacco + 1 tablespoon of soap, pour hot boiled water. After it has cooled, strain through cheesecloth and treat the onion, and especially the soil around it, at the rate of 1 liter per square meter;
- infusion based on red capsicum - boil 1 kg of pepper, cut in half, in a saucepan with 10 liters of water, strain after cooling. Processing is carried out at the rate of 130 g of concentrate per bucket of water + 40 g of soap. The concentrate itself should be bottled and stored in a cool, dark place.
The hoverfly is an infrequent pest guest, but no less harmful than a fly. It usually appears on onions and causes damage in the second half of the growing season.
Damage manifested by stunting and yellowing of leaves, and then their wilting. The bulb becomes soft and acquires an unpleasant specific odor. If one bulb is attacked by a group of root beetles, it turns into a black putrid mass.
Description. Stocky flies of medium size. The female (up to 7 mm) is slightly larger than the male (up to 6 mm). Female hoverflies have a flat abdomen, while males have a slightly swollen apex. The body is bronze-green, and the back has two light gray stripes. Black mustache. The abdomen can be blue or green. The paws are brown-black or simply black. Females lay eggs on already weakened plants that can be damaged by other pests. Laying is carried out in small groups, one female brings up to 100 eggs. Control measures the same as with the onion fly.
Did you know? The composition of natural sugar in onions is much higher than in pears and apples. One onion contains up to 6% sugar. When fried, caustic substances evaporate and the onion becomes sweet.
Onions are a favorite treat of tobacco thrips. This pest causes damage to both the bulb itself and the leaves. During the wintering period it lurks in dry onion scales and reduces the quality of the vegetable.
Damages fleshy scales, which become rough and then dry out completely. Whitish stripes and dark dots appear on the leaf (thrips feces). Leaves that are severely affected completely change their color to whitish, become distorted and dry out. Onion growth stops and the seeds are mostly unsuitable for sowing. The adult has an elongated shape with narrow wings that are folded along the entire body. The body is 1–1.5 mm, has a general yellowish color. The antennae are yellow, the eyes are red. The short forewings are darker in tone than the long hind wings.
The eggs are white, kidney-shaped. The larva has two growth stages. In the first, the light-colored larva feeds on the plant; as it grows, the yellow-green intestine becomes visible on the abdomen. At the second stage, it does not feed on onions, but is in the ground. It overwinters in dry onion leaves in storage, or under a layer of soil on the planting site.
The female brings up to 100 eggs, which she places one at a time in the leaf tissue under the skin. After just 3–7 days, the larvae appear. Generational development in warm areas reaches 2–4 weeks.
It’s not difficult to identify them on onions, but not everyone knows how to deal with them, because not all chemicals affect them. Experienced gardeners have proven themselves to be the most effective in practice:
Important! Two treatments close in time should be observed with an interval of no more than 7 days. The reason for this is that eggs and nymphs are highly resistant to the drugs, or the drug may not immediately reach them.
Causes damage in patches. In the southern zone it can give two generations, and in the middle zones it usually gives one. Onion rattle can often be confused with lily rattle; their only difference is that lily has black legs and a head, and onion has red ones.
Damages onions, gnawing through holes, as a result of which the leaves break. An adult is able to penetrate inside the tubular leaf.
Description. The bugs are completely bright red, only the tip of the abdomen is black, 6 mm in length. The eggs are 1 mm long, orange, smooth. The larva is six-legged, has black dots on its sides, and is off-white in color. The paws, head and chest shield are black. A brown mass forms around the larva due to the fact that it covers itself with excrement.
How to treat onions against these pests:
To combat rattles, use drugs used in systems for integrated management of the number of phytophages - “Proclaim”, “Spintor” (use according to the instructions). 
Description. Bug up to 3 mm long. At the end of the head there is a “proboscis”, bent down. The antennae are club-shaped, thickened at the end, and geniculate. The body is black, but due to the white scales it appears gray. There is a white stripe along the suprawing suture. Paws are red-brown.
The eggs are white, round, small - up to 0.5 mm. The female lays them in April, and within two weeks the larvae appear, which can damage 100% of the onion leaves. One leaf can contain from 7 to 17 larvae. The larvae are yellow, with a brown head, without legs, up to 7 mm. Then the larva gnaws its way into the bulb through the leaves, and emerges from it into the ground and begins to pupate. The larval development stage lasts up to one month. The bug overwinters in lumps of soil and under dried grass. Wakes up in early spring. 
Damages initially diseased sprouted bulbs that were not removed from the site, then moves on to new crops. It pierces onion leaves with its nose and feeds on the pulp. Affected leaves develop whitish round spots that look like needle pricks. Then the leaves dry out and the plant dies. Onion crops planted with seeds suffer catastrophically.
The most effective protection from is regular loosening of the soil in order to break up the “earthen cradles” of the pupae and the wintering grounds of the bug itself.
Extremely dangerous for onions; in very contaminated areas, complete destruction of the crop was observed.
