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.
Advice 2 : Why is onion rot in the garden
The overabundance of moisture in the soil
Bow does not like excess moisture, so it is impossible to fill. And in the rainy season the plant is necessary to protect the drainage. Prepare for this before planting, a small trench at the bottom where you pour the sand, then drop it in the bulbs. Moreover, a sand layer must be equal to one quarter of medium size onions. We find that the excess moisture will go into the soil through the established micro moisturizing.
Downy mildew (downy mildew) struck landing
First, the yellow feathers, then the downy mildew spores down into the very flesh, which ceases to grow. Contribute to the spread of this disease evening watering, morning dew, temperature, placement in the shade, poor heating and ventilation, excessive moisture, lack of phosphorus and potassium with an excess of nitrogen. And in order to avoid this trouble: do not put onions fresh manure, use of crop rotation, use fungicides, and cases of vegetables immediately clean up because the spores dissipate quickly, infecting healthy fruit.
The onion fly has damaged the onion
If not take the proper measures, this pest can easily destroy an entire garden. First, the onion planting need to be alternated with carrot and dill, only one carrot smell may deter the onion fly, so experienced gardeners often rotate your crops. Secondly, you need time to remove and destroy all plants with signs of infection. Thirdly, onions can be watered with a solution of ash, for the prevention of infection. To do this, collect the weeds-deadwood and branches of trees, burn everything on a fire, the resulting ash dissolve in water and pour it in the garden. To enhance the effect of the solution add grinded tobacco leaves and red pepper.
Advice 3 : The causes of decay of onions in the garden
The reasons for rotting onions still growing in the garden, several. The first and most common is, of course, high humidity, especially during the long rains. Many gardeners bow regularly watered in dry weather, but do not need. The roots of the plants are quite long, and they are able to provide a bow with the necessary amount of moisture. In addition, the glaze inhibit the maturation of vegetable, but before harvest, the feathers should be well dried, otherwise the bulbs will not be stored.
The next cause of rotting onions in the garden can become too large amount of introduced nitrogen fertilizer. Moreover, they can accumulate in the bulbs of harmful nitrates, so the use of these fertilizers need to be very wary.
Another major cause of rotting onions can be Fusarium rot stems of the bulbs. It is a common fungal disease. It pathogens overwinter on plants and in soil. Therefore it is very important to remove all plant residues from the garden. Proper crop rotation will also help in the fight against this disease. Return the vegetables to the former place is recommended only after 4 years.
Sakova rot often affects the bow. This disease can develop because of a broken onion. In addition, Sakova rot manifests itself in damp weather.
Onion fly mercilessly striking the bulbs. Their larvae feed on the juices of the onion heads, whereby the plant rots. Onions to rot in the garden can be caused by and the defeat of its stem nematode. This pest can be seen only through a microscope, but yield damage he can inflict quite serious. Preventive measure is the disinfection sets before planting, and the cultivation of onions only on healthy soil.