The onion began to turn yellow what to do. When to harvest onions. Fungal diseases and control methods

Peronosporosis, or downy mildew of onions and garlic . The causative agent of the disease is a fungus Peronospora destructor (Berk) Casp.The disease affects all types of onions: batun, shallots, chives, leeks and garlic. The disease manifests itself in the spring with the growth of perennial onions and onion seed plants. In the middle of summer (late June - early July), downy mildew appears on turnip and onion sets.
The disease is transmitted from year to year with the bulbs, in which the infection persists as a mycelium, without causing them to rot. Infected bulbs planted in the field produce diseased plants. With the beginning of their growth, the mycelium located in the tissues also begins to grow, which diffusely penetrates the leaf tissues through the intercellular spaces. Inhibition of plants becomes noticeable 3-4 weeks after planting the bulbs. The leaves do not develop well, turn yellow, wither with a strong lesion and break. Seeds are underdeveloped, remain feeble. In dry weather, pale green spots appear on the leaves and arrows. In wet weather, a grayish-purple coating is formed on the spots, consisting of branched conidiophores and conidia. Conidia are ovoid, gray-violet, 35-60x22-35 microns in size. With their help, the disease spreads and re-infections occur. In this case, peronosporosis manifests itself in the form of oval, yellowish spots of various sizes with a noticeable coating. Diseased leaves and arrows dry out prematurely. Seeds often do not have time to form.
From the leaves, the disease passes to healthy bulbs, which then develop slowly and usually reach smaller sizes. The average weight of a turnip bulb is reduced by 1.5-2 times. The scales of infected bulbs are fleshy, they become wrinkled, with uneven surface. The mycelium of the causative agent of the disease is concentrated mainly in the region of the donets and remains there to winter. In addition, the fungus, when unfavorable conditions for it, can form oospores, which also persist on plant remains during the winter and can serve as a source of primary infection.
The degree of manifestation of peronosporosis in the field depends on weather conditions. The disease develops strongly in wet weather. In dry, hot weather, its spread stops, the conidia of the fungus die in the sun without causing infection. The optimal conditions for the development of the fungus and infection of plants are formed at a temperature of ten to fifteen degrees and a relative humidity of more than eighty percent.
The main sources of primary infection of peronosporosis are planting material and perennial onion species, in the roots of which the fungus overwinters. In some areas, the resumption of the disease on onions can occur due to overwintered oospores. V last years reports appeared in the literature that the infection can also be transmitted with seeds (V. I. Glushchenko).

Control measures. The main measure in the fight against downy mildew of onions and garlic is to obtain healthy planting material. To do this, crops of nigella and garlic must be placed in fields with the greatest isolation from perennial onions, turnips and seed plants. Positive results are obtained by autumn warming of small bulbs before the end of drying at a temperature of 40 ° for 8 hours and large bulbs - 24 hours and spring warming no later than 1.5 months before planting. A necessary condition for obtaining healthy material is a systematic inspection and cleaning of crops from diseased plants, starting from the 3rd-4th week after planting.
At the first detection of the disease, it is recommended to spray with fungicides: 0.4% suspension of arceride, or 1% Bordeaux liquid, or 0.4% suspension of polycarbacin (turnip onion), or 0.4% suspension of polychoma (testes), or 0.2% suspension of ridomil, or 0.4% suspension of tubaride, or 0.4% suspension of copper oxychloride, or 0.4% suspension of cineb (except for onions on a feather) .
In conditions where the development of peronosporosis almost annually reaches the level of epiphytosis, it is necessary to cultivate varieties with relative resistance to the disease. These include Golden, Pogarsky, Tsitaussky, Strigunovsky, Sivirsky, Stuttgarter, Myachkovsky 300.

Bacterial bulb rot . The causative agents of the disease are bacteria Erwinia carotovora (Jones) Holland., Erwinia aroideae (Town.)Holland. The disease manifests itself during the growing season of onion sets and on the testes. The leaves turn yellow, areas of dying weeping tissue appear. On the testicles, the arrows turn yellow, fade. On bulbs, signs of bacterial rot can only be detected on a longitudinal section. Under healthy outer scales, dirty-brown, softened and mucilaginous scales are found. After 2-3 months, such bulbs completely rot and emit bad smell.
The development of bacteriosis, according to the literature, is promoted by sunburn, a sharp change in weather conditions during the ripening period - from wet, moderate to dry and hot, storage of onions in warm and humid conditions.

