Began to turn yellow onions what to do. When to clean the bow. Fungal diseases and control methods

Perinospora, or downy mildew of onion and garlic . The causative agent of the disease - the fungus   Peronospora destructor (Berk) Casp.The disease affects all types of onions: batun, shallot, shnitt, leek and garlic. The disease manifests itself in the spring with the regrowth of perennial onions and testicles of onions. In the middle of summer (the end of June - the beginning of July) perinospora appears on a turnip and onion sets.
From year to year, the disease is transmitted with bulbs, in which the infection remains in the form of a mycelium, without causing them to rot. Infected bulbs planted in the field, give sick plants. With the beginning of their growth, the mycelium, which is located in the tissues, begins to grow; it diffuses through the intercellular membranes and penetrates the leaf tissues. Inhibition of plants becomes noticeable in 3-4 weeks after the planting of the bulbs. The leaves develop poorly, turn yellow, with a strong lesion they dry up and nadlamyvayutsya. Seeds are underdeveloped, remain puny. In dry weather, pale green spots appear on the leaves and arrows. In wet weather, a grayish-purple plaque is formed on the spots, consisting of branched conidiophores and conidia. Conidia ovoid, gray-purple, 35-60х22-35 microns in size. With their help, the disease spreads and repeated infections occur. In this case, peronosporosis appears as oval, yellowish spots of various sizes with a noticeable bloom. Diseased leaves and arrows dry prematurely. Seeds often do not have time to form.
   From the leaves, the disease is transferred to healthy bulbs, which then slowly develop and usually reach smaller sizes. The average weight of the turnip bulb is reduced by 1.5-2 times. The scales of infected bulbs are fleshy, they become wrinkled, with an uneven surface. The mycelium of the pathogen is concentrated mainly in the region of the Donets and remains to winter there. In addition, the fungus, when adverse conditions occur, can form oospores, which are also stored on plant debris during the winter and can serve as a source of primary infection.
   The degree of peronosporosis in the field depends on weather conditions. The disease develops strongly in wet weather. In dry hot weather, its distribution is stopped, the conidia of the fungus die in the sun without causing infection. Optimal conditions for the development of the fungus and infection of plants are formed at a temperature of ten to fifteen degrees and relative humidity above eighty percent.
   The main sources of primary infection of peronosporosis are planting material and perennial species of onions, in the roots of which the fungus is overwintering. In some areas, the resumption of the disease onion can occur due to overwintering oospores. In recent years there have been reports in the literature that the infection can be transmitted with seeds (V. I. Glushchenko).

Control measures. The main event in the fight against onion and garlic pernosorosis is to obtain a healthy planting material. To do this, crops of Chernushka and garlic must be placed on the fields with the greatest isolation from perennial onions, onions, turnips and seed plants. Positive results are provided by autumn warming of small bulbs before drying is completed at 40 ° C for 8 hours and large ones - 24 hours and spring warming no later than 1.5 months before planting. A prerequisite for obtaining healthy material is a systematic inspection and cleaning of crops from diseased plants, starting from the 3-4th week after planting.
   When the disease is first detected, it is recommended that fungicides be sprayed with a 0.4% suspension of arceride, either a 1% Bordeaux liquid, or a 0.4% suspension of polycarbacin (a bow on a turnip), or a 0.4% suspension of a polychoma (testes), or a 0.2% suspension of Ridomil, or a 0.4% suspension of Tubaride, or a 0.4% suspension of copper oxide, or a 0.4% suspension of Zineb (except onions on a feather) .
   In conditions where the development of peronosporosis almost annually reaches the level of epiphytotics, it is necessary to cultivate varieties that are relatively resistant to the disease. These include the Golden, Pogarsky, Tsitausky, Strigunovsky, Sivirsky, Stuttgarter, Myachkovsky 300.

Bacterial Bulb Rot . Pathogens - 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, there are areas of dead weeping tissue. On testes arrows turn yellow, fade. On bulbs, signs of bacterial rot can be found only in a longitudinal section. Under the healthy outer scales are found dirty-brown softened and lousy scales. After 2-3 months, these bulbs completely rot and produce an unpleasant odor.
The development of bacteriosis, according to literary information, is promoted by sunburns, a sharp change in weather conditions during the ripening period - from humid, moderate to dry and hot, storage of onions in warm and humid conditions.