Description. The stem nematode is a thread-like small worm, its structure can be seen using a microscope, its length is up to 1.5 mm and its width is 0.04 mm. The ends of the body have narrowings, and in the mouth there is a needle-shaped stylet (hollow, passing into the esophagus), thanks to which it is able to suck juice from plants. At the base the stiletto has three swellings similar to a ball. Eggs are not visible to the naked eye and their sizes are measured in microns.
It can overwinter in the soil, in the onion itself and its seeds. In dried plants it remains viable for up to five years, and when placed in a humid environment it regains its vital activity.
Causing harm. It gets into the onion both through the leaves and through the bulb itself from the bottom. During the larval and adult worm stages, it feeds on plants. Egg deposition also occurs in onion tissues. Damage is caused to the plant as soon as it begins to grow.
Damaged Bow in the early growth phase it has a flaccid appearance, and the affected areas are distinguished by thinner areas. When infected later in the growing season, onions may have a healthy appearance, sometimes distinguished by the appearance of white spots. But inside it is loose, the scales do not fit tightly to each other, the grainy structure of the fleshy scales appears, in the affected areas it is more refined and pigmented with white and brown spots. The onion may crack and the inner scales may bulge outward. Such a plant rots at high humidity, or dries out quickly at low humidity. 
Usually strikes in mid-summer. How to treat onions against pests such as nematode worms is a complex question, because fighting a nematode rarely leads to its complete destruction. Drugs that can destroy it are very toxic to the plant itself. The main principle of nematode removal is prevention:
- do not plant plants that are susceptible to nematode invasion in the same place for several years in a row;
- during harvesting, carefully select the seed onions and repeat it in the spring before planting;
- carry out deep loosening of the soil at the planting site;
- Before planting onions in the soil, add contact poisons in small doses.
The nematode does not tolerate temperatures above 40 °C, so an effective method of control before planting is to soak the onion set in water up to 55 °C for 15–20 minutes. This method will not harm the crop, but will destroy the nematode.
Did you know? Fresh onion juice is very nutritious and healthy, perhaps for these reasons it attracts various pests.
Most often, onions are intensively affected during storage. It often enters the bulb from the bottom, but it can also penetrate through damage caused by other pests. It settles between the scales of the onion, and it gradually begins to rot.
Description of the pest. The female is up to 0.2 mm long, has an elongated body, is white, has two pairs of legs, which are located in the front of the body. Shield without visor, semicircular. The skin has ring grooves: dorsal - up to 87, ventral - up to 76. The larvae are smaller and have fewer rings. They lay one egg per day, 1 female can lay up to 25 eggs. Ripening occurs in three days at temperatures above 10 °C. In cold conditions they slow down their vital activity, when favorable they multiply, and at temperatures above 18 °C they are spread to other bulbs.
Signs habitat in onions. Yellow or green pigmentation appears on the inner scales. When drying during storage, the pigments are more noticeable. During the growing season, the leaves turn yellow, curl, look as if they are affected by chlorosis, and are stunted in growth.
basis struggle is prevention:
Scoops
There are leaf-gnawers and gnawing ones. The first ones feed on the tops, and the second ones are in the ground and gnaw the bulb itself. Usually they are active at night, and during the day they are in a phase of immobility.
Description. The adult individual is represented by a butterfly with a wingspan of up to 5 cm. The front wings are brown with transverse white stripes, and the hind wings are light brown.
The eggs are dark gray. hemispherical. One butterfly can lay up to 40 eggs. The larva appears after 12 days. Larva: green caterpillar on the sides with yellow stripes, sometimes gray-green or yellow-green. In warm regions it produces two generations. 
Damage. The larvae crawl and gnaw leaves, and are able to bite into the bulb itself. Damaged onions emit an unpleasant odor and rot.
Struggle:
Onion pests cause great damage, and the fight against them lasts for many centuries, so there are many folk remedies. One of them is treatment with a solution during its flowering period: 300 g of crushed wormwood per 1 cup of wood ash and a tablespoon of ground soap, pour 10 liters of boiling water, cover with a lid and leave for one week. Spray after the settling period has expired. shallot aphid
Description. The body is brown in color, ovoid in shape. Larvae are dark shades of yellow or green. The eyes are brownish-black. Developed antennal tubercles, converging in front and longer than the body. The Spitz's sixth segment and segments 4–5 are black, and the rest are the same color as the body. The tubes are light, cylindrical, tapering towards the apex, ending in a dark funnel. The tubes are 8 times thicker than their length.
Signs of damage. The leaves fade, become distorted, and the crop lags behind in growth. The leaf feather that goes to the greens becomes contaminated with aphid feces and skins that the larva sheds. It is located on the leaves, under the outer shell of the onion.
Main protective measures are agricultural techniques:
By following some tips, you can prevent onions from becoming infested with pests.
- Compliance with crop rotation (plant onions in their original place no earlier than after 5 years).
- Carrying out sowing on time with zoned varieties.
- Autumn and spring digging of the landing site.
- Disinfection with a solution of copper sulfate before planting.
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