Control measures

onion stemfiliasis. The causative agent of the disease is the fungus Stemphylium allii Oud. It affects onions, garlic, leeks. Especially dangerous for testes. On the leaves, as well as on the arrows of the testes, mainly on plants affected by false powdery mildew, clearly visible brown-violet spots appear, covered with abundant pinkish-purple at first, later brown bloom of the fungus, consisting of colorless conidiophores and oblong, packet-shaped, brown-violet, smoky-brown spores 20-50 X 12-25 microns in size. Leaves and arrows break in places of defeat. Seeds do not have time to form or are formed feeble.
Stemfiliasis completes the death of leaves, started by peronosporosis. It develops especially strongly in dry and warm weather.
The main source of infection is overwintering affected plant residues and bulbs, on which the fungus can persist throughout the entire storage period.

Control measures the same as with peronosporosis

Onion smut. The causative agent of the disease is the fungus Urocystis cepulae Frost. The disease appears only on onions of the first year in the form of dark, slightly swollen stripes, translucent through the skin on the cotyledon leaf, as soon as it comes to the soil surface. Over time, the skin cracks and a mass of black spores of the fungus is found. Most of the affected seedlings die at the age of 3-4 weeks. In those plants that do form bulbs, dark stripes also form at the base of their scales. When the skin cracks, a mass of black spores is found, which enter the soil and can remain viable in it for 5-6 years. Onion seedlings are most susceptible to smut starting from the second day after seed germination and ending with the formation of the first leaf, i.e. within 12-15 days after germination.
Onion smut is distributed mainly in individual gardens, where nigella is often sown, and in farms specializing in the cultivation of this crop.
The most favorable temperature for spore germination and plant infection is 13-20°C. At 26° and above, seedlings are not affected by smut.
Soil is the main source of infection. The disease is not transmitted with seeds.

Control measures with smut are reduced to observing the correct crop rotation with a 4-5-year break for sowing black onions in one area. Onion sets and turnips can be grown on contaminated soils. Early sowing or sowing with germinated seeds is recommended, as well as growing onion seedlings on uninfected soil and planting it in the ground

Neck rot of onion and garlic . The causative agent of the disease is the fungus Botrytis allii Munn. The most common and harmful disease of onions and garlic. The primary infection of plants occurs in the field even before harvesting when the leaves are lodging, which is a favorable substrate for the development of the fungus. The causative agent of cervical rot penetrates into tissues through a loosely closed neck and mechanical damage. Infection in the initial period is not detected, so the affected bulbs, along with the healthy ones, fall into the storage. The first symptoms of the disease become noticeable already at the beginning of storage (September-October). Neck rot develops as a result of infection in the field and rot of the lateral parts or bottom due to re-infection from nearby diseased bulbs. The bulb softens in the affected areas, the tissue becomes watery, yellow-pink in color, with bad smell. If all scales are affected, the bulbs become mummified. On the surface of the affected scales, a dense gray mold is formed, which is a mass of conidiophores of the fungus and colorless, oval, unicellular conidia 7-16x4-9 microns in size. Later, sclerotia of the fungus appear among the mold, often merging into a solid black crust.
The intensity of the manifestation of cervical rot depends on many environmental factors. rapid development diseases in storage are facilitated by increased humidity and temperature. The optimum temperature for the fungus is 20°, but it can develop at 3-4°. The growth and development of the pathogen stops only at 0°C.
The main source of infection in the culture of onion from sets are seed bulbs. When they are planted in the field, the causative agent of the disease can affect arrows and seed heads. The arrows break, the seeds are underdeveloped, have poor germination. The infection that has formed on the testes is transferred to the turnip, where it gets to the lower dying leaves, and then to the bulb, causing it to become infected. When onion is cultivated from seeds, the plant becomes infected mainly from turnip crops and seed plants. The role of soil as a source of infection is less significant. In it, mainly sclerotia of the fungus can be preserved. There is a possibility of spreading the disease with seeds, since the causative agent of neck rot is able to infect seed heads.
The development of the disease is greatly influenced by the growing conditions of onions. In the same weather, onions are more affected on loamy soils; weaker - on sandy loam. With more high humidity soil creates favorable conditions for the fungus. In addition, the duration of the vegetation of plants is lengthened, the ripening of the bulbs slows down, and the leaves dry out more slowly.
Increased doses of nitrogen, violation of harvesting terms and post-harvest drying conditions contribute to increased damage to onions. Harvesting immature bulbs and storing them without sufficient drying dramatically increases the susceptibility of bulbs to neck rot.

