Gardeners and agricultural enterprises are constantly faced with the emergence of diseases that can cause great damage to onion plantings. To prevent this from happening, it is necessary to take preventive measures and follow the rules for growing them, as well as know what infections onions are susceptible to, the reasons for their occurrence, means of protection and methods of combating them.
There are about fifty species of fungi and pests that cause onion diseases
Major diseases
There are about fifty species of fungi and pests that can cause various onion diseases. They also appear in open ground, and in the greenhouse. Some of the common diseases are downy mildew, neck rot, jaundice, and fusarium.
Powdery mildew. This common bacterial infection is called peronosporosis. It manifests itself in such well-known varieties as turnip onions, spring onions, and leeks. The bulbs change shape and stop developing. The fungus, which is the causative agent of peronosporosis, leads to the formation of a yellowish coating on the leaves of the plant and their gradual death begins. For treatment, the following measures must be taken:
- Apply fertilizers containing potassium and phosphorus. This will increase the vegetable’s resistance to infection and strengthen protection against peronospora.
- To combat downy mildew, it is necessary to carry out preventive treatment with fungicides.
- When growing, you should not thicken the plantings and encourage the growth of weeds.
- When signs of downy mildew appear, they stop watering the crop and no longer feed the soil with nitrogen fertilizers. If by that time the bulbs are formed, they must be removed and dried in the sun for two weeks.
Bad weather conditions contribute to the development of powdery mildew or peronosporosis.
Gray (cervical) rot. This dangerous disease onions, which is characterized by gradual damage to the scales near the neck. Early ripening varieties, such as spring onions, are less susceptible to infection. It usually occurs through the soil or affected bulbs after harvesting, both in the garden bed and in the greenhouse. Rain and pests spread the infection. To combat gray mold, it is necessary to take measures:
- when growing, you need to use only healthy planting material, choose early varieties for sowing;
- to provide protection from rot, the soil is fertilized with nitrogen substances, and at the end of ripening, potassium and phosphorus are used.
Neck or gray rot is one of the most dangerous onion diseases.
Fusarium. The disease is manifested by softening of the bottom of the bulb and death of the root system. The leaves turn yellow and the bulb dies. This fungal disease is often found in onions and trumpets.
Regarding treatment, it is necessary to take measures to cultivate the soil before growing. Only high-quality planting material should be used. Diseased plants must be removed immediately. They are destroyed, and the remaining ones are treated with a special preparation. A folk remedy is also suitable: horsetail decoction or ash infusion.
Fusarium - softening of the bottom of the bulb and death of the root system
Onion jaundice. It affects all varieties of vegetables, but its signs are most clearly visible on the inflorescences of turnips and leeks. With the development of this onion disease, the leaves of root crops become spotted, their arrows turn yellow.
This virus has no cure. Fighting it involves regularly removing diseased plants. At the same time, all weeds are removed and spraying is carried out.
Pests
Some pests can cause diseases:
Onion fly. It infects fruits, penetrating the bulbs in the form of larvae. As a result, the vegetable stops growing and rots, the feathers become yellow and dry. Of the types of onions, the fly prefers onions, leeks and spring onions. If diseases with signs of these pests are identified, it is necessary to take a number of appropriate measures to protect against and control insects:
- It is necessary to treat the soil around the root crops by spraying. To do this you need to mix three hundred grams table salt and ten liters of water. Root crops are treated with this solution every 10 days, watering them at the root without touching the leaves.
- Bulbs are planted far from their previous place growing.
The onion fly is found in all regions of Russia
Root mite. Various varieties of vegetables are susceptible to infection. These moisture-loving pests very often attack onions, spring onions and leeks. The bulbs rot and a fungus forms. Thus, you will have to fight both the mite and the fungus. Measures taken to kill ticks:
- if a piece of land has been infested with a mite, you should not grow such plants on it for three years;
- one of the ways to combat it is heat treatment of fruits;
- You can get rid of the insect during the growing period by spraying the plants with a 0.2 percent solution of keltan.
Onion moth. This small butterfly gnaws the pulp of the leaf, forming passages in the tissue. The leaves gradually begin to die. These insects are common pests of onions, onions and leeks. Moth control measures:
- plants need to be sprayed;
- be sure to remove post-harvest residues;
- the soil is deeply plowed and loosened.
Greenhouse conditions and diseases
Growing onions in a greenhouse will help reduce the risk of contracting certain infections. After all, in such a room it is easier to maintain temperature regime, maintain humidity. Ventilating and circulating air in the greenhouse will help prevent the formation of mold and mildew. However, it is not possible to completely get rid of all pathogenic fungi and infections. For example, downy mildew can cause damage both in the field and in the greenhouse. Therefore, to combat it, the soil for planting must be treated with special means.
When growing onions in a greenhouse, a procedure is carried out to cut off the leaves so that dry leaves do not become a source of disease. Resistance to them also depends on the variety of onion. With proper care in a well-equipped greenhouse, you can grow a decent harvest of green onions from it.
Along with peronospora and fusarium, diseases such as onion bacteriosis, smut, anthracnose, cercospora and others are common. It is necessary to apply some preventive measures in order to provide vegetables with protection from infections and pests:
- It is necessary to start growing onions by preparing the greenhouse and disinfecting the soil in the garden. If you plan to grow green onions, you cannot spray the vegetables.
- Maintaining crop rotation.
- After the harvest is harvested, measures must be taken to ensure comfortable storage conditions.
- The harvest is harvested after full ripening. The bulbs are well dried and only after that they are sent for storage.
Preventing the occurrence of a disease is much easier than fighting it later. Therefore, it is important to follow the rules of plant care.
The main condition for obtaining a healthy harvest of onions and garlic is compliance with crop rotation. You cannot return lily crops (onions, garlic) to their original bed earlier than after 4-5 years.
Before storing onions and garlic, you need to disinfect the storage 2 months in advance with a solution of bleach (400 g per 10 liters of water). It is recommended to warm up the sets before planting. warm air(40°-42°) for 10 hours.
