The symptoms of the disease
Onion leaves lose their emerald color, becoming more settle, with well-marked yellow at the tops. The shape of the pen is flat and tape. The top leaves often take a curved direction downwards. In wet weather the diseased green leaves are covered with grayish or grayish-purple powdery coating of fungal spores that are wind and rain learn the new planting.
The leaves continue to turn yellow and wither. Plant growth is suspended. Fungal infection continues its "path" in the onion. Planted onion or onion next year in the garden, give the new young leaves, which are "fetch" the same fungus.
Sources of infection
"Home" for the disease are affected perennial rhizomes bows, bulbs, seeds and residues.
What to do?
You mustbe obligate rotation. Planting onion return to the problem of beds in 2-3 years.
Apply manure only under previous culture.
Do not overfeed the plant with nitrogen supplements. Use fertilizers with increased dose of phosphorus. On poor lands nitrogen fertilizer to apply in early growth, in the second half of the vegetation - phosphorus-potassium, which increase disease resistance.
Before planting onions (pearl onion) is useful to make the thermal disinfection. The bow should be warmed at 40-45 ° C during the day. You can soak the onions before planting in solutions of copper sulfate or other fungicides.
At the first sign of the disease bow should be treated with Hom (40g per 10 liters of water) or Ridomil (25 g per 10 liters of water). Through one to two weeks, repeat the treatment.
With the appearance of 3-5 leaves the bow it is possible to prevent spray landing a 3% solution of potassium permanganate every 7-14 days 2-3 times.
To handle the bow for "green" not by any drugs.