Control measures. To reduce onion losses from neck rot, it is first necessary to obtain healthy planting material. To do this, black onion should be sown in separate areas remote from fields occupied by turnips and seed plants. Harvesting of the bulbs should be carried out during the period of their full maturation, followed by drying of the bulbs in sunny weather in an open place in one layer, in wet weather - first under a canopy, and then for 7-10 days indoors when the air is heated to 26 - 35 °. When cutting onions, leave a neck 3-6 cm long. It is recommended to store onions at optimal conditions: food - at a temperature of 1-3 ° and a relative humidity of 75-80%, uterine bulbs - at 2-5 ° and 70-80%, sets - at 18-20 ° and 60-70%.
When dressing onions and garlic against neck rot, it is allowed to use the following fungicides: benlat (foundazol) - 0.7% suspension (immersion of the bulb in the drug suspension for 20 minutes before storing, followed by drying), or tigam-3-4 kg/t ( sevka processing, seed treatment), or TMTD-4-5 kg/t for seed treatment and 2-3% suspension for seed treatment.
Onion varieties resistant to cervical rot have not yet been identified. Varieties Mstersky local, Danilevsky 301, Bessonovsky local are less affected. Warsaw, Pogarsky, Tsitaussky and varieties with dark colored scales. Early-ripening onion varieties are less susceptible to cervical rot.

gray onion mold . The causative agent of the disease is the fungus Botrytis cinerea Pers. It affects onion testicles in the phase of seed filling and bulbs during storage. Unlike cervical rot, the disease does not affect the neck, but develops on the lateral and bottom parts of the bulb. Gray mold infection can occur both in the field and in storage in the same ways as neck rot infection. The affected tissues are weeping, with an unpleasant odor, yellowish in color, covered with a gray fluffy coating of the fungus, consisting of conidiophores and unicellular, colorless, oval conidia 9-17x6-10 microns in size. Later, numerous sclerotia are formed in the plaque.
The source of infection is the affected bulbs and sclerotia wintering in the soil.

Control measures with mushrooms and bacterial rots onions and garlic include the same tricks as with neck rot.

Green mold onions and garlic, or penicillosis . The causative agents of the disease are fungi from the genus Penicillium (Penicillium glaucum Link.). One of the most common diseases of garlic during storage. Less common on onions. On the bulbs, first on the bottom or outer scales, brown watery spots appear. In garlic, individual cloves become sluggish, depressed light yellow spots are visible on the juicy tissue. In the future, the affected tissues soften and become covered at first with a light, whitish, and then with a green moldy coating. The spores of the fungus are elliptical or spherical, small, with a diameter of 3-3.5 microns. When the scales break, they spill out in large quantities. The disease also spreads to the internal teeth. They shrivel, darken and crumble. The bulbs feel empty to the touch.
Mass manifestation of green mold reaches 2-3 months after laying onions and garlic for storage. strong development diseases are promoted by high temperature and humidity in storage, freezing, mechanical damage.
To reduce the loss of onions and garlic from green mold, it is first necessary to dry them thoroughly before storing them. Air humidity should be within 60-80% at a positive temperature and not higher than 90% at a temperature of -1-3 °.

Control measures with fungal and bacterial rots of onions and garlic include the same techniques as with neck rot.

Black mold onion and garlic, or aspergillosis . The causative agent of the disease is the fungus Aspergillus niger Tiegh. The disease develops when onions and garlic are stored at a high temperature (18-25 °). The greatest damage is caused by onion sets and onion selection. Black mold affects the upper juicy scales. Sick bulbs soften, a black, dusty mass of small, up to 2-5 microns in diameter, spherical spores is formed between the scales. Unripened, poorly dried onions are more susceptible to the disease. During storage, re-infection of the bulbs can occur through direct contact, as well as with the help of spores that spread through the air.

Control measures with fungal and bacterial rots of onions and garlic include the same techniques as with neck rot.

White rot of onions and garlic . The causative agent of the disease is the fungus Sclerotium cepivorum Berk. It affects plants of any age during the growing season, as well as during storage. When infected in the field in young plants, the leaves turn yellow, starting from the top, and die off. Plants quickly wither and die. A white fluffy mycelium forms on the roots and scales of the bulbs, the garlic cloves become watery and rot. Small, poppy-seed-sized sclerotia appear on the affected tissue. The fungus develops well at a temperature of 10-20 °. It overwinters as sclerotia in the soil and in storage on infected bulbs.