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: on different types In plants, signs of disease can manifest themselves in different ways. This could be rotting of the head of cabbage, cobwebs on the underside of the leaves, white coating on root vegetables, rotting of the bottom of the onion... The disease is often common in storage areas. The disease is especially evident on lettuce, parsley, cucumber, carrots, horseradish, cabbage, peppers, beans, onions, and sunflowers. |
: the harmful centipede is an insect pest similar to a long-legged mosquito, with a body length of up to 2.5 cm. The larvae of the centipede overwinter in the soil. In the spring, they begin to feed on the humus of plant roots, damaging them in the garden and greenhouses, causing great harm to young plants. The harmful fat stalk damages cabbage, celery, leeks and other vegetable plants in the garden. |
Diseases and pests of onions and garlic
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To grow healthy onions and garlic, you need to know what diseases and pests of onions and garlic can threaten healthy and tasty vegetables. In this article we have collected information on how to deal with major pests and how to preserve the crop. It must be said that these so healthy and tasty plants often suffer from stem nematodes. A nematode is a small worm that likes to lay its eggs in the roots of plants. This causes the onion heads to begin to crack and the garlic to begin to disintegrate into cloves. Plant leaves are subject to deformation. Onion processing before planting. To disinfect onion sets from nematodes before planting, planting material must be soaked for two days in aqueous solution salt at the rate of 3 tbsp. spoons into a bucket of water. Fighting onion diseasesIn the photo, the onion fly affects the onion like this. The onion fly is considered an equally dangerous pest of garlic and onions. The larvae of this insect penetrate into the bulb itself through the bottom or at the very base of the leaves, which usually leads to the death of the bulbs. Typically, the onion fly infestation begins in the spring, and it coincides with the cherry blossoms. 20 days after the eggs are laid, the larvae hatch from them, go deep into the ground and pupate there. They are replaced by young flies, and everything is repeated all over again. How to grow a good onion crop To grow a healthy vegetable, you need to correctly take into account the timing of the appearance of onion flies.
If possible, plant marigolds nearby. An attentive gardener and gardener can avoid the next misfortune in the struggle for the harvest. Damage to onions and garlic by downy mildewThis vegetable disease is especially relevant during the rainy season. Vague spots begin to appear on the leaves of plants, which gradually begin to increase in size, forming a gray coating, which is fungal spores. These spores can fly away with gusts of wind in different directions, infecting other plants. Methods for processing and protecting onions and garlic from downy mildew.
How to treat onions against pests: folk methods for downy mildew
Everyone has dairy products in their home; do not throw away sour milk or fermented milk whey from kefir. Lactic acid bacteria have a negative effect on the powdery mildew pathogen and at the same time do not harm plants. Recipe for onion diseases - powdery mildew: a spray product is made from fermented milk whey separated from dairy products. Let's take it cold water and dilute its serum in a ratio of 1:8 -1 to 10. Stir until smooth. Pour the prepared solution into spray containers. Now you can treat the plants in the morning or evening. Harvesting and storing onions and garlicTo prevent neck rot of onions, you must try to remove the vegetable immediately after it ripens, without delaying this matter. After the neck begins to dry out and the feathers fade, this is your signal - you need to start harvesting. After the onions and garlic are dug up, they are dried in the wind and sun for 3-4 days, usually left directly on the ridges. Of course, it is better to choose a sunny day in August for harvesting. Remove the soil from the garlic gently, shaking it off with your hands; you must try not to damage the scales (the quality of storage and resistance to disease depend on them). These medicinal vegetable crops need to be dried in the sun; you can move them closer to home and spread the onions and garlic on oilcloth. The remaining leaves should be trimmed. Trim the onion so that the tail of the vegetable remains approximately 3 cm. Store harvested onions and garlic< надо в cardboard boxes or baskets in a cool but dry place. They are also woven into “braids” and hung in storerooms, while protecting them from cold and moisture. Find out more about the increasingly popular, very healthy vegetable daikon Read our other useful article about ways to combat plant pests: Marigolds - protecting plants from pests Nowadays, coupons for discounts for various entertainment and health activities and products are of great interest among Internet users. To navigate where and what kind of discount promotion is taking place, there are specialized discount sites. Any resident or guest of Perm and other regions can receive discount coupons in Perm on the discount website Couponator. ©foto-flora.ru |
Onions suffer from onion fly damage from year to year. The first flight of the fly is observed when the dandelions bloom. At this time, a repellent is used - watering with ammonia (1 tablespoon per bucket of water).
This event is held every week. The onion bed must be moved to a different place every year; the best predecessor is carrots.
Pre-planting treatment of the sets helps onions to grow healthy - heating them in the sun several hours before planting, soaking them in hot strong potassium permanganate, and then dusting them with ash. You can dust the onions with bazodin, but under no circumstances use such onions on the feather - the drug is poisonous.
As soon as the bow emerges from the ground, the secretive proboscis attacks. The feather becomes pale, and the larvae of the secretive proboscis settle inside it. For prevention, you need to constantly sprinkle the onion with ash, cut off the affected feather and destroy it.
The onion fly (Delia antiqua Mg.) and the hoverfly (Eumerus strigatus Fall.) are dangerous pests of onion plants that damage the underground parts of onions, spring onions, leeks, shallots, and garlic. The pests are common in all areas where onion plants are grown and are especially harmful on sandy and loamy soils, as well as in garden plots during continuous cultivation. The onion fly overwinters in the puparia (a pupa in a reddish-brown, shiny cocoon, about 7 mm long) in the soil on depth from 10 to 20 cm.
The flight of the first generation flies begins in early May at a sum of effective temperatures of 103-141°C (this coincides with the flowering of lilacs) and lasts 30-40 days. The flies are ash-gray, with a distinct brownish longitudinal line on the abdomen.
Flies emerging after overwintering feed on the nectar of flowering plants. 5-10 days after departure, females lay eggs (5-12 pieces each) near plants, in cracks in the soil, between the bulb and the soil, openly on the soil, leaves, in the axils of the leaves and between dry scales of the bulb.