Control measures

Onion Stemfilios. The causative agent of the disease is the mushroom Stemphylium allii Oud. It affects onions, garlic, leeks. Especially dangerous for testes. On the leaves, as well as on the shooters of the testes, mainly on plants affected by downy powdery mildew, there are clearly visible brownish-purple spots, covered with abundant pinkish-purple at first, later brown bloom of the fungus, consisting of colorless conidiophores and oblong, bag-shaped, 20- 50 X 12-25 microns, brown-violet, smoky-brown spores. Leaves and arrows in places of defeat are breaking into pieces. Seeds do not have time to form or are puny.
   Stemfiliosis completes the death of leaves, initiated by peronosporosis. It develops particularly strongly in dry and warm weather.
   The main source of infection are overwintering affected plant debris and bulbs, on which the fungus can persist throughout the entire storage period.

Control measures the same as with peronosporosis

Golovnya bow. The causative agent of the disease is the fungus Urocys-tis cepulae Frost. The disease manifests itself only on the first year old onion in the form of dark, slightly swollen stripes, translucent through the peel on the cotyledon leaf, as soon as it comes to the surface of the soil. Over time, the skin will crack and a mass of black spores of the fungus will be found. Most of the affected seedlings die at the age of 3-4 weeks. For those plants that still form bulbs, dark stripes also form at the base of their scales. When cracking the skin, there is a mass of black spores that fall into the soil and can remain in it for 5-6 years. The onion shoots are most susceptible to head smut 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 common mainly in individual kitchen gardens, where Chernushka 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 °. At 26 ° and higher shoots of the head are not affected.
   The main source of infection is soil. With seeds, the disease is not transmitted.

Control measures with smut come down to observing the correct crop rotation with a 4-5 year break for planting onions Chernushki on one plot. Onion sets and turnip on contaminated soils can be grown. Early terms of sowing or sowing with germinated seeds are recommended, as well as growing onion seedlings on uninjured 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 is onions and garlic. Primary infection of plants occurs in the field before harvesting when lodging leaves, which is a favorable substrate for the development of the fungus. The causative agent of cervical rot penetrates the tissues through a tightly closed neck and mechanical damage. Infection in the initial period is not detected, therefore, the affected bulbs, along with healthy ones, end up in storage. The first symptoms of the disease become noticeable already at the beginning of storage (September-October). Cervical rot develops as a result of infection in the field and rot in the lateral parts or the bottom as a result of re-infection from a number of diseased bulbs. The bulb in places of defeat softens, the fabric becomes watery, yellow-pink in color, with an unpleasant smell. With the defeat of all the scales onion 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, single-celled conidia of 7-16x4-9 microns in size. Later, sclerotia of the fungus appears among the molds, often merging into a solid black crust.
   The intensity of cervical rot depends on many environmental factors. The rapid development of the disease in the repository contribute to increased humidity and temperature. The optimal temperature for the fungus is 20 °, but it can develop at 3-4 °. The growth and development of the pathogen stops only at 0 °.
The main source of infection in the culture of onion seedlings are seed bulbs. When they land in the field, the causative agent of the disease can affect shooters and seed heads. The arrows nadlamyvayutsya, the seeds are underdeveloped, have poor germination. The infection that has formed on the testes is transferred to the turnip where it falls on the lower dying leaves and then on the bulb, causing it to become infected. When an onion is planted from seeds, the plant becomes infected mainly from turnip plantings and seed plants. The role of soil as a source of infection is less significant. It can preserve mainly sclerotia of the fungus. There is a possibility of spreading the disease with seeds, as the causative agent of cervical rot is capable of infecting the seed heads.
   Onion development is greatly influenced by onion growing conditions. With the same weather, onions are more strongly affected on loamy soils; weaker - on sandy. At higher soil moisture conditions are favorable for the fungus. In addition, the vegetation period of the plants is extended, the ripening of the bulbs slows down, and the leaves dry out more slowly.
   Increased doses of nitrogen, violation of the timing of harvesting and post-harvest drying conditions contribute to enhanced lesion of onions. Harvesting unripe bulbs and laying it for storage without sufficient drying dramatically increases the susceptibility of the bulbs to neck rot.