Control measures with fungal and bacterial rots of onions and garlic include the same techniques as with neck rot.

Fusarium, or root rot of onions and garlic . The causative agents of the disease are fungi from the genus Rizagsht. The first signs of the disease appear even in the field, during the ripening of onions and garlic. In affected plants, the leaves die off quickly, starting from the top. Most of the roots rot. On the bulbs in the area of ​​the bottom, a pink, yellow, often white mycelium bloom with clearly visible pads, consisting of elongated, crescent-shaped, with 3-5 partitions, colorless spores 30-50x3-4 microns in size, is always noticeable. Accumulations of mycelium and spores are also clearly visible between the scales. The affected tissues dry out, and by the end of storage, the bulbs are mummified. The disease is promoted by pest damage. Unlike white rot, Fusarium rot develops more often in years when onions and garlic ripen at high soil temperatures. During storage at elevated temperatures, the disease also progresses rapidly.
Sources of infection are contaminated soil and planting material.

Control measures with fungal and bacterial rots of onions and garlic include the same techniques as with neck rot.

Bacteriosis of garlic . The causative agents of the disease are the bacteria Erwinia carotovora (Jones) Holland., Pseudomonas xanthochlora (Schuster) Stapp. During storage, deep sores or stripes appear on the cloves of garlic, going up from the bottom. Fabrics acquire a pearly yellow color. In places of defeat, fungi from the genus Penicillium usually settle. Affected bulbs during planting in most cases germinate and develop normally.
The development of the disease is most often facilitated by the cleaning and storage of unripe, poorly dried garlic and non-compliance with storage regimes.
Well-formed and matured teeth are resistant to bacteriosis.
The onion and garlic diseases described above rarely appear in their pure form. As a rule, they develop in the form of mixed rots. The most common lesions of onions are neck rot and black mold, bacteriosis and fusarium, neck rot and gray mold, bacteriosis and neck rot, neck rot and fusarium, bacteriosis and green mold, etc.
Often, three or even four diseases can be found on one bulb. We observed the simultaneous development of cervical rot, fusarium and green mold; fusarium, bacteriosis and green mold; cervical rot, bacteriosis and fusarium; black and green mold, fusarium and bacteriosis.

Control measures with fungal and bacterial rots of onions and garlic include the same techniques as with neck rot.

yellow dwarfism . The causative agent of the disease is the Onion yellow dwarf virus. The disease is more pronounced on the testes and is detected shortly after the planting of the queen cells. Plants have a depressed appearance: the leaves turn yellow, often become folded or corrugated, fall to the ground due to the loss of turgor, and become flat. Peduncles also turn yellow, curl and give the plant a dwarf appearance. Flower heads and seeds are smaller than those healthy plants. Onions, which have been propagated vegetatively for a long time, are more susceptible to dwarfism.
On sets, the disease is transmitted by many species of aphids that feed on onions and other related plants, and mechanically. The transmission of pathogens by onion seeds has not been established. The earlier in the season the sevok is infected, the stronger the disease will manifest itself next year.
The prevalence of dwarfism depends on the presence of aphid vectors and environmental conditions. With slow growth of plants, the disease may not appear.
Yellow dwarfism affects shallots, garlic, perennial onions, which are often virus reservoirs.

Control measures. The main measures to combat viral diseases of onions and garlic are obtaining healthy planting material by isolating (up to 1.5 km) black onion crops from crops of other crop years, perennial onions and garlic, protecting against virus vectors, selecting uterine bulbs from healthy plants, removal of diseased onion sets.

Onion and garlic mosaic . The causative agent is Allium virus I Smith. Leaves and inflorescences are affected. On leaves, the disease appears as small, more or less elongated speckles or wide light green or cream stripes. Sometimes the leaves become corrugated, stunted and lodging. The arrows are bent, longitudinal mosaic stripes are visible on them. The inflorescences of the affected plant are loose, the flowers are sterile or produce very few seeds. Instead of stamens and pistils, long leaves often develop, and bulbs instead of flowers. Germination of seeds from diseased plants is reduced. Bulbs from infected plants often have an elongated shape and, before reaching maturity, germinate. The disease is carried by the four-legged garlic mite. The infection persists in onion sets, mother onions and perennial onions, on which the disease manifests itself in the form of a weak leaf mosaic.