After 4-6 days, at an air temperature of 18.5-21.5°C and a relative air humidity of 65-75%, the larvae hatch. The adult larva is white, legless, narrowed in front and widened at the rear end, up to 10 mm long.
On the obliquely cut segment there are two spiracles, and along the edges there are 16 small outgrowths (tubercles), of which the most noticeable are the 4 lower middle outgrowths. Of all types of onions, female onion flies prefer onions.
Moreover, the plants of the first generation are the most populated. In nigella crops for sowing, egg laying is already observed, starting from the phase of 2-3 true leaves. The larvae hatched from the eggs bore into the underground part of the bulb and damage the conducting bundles of the plant.
If there is not enough food for the further development of the larva, it moves to a neighboring plant. In damaged plants, the bulbs rot, the leaves turn yellow, wither and dry out. Plants are easily pulled out of the soil.
On onions of the second year of development (turnip sowing), at the beginning of the growing season, the fly lays eggs mainly on the soil and onion, and as the plants develop, in the axils of the leaves and openly on the leaves. The hatched larvae migrate to the plant and actively penetrate into it either through the bottom or through the neck.
In this case, the former feed on the tissues of the bottom (false stem), the latter - on the tissues of fleshy scales and leaves. Regardless of the type of damage, onion sets die when only 1-2 larvae penetrate the plant.
The same thing is observed on onion plants (especially in the first half of the growing season), if their growing point is damaged. The first generation larvae damage onions in May - June. Their development lasts about 20 days.
Then, having finished feeding, they emerge from the bulb into the soil and pupate in it. At the end of June - in the first half of July, the years of the second generation of flies begin. There are few of them, since a significant part of individuals (up to 35%) of the first generation go into diapause.
The onion fly develops in two generations. The greatest damage to plants is caused by onion fly larvae in the early stages of development.
As a result of the research, it was established that all types and varieties of onions are colonized and damaged by phytophages to one degree or another during the growing season. But the main type of onion that is largely damaged by dipterous pests is onion.
Sweet onion varieties (Yalta local, Orange), which have a minimum content of dry matter (6-9.7%) and essential oil (0.018-0.025%), are severely damaged (up to 44.5%). On the crops of these varieties, the maximum number of eggs laid is noted - 14.8-18.2 eggs/plant.
On spicy varieties (Strigunovsky, Skvirsky, Zolotisty) with high content dry matter (up to 18%) and essential oil (up to 0.05%), the number of eggs laid per plant and damage by onion fly is 3-4 times lower compared to sweet onion varieties. The peninsular varieties Lugansky and Karatalsky with an average content of secondary substances occupy an average position, the damage of which is about 26%.
Research has shown that, depending on the number of nests in the bulb, onion varieties with 1-2 nests were less colonized and damaged by the onion fly. Thus, the crops of multi-nest shallots with 6-7 nests were almost half infested with pests, and their damage was at the level of 40.5%.
At a time when the population of small and medium-sized onion varieties was at the level of 20.5-28.0%, and the damage was 10-21.6%. This indicates that onion fly larvae can leave damaged plants and crawl onto others only when the plants are very close to each other.
Onion hoverfly. The fly is 7-10 cm long, shiny, greenish-bronze, with three semilunar spots on the top of the abdomen. The male differs from the female in having larger eyes that almost touch at the base of the antennae.
The pest overwinters in the pupa stage (puparia) in the soil at a depth of 10-25 cm and in the larval stage (middle and older ages) in the plant remains of mother bulbs, as well as in planting material stored for storage, in which they form puparia by mid-winter and pupate. Thanks to this intraspecific flexibility, the population size of the onion hoverfly is constantly maintained at a high level.
The onion hoverfly emerges at the end of May. The fly is active throughout daylight hours, and high temperatures are not a deterrent.
After additional feeding with nectar, the female selects well-lit open areas and lays white eggs, somewhat concave in the middle part, on the soil surface near the plant, on the outer covering scales and in the neck of the bulb. After 4-7 days, larvae hatch, a distinctive morphological feature of which is the presence of spiracles clearly visible to the naked eye, protruding at the posterior end of the body, as well as their high plasticity.
In the bulb, the larvae feed on the succulent internal tissues of the plant for 17-25 days, mainly in the lower, root part. They molt three times, after which they form a false, light yellow cocoon with a brownish tint.
In July, flies of the second generation fly out, the larvae of which damage onions and garlic after planting. The onion weevil (Cruthorrhynchus jakovlevi Schultze.) is a small beetle 2-2.7 mm long. Its body is black, covered with white scales, oval in shape, with a long, slightly curved rostrum, and club-shaped antennae.
The end of the head is extended into a “proboscis”, usually bent down. The abdomen is not covered on top with elytra. It damages onions, spring onions, most often shallots, less often garlic and leeks.
Beetles overwinter under plant debris, dried grass and lumps of soil on the turfed slopes of ditches, ravines, along roadsides, and forest belts. They awaken in early spring, in the second half of April (according to observations, their years coincide with the flowering of dandelions).
At first, the beetles feed mainly on sprouted onions left in the field, then they move to early onion crops. They gnaw small holes in the leaves and, plunging their proboscis into them, eat out small cavities in the pulp of the leaf, under the skin.
The damage looks like round whitish spots located along the edge of the leaf. Onion seedlings are particularly affected. They often dry out and die.
It should be noted that in last years The number and harmfulness of the onion secretive proboscis has greatly increased, which is primarily due to high temperatures and lack of precipitation during the period of its development (late April - May). Females lay small, whitish, round-oval eggs through a hole they make in the feathers on the inside of the leaves.
The larvae that hatch after 5-16 days are yellowish, legless, C-shaped bent, with a brown head, up to 6.5 mm long, gnaw passages in the pulp of the leaves, and whitish longitudinal stripes form on the outside. The leaves turn yellow, starting from the top, and if severely damaged, they dry out.
