Based on certain signs, a vegetable grower can figure out why garlic is rotting in the garden. This will help you take action and avoid large crop losses. The main causes of bulb rot can be listed:
- fungal diseases;
- bacterial rot;
- viral diseases;
- pests
Simple rules of agricultural technology will help reduce the risk of infection:
- Compliance with crop rotation rules. An annual change of place for crops on the site helps to avoid the proliferation of microorganisms and pests that affect a certain group of plants.For garlic, the time to return to the garden is at least 4–5 years. The best predecessors are young cabbage, cucumbers,
- Choosing a sunny and elevated place on the site for planting garlic. For this crop, especially winter varieties, spring stagnation of water after the snow melts is dangerous. To prevent the garlic from rotting, you can protect the plants by arranging a high bed.
- Conscientious autumn cleaning of the site from all plant remains and annual digging. Most pests and microorganisms are able to overwinter on forgotten rotting bulbs and stems, and in the spring move to vulnerable young shoots.
- Use healthy seed. Before planting, you need to sort through and weed out all garlic cloves with signs of disease. Seed bulbs should be stored in a cool, dry place (+1–2 ⁰С) in small canvas bags or boxes with holes. It is useful to renew the supply of planting garlic by growing bulbs (for bolting varieties).
- Thoroughly dry the seed bulbs before storing them.
- Treatment of planting material with fungicides before planting.
- Timely watering and loosening of beds.
- Removal of diseased plants beyond the boundaries of the site.
- Preparation of fertile neutral soil mixture in the garden bed and timely fertilizing with complex fertilizers.
- Compliance with optimal planting and harvesting dates.
Fungal diseases
The main culprits of garlic rotting in the garden and during storage are mushrooms. Irregular watering coupled with unfavorable weather conditions provokes the development of pathogenic microorganisms.
To reduce the risk of infection through contaminated seed material, pre-sowing treatment of garlic cloves with fungicides: Maxim, Fitosporin, HOM.
Fusarium (bottom rot)
Optimal conditions for the growth of imperfect fungi of the genus Fusarium are high humidity and warm weather (above 13-20 ⁰C). Therefore, this disease most often occurs in the southern regions.
Fusarium affects many cultivated plants and usually overwinters on plant debris. The reason for the rapid infection and rotting of the bulbs is mechanical damage by pests and during harvesting.
Symptoms:
- After 5–7 leaves have formed, their tips begin to turn yellow and wither, gradually taking over the entire plant.
- Brown stripes can be seen on the leaves. A small pink coating sometimes appears in the sinuses.
- If you try to pull garlic out of the ground, it can be easily separated, since the roots quickly rot with fusarium.
- The bottom of the bulbs and cloves softens and becomes covered with light mycelium. When opening the bulb between the cloves, you can also notice traces of mycelium.
If a fusarium disease is detected, diseased plants are immediately removed from the site and, regardless of weather conditions, watering of the beds is temporarily reduced.
White rot of garlic
A frequent uninvited guest in a garlic bed and the reason why bulbs rot is the fungus Sclerotium cepivorum Ber. What does white rot do to garlic:
- The first sign of infection visible to the grower is yellowing of the tips of the leaves, which quite quickly covers the entire green part of the plant.
- If you pull diseased garlic out of the ground, a white coating of fungal mycelium is visible on the roots. It quickly penetrates the bulb through the bottom. The garlic begins to rot and takes on a watery appearance.
Often the owner of the garden bed does not pay attention to the drying of garlic foliage and learns about the disease when the bulbs are already rotting.
Fungicides help save most of the crop with timely treatment and removal of infected plants from the site (Uniform, Switch, Custodia).
Downy mildew (peronospora)
A fungal disease of most bulbous plants, the causative agent of which is Peronospora destructor Casp. Suitable conditions for growth are very high humidity and cool weather (7–16 ⁰C). Rotting of the bulbs is promoted by summer with frequent fogs and prolonged precipitation. Under such conditions, downy mildew can destroy most of the crop in 2–3 weeks. After the onset of dry, sunny days, the spread of infection slows down.
In order not to miss the initial stage of the disease, you need to know the main symptoms:
- The leaves are covered with yellowish oval spots.
- In very humid weather, a light purple coating of spores is noticeable on the plants.
- The leaves curl and fall off. Gradually, the infection captures the entire above-ground part, descends into the bulb and starts rotting processes.
Downy mildew overwinters in the soil in forgotten bulbs or in seed material.