Control measures. The main measures to combat viral diseases of onions and garlic are obtaining healthy planting material by isolating (up to 1.5 km) black onion crops from crops of other crop years, perennial onions and garlic, protecting against virus vectors, selecting uterine bulbs from healthy plants, removal of diseased onion sets

OnionflyDelia (Hylemia) antigua Meig . Widespread dangerous pest(especially in wet years). More harmful on sandy and loamy soils, less on peat. More damage to bows household plots with permanent cultivation of culture, less - garlic.
The emergence of flies is noted in mid-end May and coincides with cherry and dandelion blossoms. Eggs are laid in groups of 5-12 between onion leaves or in cracks in the soil near plants. After 5-9 days, depending on the conditions of the year, larvae hatch. They penetrate plants through the base of the leaves or bottom. The larvae, hatched from one masonry, keep in a group, gnawing large cavities in the bulb. Due to damage, the bulbs rot, the leaves turn yellow, usually in the apical part, and fade. Damaged bulbs emit an unpleasant odor, and when they are opened, white, legless, headless larvae up to 10 mm long are found inside. The posterior end of the body is blunt, in the middle of it there are two round brown plates with breathing holes. The development of larvae takes 16-20 days, after which they go into the soil to pupate. Pseudococoon reddish-brown, shiny, about 7 mm long.
The flies are yellowish-gray, with a distinct brownish longitudinal line on the abdomen. The body is narrow, long. Legs, antennae, tentacles are black. Flies hatched after overwintering require additional nectar feeding flowering plants. 5-10 days after departure, they start laying eggs. The eggs are white, 1.1 mm long, elongate-oval, with a narrow oblong groove in the middle.
The pupae overwinter in false cocoons in the soil at a depth of 6-20 cm. The fly develops in Belarus in two generations. Harmfulness of larvae of the 1st generation appears in June, the second - at the end of July - August.

Control measures. Spatial isolation of onion crops from last year's crops. Arrangement (or alternation) of onion and carrot rows, onion crops next to carrot crops. Phytoncides secreted by carrot leaves repel the onion fly. Early sowing of onions contributes to resistance to onion fly damage, since by the time the flies emerge, the plants will get stronger, coarsen and less damaged by the pest. There is an opinion that mulching with peat between rows helps to scare away the onion fly, since the pest avoids peaty soils. The use of drugs with a strong odor such as naphthalene mixed with sand in a ratio of 1: 1, tobacco dust in its pure form or in half with lime or ash (1-2 kg per 10 m2). Processing is carried out in the initial period of laying eggs. Subsequent - in 7-8 days. It is necessary to periodically inspect crops, remove and destroy damaged bulbs. At the end of the growing season, remove the tops, the remaining damaged bulbs, followed by digging the soil. Good results are obtained by treatment with an infusion or decoction of a volatile plant - tobacco. Leaves and stems are used. For infusion, take 400 g of crushed raw materials or dust, insist two days in 10 liters of water. The infusion is filtered. To the resulting solution add 40 g of soap. For a decoction, take 400 g of dried raw materials per 10 liters of water, insist for a day, then boil for 2 hours. After cooling, another 10 liters of water are added and for every 10 liters of solution, 40 g of soap are added.

Onionhoverfly(Eurnerus strigatus Fall).Moisture-loving insect. Widespread. Damages all kinds of onions, garlic, gladioli, tulips, daffodils and other plants. The larvae that have penetrated the bulbs destroy them and cause decay.
The adult fly is about 9 mm long, greenish-bronze in color, with short light hairs. Antennae black-brown. Legs black, tibiae at base, apices of femora and tarsomeres yellow. The eggs are white, elongated without a longitudinal groove, 0.8 mm long. Larvae are grayish-yellow, strongly wrinkled, flattened on the ventral side, up to 11 mm long. At the posterior end of the body there is a reddish-brown process with two outgrowths on the sides. False cocoons about 8. mm long, yellowish Brown. The posterior end of the body is the same as that of the larva.
The larvae overwinter in the bulbs left unharvested in the field, in the soil and storages. In the spring, they pupate, and by the beginning of June (coinciding with the flowering of wild rose), flies fly out. Females additionally feed on flowering nectarifers and after 7-9 days start laying eggs in small groups of 6-10 pieces. After 5-10 days, larvae hatch. The development of larvae lasts about one month, after which they go to the topsoil to pupate. The second generation of the pest appears in early August. With severe damage by a phytophage, only the peel of the bulb remains, filled with a black rotting mass. Develops in two generations.