If there are 3-5 larvae on one leaf, especially in dry, hot weather, the seedlings die. The larvae stop causing damage by early June, and new leaves grow on the affected plants. However, the yield as a result of the “activity” of the secretive proboscis is significantly reduced.
The larvae develop for 15-20 days, then gnaw holes in the leaves, go into the soil and pupate at a depth of 3-6 cm. The pupa is located in the soil, in a loose earthen cradle.
The second generation of beetles appears in late June - early July and feeds on leaf tissue and inflorescences of onion plants in the summer. If the succulent stalks are completely gnawed, the flowers die, and if partially, puny seeds are obtained. The onion moth (Acrolepia assectella Zell.) damages onions, leeks and partly garlic during the growing season.
Butterflies overwinter in plant debris. The butterfly is up to 12-14 mm in wingspan, the front wings are brown with large stripes and spots, and the hind wings are gray with long fringe. The summer of onion moth butterflies begins in mid-May.
They fly at night, soon after feeding additionally with nectar, they mate and lay yellowish, round, up to 0.4 mm long eggs on the underside of the leaf, on the neck of the bulb, and on the flower shoots of onions and garlic. After 5-7 days, yellowish-green caterpillars with brown warts hatch, penetrate into the leaves, shoots and inflorescences, eat up the flower primordia, and during the flowering of the plants, gnaw the pedicels.
Caterpillars pupate on leaves, on the surface of the soil near the bulbs. The development of the pupa lasts 9-12 days. In July, butterflies of a new generation emerge, the caterpillars of which usually cause damage in the second half of July and in August.
Tobacco (onion) thrips (Thrips tabaci Lind.) are most common in the southern regions of Ukraine (and today almost throughout the entire territory of Ukraine) and harm not only onions, but also cucumbers, watermelons, and cabbage. When onion sets and garlic are stored warmly (+18°C), thrips feed and reproduce throughout the winter, significantly reducing their planting qualities.
Thrips overwinter in the top layer of soil, in plant debris under dry scales of onions and garlic. Appears on crops in late April - early May. The female lays up to 100 small whitish eggs, placing them singly in the fleshy scales of the bulbs.
The root mite penetrates into mature bulbs through the bottom, which cracks and turns into a rotten mass. Thrips and their larvae feed by sucking juice from leaves. Whitish spots form on the leaves, which merge when severely damaged.
Damaged leaves turn yellow and dry out. You can see small black dots on them - the excrement of the pest. The bulb of the affected plants is small. By the time of onion harvesting, if the weather is warm, thrips fly to cabbage, cucumbers, and various weeds.
Onion crops are damaged by root (onion) mite (Rhizoglyphus echinopus R. et F.) and garlic four-legged mite (Aceria tulipae Keif.). Ticks are small arthropod insects, ranging from 0.5 to 1.1 mm in length.
Moisture-loving and heat-loving organisms, reproduce weakly at temperatures above +13°C and relative air humidity above 70%. They are distinguished by their fertility: one female lays up to 800 eggs. Each generation develops within 10-30 days.
When conditions worsen or there is a lack of food, a very resistant form of the pest (hypopus) appears. In this form, ticks can exist for a long time without feeding. The root mite penetrates into mature bulbs through the bottom.
With severe damage, the outer scales lag behind the bottom - it becomes bare, becomes rotten, and the bulb rots. With mild infestation, the mites remain between the fleshy scales and damage onions in storage.
The root mite can also feed on bulbs of hyacinths, daffodils, and even potato tubers and rotting roots of carrots and beets. The garlic mite, unlike the root mite, damages the leaves and juicy scales on the outside of the bulb and causes especially great harm to onion sets.
Overwinters in bulbs, soil and seeds. In onion waste, on dry scales, being in the dormant stage, it can persist for more than two years, and in dried garlic - up to five.
When introduced into a humid environment, the nematode leaves the dormant state and becomes active. After sowing or planting onions and garlic in contaminated soil, the stem nematode penetrates the plant tissue and lays eggs in them. The emerging larvae and adult nematodes feed on the sap of plants, which at the same time lag behind in growth, their first cotyledon leaf swells and bends.
Severely damaged seedlings die. In plants, leaves (feathers) become deformed, wrinkled with yellowish veins, bend, and thicken at the bottom. The internal tissues of the bulbs when cut have a loose granular structure.
Cavities often form between the juicy scales of a diseased bulb (that’s why it feels soft to the touch), and its bottom cracks. Affected bulbs continue to deteriorate during storage. The set is drying up.
When garlic is infected with a nematode, it is stunted in growth, its pseudostem thickens, and longitudinal cracks form on it. The bulb becomes loose and wet, and it completely collapses. The onion leaf beetle (Lilioceris merdigera) is found everywhere, but causes damage in patches.
The beetle overwinters in plant debris. Before germination, it feeds on unharvested queen cells and sets discarded during planting, and on the shoots of overwintered bulbs from last year.
With the emergence of seedlings, it moves on to young shoots and inflorescences - it gnaws holes in the shoots, gnaws on pedicels and flowers. The larvae damage leaves and arrows; pupate in the soil. Leaf beetle larvae are large and are collected by hand.
The topic is vast, read more.
Fungal diseases of onions are widespread, and every summer resident may need their treatment. We have also prepared for you a catalog with photos and descriptions: “The main pests of onions and their control.” Proper crop rotation, prevention, medicinal treatments and folk recipes will help grow a healthy and generous harvest.
Onion diseases are often associated with non-compliance with the rules of crop rotation and agricultural technology. This crop belongs to the lily family, therefore, like other representatives of the species, it needs to take all necessary measures to protect it from bacteria and insects.
For the reader's reference
Onion (lat. Allium) is a unique plant that can be biennial or perennial. At the same time, it is classified as a member of the lily family (lat. Liliaceae) based on botanical characteristics: appearance, development and structure of the plant. And to the onion family (lat. Alliaceae) according to production characteristics: harvesting and storage, purpose and method of cultivation. Often when describing a culture, it is classified as a subfamily - Onion.