Control measures. To reduce onion losses from cervical rot, it is first necessary to obtain healthy planting material. To do this, black onion must be sown in separate areas, remote from the fields occupied by onion turnips and seed plants. Harvesting of bulbs should be carried out during their full maturation, followed by drying of the bulbs in sunny weather in an open place in a single layer, in a wet place - 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 with a length of 3-6 cm. Onions are recommended to be stored under optimal conditions: food - at a temperature of 1-3 ° and 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 (basezol) - 0.7% suspension (immersion of the bulb suspension of the preparation for 20 minutes before putting it into storage with subsequent drying), or tigam-3-4 kg / t (seed treatment, seed dressing), or TMTD-4-5 kg ​​/ t for seed dressing and 2-3% suspension for seed treatment.
   Varieties of onions resistant to cervical rot, currently not identified. Weaker affected varieties Mstersky local, Danilevsky 301, Bessonovsky local. Warsaw, Pogarsky, Tsitaus and varieties with dark-colored scales. Early ripening varieties of onions are less susceptible to cervical rot.

Gray onion mold . The causative agent of the disease is the fungus Botrytis cinerea Pers. Affects onion testicles in the phase of loading seeds and bulbs during storage. Unlike cervical rot, the disease does not affect the cervix, but develops on the lateral and bottom parts of the bulb. Infection with gray mold can occur both in the field and in storage in the same way as infection with cervical rot. The affected tissues are weeping, with an unpleasant odor, yellowish in color, covered with a gray fluffy fungus coating, consisting of conidiophores and unicellular, colorless, oval conidia of 9-17х6-10 microns in size. Later in the raid numerous sclerotia form.
   The source of infection is affected bulbs and sclerotia hibernating in the soil.

Control measures with mushroom and bacterial rot of onion and garlic include the same techniques as with neck rot.

Green onion and garlic mold, or penicillus . The causative agents of the disease are mushrooms of the genus Penicillium (Phenicillium glaucum Link.). One of the most common diseases of garlic during storage. Onion is less common. On the bulbs, first on the bottom or outer scales, brown watery spots appear. In garlic, the individual teeth become lethargic, on the succulent tissue visible dented light yellow spots. Subsequently, the affected tissues soften and become covered first with a light, whitish, and then green moldy bloom. The spores of the fungus are elliptical or spherical, small, with a diameter of 3–3.5 microns. When you break the scales, they pour out in huge quantities. The disease also extends to the inner teeth. They shrink, darken and crumble. Bulbs feel empty.
Mass manifestation of green mold reaches 2-3 months after the onion and garlic are put for storage. High temperatures and humidity in the storage, under-freezing, mechanical damage contribute to the strong development of the disease.
   To reduce the loss of onions and garlic from the green mold, first of all, it is necessary to thoroughly dry them before storing them. Humidity should be in the range of 60-80% at a positive temperature and not higher than 90% at a temperature of 1-3 °.

Control measures with mushroom and bacterial rot of onion and garlic include the same techniques as with neck rot.

Black mold of onion and garlic, or aspergillosis . The causative agent of the disease is the fungus Aspergillus niger Tiegh. The disease develops if onions and garlic are stored at a high temperature (18-25 °). The greatest damage is inflicted on the onion sets and onion sampling. Black mold strikes upper succulent scales. Diseased bulbs soften, a black, dusty mass of small, up to 2-5 microns in diameter, spherical spores are formed between the scales. More susceptible to the disease nevzreshviy, poorly dried onions. During storage, the bulbs may be re-infected by direct contact, as well as by airborne spores.

Control measures with mushroom and bacterial rot of onion and garlic include the same techniques as with neck rot.

White rot of onion 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 a field in young plants, the leaves turn yellow, starting from the top, and die. Plants quickly wither and die. On the roots and scales of the bulbs, a white fluffy mycelium is formed, the chives become watery and rot. Small, with poppy seeds, sclerotia appear on the affected tissue. The fungus develops well at a temperature of 10-20 °. Overwinters in the form of sclerotia in soil and in storage on infected bulbs.

Control measures with mushroom and bacterial rot of onion and garlic include the same techniques as with neck rot.

Fusarium, or onion and garlic donut rot . Pathogens-fungi of the genus Rizagsht. The first signs of the disease appear even in the field, during the ripening of onions and garlic. In affected plants, leaves die off quickly, starting at the top. Most roots rot. On the bulbs in the region of the Donets, a bloom of pink, yellow mycelia is always noticeable, usually white in color with clearly visible pads consisting of elongated, sickle-shaped, with 3-5 partitions, colorless spores of 30-50x3-4 microns in size. Accumulations of mycelium and spores are clearly visible between the scales. Affected tissue dries out, and by the end of storage the bulbs mummify. The disease is promoted by pest damage. Unlike white rot, Fusarium rot of Donets develops more often in years when onion and garlic ripen at high soil temperatures. During storage at an elevated temperature, the disease also progresses rapidly.
   Sources of infection are contaminated soil and planting material.