Control measures. The same as against the onion fly, as well as the use of healthy planting material.

Onionmole(Acrolepia assectella Zeil.). Distributed everywhere. More harmful in hot, dry years. Damages leeks, onions, garlic. Caterpillars penetrate inside the tubular leaves of onions, eat away the parenchyma in the form of irregular stripes,. leaving the epidermis intact. Damaged leaves turn yellow and dry, starting from the apical part. On onion sets, caterpillars often penetrate the neck and even inside the bulb, causing the complete death of the plant. On leeks and garlic, the caterpillars mine the leaves, on the seed plants they feed in buds, eat out the rudiments of flowers, gnaw the pedicels, which leads to a decrease in seed yield. The onion moth is a small butterfly, with a wingspan of 8-10 mm, dark brown in color. Forewings with small white spots. In the middle of the front wings there is White spot almost triangular in shape. The hindwings are lead gray with a long fringe. Eggs are milky white and bean-shaped. The caterpillar is yellow-green in color, with a dark head, spindle-shaped, with 8 pairs of legs. Body 10-11 mm long covered with brown warts. Pupae are dark brown in color, about 7 mm long, located in a grayish cobweb cocoon. Butterflies hibernate in various shelters, on plant remains. The emergence of moths is observed in mid-May and phenologically coincides with the flowering period of bird cherry. The female lives for about two weeks and during this period manages to lay up to 100 or more eggs. Their development lasts 5-8 days. In the conditions of Belarus it develops in two generations.

Control measures. It is necessary to observe crop rotation and proper agricultural technology. Return the bow to its original place no earlier than after 3-6 years. Modern loosening and top dressing mineral fertilizers. Destruction of plant debris. spraying seed plantings insecticides during the summer of butterflies and the appearance of caterpillars.

Onion secret proboscis (Ceuthorrhynchus suturalis Schul.). Beetles and larvae damage onions, onions, chives, less often garlic. Beetles in tubular leaves eat out small cavities, as a result of which rounded white spots form on them. The larvae eat away the pulp inside the leaf, in longitudinal strips, without touching the outer skin. In damaged plants, the leaves turn yellow from the top and dry out.
On the testicles of the onion, the beetles gnaw the pedicels, causing the death of the flowers.
The beetle is 2-2.7 mm long, with a thin rostrum bent under the thorax. The body is black, covered with whitish scales and therefore appears gray.
Along the suture of the elytra, the scales form a yellowish-white stripe. Legs are red-brown. The larva is up to 6.5 mm long, legless, yellowish, with a brown head, the body is C-curved. As adults, they leave their feeding grounds, make holes at the base of the leaves, and cocoon in the topsoil.
Beetles hibernate under plant remains and lumps of soil in grassy areas along roadsides, ditches, and on ravine slopes. In early spring, when the average daily temperature rises to 8-9 ° (III decade of April-1 decade of May), the beetles leave wintering, fly over to onion crops, damaging the leaves in the form of small holes, and after mating, they start laying eggs, in groups of 1-5 pieces, on the inner surface of onion plants. After 6-10 days, larvae hatch from the eggs, which feed on the pulp of the leaves without affecting the epidermis. Light stripes form on the leaves, which are very clearly visible against the background of dark greenery. The development of the larva lasts more than a crescent. In Belarus, the pest develops in one generation.

Control measures. Collection and destruction of post-harvest residues, autumn plowing, which destroys the wintering grounds of beetles. Additional loosening of row-spacings during the period of mass pupation of larvae, followed by watering and fertilizing with mineral fertilizers. Removal of damaged leaves with the destruction of larvae. Insecticide treatment. There is a fairly effective folk method - remove and destroy damaged feathers and pour a solution under the root of the bulbs - 1 cup of ordinary table salt per 10 liters of water with the addition of potassium permanganate until pink.