Onion diseases and their control
The culture is susceptible to many bacterial and viral diseases. To prevent them from destroying the crop, it is necessary to study onion diseases and their treatment; photos and descriptions of the signs of infection that we have prepared will help you quickly determine the type of infection. There are various chemical preparations, but traditional recipes are no less effective.
Downy mildew (lat. Peronospora parasitica)
A disease such as downy mildew (popularly) is called onion downy mildew; control measures that every gardener should know. External signs infections are:
- wilting of leaves;
- the presence of vague pale spots with a gray tint on the feathers;
- plaque formation on leaves;
- gradual yellowing of greenery and its drying out.
Such diseases of green onions, photo below in the article, most often appear in the spring. Starting from the feathers, the fungus gradually spreads into the fruit, affecting the entire plant. The cause of infection is poor-quality planting material or non-compliance with crop rotation rules. Onion sets affected by downy mildew can retain fungal spores until the next sowing season.
The disease actively develops at high air humidity and moderate temperature, +15-20 degrees Celsius, and under unfavorable conditions it does not die, but only stops its development.
Planting must be done from north to south. Thus, each plant will be in sufficiently be illuminated by the sun. When the first signs of downy mildew are detected, it is necessary to remove the affected shoots. When growing onions for turnips, you can spray with Oxyx, 2 tablets of 10 g per 10 liters of liquid. The procedure is carried out every 2 weeks.
If you grow onions for plumes, chemical treatment is unacceptable. In this case, it is necessary to stop fertilizing with organic matter and limit watering for a while. It is recommended to treat the beds with potassium-phosphorus fertilizers. For preventive purposes, it is recommended to warm up the harvested crop for 12 hours at a temperature of +40 degrees Celsius before storing it. The seedlings are treated in a similar way a couple of weeks before planting. The storage room is disinfected with bleach (0.4 kg per 10 liters of water) 2 months in advance.
Gray rot (lat. Botrytis cinerea)
This disease of onions in the garden, like gray rot, begins to develop even when harvesting last year's harvest. Spores of the Botrytis fungus most often penetrate the vegetable through the neck of the onion that has not yet closed during drying. The first signs of the disease become visible already during crop storage:
- the fruits begin to deteriorate at the base of the neck: gray rot becomes visible on the surface;
- when pressing on the bulb near the neck, the tissue is crushed;
- In the section, the affected layers of the onion are visible: they are soft, cloudy, often gray, reminiscent of boiled onions.
During storage, healthy fruits can become infected with spores through damage to the surface caused during harvesting or by insects. Favorable conditions for the development of the fungus: high humidity in the storage and high temperature.
During the growing period, the beds are treated with Kvardis, Bravo and Switch, strictly according to the instructions. The fight against traditional methods consists in artificially accelerating the ripening of fruits. Limiting nitrogen fertilizing and increasing potassium-phosphorus fertilizing contributes to the rapid development and premature drying of leaves, due to which the neck closes faster.
Bacteriosis (lat. Bacteriosis)
Like gray rot, the disease manifests itself during storage:
- the fruits become soft;
- when cut, rotten brown tissue is visible between healthy scales with traces of fungal development;
- bad smell;
- presence of small flies.
The fungus penetrates into insufficiently dried and damaged bulbs. Methods for combating bacteriosis are similar to gray rot. It is necessary to follow the rules of agricultural technology and crop storage, and remove infected fruits in a timely manner.
Onion pests and their control, photos of signs of damage
Onion pests, photos of which you can find in this article, cause no less trouble than diseases. Insects infect the entire plant and can destroy the entire crop.
Onion fly (lat. Napomyza gymnostoma)
This insect is active starting from mid-May. Elongated brown flies lay eggs between the leaves, and the hatching larvae penetrate the plant itself, feed on it and destroy it. Damaged bulbs rot right in the soil, and the feathers turn yellow and dry out.
Answering the question: how to treat onions against pests, many gardeners advise using the chemical preparations Fly Eater, Aktara or Karate. But it's best to use traditional methods insect repellent:
- pungent odors: alternating plantings of onions and carrots will help repel the onion fly;
- table salt solution: 0.3 kg per 10 liters of water - watering is carried out every 2-3 weeks;
- Sprinkling the beds with ash is both a fertilizer and protection against pests.
Onion thrips (lat. Thrips tabaci)
Onion (or tobacco) thrips overwinter in the remains of vegetation in the soil, and in the spring they move to young plants. Very small insects Brown birds lay eggs at the base of the feathers, as a result of which silvery spots on the leaves and insect excrement (small black dots) can be seen. Affected plants turn yellow and die.
Chemicals are most often used on industrial plantings, and gardeners recommend repelling insects with the smells of tobacco, ash, carrots and mothballs.
Onion mite (lat. Rhizoglyphus echinopus)
Onion root mite infects plants during growing and storage. Most often, the spread of insects occurs through infected planting material. The mite and its larvae feed on the roots and the bulb itself, as a result of which the fruits become loose and covered with “dust.”
Pest control of onions with folk remedies involves timely prevention of infection:
- planting material is heated at a temperature of +35-38 degrees Celsius for a week;
- during storage, the mite infects only damaged bulbs: it is necessary to discard low-quality crops;
- You should first of all fight the mite's predecessors - the onion fly.
Prevention of onion diseases and how to repel pests
The most the best way The fight against diseases and pests of onions is prevention:
- Most diseases and pests are transmitted by infected planting material. To do this, the seedlings must be disinfected at high temperature before sowing.
- Almost all onion diseases and pests overwinter in the soil and on plant debris. In the fall, the beds are carefully dug up and disinfected. Under no circumstances should plant residues be used to make compost. You can replant onions in one place only after 4-5 years.
- Proper crop rotation will avoid many diseases. The best predecessors are tomatoes, cucumbers and cabbage.
On a small personal plot You can do without the use of pesticides. To repel unwanted insects, substances and plants with pungent odors are used:
- carrot leaves produce aromatic phytoncides that the onion fly cannot tolerate, so onions and carrots are often planted side by side;
- the beds are sprinkled with wood ash, tobacco dust or its mixture with slaked lime (1:1);
- plantings are sprayed with wormwood infusion.