Control measures with mushroom and bacterial rot of onion and garlic include the same techniques as with neck rot.

Garlic bacteriosis . The causative agents of the disease are the bacteria Erwinia carotovora (Jones) Holland., Pseudomonas xanthochlora (Schuster) Stapp. On the cloves of garlic during storage there are in-depth ulcers or strips coming from the bottom up. Fabrics become pearl yellow. Fungi from the genus Penicillium usually settle in the lesions. Affected bulbs sprout in most cases, germinate and develop normally.
   The development of the disease is most often facilitated by harvesting and storing the unripened, poorly dried garlic and non-compliance with the storage regimes.
   Well-formed and mature teeth are resistant to bacteriosis.
   The above diseases of onion and garlic are rarely manifested in their pure form. As a rule, they develop in the form of mixed rots. Most common is the joint damage of onions to cervical rot and black mold, bacteriosis and fusarium, cervical rot and gray mold, bacteriosis and cervical rot, cervical 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; neck rot, bacteriosis and fusarium; black and green mold, fusarium and bacteriosis.

Control measures with mushroom and bacterial rot of onion 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 soon after the landing of the queen cells. Plants have a depressed appearance: the leaves turn yellow, often become folded or shirred, 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 in healthy plants. The onions are more susceptible to the damage by dwarfism, which has been propagating for a long time vegetatively.
   In sevok, the disease is carried by many kinds of aphids, feeding 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 dog becomes infected, the more severe the disease will appear next year.
   The prevalence of dwarfism depends on the presence of aphid vectors and external conditions. With slow growth of plants, the disease may not appear.
   Yellow dwarfism affects shallots, garlic, perennial onions, which are often the reservists of the virus.

Control measures. The main measures to combat viral diseases of onions and garlic are to obtain healthy planting material by isolating (up to 1.5 km) the black onion crops from other crops, perennial onions and garlic, protection from carriers of viruses, the selection of uterine bulbs from healthy plants, removal of diseased onion plants.

Mosaic of onion and garlic . The causative agent is Allium virus I Smith. Leaves and inflorescences are affected. On leaves, the disease manifests itself in the form of small, more or less elongated specks or wide light green or cream stripes. Sometimes the leaves become corrugated, stunted and lagging behind. The arrows bend, they are visible longitudinal mosaic stripes. The inflorescences of the affected plant are friable, the flowers are sterile or give very few seeds. Instead of stamens and pistils, long leaflets are often developed, and bulb flowers instead of flowers. Seed germination from diseased plants is reduced. The bulbs from infected plants often have an elongated shape and sprout before they reach maturity. The disease is tolerated by a four-legged garlic mite. The infection persists in onion sets, onion womb and in perennial onions, where the disease manifests itself in the form of weak mosaic of leaves.

Control measures. The main measures to combat viral diseases of onions and garlic are to obtain healthy planting material by isolating (up to 1.5 km) the black onion crops from other crops, perennial onions and garlic, protection from carriers of viruses, the selection of uterine bulbs from healthy plants, removal of diseased onion plants

Onionfly  Delia (Hylemia) antigua meig . A widespread dangerous pest (especially in wet years). More harm on sandy and loamy soils, less - on peat. More damage to onions in the backyards with the permanent cultivation of culture, less - garlic.
   Departure of flies is noted in the middle of late May and coincides with the flowering of cherry and dandelion. Eggs are laid in groups of 5-12 pieces between the leaves of onions or in the cracks of the soil near the plants. After 5-9 days, depending on the conditions of the year, the larvae hatch. They penetrate the plants through the base of the leaves or bottom. The larvae, hatching from one clutch, are kept in a group, gnawing large cavities in the bulb. Due to damage the bulbs rot, leaves turn yellow, usually in the apical part, fade. Damaged bulbs produce an unpleasant odor, and when they are opened, white, legless, and headless larvae are found inside, up to 10 mm long. 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 occurs 16-20 days, after which they go into the soil, to pupation. Falconis reddish-brown, shiny, about 7 mm long.
   Flies are yellowish-gray, with a distinct brownish longitudinal line on the abdomen. The body is narrow, long. Legs, antennae, tentacles black. The flies that fly out after wintering require additional nectar nutrition for flowering plants. 5-10 days after departure, they start laying eggs. Eggs are white, 1.1 mm long, elongated-oval, with a narrow oblong groove in the middle.
   Pupae overwinter in pods in the soil at a depth of 6-20 cm. The fly develops in Belarus in two generations. The harmfulness of the 1st generation larvae is manifested in June, the second - at the end of July - August.