Root (onion) mite (Rhyzoglyphus echinopus). Distributed everywhere. Damages the onion, mainly during storage, but can also be harmful in the field, where it is brought with planting material. Penetrating inside the bulb, usually near the bottom, the mites feed on fleshy scales, causing them to rot. Severely damaged bulbs dry out during storage. In the field, mites prefer plants damaged by other pests. They harm garlic, hyacinths, daffodils and other crops.
The body of the root mite is oval, whitish or cloudy glassy, ​​about 1 mm long, the legs and mouth parts are brown. Moisture-loving. Relative air humidity of 60% and below is unfavorable for tick development. At optimal temperature(25-26°) one generation of the pest develops within 9 days. One female lays on average about 800 eggs. Larvae are similar to adults, but unlike them, they have three pairs of legs. Adult mites can feed on plant debris. Ticks can often be found in garden soil, greenhouses, where the pest is introduced mainly with infected planting material.

Control measures. 1.5-2 months before planting, dry heating of onion sets and uterine onions is carried out at a temperature of 40-45 ° for 16 hours or at 35-37 ° for 5-7 days. In the storages where the pest is found, gas disinfection is carried out with sulfur dioxide obtained by burning Gamma checkers (0.5-1 g per 1 m ^) or lump sulfur (50 g / m2). Exposure - 48 hours. A prerequisite for decontamination of premises is their tightness and compliance with safety regulations.

Onion nematode, or onion and garlic stem nematode (Ditglenchus allii Belj.) . Damages onions, especially garlic. Found on parsley, parsnips, tomatoes, radishes, cucumbers, thistle and other plants. Larvae and adult nematodes feed on plant sap, causing them to bend and stun. In bulbs damaged by the nematode, the internal tissues are loose, granular, grayish. Juicy scales do not fit tightly to each other, as a result of which the bulb feels soft to the touch, the bottom cracks. In garlic plants, growth retardation, thickening of the false stem, yellowing and dying of leaves, yellowing of cloves at the base are observed. Mecia nematode localization - bulb, then feather and arrow.
The onion nematode is a small (1-1.5 mm) whitish worm. Overwinters in bulbs, soil, seeds. In dry onion scales and dried garlic, it remains viable for 2-4 years. It reproduces by laying eggs in plant tissue. When the infected plants die, the nematodes go into the soil and look for a new host. Humidity close to 100% is a necessary condition for resettlement.
The nematode persists and accumulates in the remains of bulbs, feathers, arrows. In the soil, the nematode is usually absent. The pest also spreads with seeds.
Nigella seedlings infected with the nematode are ugly and thickened. Vegetating plants are infected in several ways: in rainy years, the nematode penetrates through the stomata of the leaves, in dry weather - through the bulb. In places where the nematode is introduced, a white spot is formed. It penetrates into more mature bulbs through the growth point of future roots.
With a weak infection, the bulbs are stored normally for some time, outwardly they do not differ from healthy ones, but over time, the tissue collapses inside. There are empty shells.

Control measures. Thermal disinfection of seeds and sowing in heated water at a temperature of 45-50 ° for 10-15 minutes. Sowing only healthy seed material. Compliance with crop rotation with the return of onions, garlic to their original place no earlier than in 3-4 years. Before laying the onion for storage, it is mandatory to disinfect the onion stores, dry and warm the bulbs at a temperature of 35-37 ° for 5-7 days. Carry out fumigation with sulfur dioxide (50 g of sulfur per 1 m2 of the room, exposure 24 hours). In storage at positive temperatures (maintain air humidity not higher than 70%.

Tobacco onion thrips (Trips tabaci Lind.). A very common species in the republic. In recent years, damages onions, tobacco, cabbage, watermelon, cucumbers in greenhouses. It feeds on more than 100 plant species. Adults are light yellow or brown in color with narrow wings, fringed at the edges, about 1 mm long. The eggs are small, kidney-shaped, white. The larvae are outwardly similar to adult thrips, but are smaller in size, without wings, whitish at first, then greenish in color. Adult thrips overwinter on plant debris, in the upper soil layer, but the main amount is concentrated under the scales of the bulbs. In early spring they feed on weeds, then they switch to cultivated ones. When the onion is damaged, silver-white spots appear on the leaves. In places where thrips feed, the excrement of the phytophage is visible to the naked eye in the form of black dots. Damaged leaves turn yellow, die off, starting from the top of the plant. If the inflorescences of the testes are damaged, the latter turn yellow, then dry out, no seeds are formed or they are feeble, with low germination.
Females lay about 100 eggs, placing them one at a time under the skin in the leaf tissue. After one week, larvae hatch from them. Having finished feeding, they go into the soil and there they turn into adult insects. Some part of the pest population gets into storage with bulbs, where it continues to develop under favorable conditions.

Control measures. Same as against onion nematode and onion root mite.