Bottom line
Caring for onions can cause a lot of trouble for inexperienced gardeners. One of important conditions growing good harvest is the safety and correct storage of planting material for the next season. Otherwise, caring for the crop is very simple if you protect it from pests and infections in a timely manner, which is easy to do if you know onion diseases and how to deal with them.
Onions are one of the most important ingredients in cooking. This vegetable is grown in almost every country in the world. But due to a number of obstacles, complete harvesting is not ensured almost anywhere. This is prevented by soil depletion, changing climatic conditions, excessive use of chemicals, and diseases. But the largest percentage of losses is caused by onion pests, and combating them is crucial for obtaining a high-quality harvest.
In order to begin the fight against onion destroyers, you need to learn how to correctly recognize them. Except appearance insect, it is necessary to pay attention to the nature of the plant’s lesions.
Onion fly: how to recognize and neutralize?
Every gardener knows that the most dangerous pest for onions is a fly from the hoverfly family. Due to the fact that the insect is very fond of juicy onion fibers, it was nicknamed onion. The pest can be identified at its inception stage. To do this, just inspect the green arrows of the onion. Particular attention should be paid to the area located approximately 2-3 centimeters above the soil.
If white elongated eggs, about 1.5 mm long, are noticed, then it is necessary to remove the affected stalk. This procedure needs to be done at the end of May - beginning of June, otherwise after 2-3 days the eggs will turn into cream-colored larvae. white, about 8 mm long. It is much more difficult to eliminate the larvae, because almost immediately after degeneration, they try to burrow into the soil and penetrate directly into the head of the bulb.
At this stage, the upper stems of the plant look absolutely healthy, so it will not be possible to fight the pest locally. Further, throughout the summer and the warm part of autumn, the larvae will turn into pupae. It is the larvae that cause maximum damage by actively feeding on onion pulp.
From some cocoons flies will appear, which will emerge to the surface in 3-4 weeks, and some pupae will remain overwintering in the soil and will regenerate into flies only at the end of next May. If the soil is not properly tilled during the fall harvest, the cycle will repeat again.
Signs of plant damage by onion fly:
- if the bulbs are affected by larvae, the stems first become sluggish and then die off altogether;
- if already infected bulbs were planted, the new shoots will initially look yellowish. And the harvest dug up in the fall will turn out to be rotten.
Features of plant damage by onion thrips
Thrips are very small insect pests of onions that are carriers of diseases of many plants. Thrips can be found on cabbage, potatoes, tobacco, cotton, and zucchini. Insects can be identified by the following characteristics:
- thrips eggs are white-yellow in color, bean-shaped and do not grow larger than 0.5 mm;
- the larvae look like small flies of pale yellow color, but without wings;
- the pupae are very similar to the larvae, but their color changes to dark brown;
- adult individuals look like brown, narrow (up to 1 mm) flies. Moreover, males are wingless, and females have long narrow fringed wings.
The life cycle of thrips lasts from 20 to 30 days, depending on the outside temperature. Egg incubation period: 4-5 days; lifespan of larvae: 5-7 days; Pupa development period: 8-10 days, and the life of an adult fly lasts 5-8 days. 
Thrips feed by piercing the surface of the plant and sucking out the secreted juices. Pests cause direct damage to both stems and bulbs, and can also provoke the development of various diseases in the plant. Damaged bulbs seem to become infected with ulcers, lose color, and the stems dry out. At the same time, green bow arrows become covered with silvery spots. Thrips and leeks attack. Despite the fact that the plant does not have a pronounced bulb, pests happily feed on the white part of the root.
Fighting onion flies and thrips
The methods of controlling the two pests listed above are identical and quite labor-intensive. Firstly, after harvesting, it is necessary to dig up and sift the soil, since pest larvae easily tolerate even the coldest winters. Of course, it is almost impossible to completely get rid of millimeter-sized larvae using this method. Therefore, in the next sowing season, it is recommended to plant corn, carrots, or fragrant herbs in place of the onions. The aromas of these plants are destructive to flies and thrips.
Protecting onions from pests and diseases is impossible without the use of professional products. Treatment of onion roots before planting in the ground with a mixture of 0.1% carbendazim and 0.025% carbosulfan solution will provide immunity from infection by pest larvae for 30-40 days. Also, after planting (but not earlier than 30 days), it is necessary to apply an insecticidal spray. 
Experienced gardeners recommend the use of preparations based on alpha-cypermethrin. You can check the effectiveness of the methods described above in the following way: place ordinary sticky traps of a bright (preferably green) color on the beds. As soon as the strips remain empty for at least a few days, chemical treatment can be stopped.
How to get rid of pests without chemicals?
Those who categorically refuse to work with chemicals can try using neem seed oil. This is a powerful natural insecticide that can disrupt the life cycle of insects at all stages. The oil is biodegradable and non-toxic to pets, birds and people. In addition, it is a natural fungicide that fights mold and fungal infections.
You can purchase the drug at many garden or organic stores. To use neem oil as an insecticide, mix 2 teaspoons of oil, 1 teaspoon of mild liquid soap with 1 liter of water. Pour the resulting solution into a bottle and spray on the green arrows. You need to process the onions every day for a week, then take a break. If new larvae appear on the stems, water the plants again. 
Another natural insecticide is regular garlic. Its strong smell is unpleasant not only to people, but also to garden pests. In fact, garlic spray will not destroy pests, but it will quite successfully prevent their further reproduction.
In order to prepare a natural insecticidal solution, you need to take two heads of garlic and grind them in a food processor with a small amount of water. Infuse the resulting mixture overnight, and then mix with 1/2 cup vegetable oil, 1 teaspoon of mild liquid soap and a liter of water. Spray the resulting solution onto the infected onion. Chili pepper spray has a similar effect. 
Attention! The chili pepper solution also affects people, so be sure to wear gloves on your hands and a protective mask on your face.
