Cultivation of onions on personal plot sometimes can cause some difficulties. One of them is yellowing of leaves of onions on bed. What it can be connected with and how to struggle with this illness of vegetable culture?
The person began to use onions for cooking long ago. Therefore it is grown up in all corners of the world. In the course of growth of this vegetable culture there can be some problems. Onions unexpectedly begin to turn yellow. If it occurs at the end of summer, then it is natural process of its maturing and you should not be upset here. But sometimes onions begin to turn yellow at the time of intensive growth. For what reasons it occurs also what to do in that case?
Onions on kitchen garden can turn yellow for only four reasons:
1. Environment adverse weather conditions
2. Wrong leaving
3. Impact on it from wreckers
4. Appearance of some bacterial and fungal diseases.
To solve these problems it is necessary to find the specific reason correctly.
Environment adverse weather conditions
Luk not especially love a lot of moisture, especially at the time of the beginning of maturing. If on the street to this moment there are rains, then you should not carry out additional watering. In places where near landings of onions rain water stands it is necessary to make by-pass grooves. Otherwise plants can wet through.
Wrong leaving
First, yellowing of leaves on onions can be the certificate of lack of mineral substances of the soil. Especially it concerns the shortage of nitrogen. In that case onions surely feed up or urea (10 g on 2 l of water), either bird's dung (1:20), or other nitrogen fertilizer, for example ammonium nitrate (15 g on 10 l of water).
Secondly, this process can be observed also at lack of moisture. If the earth lump dries up, it negatively affects all plant entirely. Therefore it is necessary to water onions correctly. It in the first half of summer is watered by two times a week, and in the second – once. At the same time watering needs to be carried out on 10 l of water on 1 sq.m. of landings in the morning. After watering the bed is loosened surely that oxygen arrived to the root system of plants better.
Impact on onions from wreckers
At onions there are a lot of insects wreckers. But only some of them can cause yellowing of leaves.
Onions fly
This is the main wrecker of onions on personal plot. It has external similarities to normal room fly. She lays eggs to the soil near plants in the spring. The appeared larvae get in bulbs, and in few weeks the next generation of these insects appears. At the same time at onions leaves which gradually dry up begin to turn yellow, and the bulb decays.
How to fight: The onions fly does not transfer carrots smell. Therefore nearby it is necessary to put this vegetable culture. And it is the best of all to alternate ranks of carrots and onions on bed. In the fall after harvesting carry out deep redigging of the earth not to allow eggs of insect to winter. The struck bulbs delete from bed and drench with boiled water or burn on fire. From national methods of fight against onions fly the most effective is use of tobacco dust. It is mixed with ashes 1:1 and strew the soil around plants. After loss of any precipitation this action is repeated. Use of mix of naphthalene with sand is also possible (in proportion 1:1). Important, as soon as possible to plant onions on kitchen garden that bulbs have got stronger by the time of appearance of this dangerous wrecker. If folk remedies do not help, then it is possible to use the frightening-off medicine Neksion. It is applied according to the instruction at observance of means of personal protection.
Onions thrips
It represents the small sucking insect who does harm to landings of onions. At first thrips develops in bosoms of leaves, and then on inflorescences. At the same time leaves begin to turn yellow, are bent and gradually die off. It stops growth of bulb.
How to fight: Thrips can winter in the bulbs prepared on landing. Therefore before it it is necessary pilferers or turnip to warm up in warm water at temperature of 42-45 degrees within two days. Also it is impossible to plant onions on one place within 3-4 years. If trips have appeared much, then onions are processed insecticides, for example the medicine Detsis.
Stem nematode
This is quite little worm who gets deep into plants that leads to their death. At the same time leaves of onions become wrinkled with yellow streaks. To find this wrecker it is rather simple to open any yellow feather. There it is possible to find not really pleasant picture. Several little white worms gradually eat away pulp of plants.
How to fight: If on the site the nematode was got, then onions cannot be grown up on one place within 3 years. Before landing the soil is watered with solution of table salt (3 tablespoons on 10 l of water), spending on 2-3 l of solution for 1 sq.m. Also onions it is necessary to feed up in the course of growth by ammonium sulfate (2 tablespoons on water bucket). It is done by two times: in two weeks after emergence of the first shoots and at the end of June. After harvesting carefully delete all plant debris from kitchen garden.
Appearance of bacterial and fungal diseases on onions
Leaves of onions turn yellow only at appearance of such diseases as bacterial decay, fusariosis, false mealy dew and rust.
False mealy dew
This disease begins to be shown on separate young leaves. At first it is just small pale spots, and then they increase, leaves turn yellow and dry up. This disease is promoted by cool weather and the increased humidity.
Prevention and treatment: You should not bring nitrogen fertilizers too many. Places, for cultivation of onions, need to be chosen as light and well blown by winds. To fight regularly against weeds on bed with onions. At appearance of this disease, onions are processed the Bordeaux liquid or oxychloride of copper. Further use of such onions on green feather is not admissible. These medicines need to be applied no later than 2-3 weeks before harvesting. Such processings carry out no more than two times during the season. It is important to remove onions correctly. It in good weather is dried on bed before full drying of leaves, and then removed on storage.
Onions rust
As soon as this disease affects plants, on leaves of onions small yellow small pillows appear. They darken over time, and leaves begin to dry up. The infection can remain on plant debris and also on long-term onions.
Prevention and treatment: In the fall carefully collect all plant debris and delete them from kitchen garden. It is impossible to plant normal and long-term onions nearby. At appearance of this dangerous disease, onions are processed protective medicines, for example suspension of polikarbatsin. Also not less effective is preseeding processing of bulbs.
Onions fusariosis
This disease begins to be shown at the time of full maturing of bulbs. At the same time leaves begin to turn yellow and to die off gradually. The bulb begins to decay with collum. This disease can proceed also in storage time, especially at non-compliance with the main conditions.
Prevention and treatment: Bulbs before landing ret in copper vitriol for 30-40 minutes. The soil is spilled dense solution of potassium permanganate. At the same time the struck bulbs cannot be used for landing. After harvesting attentively examine all onions and destroy copies on which there are symptoms of this disease. During cultivation of onions the space between beds or grooves is powdered with yellow bank sand.
All these reasons of yellowing of onions to a degree can significantly reduce productivity of plants. Therefore it is necessary competently and in due time to eliminate them.