Control measures. Spatial isolation of onion crops from last year's crops. The location (or alternation) of the rows of onions and carrots, onion crops next to the crops of carrots. Phytoncides emitted by carrot leaves scare away an onion fly. Early sowing of onions contributes to resistance to damage by the onion fly, since by the time of the departure of the flies the plants will get stronger, harden and to a lesser extent be damaged by the pest. It is believed that mulching with peat between the rows contributes to scaring onion flies, since the pest avoids peaty soils. The use of drugs with a strong smell like naphthalene in a mixture with sand in the 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 to remove the tops, the remaining damaged bulbs, followed by digging the soil. Good results are obtained by treatment with an infusion or a decoction of a phytoncide plant - tobacco. Use leaves, stalks. For an infusion take 400 g of crushed raw materials or dust, insist two days in 10 liters of water. Infusion filter. To the resulting solution add 40 g of soap. For broth, take 400 g of dried raw materials for 10 liters of water, insist day, then boil for 2 hours. After cooling, add another 10 liters of water and add 40 g of soap to every 10 liters of solution.

Onionhotshot  (Eurnerus strigatus Fall).Moisture-loving insect .. Widespread. Damages all types of onions, garlic, gladioli, tulips, daffodils and other plants. The larvae that have penetrated into the bulbs destroy them and cause rotting.
   Adult fly about 9 mm long, greenish-bronze in color, with short blond hairs. Antennae black-brown. Legs are black, the legs at the base, the tops of the thighs and the main segments of the paws are yellow. Eggs are white, elongated without longitudinal groove, 0.8 mm long. Larvae are grayish-yellow, strongly wrinkled, flattened from the ventral side, up to 11 mm long. At the rear end of the body is a reddish-brown appendix with two processes on the sides. Lozhokokony about 8. mm long, yellowish-brown color. The posterior end of the body is the same as that of the larva.
The larvae overwinter in the bulbs that have not been harvested in the field, in the soil and in the storehouses. 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 nekaronosah and after 7-9 days begin to lay eggs in small groups of 6-10. After 5-10 days the larvae hatch. The development of larvae lasts about one month, after which they leave for pupation in the upper soil layer. The second generation of the pest appears in early August. With severe phytophagous damage, only the skin of the bulb remains, filled with a black rotting mass. Developed in two generations.

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

Onionmole  (Acrolepia assectella Zeil.). Distributed everywhere. Harm more in hot, dry years. Damages leeks, bulb, garlic. The caterpillars penetrate into the tubular leaves of the onion, eat out the parenchyma in the form of irregular bands,. leaving the epidermis intact. Damaged leaves turn yellow and dry out, starting from the apical part. On the bow, the caterpillars often penetrate into the neck and even inside the bulb, causing the complete death of the plant. On leek and garlic, caterpillars mine leaves, feed on buds, eat flower buds, gnaw stalks, 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. The front wings are in small white flecks. In the middle of the front wings there is a white spot almost triangular in shape. Hind wings are lead-gray with long fringe. The eggs are milky-white, bean-shaped. The caterpillar is yellow-green, with a dark head, spindle-shaped, with 8 pairs of legs. The body length of 10-11 mm is covered with brown warts. Pupae of dark brown color, about 7 mm long, are in a grayish spider cocoon. Butterflies winter in various shelters, on plant remains. Departure of the moth is noted in mid-May and coincides phenologically with the flowering period of the bird cherry tree. The female lives about two weeks and during this period has time to lay up to 100 or more eggs. Their development lasts 5-8 days. Under the conditions of Belarus, it develops in two generations.

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

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

Control measures. Collection and destruction of post-harvest residues, autumn plowing, destroying wintering places for beetles. Additional loosening of inter-row spacing in the period of mass pupation of the larvae, followed by irrigation 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 shed at the root of the bulbs with a solution — 1 cup of ordinary table salt per 10 liters of water with the addition of potassium permanganate to pink.