Root bulb mite
The root onion mite, despite its name, attacks garlic more often than onions. Ticks are translucent, cigar-shaped, microscopic in size (adults do not grow more than 1 mm in length), and almost invisible to the naked eye. The eggs are attached with a thin adhesive tape to the stem of the plant, and after maturation they are moved into the soil.
Signs of damage to onions by microscopic mites are not very obvious. Pests very slowly grind down the roots and pulp of the bulbs. This leads to stunted plant growth, twisting and discoloration of the stems. But small yellow specks appear mainly at the very edge of the arrows, which means that not every gardener will be able to notice such an important sign in time. Mites can also damage healthy bulbs that have already been dug up. 
To prevent the occurrence of onion mites, it is necessary to avoid sequentially planting onions and garlic in the same bed for several years. Before the start of the summer season, it is necessary to treat the soil with a solution of sulfur (0.3%) and dimethoate (0.03%) or dicofol (0.05%) in an amount of 2 ml. for 1 liter of water. It is recommended to use preparations based on clofentesine as post-sowing soil prophylaxis.
Gnawing (cotton) bollworm
The gnawing armyworm is dangerous only in the form of a caterpillar. The adult cutworm looks like a large light brown moth. When the wings are folded, a V-shaped spot is formed on the back. The butterfly lays single creamy-white eggs. Larvae emerge from them, which degenerate into brown or greenish caterpillars. It is at this stage of life that the cutting armyworm causes the most problems for gardeners.
The larvae are usually located inside the stem, but subsequently (during the transition to the next life stage), they begin to move closer to the soil. The caterpillar burrows into the soil and begins to chew through the white flesh of the onion. As a result, the green stems dry out completely, and the vegetable itself becomes unsuitable for consumption. To get rid of the gnawing armyworm, you can use the same insecticides that are used against thrips. 
Careful cultivation of the topsoil is also recommended. Regular loosening of black soil creates unfavorable conditions for the laying and normal development of eggs. If on summer cottage If only root crops are planted, then you can hang several feeders on the surrounding trees. This is the most natural and inexpensive method of getting rid of pests. Cutworm caterpillars are the best treat for birds.
How dangerous is onion nematode?
The onion nematode is dangerous because it can literally reproduce continuously. The translucent white eggs mature within three days, after which the cycle repeats. An adult nematode looks like a whitish, oval-shaped worm, 2 mm long. Since the life cycle of this pest does not exceed a year, larvae and adults often develop in the same bulb. Ultimately, the dug up vegetable turns out to be hollow inside.
And if an infected onion gets into the warehouse before a clean harvest, then within a few weeks most of the vegetables will begin to rot. Although the nematode is not considered too dangerous, care must be taken to ensure that the pest does not infect any vegetables. Otherwise, the pulp of all the bulbs will very quickly turn into rot. Sometimes infection of vegetables can be caused by mechanical damage or improperly organized storage. 
The simplest and most natural method of preventing the spread of nematodes is to plant marigolds. Pests cannot stand the smell of these flowers. It is advisable to plant marigolds over several seasons as the effect is cumulative. If worms have already infected vegetables, it is recommended to treat the crop with chitosan-based preparations.
In addition, before planting onions, you can flood the soil with chemicals (but this method will kill not only pests, but also beneficial land fauna). If you don’t want to use chemicals, you can add compost, manure, or any other natural fertilizers to the soil. Organic matter They are unlikely to kill pests, but they will increase the soil’s ability to retain moisture and nutrients. This means that onions will receive additional sources for fast and healthy growth.
- Nematode activity slows when soil temperatures drop. This means that late onion varieties are much less susceptible to pests.
- Before planting the bulbs, you must carefully inspect all the roots. If a whitish coating is noticed, the plant should be thrown away rather than trying to be cleaned or treated with a solution.
- Sometimes nematodes infest the soil so deeply that the only solution is to completely replace the topsoil. This is a fairly expensive option, which will provide a guarantee of getting rid of pests for 1-2 years.
Before starting pest control, it is necessary to assess the extent of damage. If you have a whole plantation planted with onions, then it is worth using chemicals. But if you only have a couple of onions growing in your garden for a homemade salad, you need to try natural remedies.
Onions and garlic contain a large number of vitamins, essential oils and phytoncidal compounds. They have long been used not only for food, but also for the prevention and treatment of many, primarily colds. However, even specific chemical composition does not save plants from diseases and pests.
Diseases can affect both plants in the garden and bulbs during storage. Signs of the disease may include discoloration or spotting of the feathers. Diseases include drying of the above-ground parts, softness of the bulbs, or the appearance of a white, grayish or black coating on them.
Onion fly
Very similar to an ordinary fly. Larvae pose a danger to onions.
The onion fly emerges from hibernation around mid-May and lays eggs in early June. The larvae hatch on the fifth to tenth day, penetrate the young bulbs and eat them from the inside.
The feathers of affected plants turn yellow and dry out, starting from the tips, and the bulb itself rots. One larva during a month of growth can damage the entire bed. After a month, the larva pupates, and soon a new generation of flies appears.
The fight against this pest begins with prevention. After harvesting the onion, you need to carefully sort it out and remove all damaged bulbs. Dry the remaining onions. In the spring, before planting, sort through the bulbs again and select damaged ones again.
It is strictly not recommended to plant onions in the same area for two years in a row. In fact, correct onion crop rotation involves returning the planting to the same place no earlier than in the fourth or fifth year; it is good to sow onions and garlic in the place where cabbage, nightshade or pumpkin crops were last year. The onion fly overwinters at a depth of up to 20 centimeters, so in the fall the beds need to be dug deep and all plant debris removed.
The onion fly does not like the smell of carrots, so it is advisable to plant onions and carrots (or garlic and carrots) in the same bed, alternating rows. Before planting, onion sets must be disinfected hot water. To do this, keep it in water at a temperature of 45-46 degrees for ten to a maximum of fifteen minutes.