If a disease is detected, the beds must be treated with fungicides: Quadris, Areva Gold VG, Ridomil Gold.
Bacterial rot
Mechanical damage to garlic is the main reason why garlic is affected by bacterial rot.
Usually the culprits are insect pests that damage the integrity of the bulbs. Infected teeth become covered with streaks and specks, the flesh becomes glassy, acquires a pearlescent hue and a “cooked” appearance. This garlic has an unpleasant putrid odor and gradually turns into mucus.
The danger of this infection is that the final decay of garlic usually occurs during storage and is difficult to recognize by the appearance of the unopened bulb.
How to deal with bacterial rot:
- pest control;
- in the fall, the garden is conscientiously cleaned of organic residues;
- fertilizing with mineral fertilizers with a high phosphorus content;
- compliance with crop rotation.
Pests
A common reason why garlic rots in the ground is damage to plants by insect pests. Violation of crop rotation rules, depleted soils and unstable watering of beds can lead to the rapid spread of pests and large crop losses. For integrated pest control, general purpose insecticides (Intavir) are used.
Onion fly
Onion fly larvae feed on garlic pulp. The insect overwinters in the soil at a depth of 10–20 cm in the form of a pupa. During the flowering of garden crops, the fly crawls to the surface and after 5–10 days lays white eggs on the garlic or nearby on the soil. After 3–7 days, the larvae appear and gnaw their way inside the bulbs.
Over the course of a season, 2–3 generations of onion flies appear. The reason for the rapid growth of the onion fly population is the rainy summer. Damaged bulbs quickly rot due to secondary fungal and bacterial infections. Garlic leaves turn yellow, curl and dry out. When you cut the bulb, you can see the larvae.
The following measures will help protect garlic beds:
- Deep autumn digging of the site.
- Mulching beds with garlic with peat, since onion fly does not like peaty soils.
- Planting carrots between rows.
- Dust the plants once a week from late April to mid-July with a mixture of 10 g of tobacco dust, 100 g of ash and 5 g of ground pepper.
- Spraying the soil and plants with the composition: stir 2-3 teaspoons of ground red pepper and 250 g of tobacco dust in 2-3 liters of boiling water. Leave for three days in a warm place and dilute in a bucket of water with the addition of 50 ml of liquid soap. Treatment is carried out once every 7 days starting from the end of April.
Onion root mite
This small eight-legged pest of the species Rhizoglyphus echinopus, under suitable conditions (23–26 ⁰C and humidity 60–65%), can damage a significant portion of the garlic and onion crop. It lays 200–300 eggs in the bulb, from which root mite larvae hatch within 7–8 days. After a month, the new generation is ready for further reproduction.
Distribution methods:
- The tick is easily carried by the wind;
- he is able to move between plants independently;
- the pest is able to overwinter on garlic and onion residues in the soil or in the seed bulbs between the cloves.
The mite gnaws at the bottom of the bulb, causing it to lag behind and the garlic in the garden to begin to rot. The leaves of diseased plants turn yellow, and when the bulb opens, brown waste products of the mite are visible between the cloves.
Control measures:
- infected beds can be treated with an insecticide (Keltan or Rogor);
- After harvesting, it is useful to dry the garlic for a week at a temperature of 30–35⁰С;
- Before planting, pickle the cloves for 20 minutes in a 0.8% solution of colloidal sulfur.
Onion stem nematode
First place among garlic pests belongs to the stem nematode, the worm of the species Ditylenchus allii Bej. In heavy clay soils it can destroy most of the crop.The reason for garlic rotting is not only mechanical damage to the bulbs, but also secondary damage by fungi and bacteria.
The remains of garlic plants, cloves and seed bulbs forgotten in the ground are suitable for wintering for these pests. Larvae and adults feed on the succulent parts of the cloves and stems. Favorable conditions for spread include high humidity and cool weather.
Signs:
- First of all, the worms eat the bottom of the bulbs. The root quickly rots and dies.
- The scales crack and fall off, the bulb quickly rots.
- The plant noticeably lags behind in development, the leaves first become covered with light stripes, then turn yellow and dry out.
- An infected plant easily lifts off the ground and has an unpleasant putrid odor.
- With late infection, white traces of the nematode’s penetration into the plant can be seen on the leaves.
To general precautions you can add:
- Lightening heavy soils by adding loose organic components: peat, straw, sawdust.
- Infected areas are sowed with green manure followed by digging.
- Pickling seed cloves in a 0.5–1% formaldehyde solution or wood ash infusion.