Root (onion) mite (Rhyzoglyphus echinopus). Distributed everywhere. It damages onions, 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, mites feed on fleshy scales, causing them to rot. Heavily 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 dull-vitreous, about 1 mm long, the legs and mouthparts are brown. Hygrophilous. Relative air humidity of 60% and below is unfavorable for tick development. At the optimum temperature (25-26 °), one generation of the pest develops within 9 days. One female lays an average of about 800 eggs. The larvae resemble adult individuals, but, unlike them, they have three pairs of legs. Adult mites can feed on plant debris. Ticks can often be found in garden soil, hotbeds, where the pest is brought mainly with infected planting material.

Control measures. 1.5-2 months prior to planting, dry heating of onion sets and uterus is carried out at a temperature of 40-45 ° for 16 hours or at 35-37 ° for 5-7 days. In storages where a pest is detected, gas disinfection is carried out using sulfur dioxide gas obtained by burning Gamma drafts (0.5–1 g per 1 m ^) or lump sulfur (50 g / m2). Exposure - 48 hours. A prerequisite for disinfecting rooms is their tightness and compliance with safety regulations.

Onion nematode, or stem nematode of onion and garlic (Ditglenchus allii Belj.) . Damages onions, especially garlic. It is found on parsley, parsnip, tomatoes, radishes, cucumbers, saute and other plants. Larvae and adult nematodes feed on plant sap, causing their curvature and growth retardation. In the nematode-damaged bulbs, the internal tissues are friable, grainy, grayish. Succulent scales loosely adjoin each other, as a result of which the bulb feels soft to the touch, the bottom cracks. In garlic plants, there is a lag in growth, thickening of the false lance, yellowing and dying of leaves, yellowing of cloves at the base. The nematode localization mecia is an onion, then a feather and an arrow.
Onion nematode - small (1-1.5 mm) whitish worm. Overwinters in bulbs, soil, seeds. In dry scales of onion and dried garlic retains viability for 2-4 years. Propagated by laying eggs in plant tissue. When the infected plants die off, the nematodes go to the soil and look for a new host. Humidity close to 100% is a prerequisite for relocation.
   The nematode is stored and accumulated in the remnants of the bulbs, feathers, arrows. In the soil the nematode is usually absent. The pest spreads with seeds.
   The shoots of blacks infected with a nematode are ugly and thickened. Vegetative plants are infected in several ways: in rainy years, the nematode penetrates through the stomata of leaves, in dry weather - through the bulb. In places where the nematode is introduced, a white spot is formed. In more mature bulbs penetrates the growth point of future roots.
   With a weak infection of the bulbs for some time stored normally, apparently no different from healthy, but over time the tissue is destroyed inside. There are empty shells.

Control measures. Thermal disinfection of seeds and seed in heated water at a temperature of 45-50 ° for 10-15 minutes. Sow only healthy seed. Compliance with crop rotation with the return of onions, garlic to its original place no earlier than 3-4 years. Before storing the onion for storage, it is necessary to disinfect the lukoraries, 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 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, onions, tobacco, cabbage, watermelon, cucumbers in greenhouses have been damaged. It feeds on more than 100 species of plants. Adults are light yellow or brown with narrow wings, fringed at the edges with a fringe, about 1 mm long. Eggs are small, kidney-shaped, white. The larvae outwardly resemble adult thrips, but are smaller in size, without wings, whitish at first, then greenish. Adult thrips overwinter on plant debris, in the upper soil layer, but the bulk of it concentrates under the bulb scales. In the early spring they feed on weeds, then transfer to cultivated ones. When the onion is damaged, silvery-white spots appear on the leaves. In places where thrips are fed with the naked eye, phytophagal excrement is seen as black dots. Damaged leaves turn yellow, die off, starting from the apical part of the plant. When the inflorescences of the testes are damaged, the latter turn yellow, then they dry up, no seeds are formed or they are puny, with low germination.
   Females lay about 100 eggs, placing them one by one under the skin in the leaf tissue. After one week, the larvae hatch from them. After feeding, they go to the soil and turn into adult insects there. Some of the pest population enters the repository with the bulbs, where under favorable conditions it continues to develop.

Control measures. The same as against onion nematode and onion root tick.