The onion fly is afraid of salt. You can treat the beds two or three times per season. The first treatment is carried out when the seedlings are about 5 cm. For each subsequent treatment, the amount of salt must be increased. The first ratio is 300 grams per 10 liters, then 400 grams and, if the treatment is carried out for the third time, 600 grams of salt.
The beds (the plants themselves) need to be watered with a saline solution, and after four or five rinses thoroughly with clean water. The interval between treatments is about two weeks. Within a week after the emergence of the onion fly, you can treat the row spacing of onion plantings with a mixture of tobacco dust and sunflower ash. Lime or ammonium carbonate salt is also allowed.
Useful tips for exterminating pests and treating diseases of green onions and garlic.
Secretive Proboscis
The onion secretive proboscis, also known as the weevil, is a small beetle of dark gray or black color. Both beetles and larvae are dangerous for the plant. The body of the beetle is up to 2.5-2.7 mm long, with a characteristic proboscis curved downwards. The larva is a yellowish caterpillar with a brown head, 6-6.5 mm long. The pest feeds on the pulp of leaves, causing white dots or stripes to appear on it.
Particularly affected leaves dry out. Despite the fact that the secretive proboscis does not directly harm the bulb. Due to damage caused to the green part of the plant, the onion yield in the infected area is significantly reduced.
The secretive proboscis begins activity quite early - in mid-April, and initially feeds on unharvested remains or sprouted onions.
At the end of April or early May, females lay eggs inside the tubular leaves of the onion. After a week or two, the hatched larvae move into the leaves.
The larvae actively feed on the pulp of the leaves, and after three weeks they emerge into the soil and pupate. This usually happens in July. A new generation of beetles appears in the same summer and continues to feed on the leaves and inflorescences of onions. The fight against this pest is primarily based on crop rotation.
A new onion planting must be placed in a place as far as possible from the previous planting, and always carefully remove all onion residues and waste. Next, at the time of pupation of the larvae, it is necessary to regularly loosen the onion rows to a depth of 5-10 centimeters. This is necessary so that the maximum number of secretive proboscis pupae end up on the soil surface and die.
Onion crops can act as bait for the secretive proboscis. They can be placed next to regular onions, and then the beds of onions can be destroyed along with the pests. It is advisable to do this at the stage of the first white stripes on the leaves. This is very important, because during this period the larvae are just beginning to grow and do not have time to infect the soil with pupae. A mixture of tobacco dust and wood ash
. To do this, you need to sprinkle the plants themselves in a ratio of 1 to 2 after watering), tansy and celandine (sprinkling with dry powder or spraying the plants with a decoction).
Thrips are prolific and develop quickly; in a season they can produce from 3 generations in open ground and up to 8 in greenhouses. Thrips larvae suck the juice from the vegetative parts of plants. If they are significantly damaged, the stem becomes bent, the bulb softens, the plant lags behind in growth and does not produce seeds.
The most dangerous for onions are tobacco thrips and onion thrips. Measures to combat them include the destruction of the food supply and individuals that are dormant in the soil. This means that in the fall you need to carefully dig up the beds, to a depth of 15-20 centimeters (the bulk of thrips overwinter at a depth of 5-7 centimeters) and remove as much as possible any plant debris and roots that can serve as food for the pest. After harvesting, the greenhouse can be treated with 0.15% karbofos.
In the summer, deep loosening of onion rows is effective in order to destroy thrips pupae. Also, to protect onions from thrips, it is recommended to maintain crop rotation and not plant onions next to other crops that provide food for the pest: cucumbers, cabbage, tomatoes. For small lesions, spraying plants with decoctions of odorous and caustic herbs celandine, tobacco, mustard, and hot pepper is effective.
To do this, you can take 1 kg of fresh hot pepper and boil it in 10 liters of water for an hour. Then leave for a day and pour into dark bottles. Before use, 125 ml of pepper concentrate is diluted in 10 liters of water and the plants are sprayed with this solution. The treatment is repeated at intervals of two weeks.
Winter and potato cutworms
Cutworms are small (up to 4.5 cm in wingspan), inconspicuous butterflies that are universal pests. Cutworm caterpillars infect plantings various types cabbage, potatoes, tomatoes, onions, carrots - in fact, all garden crops, and both above-ground parts of plants and roots are eaten. At the end of August-September, female cutworms lay eggs.
Caterpillars emerge from overwintered eggs in late April-early May and begin to actively feed on both cultivated and weed plants. Caterpillars pupate no later than mid-July, in the soil, at a depth of 6-10 cm. After some time, butterflies emerge from the pupae and lay new eggs.
Based on this life cycle of cutworms, the fight against them, first of all, consists of carefully digging and loosening the soil. This is done in order to destroy as many eggs and pupae as possible by removing weeds. Because they allow the caterpillars to become saturated before the active growth of cultivated plants.
Of the famous folk remedies You can use a decoction of wormwood against the cutworm. It is necessary to boil 1 kg of herb per volume of 3 liters of water for 15 minutes. Treatment is carried out twice, with a break of a week.
An infusion of white mustard is also suitable. To prepare, you need to infuse 2 grams of powder in a glass of water for two days, then strain and dilute with plain water to a volume of 1 liter). Unfortunately, a pest such as the fall armyworm is quite aggressive, and if the plantings are significantly damaged, broad-spectrum industrial insecticides may be needed.
Thus, the optimal protection of onions and garlic from pests will be:
- complex wrestling throughout the season;
- compliance with crop rotation (thus, pests of onions and garlic are left without food supply for the next season);
- deep digging of the soil in the fall, removing plant debris and weed roots;
- destruction of plant parts infected with pests;
- thoroughly drying the onion seedlings and checking them before planting;
- loosening the beds of onions and garlic to a depth of at least 10 cm several times a season, which allows you to destroy a significant part of the pupae;
- treating plants with various infusions of herbs and seasonings that repel insects;
- treatment of plantings with a solution of ordinary table salt;
- use of tobacco dust. This auxiliary product is sold in specialized stores and, when used in garden beds, disorients pests by interrupting the smell of plants;