Most often, the yellowing of feathers can be seen in winter garlic, especially those representatives who were planted in the fall too early. In this case, can not do anything, however, this phenomenon is a warning, what to plant garlic for next year should not be earlier than the second half of October (the weather is cold, the germs will not have time to hatch).
If the feathers turned yellow in the spring, and this was preceded by a slight frost (and frost it can provoke this disease), in this case, will the spraying of plants by preparations Zicron, HB-101, EPIN, etc. Spraying should be repeated every three to five days before until the garlic will not recover.
Another reason for the yellowing of garlic - the lack of moisture. This problem will help to cope timely watering and tillage of the soil.
Cause change the color of the feathers of garlic can pests in the form of, for example, the onion fly. Data insects are not afraid of strong smell, so the methods of spraying with extracts of wormwood and other odorous tools will not fit here. The most effective drug against these pests is a mixture of ash and tobacco dust (1:1). Protrusive the soil around the garlic like a "cure", you will create unfavourable conditions for the survival of the onion fly in garlic bed.
Fungus is another reason for which it is possible to notice a slight yellowing of the feathers of garlic. Most often, the fungus damages the roots of these plants, so always try before planting, soak the bulbs in a special preparations (fitosporin, Maxim) or a weak solution of potassium permanganate.
Yellow garlic, maybe from lack of nitrogen and potassium. In the first case, help fertilizing with urea (for 10 liters of water a tablespoon of urea), the second soil application of fertilizer potassium sulfate (teaspoon per liter of water).